Fuel Cost Calculator

Estimate fuel cost for a trip based on distance, fuel efficiency, and gas price. Supports miles, kilometers, mpg, km/L, and L/100km.

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How to Calculate Fuel Cost

The formula is straightforward:

Fuel Cost = (Distance ÷ Fuel Efficiency) × Fuel Price

For a 500-mile trip at 25 mpg with gas at $3/gallon: 500 ÷ 25 = 20 gallons × $3 = $60.

Unit Support

Distance: miles or kilometers
Efficiency: miles per gallon (mpg), kilometers per liter (km/L), or liters per 100 km (L/100km)
Fuel price: per gallon or per liter

Average Fuel Efficiency by Vehicle Type

Compact car: 28–35 mpg
Midsize sedan: 25–32 mpg
SUV: 20–28 mpg
Pickup truck: 15–22 mpg
Hybrid: 40–60 mpg
Electric (equivalent): 100+ mpge

Tips to Save on Fuel

Drive steadily: Aggressive acceleration and braking can reduce efficiency by 15–30%
Check tire pressure: Underinflated tires increase fuel consumption by 2–3%
Reduce speed: Each 5 mph over 50 mph costs roughly $0.15–$0.30 more per gallon
Minimize idling: Idling uses ¼ to ½ gallon per hour
Use cruise control: Maintains steady speed on highways, improving efficiency
Plan routes: Avoid traffic, combine errands, and use highway routes when possible

Fuel Efficiency Conversions

1 mpg = 0.4251 km/L
1 km/L = 2.352 mpg
To convert mpg to L/100km: 235.215 ÷ mpg
25 mpg = 10.6 km/L = 9.4 L/100km

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On conv.awajis.com

MPG to L/100km Convert fuel economy figures.

Frequently Asked Questions

How do you calculate gas cost for a trip?

Divide the trip distance by fuel economy to get gallons, then multiply by the price per gallon. A 500 mile trip in a car getting 25 mpg uses 20 gallons, and at $3 a gallon costs $60. The same rule works in metric: liters needed = kilometers x L/100km / 100, times the price per liter.

How much gas does a round trip use?

A round trip uses twice the fuel of the one-way distance. A destination 300 miles away is a 600 mile round trip, which takes about 21.4 gallons at 28 mpg, or about $64 at $3 a gallon. Running each leg separately and adding the costs gives the same answer when both legs are similar.

$38.40 for 16 gallons of gas is how much per gallon?

$38.40 for 16 gallons of gas is $2.40 per gallon. Price per gallon is the total paid divided by the gallons pumped, so $38.40 / 16 = $2.40. Multiplying back checks it: 16 x $2.40 = $38.40. Divide the same total by the miles driven on that tank to get the fuel cost per mile.

What is 8 L/100km in mpg?

8 L/100km is about 29.4 US mpg. To convert, divide 235.2 by the L/100km figure, and the same division converts mpg back to L/100km. Lower L/100km means better economy, the opposite of mpg. To convert mpg to kilometers per liter, multiply by 0.4251, so 25 mpg is about 10.6 km/L.

Why is my real mpg lower than the EPA rating?

Real-world fuel economy usually runs 10 to 20 percent below the EPA rating on mixed driving. EPA figures come from controlled lab tests, while real driving adds speeds above 60 mph, cold weather, air conditioning, extra cargo and stop-and-go traffic. A car rated 30 mpg may deliver 24 to 27 mpg in daily use.