Numbers & money · Free
Fuel cost calculator – what your trip costs in gas
Work out what a drive costs in fuel – one way or round trip, split between passengers, in mpg or l/100 km. Fuel Studio also keeps your fill-ups and real mileage, compares electric and gas cars, and shows live pump prices in France, Spain and Austria. Free, no signup.
- No account
- Runs on your device
- Phone & desktop
Work out a trip’s fuel cost
Stays on your device
My stations
Live prices from the official price data of Germany, France, Spain and Austria, updated within minutes. In the US there is no free official station-by-station price data: use the trip calculator with the price at your pump.
Fuel spending, last 12 months
Your fill-ups
No fill-ups yet. Add one each time you fill up – after two full tanks you see your real mileage.
Your fill-ups are saved in this browser only. Export them as CSV to keep a copy or move them to another device.
Private by design. Calculations and your fill-up diary stay in this browser. A price search sends only a rounded place (about 1 km) to the official price services.
Estimates, not a receipt. Real fuel use depends on speed, traffic, load and weather. Your own fill-ups give the most accurate number.
How to calculate the fuel cost of a trip
Enter the distance
Type the one-way distance from your map app and tick “Round trip” if you drive back.
Add your fuel economy
Use your car’s real mpg (US or UK) or l/100 km. The “Fill-ups” tab works it out from your own fill-ups.
Enter the price and share
Type the price at your pump, add tolls or parking, and the number of people sharing. The cost appears as you type.
The formula behind it
Fuel cost = distance ÷ miles per gallon × price per gallon. In metric: distance × litres per 100 km ÷ 100 × price per litre. Example: 300 miles at 30 mpg is 10 gallons; at $3.50 a gallon that is $35, or $17.50 each for two people.
Fuel Studio converts between US mpg, UK mpg, km/l and l/100 km for you, so you can mix a European car spec with a US trip, or the other way round.
Track your real mileage
Window stickers and brochures are measured on test cycles; everyday driving often uses more. Log each fill-up with the odometer reading and tick “Filled up to full” when the tank is full. From the second full tank on, Fuel Studio shows your real average, the cost per 100 miles and your spending per month. The diary stays in this browser; export it as CSV any time.
Electric or gas: compare the energy cost
Enter how far you drive in a year, the electric car’s consumption in kWh, your home electricity rate and the public charging price, and how much you charge at home. Fuel Studio shows the energy cost per 100 miles and per year for both cars. Purchase price, insurance and maintenance are not part of this comparison.
How to split gas money for a road trip or carpool
For a shared ride, enter everyone in the car in “People sharing” – the driver included. Fuel Studio divides the fuel plus tolls and parking evenly. For a round trip, tick “Round trip” so the drive home is counted too.
Fair carpools often agree on something simple: the passengers pay the fuel, the driver covers wear and tear. If someone joins only for part of the way, work out their part separately with that distance and add it to their share. Settle up with the total on screen rather than a guess: it avoids the classic “roughly twenty each” that never quite matches the receipt.
MPG to l/100 km and back
US cars are rated in miles per US gallon, British cars in miles per imperial gallon, and most other countries use litres per 100 km – where lower means more efficient. Pick the unit next to “Fuel economy” and Fuel Studio converts for you.
| US mpg | UK mpg | l/100 km |
|---|---|---|
| 20 | 24 | 11.8 |
| 25 | 30 | 9.4 |
| 30 | 36 | 7.8 |
| 40 | 48 | 5.9 |
This matters when you rent a car abroad: a European spec sheet with 6.5 l/100 km is about 36 US mpg.
Spend less on gas without driving less
- Compare before you fill up. In Germany, France, Spain and Austria the “Prices” tab shows every nearby station; the box “Saved on a 50 l tank” tells you what the cheapest one saves against the average.
- Watch your own trend. Save the stations you pass with the star – “My stations” shows whether their price went up or down since you last looked.
- Drive steadily. Higher highway speeds and roof boxes raise consumption noticeably; your fill-up diary shows the effect in real numbers.
- Check tyre pressure. Under-inflated tyres cost fuel and grip.
Frequently asked questions
How do I calculate gas cost for a trip?
Divide the distance by your car’s miles per gallon to get the gallons you need, then multiply by the price per gallon. Fuel Studio does this as you type and adds tolls, parking and the share per person.
Is Fuel Studio free?
Yes. It is free with no account and no limit. The prices come from free official data, and your fill-up diary is stored in your own browser.
Does it show gas prices in the US?
Not yet: there is no free, official station-by-station price feed in the US. Live pump prices are available for France, Spain and Austria, with Germany coming next.
Is my fill-up diary private?
Yes. It is saved in this browser only and is never uploaded. Export it as CSV to keep a backup or to move it to another device.
How much gas will I use for 100 miles?
Divide 100 by your car’s mpg: at 25 mpg you need 4 gallons, at 40 mpg 2.5 gallons. Enter 100 miles in Fuel Studio and it also shows the cost at your pump price.
How do I convert mpg to l/100 km?
Divide 235.2 by the US mpg value (282.5 for UK mpg). 30 US mpg is about 7.8 l/100 km. Fuel Studio converts automatically when you switch the unit.
Can I add tolls and parking?
Yes. Enter them in “Tolls and parking”; they are added to the total and split between everyone sharing the ride.
Is the CO₂ figure exact?
It is an estimate from the fuel burned, using typical values per litre of gasoline, diesel, LPG and E85. Real emissions depend on the fuel blend and the car.
