Why Understanding “c/o” Could Save Your Mail from Getting Lost

If you’ve ever needed to send important documents to someone but didn’t know the recipient's home address or didn't know the recipient's exact home or business address, you’ve probably seen—or should’ve used—the “c/o name” format. Short for “care of,” it’s a simple yet powerful way to ensure your letter or package gets delivered to the right person, even if you’re routing it through someone else.

Maybe your intended recipient is staying at a friend’s apartment. Maybe they’re on vacation at a hotel. Or maybe you’re trying to reach an executive at a large corporation without access to their recipient’s primary address. In all these cases, when you don’t know the recipient's home address or business address, properly using c/o helps you bridge the gap between sender and final recipient.

Despite being one of the oldest notations in mailing, c/o still plays an important role in business correspondence, mailing address accuracy, and ensuring your letter or package doesn’t end up in the wrong hands—or worse, returned to you undelivered.

As businesses grow more mobile and remote, the importance of understanding how to use c correctly is only increasing. Whether you’re sending mail to a family member, a traveling employee, or a company name at a shared office, getting the address structure right is critical to making sure they receive correspondence reliably.

💡 If you’re planning a direct mail campaign to reach customers or key decision-makers at alternative addresses, LettrLabs offers flexible delivery formats—including handwritten mailers, postcards, and printed letters—that can be customized to reach the right individual, even through a secondary contact.

What Does c/o Mean in a Mailing Address?

Understanding c/o: What It Simply Means

c/o—short for “care of”—is used in a mailing address when you’re sending a letter or package to someone at an address that isn’t theirs. It tells the postal service that the final recipient isn’t the main person living or working at that location, but that this person's name should be included so they can accept the correspondence on the recipient's behalf.

Put simply, it’s a way to send mail through someone else. You’re essentially saying, “Deliver this to the recipient's name, but c/o Jane Smith, because Jane Smith lives or works at the address where the recipient can pick it up.”

This format is especially useful when:

• You don’t know the recipient’s home address
• You’re mailing to someone staying at someone’s hotel
• You’re sending correspondence to an employee via the company’s general business address
• The recipient is temporarily living at a friend’s address

When formatting the address, always place the recipient's name on the top line to ensure proper delivery.

This notation is a small but essential part of ensuring mail reaches the right person without delays or misdeliveries.

When Should You Use c/o?

Here are the most common real-world scenarios where using c/o makes sense:

• Sending business letters to a specific person at a large company or organization
• Mailing something to a friend’s address because the recipient is temporarily staying at their friend's place
• Sending an invite to someone through a friend's address when you don't have the recipient's direct address
• Delivering important documents to someone at a secondary address while they’re away from home
• Forwarding mail to a family member using another household’s street address
• Sending mail to a guest at a hotel when you only know their room number

In all these cases, the c/o name helps the delivery staff, receptionist, or hotel staff direct the mail or package to the correct addressee, rather than treating it as undeliverable or misrouted.

Example: Michael Ross
c/o Sarah Lin
55 Sunset Blvd, Unit 210
Los Angeles, CA 90028

In this address format, Michael is the intended recipient, but Sarah lives at the location, so she can accept or forward the mail.

💡 Not sure which direct mail format is best for reaching your intended recipient? Browse LettrLabs’ guide to mail formats to find the right fit for your campaign, whether you’re reaching someone at home, a business, or a hotel.

How to Structure a Mailing Address with c/o

Proper Use of the c/o Format

The address format you use when mailing something with a c/o name is just as important as the message inside. Get it wrong, and the postal service might delay or misdeliver your letter—or return it altogether.

Here’s a breakdown of the standard format when using c/o in an envelope or package:

Top Line: Recipient's name (the person you want the mail to reach) Second Line: c/o followed by the name of the person or entity receiving the mailThird Line: Full street address, including apartment number or room number if applicable Fourth Line: City, state, and ZIP code

Standard Example Format: John Doe
c/o Jane Smith
123 Orange Hills Ave, Apt 3C
Denver, CO 80203

In this example, John Doe is the final recipient, and Jane Smith is the person actually living at that address. The c/o is used when the recipient's address is not known, so Jane Smith will receive the mail on John’s behalf.

Where Does the Return Address Go?

Your return address is just as critical. It ensures that if something goes wrong with the delivery—say, the recipient no longer lives there or the mailing address is incomplete—the item will be sent back to you.

The return address should always go in the top left-hand corner of the envelope or package. Include your full name, street address, city, state, and ZIP code. This information also plays a role in calculating postage and facilitating smooth delivery.

