Fuel Savings Calculator
Find out what your driving costs each month, then see what using a little less fuel would be worth over a year. Works with MPG, L/100 km or km/L.
Estimate your fuel costs and savings
Change units and currency
Your trip computer or a fill-up log gives the most realistic figure.
You could save approximately $12.50 per month and $150.00 per year.
- Current monthly cost
- $125.00
- Improved monthly cost
- $112.50
- Reduction
- 10%
- Fuel used now
- 35.7 gal/month
- Fuel used after
- 32.1 gal/month
- Economy needed
- 31.1 MPG
Actual savings depend on driving conditions, vehicle condition, fuel prices and the improvement you achieve. This is an estimate, not a guarantee.
How the calculation works
The calculator uses three simple steps:
- Fuel used = distance ÷ fuel economy (for L/100 km: distance × L/100 km ÷ 100)
- Monthly cost = fuel used × fuel price
- Saving = monthly cost × your expected reduction in fuel use, then × 12 for the year
Units are converted behind the scenes, so you can enter miles with a price per litre, or kilometres with MPG, and still get a consistent answer. The “economy needed” figure shows the fuel economy you’d have to average to reach that saving.
Check a cheaper fuel station
A lower price on the sign only saves money if the detour doesn’t burn the difference. Enter both prices and the extra distance to find out.
Is the cheaper fuel station actually cheaper?
Compare the price saving with the fuel you burn getting there and back.
Usually your tank size minus what's left in it.
Only the detour beyond your normal route.
Worth it: you’d come out about $0.94 ahead.
- Saving from the lower price
- $1.68
- Fuel cost of the detour
- $0.74 (0.21 gal)
- Net saving
- $0.94
- Break-even detour
- 13.6 mi round trip
This counts fuel only. Your time, queues and wear on the car aren’t included.
How to reach your target
Smoother driving, correct tyre pressures and fewer short trips are some of the most reliable ways to use less fuel. Our guide explains each habit in detail and what the evidence says.
Fuel savings calculator FAQs
How is the monthly fuel cost calculated?
The calculator converts your distance and fuel economy into the amount of fuel you use each month, then multiplies that by your fuel price. For example, 1,000 miles at 25 MPG uses 40 gallons; at $3.50 a gallon that is $140 a month.
What reduction percentage should I use?
There is no universal figure, because it depends on how you drive now and which habits you change. Starting with a small figure such as 5% or 10% gives a conservative estimate. You can then track your real fuel economy over a few fill-ups to see what you actually achieve.
Which fuel economy units does the calculator support?
MPG using US gallons, MPG using UK (imperial) gallons, litres per 100 km and kilometres per litre. Distance can be in miles or kilometres, and the fuel price can be per litre, US gallon or UK gallon, in several currencies.
Results are estimates. Actual savings depend on driving conditions, vehicle condition, fuel prices and the improvement you achieve.