Free · Ratios and rates
Unit Rate from Two Quantities
Divide one quantity by a nonzero second quantity, or recover a quantity from a known rate.
- Formula & worked example
- Private in your browser
- No signup
Calculator inputs
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How to use this calculator
- Enter the known values in the units shown. Results update as you type.
- Where results are editable, change one to solve backwards. Lock a value to hold it fixed.
- Use the worked example to check the method. Reset restores the starting fields.
Private by default
Inputs and results stay in this browser tab. Bookify does not upload or store the values you enter.
Formula and method
180 miles over 3 hours gives 60 miles per hour. The calculator divides 180 by 3; you supply the meaning of the units.
Unit rate = quantity A ÷ quantity B
Worked example
Enter these known values and leave the other values blank.
- Quantity A — numerator
- 180
- Quantity B — denominator
- 3
- A-units per one B-unit
- 60
Assumptions and limitations
- The denominator must be nonzero. Signed values are allowed for mathematical rates; physical quantities may require additional constraints.
- No unit conversion is performed. Convert quantities to consistent units before entry and attach numerator-units per denominator-unit to the result.
- When both numerator and rate are zero, the denominator is not uniquely determined.
Common questions
Does the calculator know whether I entered miles or kilometers?
No. It performs the ratio arithmetic. You assign units and convert them before calculating.
Can I calculate a total from a rate?
Yes. Enter the rate and denominator quantity; the numerator is their product.
References
The calculation equations, inverse formulas, units, and input rules were imported from this source. Bookify provides the interface and equation solver.