Unit Price CalculatorCompare pack sizes & find the best buy
Unit price is the price divided by the quantity, and it shows which package size is the better buy. Example: 24 oz for $4.29 is $0.179/oz, while 40 oz for $6.49 is $0.162/oz — the larger box is about 9% cheaper per ounce.
- Up to 6 products
- Weight, volume & count
- Multi-pack sizes
- Yearly savings
By Manzoor Ahmad · 13+ years of web development & SEO · Updated October 25, 2026Compare products
Up to 6Unit price ranking
What Is Unit Price?
Unit price is the cost of one unit of a product — per ounce, pound, liter or item — found by dividing the total price by the total quantity. It is the only fair way to compare different package sizes. A 24 oz box for $4.29 costs $0.179 per ounce; a 40 oz box for $6.49 costs $0.162 per ounce, so the bigger box is about 9% cheaper per ounce.
Unit Price Formula
Single pack
Unit price = Price ÷ Quantity$6.49 ÷ 40 oz = $0.162 per oz.
Multi-pack
Unit price = Price ÷ (Items × Size of each)$11.49 ÷ (2 × 40 oz) = $0.144 per oz.
Different units
Convert first: 1 lb = 16 oz, 1 kg = 1,000 gA 2 lb bag for $5 is $5 ÷ 32 oz = $0.156 per oz.
Percent cheaper
Saving % = (High − Low) ÷ High × 100($0.179 − $0.144) ÷ $0.179 = 19.6% cheaper per ounce.
Example: Three Cereal Sizes
| Product | Price | Total size | Price per oz | vs cheapest |
|---|---|---|---|---|
| Small box | $4.29 | 24 oz | $0.179 | +24.5% |
| Family size | $6.49 | 40 oz | $0.162 | +13.0% |
| Warehouse 2-pack | $11.49 | 2 × 40 oz | $0.144 | Best buy |
Buying the warehouse pack instead of the small box, for a household that buys 24 oz a month, saves about $10.12 a year — these are the calculator’s default products.
Unit Conversion Cheat Sheet
| Unit | Equals | Also equals |
|---|---|---|
| 1 pound (lb) | 16 ounces (oz) | 453.6 grams |
| 1 ounce (oz) | 28.35 grams | 0.0625 lb |
| 1 kilogram (kg) | 1,000 grams | 35.27 oz / 2.205 lb |
| 1 US gallon | 128 fluid ounces | 3.785 liters |
| 1 US quart | 32 fluid ounces | 946 ml |
| 1 liter | 33.81 fluid ounces | 1,000 ml |
| 1 fluid ounce | 29.57 ml | — |
Fluid ounces measure volume and ounces measure weight, so they can’t be compared directly. For a single item, the Price Per Ounce Calculator converts between per-ounce, per-pound and per-100 g prices.
How to Read a Unit Price Label
Many grocery stores print the unit price in a corner of the shelf tag. NIST Handbook 130 sets out a model uniform unit pricing regulation that states can adopt, but rules differ, and stores sometimes use different units for neighboring products (per ounce on one, per count on another). When the units don’t match, calculate it yourself.
Bigger isn’t always cheaper
A small size on sale can beat the bulk size. Always compare unit prices, not package prices.
Watch for shrinkflation
If a pack shrinks but the price stays the same, the unit price has gone up. Compare against your last receipt.
Count what you’ll use
A bulk pack that expires before you finish it costs more per unit you actually use.
Multi-buy offers
For BOGO and buy-2-get-1 deals, find the per-item price with the BOGO Calculator.
Durable goods
For clothes and gear, compare price per use with the Cost Per Wear Calculator.
Sale price per unit
Enter the sale price, not the tag price. Work it out with the Percent Off Calculator.
Related Shopping Calculators
Each of these answers the next question shoppers usually ask after this one.
Price Per Ounce Calculator
One product? Get its price per ounce, per pound and per 100 g instantly.
Cost Per Wear Calculator
For clothes, shoes and gear, compare cost per use instead of cost per ounce.
BOGO Calculator
Multi-buy deals change the unit price — find the real per-item cost.
Percent Off Calculator
Find the sale price first, then compare its unit price here.
50/30/20 Budget Calculator
See where grocery savings fit into a 50/30/20 monthly budget.
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Unit Price Calculator FAQs
Divide the price by the quantity. A 40 oz box for $6.49 has a unit price of $6.49 ÷ 40 = $0.162 per ounce.
Convert both to the same unit first. 1 pound = 16 ounces and 1 kilogram = 1,000 grams. A 2 lb bag for $5 is $5 ÷ 32 = $0.156 per ounce.
Multiply the number of items by the size of each, then divide the price by that total. A 2-pack of 40 oz boxes for $11.49 is $11.49 ÷ 80 = $0.144 per ounce.
No. Sales, store brands and shrinkflation often make a smaller size cheaper per unit. Always compare the unit price, not the package price.
Not directly. Ounces measure weight and fluid ounces measure volume. Compare products sold the same way, or use the product’s density if you know it.
It is the store’s calculation of the cost per standard unit, such as per ounce or per 100 count. Check that neighboring products use the same unit before comparing.
It depends on the state or country. NIST Handbook 130 includes a model unit pricing regulation, and some states require unit pricing in grocery stores while others leave it voluntary.
Divide the price by the number of items. A 24-pack of water for $5.99 is about $0.25 per bottle.
It depends on what you buy. In this calculator’s default cereal example, choosing the cheapest size saves about $10.12 a year on one product bought monthly; across a full grocery list the savings add up.
Yes. Enter the price you will actually pay after any sale or coupon, so the comparison reflects the real cost.
Compare per sheet rather than per roll, because roll sizes vary widely. Use the sheets option and the total sheet count from the package.
Yes. It is free, needs no sign-up and runs entirely in your browser.
Manzoor Ahmad
Founder of DexoCalc · 13+ years of web development & SEO experience
Manzoor built this unit price calculator for real grocery aisles: mixed units, multi-packs and sale prices. Conversions use exact NIST factors (1 oz = 28.3495 g, 1 fl oz = 29.5735 ml), and the yearly savings use the size of the priciest option you compare.
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Last reviewed and updated: October 25, 2026
Sources & References
- National Institute of Standards and Technology — NIST Handbook 130: Uniform Unit Pricing Regulation
- National Institute of Standards and Technology — Unit conversion: SI and U.S. customary units
- Federal Trade Commission — Consumer Advice: Shopping and Saving
Disclaimer: results are estimates for planning and comparison. Store policies, coupon terms and local tax rules vary, so your receipt may differ. This calculator is not financial, legal or tax advice.