Table of Contents
Table of Contents
Picture this. Your campaign just funded. There's a box of enamel pins on the kitchen table, a stack of art prints, and a roll of stamps you bought "just in case." You put one pin in an envelope, drop it on the kitchen scale, and the number says 1.4 oz.
If a piece breaks any limit for its lane, it gets bumped up to the next lane. A "letter" that's 3/8 inch thick is not a letter anymore. A flat that's stiff like a board is not a flat anymore. Kind of annoying, honestly, but it's how the system works.
So... two stamps? One stamp and a bit? And what about the backer in Germany?
That little moment is where a lot of creators lose money without noticing. Stamps feel simple. And for some rewards, they really are. But once the weight, the thickness or the destination changes, the stamp math changes too. Sometimes it stops working at all.
This guide walks through how postage works by weight, how many stamps you actually need, which crowdfunding rewards can ship with stamps, and when it's time to switch to labels or a fulfillment partner. All prices below come from the official USPS price list that took effect on October 4, 2026. Prices change, so give them a quick re-check before you print anything.
How a Stamp Calculator by Weight Actually Works
A stamp calculator by weight does one boring but useful thing. It turns the weight of your mailpiece into a postage amount, then turns that amount into a number of stamps.
The basic rule is this. One Forever stamp covers a standard letter up to 1 ounce. Every extra ounce adds a fixed amount on top. That's it for letters.
The formula looks like this:
Stamps needed = postage required ÷ value of one stamp, rounded up
Rounded up is the key part. If the math says 1.3 stamps, you need 2. The post office doesn't do partial credit. Short postage means the piece can come back to you, or the backer gets a "postage due" notice. Neither is a great look for a creator.
A Forever stamp has no number printed on it. It's always worth the current price of a 1-ounce letter, even if you bought it years ago. That's handy. A stamp you bought at 78 cents still covers a full 1-ounce letter today.
Letters, Large Envelopes and Packages: Three Price Lanes
Here's the part most stamp charts skip. Weight is only half the story. USPS first checks the shape and size, then the weight. Your mailpiece falls into one of three lanes.
|
Lane
|
Size limits (USPS)
|
Max weight
|
Typical reward
|
|
Letter
|
Up to 6-1/8 x 11-1/2 inches, up to 1/4 inch thick
|
3.5 oz
|
Stickers, postcards, small flat prints
|
|
Large envelope (flat)
|
Up to 12 x 15 inches, up to 3/4 inch thick, must be flexible
|
13 oz
|
Art prints, zines, thin comics, patches
|
|
Package
|
Bigger, thicker, rigid or lumpy
|
Up to 70 lb
|
Books, board games, gadgets, plushies
|
If a piece breaks any limit for its lane, it gets bumped up to the next lane. A "letter" that's 3/8 inch thick is not a letter anymore. A flat that's stiff like a board is not a flat anymore. Kind of annoying, honestly, but it's how the system works.
Stamps by Weight Chart (2026)
Okay, the chart you came for. These are USPS retail prices for First-Class Mail, effective October 4, 2026. The Forever stamp is $0.82 and the additional-ounce price is $0.29.
Letters (up to 3.5 oz)
|
Weight not over
|
Postage
|
Forever + additional-ounce stamps
|
Forever stamps only
|
|
1 oz
|
$0.82
|
1 Forever
|
1
|
|
2 oz
|
$1.11
|
1 Forever + 1 additional-ounce
|
2
|
|
3 oz
|
$1.40
|
1 Forever + 2 additional-ounce
|
2
|
|
3.5 oz
|
$1.69
|
1 Forever + 3 additional-ounce
|
3
|
Large envelopes / flats (up to 13 oz)
|
Weight not over
|
Postage
|
Forever stamps only
|
|
1 oz
|
$1.69
|
3
|
|
2 oz
|
$1.98
|
3
|
|
3 oz
|
$2.27
|
3
|
|
4 oz
|
$2.56
|
4
|
|
5 oz
|
$2.85
|
4
|
|
6 oz
|
$3.14
|
4
|
|
7 oz
|
$3.43
|
5
|
|
8 oz
|
$3.72
|
5
|
|
9 oz
|
$4.02
|
5
|
|
10 oz
|
$4.32
|
6
|
|
11 oz
|
$4.62
|
6
|
|
12 oz
|
$4.93
|
7
|
|
13 oz
|
$5.24
|
7
|
Look at the "Forever stamps only" column for a sec. Using only Forever stamps is easy, but you overpay on most rows. At 2 oz a letter costs $1.11, and two Forever stamps are worth $1.64. That's 53 cents gone on every envelope. Fine for ten backers. Not fine for two thousand.
