To calculate MPG, divide the miles you drove by the gallons you used — for example 320 miles ÷ 11.5 gallons = 27.8 MPG. Fuel cost per mile is gas price ÷ MPG, so a 24-mpg car at $3.50/gal costs about $0.15/mile. A good MPG is anything above the ~24 mpg average of a new car; hybrids clear 45–57 mpg. Use the calculator above for your exact numbers.
In our copy of the EPA database the average new vehicle went from 19 mpg in 1990 to 42.4 today — a 123% jump. But strip out electrics and plug-ins, and cars that actually burn fuel only went from 19 to 22.5 mpg — 18% in 37 years. Almost all of the headline improvement is electrics, now 25% of new models rated. At 15,000 miles a year that 18% is worth about $430 a year in fuel. Calculated from 49,972 EPA ratings.
Fuel economy over time
Average combined rating of every vehicle EPA tested, by model year. The line climbs steeply after 2020 — that's electrics entering the average, not engines suddenly getting better.
Counting only vehicles that burn fuel, the same span goes from 19 to 22.5 mpg. Use the calculator above with both numbers — the difference in annual fuel cost is smaller than the headline suggests.
How to calculate MPG
MPG (miles per gallon) is miles driven ÷ gallons of fuel used. To measure your real-world number:
- Fill up completely and reset your trip odometer (or note the reading).
- Drive normally until you're ready to refuel — more miles = more accurate.
- Fill up again and note the gallons the pump added and the miles since the last fill.
- Divide miles by gallons — that's your real MPG. The calculator above does it instantly, with your cost.
Example: 320 miles on 11.5 gallons = 27.8 MPG. Real-world MPG usually runs a bit below the EPA sticker — this shows what you actually get.
Fuel cost by MPG — per year
What a year of driving costs at each MPG level (15,000 miles a year, $3.50/gal), and what you'd save versus a typical 24-mpg car — a quick reference before you plug in your own numbers:
| MPG | Fuel / year | Fuel / month | vs 24-mpg car |
|---|---|---|---|
| 15 mpg | $3,500 | $292 | +$1,313 |
| 18 mpg | $2,917 | $243 | +$729 |
| 20 mpg | $2,625 | $219 | +$438 |
| 22 mpg | $2,386 | $199 | +$199 |
| 25 mpg | $2,100 | $175 | −$88 |
| 28 mpg | $1,875 | $156 | −$313 |
| 30 mpg | $1,750 | $146 | −$438 |
| 35 mpg | $1,500 | $125 | −$688 |
| 40 mpg | $1,313 | $109 | −$875 |
| 45 mpg | $1,167 | $97 | −$1,021 |
| 50 mpg | $1,050 | $88 | −$1,138 |
Going from 24 to 40 mpg saves roughly $875/year at these assumptions. Change the gas price and mileage in the calculator above for your own figures.
MPG is a number. Dollars per year is the answer.
- Fuel profile built from your actual mileage and local prices
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Cheapest cars to fuel right now
The 2026 models with the lowest annual fuel cost (EPA estimate at ~15,000 mi/yr) — what the calculator would show for a full year of driving each:
| # | Car | Annual fuel | Combined MPG |
|---|---|---|---|
| 1 | Toyota Prius | 57 mpg | |
| 2 | Hyundai Elantra | 54 mpg | |
| 3 | Kia Niro | 53 mpg | |
| 4 | Toyota Camry | 51 mpg | |
| 5 | Hyundai Sonata | 51 mpg | |
| 6 | Honda Civic | 49 mpg | |
| 7 | Toyota Corolla | 50 mpg | |
| 8 | Honda Accord | 48 mpg | |
| 9 | Honda Prelude | 44 mpg | |
| 10 | Lexus UX | 43 mpg |
See the full best MPG ranking, by type (SUVs, hybrids), or the most efficient cars under $25k.
Is your MPG good?
The average new car in 2026 gets about 24 mpg combined. Above that beats the pack; hybrids clear 45–57 mpg. See what's a good MPG by car type. The most fuel-efficient new cars right now:
- Toyota Prius — 57 mpg combined
- Hyundai Elantra — 54 mpg combined
- Kia Niro — 53 mpg combined
- Hyundai Sonata — 51 mpg combined
- Toyota Camry — 51 mpg combined
MPG conversions
US MPG converts to the metric and UK figures like this — divide 235.21 by your MPG for L/100km, or multiply by 1.201 for UK (imperial) MPG:
| US MPG | L/100km | km/L | UK MPG |
|---|---|---|---|
| 20 US mpg | 11.8 L/100km | 8.5 km/L | 24.0 UK mpg |
| 25 US mpg | 9.4 L/100km | 10.6 km/L | 30.0 UK mpg |
| 30 US mpg | 7.8 L/100km | 12.8 km/L | 36.0 UK mpg |
| 35 US mpg | 6.7 L/100km | 14.9 km/L | 42.0 UK mpg |
| 40 US mpg | 5.9 L/100km | 17.0 km/L | 48.0 UK mpg |
| 45 US mpg | 5.2 L/100km | 19.1 km/L | 54.0 UK mpg |
| 50 US mpg | 4.7 L/100km | 21.3 km/L | 60.0 UK mpg |
MPG calculator — FAQ
How do I calculate MPG?
Divide the miles you drove by the gallons of fuel you used: MPG = miles ÷ gallons. Fill up, drive, fill up again, then divide the miles since the last fill by the gallons it took.
What is a good MPG?
Above the ~24 mpg average of a new car is good; 40+ mpg is excellent and usually means a hybrid. SUVs and trucks average lower — see best MPG by class.
Why is my real MPG lower than the EPA rating?
EPA numbers come from standardized lab tests. Real driving — cold starts, traffic, speed, AC, cargo and terrain — usually lands a few MPG below the sticker. This calculator shows your actual mileage.
How do I calculate fuel cost?
Cost per mile = gas price ÷ MPG. For a trip, multiply by the distance; for a year, by your annual miles. The calculator does all three once you add a gas price.
How do I convert MPG to L/100km?
Divide 235.21 by your MPG — e.g. 30 MPG ≈ 7.8 L/100km.
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