How is this calculated?
L/100 km = 235.215 / MPG (US) L/100 km = 282.481 / MPG (Imperial UK) MPG (US) = 235.215 / L/100 km km/L = MPG (US) * 0.425144 mi/L = MPG (US) / 3.78541
Example: 30 US MPG equals 7.84 L/100 km, 12.75 km/L and 7.93 miles per liter. In Imperial MPG, the same 7.84 L/100 km equals about 36.0 MPG.
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?
- US MPG
- Miles per US gallon.
- Imperial MPG
- Miles per UK gallon; numerically higher than US MPG.
- L/100 km
- Liters used per 100 kilometers; lower means better economy.
- km/L
- Kilometers per liter; higher means better economy.
- mi/L
- Miles per liter, useful for mixed unit comparisons.
What are real-world examples?
| Scenario | Inputs | Result | Notes |
|---|---|---|---|
| Efficient hybrid | 50 US MPG | 4.70 L/100 km | 21.26 km/L |
| Family SUV | 24 US MPG | 9.80 L/100 km | 10.20 km/L |
| European listing | 6.5 L/100 km | 36.2 US MPG | 15.38 km/L |
| UK figure | 45 Imperial MPG | 6.28 L/100 km | 37.5 US MPG |
What tips improve accuracy?
- Remember that lower L/100 km is better, while higher MPG is better.
- Imperial MPG is about 20% higher than US MPG for the same fuel use.
- Use US MPG for EPA labels and Imperial MPG for many UK references.
- Round converted figures to one decimal for shopping comparisons.
- Do not compare lab ratings directly to loaded towing or city bus usage.
- Use km/L when budgeting fuel in countries that price fuel by liter.
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.