Postcards are their own thing, by the way. A standard postcard costs $0.65, which is less than a Forever stamp.
If you want to double-check a piece with odd dimensions, the official USPS Postage Price Calculator lets you enter shape, weight and ZIP codes and see the exact price.
The Nonmachinable Surcharge Nobody Warns You About
This one bites creators all the time. If a letter can't go through the sorting machines, USPS adds a nonmachinable surcharge. Right now it's $0.49 per letter.
Things that usually trigger it:
Square envelopes, like a lot of greeting cards
Rigid letters that don't bend
Lumpy contents, like a pin, a coin or a keychain
Clasps, strings or buttons on the envelope
Very skinny or very tall envelopes
A 1-ounce enamel pin in a square card mailer can cost $0.82 + $0.49 = $1.31. That's a 60% jump over what you probably budgeted. And if the lump is big enough, the post office may not treat it as a letter at all.
Which Crowdfunding Rewards Can Ship With Stamps?
This is where a generic stamp chart stops helping. Backers don't get "letters." They get stuff. So let's sort common rewards by how well they work with stamps.
|
Reward
|
Usual lane
|
Stamps work?
|
What to watch
|
|
Stickers, postcards
|
Letter
|
Yes
|
Keep it flat and under 1/4 inch
|
|
Art print (unframed)
|
Flat
|
Usually
|
Use a stiff-ish board, but keep it flexible
|
|
Enamel pin
|
Letter or package
|
Risky
|
Lumpy = surcharge, may get bumped to package
|
|
Zine or thin comic
|
Flat
|
Usually
|
Over 10 oz with stamps means a counter trip
|
|
Embroidered patch
|
Flat
|
Usually
|
Uniform thickness matters
|
|
Paperback book
|
Package
|
Possible but messy
|
Labels are cheaper and easier
|
|
Board game
|
Package
|
No
|
Weight, size and dimensional weight all add up
|
|
Small gadget or plush
|
Package
|
No
|
Better with printed labels or a fulfillment partner
|
Here's a simple way to think about it. If the reward is flat and light, stamps are your friend. If it's thick, lumpy or heavy, stamps become a headache pretty fast.
Most real campaigns are a mix. Stretch goals add a sticker sheet, an add-on adds a pin, and suddenly your neat 1-ounce letter is a 6-ounce bumpy thing. Plan for the final bundle, not the base reward.
Weighing Your Reward the Right Way
Weigh the finished package, not the product. That means product plus packaging plus any extras like a thank-you card or a bag of stickers.
Packaging adds more than people expect. Some rough ranges, give or take:
A plain paper envelope: a fraction of an ounce
A small bubble mailer: about half an ounce to an ounce
A rigid photo mailer: an ounce or two
A small cardboard box: several ounces, sometimes more than the product inside
So a 0.8 oz pin can easily become a 1.6 oz piece once it's packed. That's a different row on the chart.
Kitchen Scale vs Postal Scale
A kitchen scale is okay to start. Just make sure it shows ounces with at least one decimal. A cheap postal scale is better if you're mailing more than a handful. It's built for this, and it usually reads in 0.1 oz steps.
Always round up. If your scale says 2.05 oz, you're in the 3 oz row. Being a tiny bit over is a classic reason mail comes back.
One more tip. Weigh five or ten finished pieces, not just one. Hand-packed rewards vary a little, and you want the heaviest one to still fit your postage.
If you're shipping from China instead of from home, it helps to think in both units. Our shipping cost calculator uses kg and cm by default and switches to lb and inches when you pick the US, so you can check a reward's packed weight either way.
When Stamps Stop Making Sense
Stamps are great until they aren't. Here are the points where most creators should switch.
The 10-Ounce and Half-Inch Rule
Since October 2019, USPS doesn't accept stamped mailpieces in blue collection boxes or lobby drops if they weigh more than 10 ounces or are thicker than half an inch. You have to hand them to a clerk at the counter.
