Fuel Cost Calculator
This fuel cost calculator works out how much a trip or a year of driving will actually cost, based on the distance you'll cover, your vehicle's real-world fuel efficiency, and the current price of fuel. Enter your numbers to see the total cost, how much fuel you'll need, and the cost per mile — useful for budgeting a road trip, comparing two vehicles, or estimating your annual driving cost before deciding whether to buy or lease.
The total miles for the trip, or your typical annual mileage if you are estimating a yearly fuel budget.
Your vehicle's real-world MPG — city driving typically runs 10–20% below the manufacturer's combined rating.
The current price you pay at the pump. Check a fuel-price app for the latest local price rather than guessing.
Total fuel cost
$1,500
What you'll actually spend on fuel for the distance entered — e.g. $1,500/year driving 12,000 miles at 28 MPG with $3.50/gallon fuel.
The volume of fuel required — useful for planning fuel stops on a long trip or checking your tank capacity.
The best number for comparing vehicles — a pricier-to-fuel car can still cost less per mile if it's more efficient.
How to use this fuel cost calculator
- 1Distance: total miles for a single trip, or your typical annual mileage (check your last service record or odometer history) for a yearly estimate.
- 2Fuel efficiency: use your vehicle's real-world MPG, not the manufacturer's rating — highway MPG is usually close to the label, city MPG often runs 10–20% lower.
- 3Price per gallon: use today's local price for the most accurate short-trip estimate; for an annual budget, use a rolling average since fuel prices fluctuate through the year.
- 4Compare the cost-per-mile figure across two vehicles to see the real running-cost difference, not just the sticker MPG difference.
Understanding your results
Total fuel cost is the headline number — what you'll actually spend on fuel for the distance entered. Fuel needed shows the volume, useful for planning fuel stops on a long trip or checking your tank capacity is sufficient. Cost per mile is the most useful number for comparisons: a more efficient but pricier-to-fuel vehicle can still cost more per mile than a cheaper, less efficient one if fuel prices or driving style differ — always compare on cost per mile, not on MPG alone.
The formula
Cost = (Distance ÷ MPG) × Price per gallonDistance divided by miles-per-gallon gives the gallons of fuel required; multiplying by the price per gallon gives the total cost. This is simple, linear arithmetic with no compounding — double the distance and the cost exactly doubles, all else equal. The only real-world complication is that MPG is not actually constant: it varies with driving style, terrain, load, tyre pressure and weather, which is why using a real-world (not manufacturer-rated) MPG figure matters for an accurate estimate.
A worked example
12,000 miles a year at 28 MPG with fuel at $3.50/gallon: fuel needed is about 428.6 gallons, for a total annual cost of $1,500 — a cost per mile of 12.5 cents. Compare a less efficient vehicle doing the same 12,000 miles at 22 MPG and the same $3.50/gallon: fuel needed rises to about 681.8 gallons, costing $2,386.36 a year — nearly $900 more, purely from the efficiency difference, even though both vehicles cover identical distance.
Notes for the UK, US and India
In the US, fuel is priced and MPG is measured per US gallon; in the UK, fuel is priced per litre and efficiency is usually quoted in miles per (imperial) gallon or, increasingly, miles per litre — convert using 1 UK gallon ≈ 4.546 litres before comparing to a US MPG figure. In India, fuel is priced per litre and efficiency is quoted in km per litre (kmpl) — convert by treating 'distance ÷ efficiency' the same way, just in km and litres instead of miles and gallons; the calculator's currency switcher changes the price display but you should re-enter distance and efficiency in your local units for an accurate result. Fuel cost is only part of total cost of ownership — insurance, maintenance and depreciation typically add more than fuel over a vehicle's life.
Frequently asked questions
How do I calculate fuel cost for a road trip?+
Divide the total trip distance by your vehicle's real-world MPG to get gallons needed, then multiply by the price per gallon. A 500-mile trip at 30 MPG with $3.50 fuel costs about $58.33 — use the calculator above for your exact numbers.
Why is my actual fuel cost higher than the manufacturer's MPG suggests?+
Manufacturer ratings are measured under ideal lab conditions. City driving, cold weather, air conditioning, cargo load and aggressive acceleration can all cut real-world MPG by 10–20% or more below the sticker figure — always budget using a real-world MPG, not the label.
How much does driving style affect fuel cost?+
Significantly — aggressive acceleration and braking can cut fuel efficiency by 15–30% in stop-and-go traffic, and highway speeds above roughly 60 mph increase aerodynamic drag enough to noticeably reduce MPG. Smooth, moderate-speed driving is the single biggest free lever on fuel cost.
Is an electric vehicle cheaper than fuel per mile?+
Usually yes on a pure energy-cost basis — electricity is typically cheaper per mile than gasoline even before considering EV tax credits, though the comparison depends heavily on local electricity and fuel prices. This calculator covers petrol/diesel vehicles; compare your local kWh price and vehicle efficiency (miles/kWh) separately for an EV.
How do I estimate my annual fuel budget?+
Use your typical annual mileage (check your last two service records and subtract the odometer readings) as the distance, your real-world MPG, and an average fuel price across recent months rather than today's price alone, since prices fluctuate seasonally.