And yes—it’s perfectly acceptable (and often recommended) to also include your return address on the back of the envelope, especially when sending important documents or formal business correspondence.

💡 Need help formatting a professional-looking letter with the correct lines and layout? Check out LettrLabs' printed letter guide for expert tips and automation options.

Why and When Businesses Use c/o

Sending Business Letters to the Right Individual

In a corporate setting, it’s not always easy to send mail directly to a specific person—especially when you don’t know their recipient’s home address or they work in a large organization. That’s where c/o becomes essential for sending correspondence that actually reaches the right person.

Imagine trying to deliver a business letter to a senior manager at a big company. If you simply addressed the envelope to the company itself, your letter or package might get lost in the mailroom. But if you use:

Michael Andrews
c/o John Smith
Acme Corp
456 Enterprise Ln, Suite 300
Atlanta, GA 30305

—you’re clearly indicating that Michael Andrews is the final recipient, and John Smith (or the front desk) can route it to him internally. This extra line ensures that the important documents land on the right desk, not just in the company’s general inbox.

This approach is especially important when you’re:

• Sending important documents to executives
• Forwarding promotional business correspondence to decision-makers
• Mailing to employees at shared workspaces or co-working hubs
• Mailing to someone’s workplace when their home address is unavailable
• Reaching someone whose business address is public, but not their private one

How c/o Helps with Business Correspondence

Using c/o correctly allows your business letter to bypass generic entry points and land with the intended recipient faster and more reliably. It’s a small but powerful tactic in improving delivery, reducing bounce rates, and making a better first impression—especially in B2B outbound lead generation scenarios.

In industries like real estate, SaaS, and ecommerce, professionals often work out of shared offices or receive mail through an assistant or gatekeeper. The proper use of c/o name ensures your letter still gets through, even when you don’t have a person’s address directly.

💡 Want to reach high-value prospects at scale while preserving that personalized touch? LettrLabs' outbound lead generation campaigns use handwritten and printed mail formats to break through the clutter and reach your ideal contacts—even if you're mailing “care of.”

Best Practices for Sending Mail with c/o

How to Write a c/o Address on an Envelope

Correctly formatting a mailing address with a c/o name isn’t just about etiquette—it’s about making sure your letter or package reaches the final recipient without delays. Whether you’re sending mail for personal or business correspondence, follow these layout rules:

Envelope Format (Front Side):

• Top Line: Recipient's name (the person you're ultimately trying to reach)
• Second Line: c/o [Person or organization receiving the mail]
• Third Line: Full street address, including room number or apartment number if needed
• Bottom Line: City, state, ZIP code

Example Envelope Front:

Jane Smith  
c/o John Doe  
87 Westview Drive, Unit 12  
Boston, MA 02118

Make sure your c/o name is clearly placed on the second line—never the first. That top line must always contain the recipient's name, so the postal service can sort mail correctly.

Where to Place the Return Address

Your return address belongs in the upper left-hand corner of the envelope. This is essential in case the delivery fails due to an incorrect or outdated mailing address, allowing the post office to return the item to you safely.

Some professionals also place the return address on the back of the envelope for a cleaner look—especially for formal business letters or premium handwritten mail.

Pro tip: Always double-check the correct address of both the sender and the intended recipient to avoid sending to the wrong person.

Tips for Mailing to Apartments, Hotels, or Offices

• Know the room number or unit—especially in buildings with shared spaces
• Avoid abbreviations that confuse postal service sorting systems
• Don’t forget to apply the correct postage for your letter or package weight
• Use professional handwriting or typed labels to ensure addresses are clearly written for clarity

💡 Want professional, correctly formatted envelopes that include a custom return address, QR code, and even merge tags? LettrLabs’ handwritten mailers ensure your mail looks polished, personalized, and lands with the right individual—even when sent care of someone else.

How to Use c/o When Mailing to a Hotel or Temporary Location

Mail Delivery at Hotels or Temporary Stays

One of the most common real-world uses of c/o is when sending correspondence to someone who’s staying at a hotel or short-term rental. Whether you’re delivering important documents, a gift, or even a business letter, the key is to include both the recipient's name and the hotel's name with their room number if known.

Hotels typically hold mail at the front desk or concierge and require the hotel staff to manually sort and notify the guest. If the mailing address isn’t formatted properly, your letter may never reach the final recipient—especially if it's missing a room number, lacks a clear return address, or doesn't specify “c/o.”

Example: Mailing to a Hotel Guest

Here’s how to structure the address for a hotel guest when you know their room number:

Jane Smith  
c/o Grandview Hotel, Room 304  
88 Oceanview Ave  
Santa Monica, CA 90401

In this example:

• Jane Smith is the recipient
• The c/o name is the hotel
• The room number helps the hotel staff route the item properly
• The full street address ensures USPS can deliver it without issue

What If You Don't Know Their Room Number?

