How Many Stamps Do I Need to Mail a Letter? 2025 Guide

Stamp prices changed again in 2025 — but figuring out how many stamps you actually need is easy. Here's the exact number based on weight, plus a way to skip stamps entirely.

How Many Stamps Do You Need by Letter Weight (2025)

What Counts as Additional Ounces When Calculating Stamps?

Common items that add weight to your letter:

• Multiple pages (5+ sheets of paper)
• Photos or cards
• Thick envelopes or padding
• Return envelopes included
• Small items like USB drives or keys

How Many Stamps for Special Situations

Large or Non-Standard Envelopes

If your envelope is larger than 6⅛" × 11½" or thicker than ¼", it requires large envelope postage starting at $1.63, regardless of weight.

International Letters

International letters require Global Forever Stamps ($1.70) or equivalent postage, regardless of destination country.

Certified Mail

For important documents, add Certified Mail. The Certified Mail service fee is $5.30 (plus regular postage). Optional receipts: Electronic Return Receipt $2.82 or the paper "Green Card" $4.40.

Skip the Stamps Entirely

With The Letter Pilot, you can mail letters without ever buying stamps. Check official USPS postage rates for the latest pricing, or skip stamps entirely:

• 📄 Upload your letter as a PDF or type it online
• 💳 Pay digitally - no stamp purchases needed
• ✉️ We print, address, and apply correct postage
• 🚚 USPS delivers it normally
• 📱 Get tracking updates on your phone

How to Determine Your Letter Weight

Without a postal scale:

• 1-5 sheets of paper: Usually under 1 ounce
• 6-10 sheets: Likely 1-2 ounces
• Thick envelope or contents: Probably over 1 ounce
• When in doubt: Add extra postage or visit a post office

FAQs

What happens if I don't use enough stamps?

Your letter will be returned to you marked "postage due" or the recipient may have to pay the missing postage to receive it.

Can I use multiple Forever Stamps instead of additional ounce stamps?

Yes, but it's more expensive. Two Forever Stamps ($1.56) cost more than one Forever Stamp plus one additional ounce stamp ($1.07).

Do I need special stamps for important documents?

No special stamps, but consider Certified Mail for legal documents, tax forms, or other important correspondence to ensure secure delivery.

How can I mail a letter online without stamps?

Use online mail services like The Letter Pilot to send letters digitally - no stamps or post office visits required.

Want to learn more? Check out our complete guides on letter mailing costs and how to mail a letter step-by-step.