Fuel Cost Calculator
Work out what a trip will cost in fuel: distance ÷ MPG × price per gallon. The price field is pre-filled with this week's official EIA national average of $4.33 for regular gasoline (week of 2026-10-12) ($6.18 diesel) — adjust it to your local price from gas prices by state.
Trip Cost
| Fuel used | –– |
| Trip fuel cost | –– |
| Cost per mile | –– |
| Round trip | –– |
Formula: (miles ÷ MPG) × price. More conversions on the energy tools page.
Quick reference (at $4.33/gal)
| Vehicle | ≈MPG | ¢/mile | 100 miles |
|---|
Annual Fuel Cost at This Week's Price
$4.33/gal · EIA week of 2026-10-12| Miles a year | 20 MPG | 25 MPG | 30 MPG | 40 MPG | 50 MPG |
|---|---|---|---|---|---|
| 8,000 | $1,732 | $1,386 | $1,155 | $866 | $693 |
| 12,000 | $2,599 | $2,079 | $1,732 | $1,299 | $1,039 |
| 15,000 | $3,248 | $2,599 | $2,166 | $1,624 | $1,299 |
| 20,000 | $4,331 | $3,465 | $2,887 | $2,166 | $1,732 |
Gallons used (miles ÷ MPG) times the EIA national average for regular gasoline. Typical US driving is around 12,000 miles a year. Each extra $1 a gallon adds about $480 a year at 12,000 miles and 25 MPG.
Gasoline vs Diesel: Cost of 100 Miles
| Fuel economy | Gasoline at $4.33 | Diesel at $6.18 | Diesel MPG needed to match gasoline cost |
|---|---|---|---|
| 20 MPG (gasoline) | $21.66 | $30.90 | 28.5 MPG |
| 25 MPG (gasoline) | $17.32 | $24.72 | 35.7 MPG |
| 30 MPG (gasoline) | $14.44 | $20.60 | 42.8 MPG |
| 35 MPG (gasoline) | $12.37 | $17.65 | 49.9 MPG |
| 40 MPG (gasoline) | $10.83 | $15.45 | 57.1 MPG |
The last column is how much better a diesel's fuel economy must be, as a percentage of the gasoline car's, to cost the same per mile at these two prices (diesel MPG = gasoline MPG × diesel price ÷ gasoline price). Diesel engines are typically 20–35% more efficient, so the break-even depends on the current gap, which is on diesel vs gasoline.
Fuel Cost FAQ
How do I calculate the fuel cost of a trip?
Divide the trip distance by your vehicle's fuel economy to get gallons used, then multiply by the price per gallon: cost = (miles ÷ MPG) × price. A 300-mile trip in a 30-MPG car at $3.50/gal costs (300 ÷ 30) × 3.50 = $35.
What MPG should I assume?
The average new US car achieves roughly 33 MPG window-sticker combined; the average vehicle actually on the road is closer to 25 MPG. SUVs and pickups typically run 18–25, hybrids 45–55. Real-world highway MPG at moderate speeds usually beats the EPA combined figure; speeds above ~70 mph and roof loads reduce it sharply.
How much does it cost per mile to drive?
Fuel alone at this week's $4.33 average: about 17¢ per mile at 25 MPG, or 11¢ at 40 MPG. Total driving cost including depreciation, insurance and maintenance runs several times higher — the IRS standard mileage rate (70¢/mi in 2025) is a common all-in benchmark.