Cost per round, explained
How to compare a 20-round box with a 1,000-round case, what the number includes, and what it leaves out.
Ammo comes in every package size imaginable: 20-round boxes, 50-round boxes, 500-round bricks, 1,000-round cases. Box price alone can't tell you which one is actually cheaper. Cost per round can.
The formula
Cost per round = listed price ÷ number of rounds in the package.
That's it. It turns every listing into the same unit so you can compare a small box and a bulk case side by side.
Worked examples
| Example package | Example price | Math | Cost per round |
|---|---|---|---|
| 50-round box | $20.00 | $20.00 ÷ 50 | $0.40 (40¢) |
| 1,000-round case | $300.00 | $300.00 ÷ 1,000 | $0.30 (30¢) |
| 20-round box | $10.00 | $10.00 ÷ 20 | $0.50 (50¢) |
In this example, the case costs 15 times as much as the 50-round box but is cheaper per round. That's the whole point of comparing by cost per round.
Try it yourself
Enter any box price and round count:
Box vs. case: when bulk wins, and when it doesn't
Bulk packaging often brings the per-round price down, but not always. Promotions, clearance boxes and retailer pricing can make a smaller box cheaper per round than a case. Run the numbers instead of assuming.
A few things to weigh before buying bulk:
- Upfront cost. A lower per-round price still means spending more at once.
- Storage. You'll need a cool, dry place to keep it.
- Fit. Try a box in your firearm before committing to a case, especially with a new load or case material.
Shotgun shells, rimfire and other packaging
- Shotgun shells: the math is per shell. Compare within the same kind of load (birdshot with birdshot, buckshot with buckshot, slugs with slugs) and the same shell length.
- Rimfire: .22 LR often comes in boxes of several hundred rounds, so the price of a single box can look high even when the per-round cost is low.
- Mixed packs and bundles: if a listing bundles ammo with other items, cost per round can be misleading. Read the listing before you compare.
What the number includes, and what it doesn't
On Price Dope, cost per round is based on the listed product price. Shipping, taxes, fees, coupons, quantity discounts and membership pricing are set by the retailer and may not be included.
How Price Dope calculates it
- We read the round count from the product details, such as a "rounds per box" field. If that's missing, we read it from the title, for example "50 RDS", "25 SHELLS" or "Box of 20".
- If we can't find a believable round count, we don't guess. The listing shows the price only and is listed after the ones we can rank by cost per round.
- Caliber pages, such as 9mm, and the Deals page rank ammo by cost per round by default, with in-stock offers first. Every price shows when it was last checked.
The full details are on How it works and our editorial and ranking standards.
Compare like with like
Cost per round measures price. It doesn't measure fit or purpose. When you compare, keep these the same:
- Caliber. 5.56 NATO and .223 Remington, for example, are listed separately for a reason. Check what your firearm is marked for.
- Bullet weight and type. A 115-grain FMJ range load and a defensive hollow point are different products.
- Case material. Brass, steel and aluminum cases differ, and some firearms' manufacturers recommend against certain types.
Live example: 9mm by cost per round
Here's the live 9mm table, cheapest per round first:
Prices change often. Check the "last checked" time on each offer, and confirm the final price on the retailer's site. Ammo purchase and shipping rules vary by state and locality, so follow the laws where you live.
Common questions
How is cost per round calculated?
Divide the listed price by the number of rounds in the package. A box listed at $20.00 with 50 rounds works out to $0.40, or 40 cents, per round. For shotgun shells it's the same math per shell.
Does cost per round include shipping and tax?
Not on Price Dope. Cost per round uses the listed product price. Shipping, taxes, fees, coupons, quantity discounts and membership pricing are set by the retailer and may not be included, so check the final price on the retailer's site.
Why do some listings show a price but no cost per round?
We read the round count from the product details or the title. If we can't find a believable count, we don't guess. The listing shows the price only and appears after the listings we can rank by cost per round.
Is the lowest cost per round always the best buy?
Not necessarily. Cost per round compares price fairly across box sizes, but it doesn't tell you whether a load suits your firearm or your purpose. Compare like with like: same caliber, similar bullet weight and type, and a case material your firearm's manufacturer approves.
Prices shown come from connected retailers' latest checks and change often. Price Dope doesn't sell anything and may earn a commission from retailer links. Disclosure · How we collect prices · Editorial standards
