A unit rate expresses one quantity per single unit of another: pounds per kilogram, miles per hour, cost per person. Reducing to a rate is what makes two differently sized offers comparable, since a bigger pack at a bigger price tells you nothing until both are on the same footing.
Two details catch people out. First, the direction matters: 3.75 per kilogram and 0.267 kilograms per pound are the same relationship read two ways, and the reciprocal is often the more natural framing — litres per 100 km rather than km per litre, for instance. Second, the larger pack is not always cheaper per unit. Retailers price on convenience and shelf position as much as volume, and a meaningful share of multipacks work out dearer per unit than the single. This page computes both rates and compares a second option directly so the answer is not left to inference.
The formula
total- The full amount — cost, distance or any measured total
quantity- How many units that total covers
unit rate- The total divided by the quantity
reciprocal- Quantity per unit of total, the same rate read the other way
How it works, step by step
- Enter the total and the quantity it covers.
- Enter a second option to compare, or leave it as it is.
- The gauge shows the rate per single unit.
- The comparison below says which of the two options is better value.
Worked examples
15.00 for 4 units against 26.00 for 7
The first works out at 3.7500 per unit and the second at 3.7143. The second is cheaper by 0.95% per unit, despite the higher headline price.
When the bigger pack is dearer
A 500 g pack at 2.20 is 4.40 per kilogram, while a 1.2 kg pack at 5.60 is 4.67. Here the small pack wins by 5.7%, which is why unit pricing on shelf labels is a legal requirement in many places.
How to read your score
Frequently asked questions
Why compare unit rates rather than totals?
Because totals confound price with quantity. Reducing both offers to the same denominator is the only way to see which is genuinely cheaper, and it takes one division each.
Is the bigger pack always better value?
No. It usually is, but far from always — pricing reflects convenience, packaging and shelf competition as much as volume. Checking takes seconds and the exceptions are common enough to be worth the habit.
What is the reciprocal rate for?
It answers the mirrored question: how much you get per unit of spend, or how far you travel per litre. Some domains conventionally use one direction and some the other, and fuel economy is quoted both ways in different countries.
Does this work for rates other than price?
Yes. Any total divided by any quantity gives a rate — miles per hour, words per minute, people per square kilometre. The arithmetic does not care what the units are.
Unit rates across pack sizes
| Total | Quantity | Rate per unit | Per 100 units |
|---|---|---|---|
| 15.00 | 4 | 3.7500 | 375.00 |
| 26.00 | 7 | 3.7143 | 371.43 |
| 2.20 | 0.5 | 4.4000 | 440.00 |
| 5.60 | 1.2 | 4.6667 | 466.67 |
| 9.99 | 3 | 3.3300 | 333.00 |
| 19.50 | 6 | 3.2500 | 325.00 |
| 44.00 | 15 | 2.9333 | 293.33 |
The lowest figure in the third column is the best value regardless of how the headline prices compare.