How to use this calculator
Replace the example values with your own measurements or specifications. Keep the units shown beside each label. Results update as you type; reset restores the example.
The monthly result is an average, not a bill forecast. Seasonal driving and changing pump prices will affect actual spending. This is fuel expense only.
The formula
A worked example
U.S. example: 12,000 miles at 30 mpg and $3.50/gallon costs $1,400 per year. Metric example: 20,000 km at 8 L/100 km uses 1,600 liters. At $1.60/liter, that costs $2,560 per year, or $213.33 per month. UK example: 12,000 annual miles at 40 Imperial mpg and £1.50/litre costs £2,045.74 per year.
Common questions
How do I estimate annual miles?
Compare odometer readings taken a year apart, or multiply a representative monthly distance by 12.
Does this include maintenance?
No. It includes only the fuel entered in the calculator.
Can I enter kilometers and liters?
Yes. Choose Metric, then enter distance in km, consumption in L/100 km, and price per liter. Use the fuel-economy converter if your vehicle figure is in MPG or km/L.
Does switching systems convert my inputs?
No. It changes which units describe your inputs. Replace the numbers with readings in the selected system.
Can I calculate UK petrol or diesel costs?
Choose UK and GBP. Enter miles, Imperial MPG, and pounds per litre. Do not mix U.S. MPG with Imperial MPG or enter pence as pounds.
Does selecting GBP or EUR apply an exchange rate?
No. Currency selection labels and formats the amount only. Enter your actual pump price in that currency.
Sources & calculation method
Related guidance: U.S. DOE / EPA: fuel economy and driving. Accessed September 9, 2026. The equation above describes this tool’s model; the reference provides practical context and does not endorse this site.
Formula examples and input validation have automated checks. This page has not received an independent automotive professional review. Read our review standards.