Road Trip Fuel Cost Calculator

Work out gas or petrol cost for any drive from distance, MPG and fuel price, then split it per person. All costs in US dollars (USD).

Road Trip Fuel Cost Calculator: How Much Will Gas Cost for Your Trip?

Planning a road trip, a camping weekend or a long drive to the trailhead? Our free road trip fuel cost calculator tells you exactly how much gas (or petrol and diesel, if you are driving in the UK) your journey will cost. Enter your trip distance, your car’s fuel economy and today’s fuel price, and the gas cost calculator instantly works out the fuel you need, the total trip fuel cost, the cost per person, the number of refuelling stops and even your driving time and CO₂ emissions.

The calculator works in miles or kilometres and accepts US MPG, UK (imperial) MPG, litres per 100 km or km per litre, so it suits drivers in the United States, the United Kingdom, Canada and beyond. Every result is shown in US dollars (USD) so you can budget consistently across trips.

How to use the road trip gas calculator

Enter your trip distance. Use the one-way distance from Google Maps, Apple Maps or your sat nav and choose miles or km.
Choose round trip or one way. The calculator doubles the distance for a return journey.
Add extra driving. Detours, scenic routes, supply runs and getting lost usually add 5–15% to a road trip.
Enter fuel economy. Pick MPG (US), MPG (UK), L/100 km or km/L. Use your real-world figure from your dashboard or fuel log rather than the manufacturer’s sticker figure.
Enter the fuel price in US dollars per US gallon, per litre or per UK gallon.
Add the number of people sharing the fuel cost to see the gas money each person owes.
Optionally add your tank size to estimate how many fuel stops you need, and your average speed for a driving-time estimate.

The fuel cost formula

Every fuel cost calculator uses the same simple maths. Once you know it, you can check any estimate on the back of a map:

Fuel needed = Distance ÷ Fuel economy
Fuel cost = Fuel needed × Price per gallon (or litre)
Cost per person = Fuel cost ÷ Number of people

US example: a 1,200-mile national park road trip

You are driving 600 miles each way to a national park (1,200 miles round trip) in an SUV that averages 28 MPG, and regular gas costs $3.40 per gallon.

Fuel needed: 1,200 ÷ 28 = 42.9 US gallons
Total gas cost: 42.9 × $3.40 = $145.71
Split between four friends: $36.43 each

UK example: a 400-mile return trip to the Lake District

You drive 200 miles each way in a car that does 45 MPG (UK) and petrol costs the equivalent of $1.85 per litre.

Fuel needed: 400 ÷ 45 = 8.89 UK gallons = 40.4 litres
Total petrol cost: 40.4 × $1.85 = $74.76
Split between two people: $37.38 each

Tip: A UK gallon (4.546 litres) is about 20% bigger than a US gallon (3.785 litres). That is why the same car shows a higher MPG figure in Britain than in America. Always pick the matching MPG unit in the calculator.

Typical fuel economy by vehicle type

Don’t know your MPG? Use these typical real-world figures as a starting point for your road trip budget:

Vehicle	MPG (US)	MPG (UK)	L/100 km
Hybrid car	50	60	4.7
Small car / hatchback	35	42	6.7
Midsize sedan / saloon	30	36	7.8
Compact SUV / crossover	28	34	8.4
Minivan / MPV	24	29	9.8
Full-size SUV	20	24	11.8
Pickup truck	18	22	13.1
Car towing a trailer or caravan	13	16	18.1

A fully loaded car with roof boxes, bikes or kayaks can use 10–25% more fuel than these figures. Mountain driving, stop-start traffic and high motorway or interstate speeds all lower your MPG. Towing? Try our RV trip cost calculator, which is built for motorhomes, campervans and trailers.

How to split gas money fairly on a road trip

The simplest way to split gas cost is to divide the total fuel bill by everyone in the car, including the driver. Many groups also:

Let the driver ride free as a thank-you for driving and for wear and tear on their car.
Add a wear-and-tear allowance of around $0.05–$0.15 per mile for tyres, oil and depreciation.
Split tolls and parking the same way as fuel.

