Fuel consumption calculator
Litres per 100 km from a fill-up, or the fuel a trip will need.
Fill in the fields and the result will appear here automatically.
Takes the litres you actually put in and the distance you actually covered, and turns them into consumption. The reciprocal figure in kilometres per litre appears alongside because people ask for it, and a third mode works forwards instead: give a distance and a known consumption and it returns the fuel required.
How it works
Formula and logic
litres per 100 km = litres ÷ kilometres × 100; fuel for a trip is distance ÷ 100 × consumption. Both L/100 km and km/L modes require litres and kilometres; fuel required uses kilometres and L/100 km. All active quantities are positive. Required fuel = distance·consumption/100; it is not a prediction of an actual journey.
Example
42 litres over 560 km is 42 ÷ 560 × 100 = 7.5 litres per 100 km.
Fields and units
- What to calculate — list option
- Litres used — L
- Distance, km — km
- Consumption, L/100 km — L/100 km
How to use
- — Choose what you want to work out.
- — Fill the tank, drive, and note the litres and kilometres.
- — For measurement modes enter litres and km; for fuel needed enter km and consumption in L/100 km.
Method and limitations
- Calculation method
- Formula and logic
- Data or methodology source
- Kia GEN017: refill-and-distance fuel measurement; manufacturer bulletin hosted by NHTSA
- Limitation
- Required fuel = distance·consumption/100; it is not a prediction of an actual journey.
FAQ
Is this a miles-per-gallon converter?
No. It computes consumption from the litres and kilometres you measured. Converting between L/100 km and mpg is a separate job that needs a reciprocal conversion.
Why does my figure differ from the on-board computer?
The dashboard estimates consumption from its own data; a refill measurement uses distance and added fuel. Resets, fill level and measurement conditions affect the comparison. Neither systematic under-reading nor one method always being more accurate can be assumed.
Should I measure over one tank or several?
Several comparable fills help reduce random fill-level differences. Add the litres and kilometres, then calculate 100·Σlitres/Σkilometres. An unweighted mean of separate rates is wrong when distances differ. No universal minimum distance guarantees accuracy.
Are city and motorway figures different?
Substantially. The calculator uses only what you enter, so measure the kind of driving you actually want to know about.