For one package, no big deal. For 300 backers, that's a lot of standing in line. Packages with printed postage labels don't have this problem, because the rule only applies to pieces paid with stamps.
Printed Labels and Ground Advantage
For packages, buying postage online and printing a label is usually cheaper than stamps. Online prices for USPS Ground Advantage and Priority Mail are often lower than counter prices, and you get tracking without extra steps. Backers ask "where's my reward?" a lot. Tracking saves you a bunch of emails.
Labels also mean you don't need to count stamps at all. The price is just the price.
Dimensional Weight
For bigger boxes, weight on the scale isn't the only weight that counts. USPS uses dimensional weight for packages larger than one cubic foot (1,728 cubic inches). The formula is length x width x height in inches, divided by 166. Whichever is higher, real weight or dimensional weight, is what you pay for.
Board games get hit by this a lot. A light but big box can be billed as if it weighed twice as much. Choose a box that fits the product snugly. Every extra inch of empty space costs money.
International Backers: Stamps, Letters and Parcels
This is the part that surprises people the most, so let's be clear.
You can mail a 1-ounce international letter with a Global Forever stamp. Right now that's $1.75 to any country. Great for a thank-you postcard or a paper letter.
But USPS doesn't allow merchandise in First-Class Mail International letters or large envelopes. That rule has been in place since 2018. A sticker sheet or a pin going to a backer in Canada or the UK has to go as a package, usually First-Class Package International Service.
And the price is a different world. For the lightest band (up to 8 oz), retail First-Class Package International Service starts at $19.40 and goes up to $27.75, depending on the country group.
|
Item to an overseas backer
|
Service
|
Starting price
|
|
Thank-you letter, 1 oz, no goods
|
First-Class Mail International (Global Forever stamp)
|
$1.75
|
|
Pin or sticker sheet, under 8 oz
|
First-Class Package International Service
|
$19.40 to $27.75
|
So that $5 pin reward can't really ship overseas for "a couple of stamps." This is the biggest reason international shipping fees on Kickstarter look so high.
Customs Forms and Duty Rules
International packages need a customs declaration. You'll list what's inside, the value, and whether it's a gift or merchandise. Pledge rewards are usually goods, not gifts. Declaring them honestly saves backers from surprises later.
Duty rules for low-value parcels have changed in several markets over the last couple of years, including the US and the EU. Check the current rules for your main backer countries before you set fees. Things move fast here.
Turning Per-Package Postage Into Pledge Shipping Fees
Knowing the postage for one package is step one. The real job is turning that into shipping fees backers pay when they pledge.
Use a Weighted Average by Backer Region
You don't know exactly where every backer will be. But you can guess from past campaigns, your social following or similar projects. Then you build a weighted average.
Here's a made-up example for a pin-and-sticker reward. The postage figures are illustrations only, not quotes.
|
Region
|
Share of backers
|
Postage per package (example)
|
Weighted cost
|
|---|---|---|---|
|
US
|
60%
|
$2.00
|
$1.20
|
|
Canada
|
10%
|
$20.00
|
$2.00
|
|
Europe
|
20%
|
$22.00
|
$4.40
|
|
Rest of world
|
10%
|
$25.00
|
$2.50
|
|
Total
|
100%
|
—
|
$10.10 average
|
Look at that. US backers are 60% of the people but only about 12% of the shipping cost. That's why most creators charge shipping by region instead of one flat number.
Don't forget packaging, labels, and the time it takes to pack. Those cost real money too.
Flat Fee or Charge Shipping by Region
You've basically got two ways to charge:
Shipping built into the reward price. Simple for backers, but you'll overcharge some and undercharge others.
Shipping charged by region. Fairer and safer for your budget. Platforms support this. Kickstarter explains the options in its help center article on how to charge shipping on rewards.
Some creators also collect shipping later through a pledge manager, after the final address list is known. That way add-ons and address changes don't blow up the math. If you want a deeper look at budgeting shipping for a whole campaign, our guide on estimating crowdfunding shipping costs goes step by step.
Shipping Rewards From China Without the Stamp Headache
A lot of creator rewards are made in China anyway. Pins, acrylic standees, board games, plushies, small electronics. So here's a question worth asking. Why ship 3,000 pins to your house, then stamp them one by one, then queue at the post office?
