How to Calculate Gas Cost
The formula for US units is:
Fuel Cost = (Distance ÷ MPG) × Gas Price
A 500-mile trip at 30 MPG and $3.50/gallon: (500 ÷ 30) × $3.50 = $58.33.
For metric units: Fuel Cost = (Distance ÷ 100) × L/100km × Price per liter.
Fuel Efficiency by Vehicle Type
| Vehicle Type | Average MPG | L/100km | Cost per 100 mi* |
|---|---|---|---|
| Compact Car | 35 | 6.7 | $10.00 |
| Midsize Sedan | 30 | 7.8 | $11.67 |
| SUV | 25 | 9.4 | $14.00 |
| Pickup Truck | 20 | 11.8 | $17.50 |
| Hybrid | 50 | 4.7 | $7.00 |
* Based on $3.50/gallon
Saving Money on Gas
- Keep tires properly inflated. Under-inflated tires lower fuel economy by about 3%.
- Remove excess weight from the trunk. Every 100 lbs reduces MPG by about 1%.
- Use cruise control on highways to maintain consistent speed.
- Avoid aggressive acceleration and hard braking.
- Plan routes to minimize distance. Combining errands into one trip saves more than you think.
Want to see how gas savings compound over time? Run the numbers on our compound interest calculator — investing $100/month in gas savings at 7% for 20 years grows to over $52,000.
Gas vs. Electric: Cost Comparison
A gas car at 30 MPG and $3.50/gal costs about $0.117 per mile. An EV averaging 3.5 mi/kWh at $0.16/kWh costs $0.046 per mile — 60% less. Use our electricity cost calculator to estimate EV charging costs.