How is this calculated?
MPG (US) = miles driven / US gallons used MPG (Imperial) = miles driven / Imperial gallons used km/L = kilometers driven / liters used L/100 km = (liters used / kilometers driven) * 100 Cost per mile = fuel price per gallon / MPG
Example: a car that travels 312 miles on 11.2 gallons gets 27.9 MPG. At $3.60 per gallon, fuel costs about $0.13 per mile and the fill-up costs $40.32.
How do I use this calculator?
- Choose the unit or currency setting that matches your vehicle data.
- Enter the required vehicle, route, fuel, weight or loan values in the calculator form.
- Review inline warnings and correct any missing or negative inputs.
- Read the live result card for the primary answer and supporting totals.
- Use the worked example if you want to check the formula with sample values.
- Copy, share or print the results for comparison or record keeping.
What do the terms mean?
- MPG
- Miles per gallon, the common US fuel economy measure.
- Imperial gallon
- A UK gallon equal to about 1.20095 US gallons.
- L/100 km
- Liters consumed to drive 100 kilometers; lower is better.
- km/L
- Kilometers traveled per liter; higher is better.
- Cost per mile
- Fuel price divided by MPG, before maintenance and depreciation.
What are real-world examples?
| Scenario | Inputs | Result | Notes |
|---|---|---|---|
| Compact sedan | 312 mi, 11.2 gal | 27.9 MPG | $0.13/mi at $3.60 |
| SUV | 285 mi, 14.8 gal | 19.3 MPG | $0.19/mi at $3.60 |
| Hybrid | 510 mi, 10.5 gal | 48.6 MPG | $0.07/mi at $3.60 |
| Metric hatchback | 620 km, 38 L | 6.13 L/100 km | 16.3 km/L |
What tips improve accuracy?
- Reset the trip meter at every fill-up for cleaner data.
- Use the same pump shutoff method to reduce fill variation.
- Track several tanks; one tank can be skewed by idling, wind or towing.
- Compare L/100 km carefully because lower is better, unlike MPG.
- For fleet work, record odometer, gallons, price and driver notes.
- Cold tires, roof racks and aggressive acceleration can reduce MPG.
Did you know? EPA estimates commonly use 8.89 kg CO2 per gallon of gasoline and 10.18 kg CO2 per gallon of diesel for tailpipe carbon dioxide calculations.
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Frequently asked questions
Is this calculator free to use?
Yes. The calculator runs in your browser, does not require an account and can be printed or copied for your records.
Can I use this for official tax, loan or compliance filing?
Use it as an estimate. For official filing, financing or enforcement decisions, verify the final numbers with your lender, tax authority, manufacturer rating label or compliance professional.
Why are my real-world results different?
Real vehicles vary with load, speed, terrain, temperature, tire condition, maintenance, driver behavior and measurement quality.
Does the calculator save my units?
Yes. Unit and currency selections that are marked as preferences are stored in localStorage on your device so the next visit starts with your preferred setting.
Can I share the result?
Yes. Use the Share button if your browser supports native sharing, or copy the permalink and result summary.
Does it work on mobile?
Yes. The layout stacks on small screens, keeps labels visible and recalculates as you type.
How accurate are the formulas?
The formulas are standard industry math for estimates. Accuracy depends on the input values and whether the assumptions match your vehicle and jurisdiction.
When was this page updated?
This page was last updated on 2026-05-01 for 2026 planning assumptions and source links.