Fuel Cost Calculator

Estimate trip fuel cost from distance, MPG, and gas price. Split costs per passenger and compare MPG what-ifs — free, instant driving math.

Reviewed / updated August 4, 2026

Your inputs

miles
MPG

Use highway MPG for long trips if your car lists both city/highway

USD/gal
people

Result

Estimated fuel cost

$39.43

11.4 gallons

Gallons needed
11.43
Cost per mile
$0.12
Per person
$39.43

Fuel for this trip is about $39.43 (11.4 gal). Pump price is near a static US average benchmark of ~$3.45/gal.

MPG what-if

MPGGallonsCost
2413.3$46.00
2811.4$39.43
3210.0$34.50

Suggested next steps

  • Efficient highway MPG helps — refine it from fill-ups with the Gas Mileage / MPG Calculator.
  • Split cost with passengers using the per-person figure when you’re ridesharing.
  • Round-trip? Double the distance (or run the calculator twice) for a full outing.

How the fuel cost calculation works

  1. Gallons = trip miles ÷ miles per gallon
  2. Total fuel cost = gallons × price per gallon
  3. Cost per mile = total ÷ miles
  4. Per person = total ÷ number of people splitting the tank

A small what-if table shows cost at MPG a bit lower and higher than your input so you can see sensitivity. Rule-based tips compare your pump price with a static US average benchmark and suggest efficiency checks when MPG is low.

Worked example

Distance 320 miles, 28 MPG, gas $3.45/gallon, 2 people:

  1. Gallons = 320 ÷ 28 ≈ 11.43
  2. Cost = 11.43 × 3.45 ≈ $39.43
  3. Per mile ≈ $0.12
  4. Per person ≈ $19.72

If MPG were 24 instead of 28, gallons rise to ~13.3 and cost rises to ~$46 — the scenario table highlights that jump.

Methodology and notes

All math runs in your browser. MPG varies with speed, load, weather, and maintenance. For fill-up-based efficiency math, use the Gas Mileage / MPG Calculator in this fuel cluster; for a fuller road-trip budget, open the Trip Cost Calculator.

Frequently asked questions

How do you calculate fuel cost for a trip?

Gallons needed = distance ÷ MPG. Fuel cost = gallons × price per gallon. Cost per mile = total fuel cost ÷ distance. This calculator updates those figures as you type.

Should I use city or highway MPG?

Use the figure that matches your trip. Highway MPG is usually better for long interstate drives; city MPG is more realistic for stop-and-go travel. Real-world MPG often lands between the two sticker numbers.

Does this include tolls, parking, or EV charging?

No. It estimates gasoline/diesel fuel cost only. Tolls, parking, food, and lodging belong in a broader trip budget — use the Trip Cost Calculator for that fuller estimate.

Why compare to an average gas price?

We keep a static US average pump-price benchmark in the app for a quick “am I paying more/less than typical?” cue. It is not a live AAA feed — update the price field with what you actually see locally.

Related tools

Related calculators — live tools and upcoming pages for internal linking.