How Multiple Fill-Up MPG Calculator Works?
This tool works by dividing the total miles driven across several fill-ups by the total gallons pumped. The result is a long-term average miles per gallon (MPG).
Log each fill-up
Record miles and gallons at every fill-up for 3 to 5 tanks.
Add the miles
Total the miles across all tanks. The default is 1,120 miles (1,802 km).
Add the gallons
Total the gallons pumped. The default is 37.5 gallons (142 L).
Enter the totals
Type both totals. The tool returns the average MPG.
Multiple Fill-Up MPG Calculator Formula
The formula is Average MPG = Total Miles ÷ Total Gallons.
Average MPG = Total Miles ÷ Total GallonsFormula variables
- Total Miles
- Sum of miles across all logged tanks.
- Total Gallons
- Sum of gallons pumped across the same tanks.
Worked example
- Total Miles Across Refills: 1,120 miles
- Total Gallons Pumped: 37.5 gal
- Divide 1,120 miles by 37.5 gallons: 1,120 ÷ 37.5 = 29.87 MPG.
Result: 29.87 (Average MPG)
Averaging the MPG of each tank gives a slightly wrong answer when tanks differ in size. Dividing total miles by total gallons weights each tank correctly.
Multiple Fill-Up MPG Calculator Conversion Table
The table shows average MPG for 4 total distances and 4 total fuel amounts.
Rows: Total Miles Across Refills (miles). Columns: Total Gallons Pumped (gal). Cells: Average MPG.
| miles | 30 gal | 37.5 gal | 50 gal | 65 gal |
|---|---|---|---|---|
| 800 miles | 26.67 | 21.33 | 16.00 | 12.31 |
| 1,120 miles | 37.33 | 29.87 | 22.40 | 17.23 |
| 1,500 miles | 50.00 | 40.00 | 30.00 | 23.08 |
| 2,000 miles | 66.67 | 53.33 | 40.00 | 30.77 |
2,000 miles (3,219 km) on 50 gallons (189 L) averages 40 MPG, while the same distance on 65 gallons averages 30.77 MPG.
What is Multiple Fill-Up MPG Calculator?
The Multiple Fill-Up MPG Calculator is a tool that finds average fuel economy over several tanks of fuel. The multi-tank average smooths out single-tank errors.
Single tanks vary with weather, traffic, and pump shutoff points. Averaging across 3 or more tanks gives a figure that reflects real-world driving.
The tool needs 2 totals, which come from a fuel log, a spreadsheet, or a fuel app.
What are the uses of Multiple Fill-Up MPG Calculator?
There are 4 main uses of the Multiple Fill-Up MPG Calculator: finding a true average MPG, comparing seasons, reporting fleet averages, and checking new car break-in.
Finding a true average MPG
Owners use the average for all cost calculators.
Comparing seasons
Drivers compare summer and winter averages.
Reporting fleet averages
Fleet managers report average MPG per vehicle each month.
Checking new car break-in
Owners track MPG rising over the first 3,000 miles.
Need every metric in one place? Open the main MPG Cost Calculator or browse all 101 fuel calculators.