Unit Rate Calculator
Calculate the price per unit or compare two rates to find the better deal.
Essential for grocery shopping and cost comparisons.
Unit rate is the cost, speed, or quantity expressed per one unit of a reference measure. It is one of the most powerful everyday math tools — used in grocery shopping, budgeting, fuel economy, wages, and countless other comparisons.
Core formula:
Unit Rate = Total Value / Total Quantity
Price comparison formula:
Unit Price A = Price A / Quantity A
Unit Price B = Price B / Quantity B
The option with the lower unit price is the better deal (assuming equal quality).
Percentage savings:
Savings % = (Higher Unit Price − Lower Unit Price) / Higher Unit Price × 100
Worked example — grocery store comparison: Option A: 32 oz bottle of orange juice for $3.49 Option B: 64 oz bottle of orange juice for $5.99
- Unit price A = $3.49 / 32 = $0.109/oz
- Unit price B = $5.99 / 64 = $0.094/oz
- Option B saves $0.015/oz → 13.8% cheaper per ounce
Unit rate in everyday life:
| Scenario | Unit Rate | Formula |
|---|---|---|
| Fuel economy | Miles per gallon (MPG) | Total miles / gallons used |
| Hourly wage | Dollars per hour | Weekly pay / hours worked |
| Internet speed | Megabits per second | File size / download time |
| Population density | People per square mile | Population / area |
| Gas cost per mile | $/mile | Gas price / MPG |
| Grocery value | $/ounce or $/lb | Price / weight |
Speed as a unit rate:
Speed = Distance / Time
60 miles per hour means you travel 60 miles for every 1 hour elapsed.
This is a unit rate — distance per one unit of time.
Converting unit rates between systems:
- $/oz to $/lb: multiply by 16
- $/kg to $/lb: divide by 2.205
- MPG to km/L: multiply by 0.425
- km/L to MPG: multiply by 2.352
Practical shopping tip: Many grocery stores display the unit price on shelf labels (usually per ounce, per pound, or per 100g). When unit prices are shown, comparison takes seconds. When they are not shown — or when comparing different units — this calculator does it instantly.