If you don’t know the recipient’s exact room number, that’s okay—as long as the hotel can identify them. Just make sure to provide the full name and expected dates of stay when notifying the front desk, and include a note like:

c/o Guest Services – Hold for Guest  
Arriving July 15 – Jane Smith

You can also call the front desk in advance to ask for their preferred handling instructions for incoming mail. Hotels often have their own internal delivery policies.

Temporary Rentals or Short-Term Office Spaces

The same concept applies when sending mail to a friend’s address, a coworking space, a temporary workplace, or a temporary stay like Airbnb. You should still:

• Include the c/o name
• Confirm the correct address and unit number
• Make sure there’s someone to receive the mail on behalf of the intended recipient

💡 Running a campaign targeting travelers, short-term residents, or temporary locations? LettrLabs supports flexible mailing options and dynamic triggers, so your messages reach the right individual—even if they’re only there briefly. Learn more about LettrLabs’ automation features for smarter outreach.

How c/o Differs from “Attn:” or “To the Attention Of”

It’s easy to confuse c/o with Attn: (short for “attention”), but they serve different purposes—especially when writing a business letter. Use c/o when the recipient's primary address is not available, and you need to send mail to someone at a different address, such as through another person or organization.

When to Use Attn:

Use Attn: when you’re sending a letter or package to a specific person within a company or organization, and the mailing address belongs to that company.

For example:
TechNova Inc.
Attn: John Smith
200 Innovation Blvd
Austin, TX 78701

In this format, John Smith works at TechNova and the company owns the business address.

When to Use c/o:

Use c/o when the intended recipient is not the person or organization at the address you’re mailing to, but you want your correspondence to be accepted or passed along by someone else.

When using c/o, the recipient's name should be on the first line of the address to clearly indicate who the mail is intended for.

For example: Michael Chenc/o John Smith200 Innovation Blvd Austin, TX 78701

In this case, Michael Chen is the recipient, but he doesn’t work at or live at the address. You’re routing the letter through John Smith, who does.

Quick Rule of Thumb:

• Use Attn: if you're reaching someone at their place of work
• Use c/o if you're sending through someone else—like a family member, friend, or organization helping forward mail

Misusing these can confuse the postal service, cause delays, or result in delivery to the wrong person—especially if you forget to include a proper return address.

💡 If you’re using LettrLabs to send B2B outreach or marketing mail to multiple decision-makers, using the correct format matters. Explore our B2B direct mail guide for tips on address formatting, personalization, and automation across departments.

Common Mistakes When Using c/o

Using c/o is simple—but mistakes in addressing mail, especially with c/o, can lead to missed deliveries, delays, or worse: your letter ending up with the wrong person. If you want your mail to reach the intended recipient, avoid these frequent mistakes:

1. Putting the c/o Line First

The most common error is putting the c/o name on the first line of the envelope. That first line should always show the name of the person you're trying to reach—not the person accepting the correspondence.

❌ Incorrect:
c/o John Smith
Jane Doe
123 Main Street

✅ Correct:
Jane Doe
c/o John Smith
123 Main Street

2. Forgetting the Return Address

Many people forget to include a return address, especially when sending casual notes. But if the postal service can’t complete delivery—for example, if the recipient no longer lives at the address—your letter could be lost forever. Always include your return address in the left-hand corner.

3. Not Including the Street Address

Leaving out the full street address—including unit, room number, or apartment number—can cause major delivery issues, especially in large buildings or hotels. Be as specific as possible to avoid confusion.

4. Sending Without Verifying the Address

Before you send important documents, confirm the recipient's name, who will receive it on their behalf, and the full, up-to-date mailing address. This is particularly important for business correspondence where outdated contact info is common.

5. Using the Wrong Format for a Company

If you're sending mail to a business, make sure you’re using the proper name for the organization and not just a person’s nickname. Example:

Correct:
Mark Taylor
c/o Jessica Lin
NextGen Partners
600 Eastwood Dr, Suite 400
Seattle, WA 98101

This makes it clear to postal service workers—and front desk staff—who the final recipient is and how the mail should be handled.

💡 Need help verifying your addresses before launching a campaign? LettrLabs includes built-in address verification to avoid mistakes and ensure you reach the right individual. Learn more in our tracking and analytics tools overview.

Why c/o Is Still Relevant Today

Some people assume that c/o is outdated—that with email, Slack, and digital forms of correspondence, there’s no reason to rely on old-school mailing conventions. But that couldn’t be further from the truth.