Travelling in more than one car? Use the group carpool cost splitter. It divides fuel, tolls and parking across several cars and riders and shows exactly who owes whom.

US vs UK: gallons, litres and MPG explained

Unit	Equivalent
1 US gallon	3.785 litres
1 UK (imperial) gallon	4.546 litres = 1.2 US gallons
US MPG → UK MPG	multiply by 1.201
US MPG → L/100 km	235.2 ÷ US MPG
UK MPG → L/100 km	282.5 ÷ UK MPG
1 mile	1.609 km

UK fuel is usually priced in pence per litre. To use the calculator, convert your price into US dollars at today’s exchange rate and select “per litre”. The calculator then gives you your petrol cost or diesel cost in USD.

10 ways to cut your road trip fuel cost

Slow down. Above about 50–60 mph, fuel economy drops quickly. Driving at 65 instead of 75 mph can save 10–15% on fuel.
Check tyre pressure before you leave. Under-inflated tyres waste fuel and wear faster.
Remove roof racks and boxes when you are not using them. They add drag.
Pack light. Every extra 100 lb (45 kg) cuts MPG by roughly 1%.
Use cruise control on flat highways and motorways.
Fill up away from the interstate or motorway. Stations a mile or two off the highway, at supermarkets or warehouse clubs, are often cheaper.
Use a fuel price app such as GasBuddy in the US or a petrol price comparison site in the UK.
Avoid idling. An idling engine uses fuel but gets you nowhere.
Take the most fuel-efficient car in your group, and fill every seat.
Plan your route to avoid city rush hours and long stop-start sections.

Other road trip costs to budget for

Fuel is often the biggest cost of a road trip, but it is not the only one. A realistic road trip budget should also include:

Tolls, turnpikes, congestion charges and bridge fees
Parking at hotels, trailheads and city centres – see our trailhead parking & permit cost tool
National park entrance fees and camping permits
Campsites or hotels, food and snacks
Camp stove fuel – estimate it with the camp stove fuel calculator
Vehicle servicing before a long drive, and a small emergency fund

Why use this road trip fuel cost calculator?

Free and instant. Results update as you type, with no sign-up.
US and UK units. Miles or km, US or imperial gallons, litres, MPG or L/100 km.
Built for groups. See the fuel cost per person straight away.
Price sensitivity table. See how your trip cost changes if gas prices rise or fall.
Works on any device. Use it on your phone at the pump, a tablet in the car or a desktop at home.

Frequently asked questions

How do I calculate the fuel cost for a road trip?

Divide your total distance by your fuel economy to get the gallons or litres needed, then multiply by the fuel price. For example, 1,200 miles ÷ 28 MPG = 42.9 gallons × $3.40 = $145.71. The calculator above does this instantly and also splits the cost per person.

How much gas money should I pay on a road trip?

The fairest method is to divide the total fuel cost by everyone in the car. Some groups let the driver ride free or add $0.05–$0.15 per mile for wear and tear. Enter the number of people in the calculator to see each person’s share.

Does the calculator work for UK MPG and litres?

Yes. You can enter distance in miles or kilometres, fuel economy in US MPG, UK MPG, L/100 km or km/L, and fuel price per US gallon, UK gallon or litre. All costs are shown in US dollars.

Why is UK MPG higher than US MPG for the same car?

A UK (imperial) gallon is 4.546 litres, while a US gallon is 3.785 litres. Because the UK gallon is about 20% larger, the same car travels further on it and shows a higher MPG number.

How accurate is a road trip gas cost estimate?

It is usually within 10% if you use your real-world MPG. Heavy loads, roof boxes, mountains, towing, air conditioning and high speeds all raise fuel use. Add 5–15% extra driving to be safe.

How many fuel stops will I need?

Add your tank size to the calculator. It assumes you start with a full tank and refuel when about 15% is left, then shows how many fuel stops your trip needs.

Is it cheaper to drive or fly for a road trip?

For two or more people, driving is often cheaper than flying for trips under about 500–600 miles, especially when you split fuel. Compare the per-person fuel cost from this calculator with airfare, bag fees and car hire at your destination.