CupieFree tool
Gas Cost Calculator
Trip cost, split any way, or compared with flying.
Quick answer
Trip gas cost = miles driven / your car's mpg x the price of a gallon. A 300 mile drive in a 30 mpg car with gas at $4.17 uses 10 gallons and costs $41.70, or $20.85 each for two. The calculator above does this live, from two cities or the miles you type, and also handles electric cars, km and litres, tolls, trips you repeat every month, and driving versus flying.
To calculate gas cost, divide the miles by your car's mpg and multiply by the price of a gallon. The calculator above does it live as you type: pick two cities or enter the miles, and it shows the total, the share for each person, and the cost per month if you make the trip often. It works for electric cars and in km and litres too. No sign-up, nothing to install.
How does the gas cost calculator work?
- Say where you are going. Type two cities and it estimates the road miles, or type the miles from your map app for the exact trip.
- Add your car. Enter your mpg, or tap an example like Midsize 30 if you are not sure. Electric cars use kWh per 100 miles.
- Check the price. In the US it starts at the AAA average for the states you drive between (the national average was $4.17 a gallon on November 2, 2026). Type your local price any time.
- Pick one way or round trip, and how many people share the cost.
The answer updates with every number you change. Your last trip is saved on this phone, and you can save trips you make often, like the drive to your partner's place.
The gas cost formula
- US: gallons = miles / mpg. Cost = gallons x price per gallon.
- Metric: litres = km x L/100km / 100. Cost = litres x price per litre.
- Electric: kWh = miles x kWh per 100 mi / 100. Cost = kWh x price per kWh.
Example: a 150 mile drive there and back is 300 miles. In a 30 mpg car that is 10 gallons. At $4.17 a gallon it costs $41.70, or $20.85 each if two of you split it.
Driving to see your partner? Plan the year, not one trip
One drive is easy to pay for. Every other weekend for a semester adds up. Tap how often you make the trip and the calculator shows the cost per month and per year, for the car and for each of you. If you live a flight apart, open Compare with flying: it puts the gas for one car next to two plane tickets, and shows how many hours the drive takes.
Want to know how many visits fit your budget, and who should travel when? Use the long distance visit planner. Counting down to the next one? Set up a countdown until I see you.
Ways to spend less on gas
- Meet in the middle. Two short drives cost the same gas as one long one, but you both get home sooner.
- Take turns. Alternate who drives, so neither of you pays every time.
- Fill up before tolls and city centers. Stations near highways and airports are often the most expensive in an area.
- Drive steady. Hard braking, fast starts and high speeds burn more fuel. fueleconomy.gov has the US government's tips.
- Swap one visit for a game night on a call. See our long distance date ideas and games to play on FaceTime.
What are the limits?
- City-to-city miles are an estimate (straight line x 1.2). Type your exact miles for a precise number.
- Real mpg depends on speed, traffic, load, weather and air conditioning. Most cars burn more fuel per mile at high highway speeds.
- Tolls and parking count only if you add them. Wear on the car is not counted.
- The Find your car list shows average EPA combined mpg for 2018 and newer gas models, rounded, from fueleconomy.gov data. Your version may differ.
- Everything runs in your browser. The share link holds the numbers you typed, so only send it to people you trust with them.
More for couples apart: our long distance relationship tips.
FAQ
How do I calculate the gas cost of a trip?
Divide the miles by your car's miles per gallon to get gallons, then multiply by the price per gallon. 300 miles / 30 mpg = 10 gallons, and 10 x $4.17 = $41.70. For a round trip, double the miles first. In metric: km x L/100km / 100 = litres, then litres x price per litre.
How do you split gas money fairly?
The simple way is the total fuel cost plus tolls and parking, divided by the number of people in the car. Couples who visit each other often take turns instead: the one who drives pays this time, the other pays next time. The calculator shows both the total and the share per person.
Is it cheaper to drive or fly to visit my partner?
For one person on a short trip, driving usually wins, because a car costs the same whether one or four people ride in it. On long trips flying can be cheaper once you count the hours. Open Compare with flying, type the ticket price, and the calculator shows both costs and the time difference.
How accurate is the distance between two cities?
It is an estimate: the straight-line distance between the two cities times 1.2, a common rule of thumb for how much longer roads are. Real routes can be shorter or longer, especially around mountains, lakes or coasts. For the exact number, type the miles from your map app into the Miles field.
Does it work for electric cars?
Yes. Tap Electric, enter your car's kWh per 100 miles (it is on the EPA label and in most car apps) and your price per kWh, either your home rate or the charger's price.
Is the gas price current?
In the US the starting price is the AAA average for regular gas in the states you drive between, from November 2, 2026 (the national average that day was $4.17 a gallon). Prices change daily, so type the price at your station for the best estimate. Nothing is looked up online, so the calculator also works offline.
How we made this page: page text and tool drafted with help from AI tools, then reviewed and edited by Niclas Illg against the sources below on November 3, 2026. The tool itself runs in your browser, with no AI generator behind it. Cupie is our own app.