In fact, c/o is more useful now than ever, especially as people become more mobile and businesses adopt hybrid work models.

Real Scenarios Where c/o Still Matters

• Executives working out of shared spaces where a direct business address isn't available
• Ecommerce brands or marketing agencies sending physical promos to a friend’s address or assistant
• Real estate agents sending correspondence to a seller temporarily residing elsewhere
• Remote workers receiving mail at a family member’s home address
• Guests traveling for work or vacation, staying at someone’s hotel or short-term rental
• Students or interns receiving paperwork at a secondary address

Even the post office recognizes the importance of c/o as a valid, widely accepted method of routing mail to the right person through an intermediary. It’s a powerful tool for sending mail when you don’t know the recipient’s primary address, but still want to ensure safe delivery.

When You Can’t Use Email (And Shouldn’t)

There are still plenty of situations where physical mail is essential. For example:

• Legal notices
• Contracts
• Checks or important documents
• Identity verification mailers
• Personalized marketing pieces

These are not the kinds of things you want lost in the shuffle or marked as spam. They need to be seen, handled, and delivered—to the final recipient, not just anyone nearby.

💡 Whether you're sending time-sensitive materials or launching a personalized campaign, LettrLabs helps you reach even hard-to-pin-down recipients. Explore our direct mail marketing platform to automate outreach that arrives where—and when—it matters.

Step-by-Step: How to Send Important Documents via Mail

If you’re sending mail that truly matters—like important documents, legal papers, a time-sensitive business letter, or any other article such as a letter or package—you can’t afford mistakes. Here’s a quick checklist to ensure your mail reaches the intended recipient, even when routed through someone else using a c/o name.

✅ 1. Know Exactly Who You’re Sending To

Start with the full, proper name of the person you want to reach—not their nickname. If you’re sending correspondence through someone else, double-check that they’re willing and able to accept the mail.

✅ 2. Confirm the Full Mailing Address

Always verify the correct address, including:

• Full street address
• Apartment number or room number
• City, state, and ZIP code
  If you're sending to a business, confirm the organization’s name and suite number if applicable.

✅ 3. Use the Proper Address Format

Structure the letter like this:

Jane Smith
c/o John Doe
123 Westlake Blvd, Unit 4A
San Diego, CA 92101

This makes it easy for the postal service to identify both the addressee and the intermediary.

✅ 4. Include Your Return Address

Place your full return address in the left-hand corner of the envelope. That way, if something goes wrong with the delivery, it comes back to you—not into the void.

✅ 5. Apply Correct Postage

Don’t forget this step. Undeliverable or underpaid mail is one of the leading causes of delays. Weigh your letter or package if you're unsure, and add extra postage for heavier items.

✅ 6. Send and Track (If Needed)

Drop your mail at the post office, schedule a pickup, or use LettrLabs to send it directly from your dashboard. For high-value or legal documents, consider using tracking or certified delivery.

💡 Want a platform that handles all this for you—address verification, formatting, printing, tracking, and more? LettrLabs offers end-to-end automation for letters, postcards, and personalized outreach campaigns, so you never have to worry about the logistics.

Real-World Examples of c/o Usage

Understanding how to use c/o is easier when you see it applied in different contexts. For example, you might be sending an article, such as a letter or package, to a friend or business using c/o. Below are several examples of properly formatted mailing addresses using the c/o name—whether you’re sending mail to a friend’s address, reaching someone at work, or contacting a guest at a hotel.

Example 1: Sending Mail to a Friend’s Address

Let’s say your friend Jane is staying with Emily while relocating. You want to send important documents to Jane, but since she doesn’t have a permanent home address yet, you can use your friend's address with c/o. Here’s how to format it:

Jane Smithc/o Emily Wong45 Pine Street, Apt 9A Boston, MA 02115

This lets the postal service know Jane is the recipient, but Emily lives at that friend's address and will receive the letter on her behalf.

Example 2: Business Mail Sent via a Colleague

Imagine you want to send a business letter to Michael Chen, but only have his coworker’s information at the company. Here’s what it should look like:

Michael Chen
c/o John Smith
TechNova Inc.
200 Innovation Way, Suite 10
Austin, TX 78701

In this case, the company name and office location help guide the correspondence through the right channels until it reaches the final recipient.

Example 3: Mailing to a Hotel Guest

If someone is staying at a hotel temporarily, and you need to get them a physical letter or package, format your mailing address like this:

Sarah Lee
c/o Grandview Hotel, Room 304
88 Oceanview Avenue
Santa Monica, CA 90401

Be sure to know their room number if possible. If not, include full name and arrival dates in a note to the hotel staff to assist with delivery.

