Road Trip Fuel Cost Calculator

Pricing Out the Gas Before You Leave the Driveway

Fuel is usually the single largest variable cost of a road trip, and it's the one most people estimate loosely with a mental "about a tank per 300 miles" guess. This calculator replaces the guess with an exact figure, working from either a US-style MPG and price-per-gallon or a metric liters-per-100km and price-per-liter, depending on which figures you have on hand.

The Formula

MPG mode: Gallons Needed = Distance ÷ MPG Fuel Cost = Gallons Needed × Price per Gallon Metric mode: Liters Needed = (Distance in km ÷ 100) × Consumption (L/100km) Fuel Cost = Liters Needed × Price per Liter

Worked Examples

Sample fuel cost calculations
Trip	Fuel use	Price	Fuel needed	Cost
500 miles	25 MPG	$3.50/gallon	20 gallons	$70.00
800 km	8.5 L/100km	$1.60/liter	68 liters	$108.80

Where This Calculation Matters

Comparing vehicles for a trip — deciding whether a more fuel-efficient rental is worth the extra rental fee once fuel savings are factored in.
Splitting costs with travel companions — an exact fuel figure is easier to divide fairly than a rough estimate.
Route comparison — weighing a longer, faster highway route against a shorter but slower one once fuel cost is added to the decision.

Fuel Consumption Reference

If you don't know your vehicle's exact MPG or L/100km figure, these commonly cited ranges give a starting point:

Typical fuel consumption by vehicle class
Vehicle class	Typical MPG	Typical L/100km
Compact/subcompact car	32–40 MPG	5.9–7.3
Midsize sedan	28–36 MPG	6.5–8.4
SUV / crossover	22–28 MPG	8.4–10.7
Pickup truck / large SUV	16–22 MPG	10.7–14.7

Actual fuel economy varies by driving style, terrain, load, and vehicle condition — use your vehicle's own rated or observed figure when available.

How to Use This Calculator

Choose either Miles / MPG / $ per Gallon or Kilometers / L per 100km / $ per Liter from the mode selector, matching the units you have.
In MPG mode, enter Distance (miles), Fuel Economy (MPG), and Price per Gallon.
In metric mode, enter Distance (km), Consumption (L/100km), and Price per Liter.
Select Calculate to see the fuel needed and total fuel cost.

Related Calculations

Add lodging and food on top of fuel with the Trip Cost Calculator, or compare fuel-only cost per mile against a flat reimbursement rate using the Travel Cost Per Mile Calculator.