Good compared to what
Twenty-two miles per gallon is disappointing in a Corolla, unremarkable in a Highlander and excellent in an F-250. The number on its own carries no information. Two comparisons do:
- Against vehicles of the same type. Useful when you are shopping.
- Against your own car's EPA rating. Useful when you already own it, which is the more common situation and the more actionable one.
Rough figures by body style
Real-world combined MPG for petrol vehicles, model year 2018 and newer. These are what people actually see, which sits below the sticker.
| Vehicle | Poor | Typical | Good |
|---|---|---|---|
| Compact car | under 27 | 30 to 34 | 36+ |
| Midsize sedan | under 24 | 27 to 31 | 33+ |
| Small crossover | under 23 | 25 to 29 | 31+ |
| Midsize SUV | under 19 | 21 to 24 | 26+ |
| Full-size SUV | under 15 | 16 to 19 | 21+ |
| Half-ton pickup | under 16 | 17 to 20 | 22+ |
| Minivan | under 19 | 21 to 24 | 26+ |
| Hybrid sedan | under 40 | 45 to 52 | 55+ |
| Hybrid crossover | under 32 | 35 to 40 | 42+ |
A diesel of the same size typically sits 20 to 30 percent above the petrol figures. Plug-in hybrids are not on this table on purpose: their MPG depends almost entirely on how often you charge, so a single figure would be meaningless.
The comparison that actually matters
Look up your exact model year, engine and drivetrain on fueleconomy.gov and take the combined figure. Then take your own average across at least five tanks. The gap between them is the only number worth acting on.
| You are getting | Verdict | Do this |
|---|---|---|
| Above the EPA combined | Good driving, or mostly motorway | Nothing |
| Within 10% below | Completely normal | Nothing |
| 10 to 20% below | Normal for city driving or winter | Check tyre pressure, remove the roof rack |
| 20 to 30% below | Something is off | Tyres, air filter, alignment, driving style, short trips |
| Over 30% below | Worth diagnosing | Oxygen sensor, dragging brake, misfire, thermostat stuck open |
One caveat on the bottom two rows: EPA figures for 2007 and earlier were calculated under an older, more generous method. Comparing a 2004 car against its original window sticker will always look bad. Use the adjusted figures on fueleconomy.gov instead.
What the gap is worth in money
At 12,000 miles a year and $3.29 a gallon:
| MPG | Gallons a year | Fuel a year | Against 25 MPG |
|---|---|---|---|
| 15 | 800 | $2,632 | +$1,053 |
| 20 | 600 | $1,974 | +$395 |
| 25 | 480 | $1,579 | -- |
| 30 | 400 | $1,316 | −$263 |
| 35 | 343 | $1,128 | −$451 |
| 45 | 267 | $878 | −$702 |
Notice how the savings flatten out. Going from 15 to 20 MPG saves $658 a year. Going from 35 to 45, a much bigger improvement on paper, saves $250. This is the trap in comparing MPG figures directly, and it is exactly why the rest of the world measures consumption per distance rather than distance per fuel: L/100 km is linear in money, MPG is not.