How to use this calculator
- Enter your own values in the labeled fields. Check the units and assumptions before comparing results. Only the fields needed for your selected calculation mode are shown.
- Your answer updates automatically. Review the calculation steps to see exactly how it was calculated.
- Copy, share, save, or download your result. Saved inputs stay on this device.
How the calculation works
Measure fuel and distance over the same interval. A tank-to-tank calculation depends on comparable fill levels, while dashboard estimates can follow other methods. Liters per hundred kilometers measures consumption, so lower is better; miles per gallon measures economy, so higher is better. Exact unit definitions connect the two.
A worked example
500 km using 35 L gives 35 ÷ 500 × 100 = 7 L/100 km.
Reading your result
Use the main result together with its units and supporting figures. Display values are rounded; calculations keep their underlying precision. A change in inputs or assumptions can change the answer. Compare the step-by-step working with your intended use before relying on an estimate.
Frequently asked questions
Why are US MPG and Imperial MPG different?
The gallon volumes differ. Imperial gallons are larger.
Can I enter only the amount bought?
It should represent fuel actually used over the measured distance.
Sources & methodology
NIST: international unit conversion factors ↗
Formula review: October 24, 2026. Read our methodology.