Why use this calculator
Knowing your trip fuel cost before you leave helps you budget for road trips, compare driving vs. flying, and make informed decisions about vehicle choices. Whether you are planning a weekend getaway or a cross-country move, this calculator gives you an accurate cost estimate based on your vehicle's actual fuel economy and current gas prices. It also helps fleet managers estimate transportation costs and reimbursement amounts.
How to use it
Select your preferred unit system (metric or imperial). Enter the total trip distance, your vehicle's fuel efficiency (MPG for imperial, L/100km for metric), and the current fuel price. The calculator instantly shows total cost, fuel needed, and cost per distance unit for your trip.
The formula
Imperial: Gallons Used = Distance / MPG. Metric: Litres Used = (L/100km / 100) x Distance. Total Cost = Fuel Used x Fuel Price. Cost Per Distance = Total Cost / Distance. These formulas assume constant driving conditions; actual consumption varies with terrain, speed, and driving style.
Worked examples
500-mile road trip in a car getting 28 MPG with gas at $3.50/gal
17.86 gallons used, $62.50 total fuel cost, $0.13 per mile
800 km trip at 8 L/100km with fuel at $1.80/litre
64 litres used, $115.20 total fuel cost
When people use it
- Budgeting for vacation road trips and family travel
- Comparing fuel costs between driving and flying for business trips
- Calculating mileage reimbursement and expense reports
- Evaluating fuel costs when choosing between vehicles for a specific trip
Tips
- Check GasBuddy or similar apps to find the cheapest fuel prices along your route
- Highway driving at moderate speeds (90-105 km/h or 55-65 mph) typically provides the best fuel economy
- Air conditioning can reduce fuel efficiency by 10-25% in city driving
- Properly inflated tires can improve fuel economy by up to 3%
Questions people ask
- Where do I find my car's fuel efficiency rating?
- Check your vehicle's window sticker, owner's manual, or look up your specific year/make/model at fueleconomy.gov. Note that real-world fuel efficiency is often 10-20% worse than official ratings due to driving conditions, speed, and vehicle maintenance.
- How accurate is this estimate?
- This provides a good baseline estimate. Actual costs vary based on driving speed, terrain, weather, vehicle load, and traffic conditions. Mountain driving and stop-and-go city traffic can reduce efficiency by 20-40% compared to highway cruising.
- How do I convert between MPG and L/100km?
- To convert MPG to L/100km: divide 235.215 by the MPG value. For example, 28 MPG is about 8.4 L/100km. To convert L/100km to MPG: divide 235.215 by the L/100km value.