The other route is to ship rewards straight from China to backers around the world. That's what SendFromChina does. We're a third-party fulfillment partner with warehouses in China, and crowdfunding fulfillment is one of our core services.
Here's how it usually works:
Your factory sends the finished rewards to our China warehouse.
We receive them, check them and store them.
You send us the backer list from your platform or pledge manager.
We pick and pack each order by reward tier, including add-ons.
We ship internationally with tracking, so backers can follow their parcel.
Shipping times depend on the route, the carrier, customs, the product type and the season. Pricing is quote-based. It's built from the actual weight, size and destination of your rewards, not a one-size-fits-all number. You can start with the shipping cost calculator mentioned above, or check our crowdfunding fulfillment service page for the full process.
Running a Kickstarter specifically? Our Kickstarter fulfillment page covers how tiers, add-ons and late pledges are handled.
The point isn't that stamps are bad. For 40 sticker packs to US friends, stamps are perfect. It's just that past a certain size, the kitchen-table method gets expensive. It eats your time too.
Common Postage Mistakes Creators Make
These come up again and again. Most of them are easy to avoid once you know.
Weighing the product, not the package. The mailer, the card and the tape all count.
Forgetting the nonmachinable surcharge. Square envelopes and lumpy pins cost more.
Using only Forever stamps on everything. Easy, but you overpay on almost every weight.
Assuming stamps work overseas for goods. They don't. Merchandise needs a package service.
Setting shipping fees before the reward is final. Stretch goals change weight. Wait, or leave room.
Ignoring dimensional weight. Big light boxes get billed like heavy ones.
Dropping heavy stamped mail in the blue box. Over 10 oz or half an inch thick with stamps, it comes back.
No tracking on higher-value rewards. One lost parcel can cost more than tracking for the whole batch.
Conclusion
Stamps are still a handy tool. For light, flat rewards going to US backers, a simple stamp calculator by weight is all you need. Weigh the packed piece, round up, check the chart, and watch out for the surcharge.
But once rewards get thick, heavy or international, stamps stop saving money. That's the time to switch to printed labels, charge shipping by region, and look at shipping straight from where your rewards are made. Do the math before launch day, not after. Your margin will thank you.
FAQs
How many stamps do I need for a 2 oz letter?
A 2 oz letter costs $1.11. You can use one Forever stamp plus one additional-ounce stamp. Or use two Forever stamps, which works but overpays a bit.
How much weight does one Forever stamp cover?
One Forever stamp covers a standard letter up to 1 ounce within the US. It doesn't cover large envelopes, packages or international mail on its own.
Can I use Forever stamps on a package?
Yes, stamps can pay for package postage. But you'll need a lot of them, and stamped packages over 10 oz or half an inch thick must be handed to a clerk. Printed labels are usually easier and cheaper.
How many stamps do I need for a 9x12 envelope?
A 9x12 envelope is a large envelope (flat). At 1 oz it costs $1.69, which is three Forever stamps. Weigh it, then use the flat chart above.
What happens if I don't put enough postage on mail?
The piece may come back to you, or the recipient may be asked to pay the difference. For backer rewards, both are bad news. Always round up.
Can I drop a stamped package in a mailbox?
Only if it weighs 10 oz or less and is no more than half an inch thick. Anything heavier or thicker with stamps has to go to a Post Office counter.
How many stamps for a bubble mailer?
It depends on weight and shape. A thin bubble mailer that stays flexible and under 3/4 inch may qualify as a flat. If it's lumpy or thick, it's priced as a package. Weigh it and check which lane it's in.
Do square envelopes need extra postage?
Yes. Square letters are nonmachinable, so USPS adds a $0.49 surcharge on top of normal postage.
Can I use Forever stamps for international mail?
A domestic Forever stamp alone isn't enough. A Global Forever stamp ($1.75) covers a 1 oz international letter. Merchandise can't go as an international letter, though. It needs a package service.
Is it cheaper to use stamps or a shipping label?
For flat, light letters, stamps are fine. For packages, printed labels bought online are usually cheaper than counter prices, include tracking, and skip the 10-ounce counter rule.
Want to know about our services, fees or receive a custom quote?