A unit rate answers “how much for one?” It turns any comparison of two quantities — 150 miles in 2.5 hours, $5.29 for 20 ounces, 1,800 words in 40 minutes — into a single number per one unit, which makes very different situations easy to compare. This calculator has two modes: a general unit-rate finder with your own unit names, and a shopping mode that compares up to four package sizes by price per unit.
How to use the unit rate calculator
Find a unit rate
- Enter the first quantity and its unit (for example, 150 and
miles). - Enter the second quantity and its unit (2.5 and
hours). - The tape shows the unit rate (60 miles per hour) and the inverse rate (hours per mile). A table scales the rate to 2, 5, 10 and 100 units.
Compare unit prices
- Type the size unit shared by all items, such as
oz,lb,sheetsorcount. - Enter the price and size of two to four options. Leave unused options blank.
- The best value is highlighted, with each option’s unit price and how much more it costs per unit than the cheapest.
Unit rate formula
For shopping, quantity A is the price and quantity B is the package size:
Worked examples
A road trip
Rate: 150 miles in 2.5 hours
Unit rate: 150 ÷ 2.5 = 60 miles per hour
Inverse: 2.5 ÷ 150 ≈ 0.0167 hours per mile — one minute per mile
Three sizes of cereal
| Option | Price | Size | Unit price |
|---|---|---|---|
| A | $3.49 | 12 oz | $0.2908/oz |
| B | $5.29 | 20 oz | $0.2645/oz |
| C | $8.99 | 36 oz | $0.2497/oz |
Option C is the best buy at about 25 cents per ounce. Buying 36 ounces at Option A’s unit price would cost about $10.47, so the large box saves roughly $1.48 for the same amount of cereal, and its unit price is about 14% lower than A’s.
Using shelf tags
Many US grocery stores print the unit price on the shelf tag, often in small type in a corner. The Uniform Unit Pricing Regulation in NIST Handbook 130, which many states adopt, sets out how those prices should be shown. Two things to watch for:
- Mismatched units. One tag may show price per ounce and the next price per pound, or price per count versus price per 100 sheets. Convert to the same unit before comparing — that is exactly what this calculator does when you type the sizes yourself.
- Sale prices. The unit price on the shelf usually reflects the regular price. Recompute when an item is on sale or you have a coupon.
Rates beyond shopping
| Situation | Unit rate |
|---|---|
| Earning $540 for 36 hours | $15 per hour |
| Typing 1,800 words in 40 minutes | 45 words per minute |
| Driving 336 miles on 12 gallons | 28 miles per gallon |
| Paying $114 for 950 kWh of electricity | $0.12 per kWh |
| Running 5 km in 27.5 minutes | 5.5 minutes per km (pace) |
Speed, pace and fuel economy each have dedicated tools — see the speed, distance and time calculator and the gas mileage calculator. For proportions such as “if 3 cost $7.50, what do 8 cost?”, the ratio calculator solves for the missing value directly.
Frequently asked questions
What is a unit rate?
A unit rate is a rate whose second quantity is 1: 60 miles per hour, $4 per pound, 25 words per minute. You get it by dividing the first quantity by the second.
How do I calculate unit price?
Divide the price by the number of units in the package. A $3.49 box holding 12 ounces costs 3.49 ÷ 12 ≈ $0.291 per ounce, or about 29 cents an ounce.
Is the bigger package always cheaper per unit?
Usually, but not always. Sales, coupons and package redesigns can make a smaller size cheaper per unit. Compare unit prices rather than assuming, and only buy the bigger size if you will use it.
Can a unit rate be a fraction or decimal?
Yes. Walking 3 miles in 50 minutes is 0.06 miles per minute, or 3.6 miles per hour. Choose the unit that makes the number easiest to understand.
What is the inverse of a unit rate?
Swap the two quantities. 60 miles per hour is the same as 1/60 hour, or one minute, per mile. Inverse rates are handy for pace (minutes per mile) and for cost comparisons (ounces per dollar).