Fuel Cost Calculator

Enter distance, fuel consumption, and price to see what a trip costs in fuel. Supports km/L, MPG, and L/100km, and compares multiple vehicles.

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How to Use the Fuel Cost Calculator

Select your regional unit system or choose units individually. Enter your trip distance, vehicle fuel consumption, and current fuel price — the total fuel cost updates instantly. Use the “Solve for” toggle to calculate distance or required efficiency from a given budget. Expand the Vehicle Comparison section to see how different cars compare on the same trip. The CO₂ estimate shows the approximate carbon impact of the journey.

About This Tool

A practical fuel cost calculator for commuters, road trippers, and fleet managers. Supports all major fuel efficiency conventions: L/100km (Europe, Iceland, Australia), MPG US (United States), MPG UK (United Kingdom), and km/L (Japan, Asia). Regional presets auto-detect from your browser locale and switch all units simultaneously. The vehicle comparison mode lets you compare up to 4 vehicles on the same trip with a visual cost bar chart and savings callout. CO₂ emissions are estimated from standard combustion factors for petrol, diesel, and LPG. Trip history persists in your browser. Pair with a tool to run more advanced calculations for custom unit conversions, estimate monthly loan payments for financing a vehicle, or calculate future dates for trip planning.

Quick Reference Table

Unit	Region	Direction
L/100km	Europe, Iceland, Australia	Lower = more efficient
MPG (US)	United States	Higher = more efficient
MPG (UK)	United Kingdom	Higher = more efficient
km/L	Japan, India, Asia	Higher = more efficient
Conversion	L/100km → MPG (US)	235.215 / L/100km
Conversion	L/100km → MPG (UK)	282.481 / L/100km

Frequently Asked Questions

How do I convert between L/100km and MPG?

The conversion formulas are: MPG (US) = 235.215 / (L/100km), and L/100km = 235.215 / MPG (US). For UK MPG, use 282.481 instead of 235.215. For example, 8 L/100km is equivalent to 29.4 MPG (US) or 35.3 MPG (UK). This calculator converts automatically when you switch between unit systems.

Why does my car use more fuel than the official rating?

Official EU consumption figures are measured under the WLTP test cycle in laboratory conditions. Real-world consumption is typically 10–25% higher due to varying speeds, traffic conditions, climate, driving style, and vehicle age.

How is the CO₂ estimate calculated?

Burning one liter of petrol produces approximately 2.392 kg of CO₂, and one liter of diesel produces approximately 2.640 kg. The estimate here is for direct emissions from combustion only — it does not include upstream emissions from fuel production.

Can I save my common trips?

The calculator automatically saves your last 20 calculations in your browser’s local storage. Access them in the Trip History section. Saved trips are stored only in your browser and are never sent to a server.

Does this calculator work for electric vehicles?

This calculator is designed for petrol, diesel, and LPG vehicles. Electric vehicle efficiency is measured differently — in kWh per 100 km or miles per kWh. A dedicated EV cost calculator would need electricity price per kWh instead of fuel price per liter.

Created by The Toobits Team · Engineering & Editorial

Toobits is built, tested, and maintained by a small independent engineering team. Every tool is written in TypeScript, runs entirely in the browser, and is reviewed against its source formulas before publication.

Editorial policy · Updated April 2026

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