MPG Calculator
MPG Calculator. Calculate mileage from distance and gallons. Enter your values and view the result.
MPG Calculator
Calculate mileage from distance and gallons.
Use the calculation engine below to model your exact costs with custom fuel prices, distances, and vehicle efficiencies:
MPG Calculator: inputs
Adjust sliders or enter exact figures
Monthly Fuel Budget
Real-Time Visual Breakdown
Comparing your expense against alternative vehicle classes
Price Fluctuation Stress Test
See how unexpected gas price surges would impact your monthly budget
How MPG Calculator Works
This tool works by dividing the miles driven by the gallons of fuel used to cover those miles.
- Step 1
Fill the tank and reset the trip meter
Fill the tank to the first click and set the trip odometer to 0.
- Step 2
Drive normally
Drive until the tank is at least half empty for a reliable result.
- Step 3
Refill and record
Fill to the first click again and note the gallons added and the trip miles.
- Step 4
Read the MPG
The calculator divides miles by gallons and shows MPG with metric equivalents.
MPG Calculator Formula
The formula divides miles driven by gallons used.
MPG = Miles Driven ÷ Gallons Used
L/100 km = 235.215 ÷ MPG
- Miles Driven
- = trip odometer reading between fill-ups
- Gallons Used
- = US gallons added at the second fill-up
- 235.215
- = conversion constant between US MPG and L/100 km
Worked Example
- A driver resets the trip meter, drives 342.6 miles (551.4 km), and refills with 11.4 gallons (43.2 liters).
- MPG = 342.6 ÷ 11.4 = 30.1 MPG.
- Metric equivalent = 235.215 ÷ 30.1 = 7.8 L/100 km (12.8 km/L).
- The result reflects real driving, which often lands 5% to 15% below the window sticker.
MPG Calculator Conversion Table
The table is a lookup grid of MPG values for common combinations of miles driven and gallons used.
| Gallons Used | 200 mi | 250 mi | 300 mi | 350 mi | 400 mi | 450 mi |
|---|---|---|---|---|---|---|
| 6 gal (22.7 L) | 33.3 | 41.7 | 50.0 | 58.3 | 66.7 | 75.0 |
| 8 gal (30.3 L) | 25.0 | 31.3 | 37.5 | 43.8 | 50.0 | 56.3 |
| 10 gal (37.9 L) | 20.0 | 25.0 | 30.0 | 35.0 | 40.0 | 45.0 |
| 12 gal (45.4 L) | 16.7 | 20.8 | 25.0 | 29.2 | 33.3 | 37.5 |
| 14 gal (53.0 L) | 14.3 | 17.9 | 21.4 | 25.0 | 28.6 | 32.1 |
| 16 gal (60.6 L) | 12.5 | 15.6 | 18.8 | 21.9 | 25.0 | 28.1 |
What is an MPG Calculator?
An MPG Calculator is a fuel economy tool that calculates miles per gallon from distance driven and gallons used.
MPG is the standard US measure of fuel economy. Window stickers show rated MPG from laboratory tests, while the MPG Calculator shows the economy a car delivers in real use. Real MPG is the input every fuel budget needs.
Repeat the calculation over 3 or more fills and average the results for a stable figure.
What are the uses of an MPG Calculator?
There are 4 main uses of the MPG Calculator, including real economy checks, budget inputs, and problem detection.
Check real fuel economy
Compare real MPG with the window sticker.
Feed fuel budgets
Use measured MPG in every cost calculation.
Detect problems
Spot a sudden MPG drop that points to a fault.
Test driving changes
Measure MPG before and after changing driving habits.