These formats work across various industries and use cases—from sending correspondence to family members, clients, or even temporary contractors.

💡 Want your business mail to be as personalized and properly formatted as these examples? LettrLabs’ handwritten card service lets you automate 1-to-1 delivery with real ink, dynamic merge fields, and proven response rates—even if you're sending care of someone else.

Mail Forwarding and c/o: What You Need to Know

Mail forwarding is a valuable service for anyone who needs to redirect their mail from one address to another—whether you’re moving, traveling, or managing business correspondence from multiple locations. When you combine mail forwarding with the “c/o” (care of) address format, you can make sure that important documents, letters, and packages reach the intended recipient, even if they’re not at their primary address.

Using a c/o address in conjunction with mail forwarding is especially helpful for businesses and individuals who want to receive correspondence at a temporary or secondary address. For example, if you’re sending mail to a colleague who’s working remotely or a family member staying at a friend’s address, the c/o format ensures your letter or package is routed through the right person and delivered to the correct location.

How Mail Forwarding Works with c/o Addresses

When you use a c/o address, you’re instructing the post office to deliver your mail to a specific person or business at a particular location, rather than the recipient’s home address. The post office processes the letter or package using the address format you provide, ensuring it arrives at the business address or secondary address listed. Once delivered, the person or company named after “c/o” is responsible for passing the mail on to the final recipient.

For example, if you want to send a letter to John Doe at a business location, you would address it as follows:

John Doe c/o XYZ Corporation 123 Main Street Anytown, USA

In this example, the post office delivers the mail to XYZ Corporation at the specified address. The company’s mailroom or front desk then ensures John Doe receives the letter. This process is especially useful for large organizations, shared workspaces, or any situation where the intended recipient does not have a direct mailbox at the location.

When to Use Mail Forwarding Services

Mail forwarding services are ideal when you need to ensure your important documents, letters, and packages reach you or your intended recipient, no matter where you are. This is particularly useful if you’re relocating, traveling for business, or working from a temporary address. Businesses often use mail forwarding to keep up with correspondence while executives or employees are on the move, ensuring that no critical business letter or package is missed.

For individuals, mail forwarding can help you stay connected and receive mail at your current location, even if you’re away from your primary residence. Whether you’re a student, a frequent traveler, or someone managing multiple addresses, mail forwarding ensures that your important documents and packages are always within reach.

Tips for Ensuring Forwarded Mail Arrives Safely

Keeping Your Mail Secure When Using c/o

While using a c/o address is a convenient way to send mail to someone at a secondary address or business address, it’s important to consider the security of your correspondence—especially when sending sensitive information or valuable packages. When you use c/o, your mail may pass through several hands before reaching the final recipient, so taking extra precautions is essential.

Risks of Using c/o for Sensitive Documents

Sending sensitive documents or packages using a c/o address can increase the risk of your mail being lost, tampered with, or delivered to the wrong person. Because your letter or package is routed through a third party—such as a business, hotel staff, or friend—there’s a greater chance that confidential information could be seen by someone other than the intended recipient. This is particularly concerning for business correspondence, legal documents, or anything containing personal or financial data.

For example, if you send important documents to John Doe c/o a company name at a business address, the mail may be handled by multiple employees before it reaches John. Similarly, sending mail to a family member or friend’s address could result in the letter or package being misplaced if the recipient lives in a busy household or shared space.

How to Make Sure Your Mail Reaches the Right Person

At the end of the day, getting your letter or package delivered to the right individual is what really matters. And using c/o name the right way is one of the easiest ways to do it—especially when the recipient isn’t located at the main mailing address or when you're routing your correspondence through someone else.

To recap:

• Use c/o when the intended recipient is staying with a friend, family member, or temporary contact
• Always include the recipient’s name on the first line, and the c/o name on the second line
• Double-check the full street address, including room number or apartment number
• Don’t forget the return address—placed clearly in the left-hand corner
• Apply the correct postage and track it if you’re sending important documents or time-sensitive mail

The c/o format is still incredibly relevant for both personal and business correspondence—especially when you're trying to reach decision-makers, temporary guests, or people with limited fixed addresses.

With the right formatting, attention to detail, and verified addresses, you’ll drastically improve your delivery success and ensure your message is seen by the final recipient—not lost or bounced.

💡 LettrLabs makes it easy to personalize, send, and track beautifully formatted mail—whether you're reaching someone at their home address, business, or through a third party. Start automating your outreach today with LettrLabs' direct mail tools.