Unit Price Calculator
Cost per unit so you can compare which package is the better deal.
Input sheet
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The cheapest sticker price is rarely the cheapest product. Unit price strips away package size so you can see what you actually pay per ounce, sheet, or count and pick the real bargain.
How it works
Divide each item's price by its size to get a price per unit, then compare. The lower per-unit price is the better value regardless of package size.
Stores deliberately mix package sizes and odd quantities so two products are hard to compare at a glance. Reducing both to a single per-unit number turns guesswork into a one-second decision.
The math only works when both items are measured in the same unit. Comparing a price-per-ounce against a price-per-pound will flip the answer — convert one side first if the labels disagree.
Unit price = item price ÷ item size, then compare the two and pick the lower number.
Worked examples
Item A is $4.50 for 32 oz; Item B is $6.00 for 48 oz. → A = $0.1406/oz, B = $0.1250/oz — Item B is the better deal by about $0.0156/oz.
4.50 ÷ 32 = 0.1406 and 6.00 ÷ 48 = 0.1250, so the larger package wins here.
Name brand is $3.00 for 12 rolls; store brand is $4.20 for 24 rolls. → $0.25/roll vs $0.175/roll — the store brand saves $0.075 on every roll.
3.00 ÷ 12 = 0.25 and 4.20 ÷ 24 = 0.175.
Tips & gotchas
- Watch the shelf tag — many stores already print a unit price, but they sometimes use different base units for competing products, which hides the real comparison.
- Bigger is not automatically cheaper. Bulk packs occasionally carry a convenience markup, so always run the numbers.
- Factor in waste. A larger size is only cheaper if you actually use it before it expires.
- For non-divisible goods (a 3-pack vs a 5-pack), use price-per-count rather than price-per-ounce.
FAQ
What counts as a unit?
Whatever you measure in — ounces, grams, sheets, count. Just use the same unit for both items so the comparison is apples-to-apples.
Should I include sales tax in the price?
Only if one item is taxed differently. For most identical product categories tax is the same percentage on both, so it cancels out and you can compare pre-tax prices.
What about a coupon on only one item?
Subtract the coupon from that item's price first, then compute the unit price. The discount can easily flip which package is cheaper.
Does a membership or bulk-club price change the comparison?
Yes. If a warehouse price requires a paid membership, amortize that annual fee across your expected purchases before deciding the bulk size truly beats the grocery option.
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