Gas Trip Cost Calculator
Find the total fuel cost of any road trip from the trip distance, your MPG, and current gas prices.
What is Gas Trip Cost Calculator?
Planning a road trip? The gas trip cost calculator estimates how much fuel you will burn and what it will cost, so you can budget accurately and split the bill fairly with your travel companions.
Formula
Gallons needed = total miles ÷ MPG
Total cost = gallons × price per gallon
Per-person cost = total cost ÷ number of travelers
Worked example
A 500-mile round trip (1,000 miles total) in a car getting 28 MPG at $3.45/gal split between 4 people:
- Gallons = 1,000 / 28 ≈ 35.7
- Total cost = 35.7 × $3.45 ≈ $123.21
- Per person ≈ $30.80
How to use this calculator
- Enter your one-way distance. Google Maps gives you this in seconds.
- Enter your vehicle's MPG — use your real-world average (from the MPG calculator), not the sticker number.
- Enter the current gas price. GasBuddy and AAA show the national average.
- Choose round-trip and the number of riders who will chip in.
Tip: add ~10% to the estimate for realistic highway trips to account for detours, idling, and traffic.
Frequently asked questions
Does this include tolls?
No, only fuel. Many road trip routes have significant tolls (e.g., I-95 on the East Coast). Check your route on a toll calculator separately — it can add $30–$100+ to a long trip.
How accurate is my MPG for highway driving?
Highway MPG is usually 10–20% higher than combined city+highway MPG. If you know your highway-only figure (many cars display it), use that for road trip estimates. Otherwise, assume ~10% above combined.
What about EVs on a road trip?
For electric cars, use cost per kWh × kWh per mile × miles. A Tesla Model 3 uses about 250 Wh/mi. At $0.30/kWh public charging, that is about $0.075/mile — similar to a 46-MPG gas car at $3.45/gal.
Why does my actual cost always come out higher?
Rest stops, detours, elevation (mountain driving cuts MPG substantially), running the AC, and heavy loads all eat fuel. Add a 10–15% buffer to any online estimate for real-world driving.