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Fuel Cost Calculator

What a trip costs in gas, MPG or L/100km, round trip, and per-person splits.

Updated July 9, 2026

How to use the fuel cost calculator

  1. 1Choose US or metric units.
  2. 2Enter one-way distance, fuel economy, and fuel price.
  3. 3Toggle round trip and set the passenger count for splits.
  4. 4Read total cost, fuel used, and per-person or per-mile figures.

Common uses

  • Budgeting gas for a road trip before leaving
  • Splitting fuel fairly among carpool riders
  • Comparing driving vs flying for a weekend trip
  • Estimating weekly commute fuel spend at current prices

Frequently asked questions

What MPG number should I use?

Your dashboard's long-term trip average beats the window sticker. Real-world economy runs 10–20% below EPA figures with speeds over 70 mph, AC, roof cargo, or a loaded car. If you only have the sticker number, use the combined figure and mentally pad the result. Highway-heavy trips can use the highway figure; mixed driving shouldn't.

How is metric fuel consumption different?

It inverts: MPG measures distance per fuel (higher is better), while L/100km measures fuel per distance (lower is better). The conversion is 235.2 ÷ either number to get the other, 30 MPG ≈ 7.8 L/100km. The calculator handles each convention natively so no conversion is needed.

How should a road trip split gas fairly?

The common convention: passengers split fuel (the per-person figure here), and many groups add a share toward wear. The driver is contributing a car, not just gas. Splitting fuel-only among all riders including the driver is the baseline; anything more generous to the driver is a judgment call the group makes.

Is fuel the real cost of driving somewhere?

It's the visible fraction. The IRS standard mileage rate (roughly $0.70/mile) approximates the true per-mile cost including depreciation, tires, insurance, and maintenance, typically 3–4× fuel alone. For 'drive vs fly' decisions, fuel cost is the fair marginal comparison; for 'what does my commute really cost', the full figure is more honest.

About this tool

The fuel cost calculator prices a drive: distance, your vehicle's fuel economy, and the local gas price give the trip's fuel cost, gallons (or liters) used, and cost per mile. Toggle round trip, split among passengers for road-trip cost sharing, and switch between US (miles/MPG/$ per gallon) and metric (km, L/100km, per liter) conventions. The number it produces is the marginal cost of driving, worth comparing honestly against flight prices for two people, or against the ~$0.70/mile figure the IRS uses once depreciation and maintenance are counted.

Like most tools on UtilityBase, the fuel cost calculator runs entirely in your browser. Nothing you enter is uploaded or stored on a server. It's free to use with no account required. Browse more calculators here.

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