How to use this calculator
Enter your total trip distance in miles, your vehicle's fuel economy (MPG), your tank size in gallons, and the current gas price. Not sure about your MPG or tank size? Use the quick presets for common vehicle types — they'll get you a solid ballpark.
Set your starting fuel level so the calculator knows when you'll need your first stop. The results show total cost, gallons needed, and a stop-by-stop breakdown so you can plan your trip with confidence.
How fuel cost is calculated
The math is simple: divide your trip distance by your MPG to get total gallons needed, then multiply by the gas price. For a 500-mile trip at 25 MPG and $3.50/gallon: 500 ÷ 25 = 20 gallons × $3.50 = $70.00 total.
Fuel stops are calculated by tracking your range — miles per gallon times tank size. The calculator builds in a safety buffer (1/8 tank) so you're never cutting it dangerously close to empty. Each stop assumes a fill-up to full.
Average tank sizes by vehicle type
| Vehicle Type | Avg. Tank Size | Avg. MPG (Hwy) | Range |
|---|---|---|---|
| Compact Sedan | 12 gal | 35 MPG | ~420 mi |
| Midsize Sedan | 14 gal | 30 MPG | ~420 mi |
| SUV (Midsize) | 18 gal | 26 MPG | ~468 mi |
| Full-Size SUV | 24 gal | 20 MPG | ~480 mi |
| Pickup Truck | 26 gal | 22 MPG | ~572 mi |
| Minivan | 20 gal | 24 MPG | ~480 mi |
| Hybrid Sedan | 11 gal | 48 MPG | ~528 mi |
Frequently asked questions
How do I find my car's MPG?
Check your owner's manual, the sticker inside your driver's door, or search your year/make/model on fueleconomy.gov. Most cars also show real-time or average MPG on the dashboard trip computer.
Should I use city or highway MPG?
For road trips that are mostly highway driving, use the highway MPG rating. If your route includes significant city driving, use the combined rating. When in doubt, use the combined number for a conservative estimate.
Why does the calculator leave a safety buffer?
Running on fumes is risky — you might miss a gas station, hit unexpected traffic, or need to detour. The 1/8 tank buffer ensures you always have roughly 30–50 miles of range when the calculator suggests a stop.
How accurate is this estimate?
This calculator gives you a solid planning estimate. Actual costs can vary 5–15% based on driving speed, terrain, weather, vehicle load, and tire pressure. It's designed to help you budget — not replace your gas gauge.