Calculator
FinanceFuel Cost Calculator
Calculate trip fuel cost in km or miles, with L/100km, MPG (US or UK) or km/L. Per-liter or per-gallon price, six currencies — works for the US, EU, UK, Asia.
Calculate fuel cost for any trip — supports km/miles, L/100km / MPG (US/UK) / km/L, and per-liter or per-gallon pricing.
Have feedback? Report bugs, suggest features, or share your thoughts — we read them allWhat is a Fuel Cost Calculator?
A fuel cost calculator estimates how much fuel a trip will burn and what that fuel will cost, given your vehicle's consumption rate, the trip distance, and the price at the pump. It's the simple math that everyone wants to know but no one wants to do at the gas station — and it works equally well for a 50-mile commute, a 2,000-km road trip, or planning a 12-hour delivery route.
Most fuel-cost tools online assume one country's units (typically L/100km and euros, or MPG and dollars) and break for users in other markets. This one supports every common unit combination — distance in km or miles, consumption in L/100km, MPG (US), MPG (UK/imperial) or km/L, and price per liter or per gallon (US or UK) — across six currencies. Pick the units you actually use, and the math is correct regardless of where you are.
How the Fuel Cost Calculator Works
Enter your trip distance, your vehicle's fuel consumption, and the current pump price. The tool normalizes everything internally to SI units (km, L/100km, price per liter), runs the math, and presents the results in whichever units you picked. Switching units after the calculation just re-renders the same trip in the new units — no need to re-enter values.
Fuel Cost Calculation Formulas
The core math, expressed in SI units (km and liters):
Fuel Needed (L) = Distance (km) × Consumption (L/100km) / 100
Total Cost = Fuel Needed (L) × Price per Liter
Cost per km = Total Cost / Distance (km)
Conversions used internally: 1 mile = 1.609344 km · 1 US gallon = 3.785411784 L · 1 imperial gallon = 4.54609 L · MPG (US) → L/100km = 235.214583 / MPG · MPG (UK) → L/100km = 282.480936 / MPG · km/L → L/100km = 100 / (km/L).
Practical Examples
Example 1: US road trip in MPG and miles
A 500-mile drive in a car rated 28 MPG (US) at $3.50/gallon (US):
- Distance: 500 mi (= 804.67 km internally)
- Consumption: 28 MPG (US) (= 8.40 L/100km internally)
- Price: $3.50/gal US (= $0.9245/L internally)
- Fuel needed: 17.86 gallons US (= 67.61 L)
- Total cost: $62.50
- Cost per mile: $0.125/mi
Example 2: EU road trip in L/100km and km
A 600 km drive in a diesel rated 5.5 L/100km at €1.65/L:
- Distance: 600 km
- Consumption: 5.5 L/100km
- Price: €1.65/L
- Fuel needed: 33.0 L
- Total cost: €54.45
- Cost per km: €0.091/km
Tips for Fuel Cost Management
- Check current pump prices with apps like GasBuddy (US/CA), Tankerkönig (DE), Fuel Map (AU/NZ), or your local equivalent before long trips
- Use your trip computer's lifetime average for consumption, not the EPA/WLTP sticker number — real-world MPG runs 10-20% worse than the spec sheet
- Highway vs city driving: highway is usually 20-30% more efficient than city for gas cars; EVs are the opposite (city regen wins)
- Tire pressure: a 1 PSI drop costs ~0.3% fuel economy. Check monthly, especially in cold weather
- A/C and roof boxes: A/C costs ~3-10% MPG at highway speeds; a roof box can cost 15-20%. Remove racks when not used
- Smooth driving: aggressive acceleration and braking cuts fuel economy 10-30%. The EPA tests show smooth driving = the single biggest variable you control
- Trip planning: combine errands into one trip with a warm engine; cold starts use 30-50% more fuel for the first kilometer
- Compare hybrids and EVs: at $3.50/gal and current US electricity rates, an EV per-mile cost is typically 1/3 to 1/4 of a gas car. Use the calculator to compare in your local prices
- Carpooling math: split the calculated cost among riders proportionally to share trip expenses fairly
- Budget 5-10% buffer: pump prices fluctuate ±10% week to week, especially in summer and after geopolitical shocks
When to Use a Fuel Cost Calculator
- Trip planning: Estimate the cost of a road trip before committing
- Commute math: Calculate weekly, monthly or annual cost of driving to work
- Comparing routes: A toll-free longer route may still beat a tolled shorter one once fuel is included
- Comparing vehicles: Before buying a car, compare yearly fuel cost at your real-world miles
- Comparing fuel types: Diesel vs gasoline vs hybrid vs electric — total cost is dominated by your miles, not the upfront price difference
- Expense reports & mileage reimbursement: Calculate the actual fuel cost component of mileage claims
- Delivery & rideshare drivers: Know your per-mile or per-km cost to set rates and accept rides profitably
- Moving day planning: Rental trucks burn 2-3× a car — budget for it
- Cross-border travel: Switch units to match where you'll actually buy the fuel
- Budgeting for fuel as a household expense: Real fuel costs are usually 5-15% of a household budget — track them like rent or food
Frequently Asked Questions
Historical inertia. The US never metricated, so when the Energy Policy and Conservation Act of 1975 created the CAFE (Corporate Average Fuel Economy) standard, it used miles per gallon — the existing American consumer unit. Europe and most of the world standardized on L/100km because it's directly proportional to fuel consumed: a 5 L/100km car uses exactly twice as much as a 2.5 L/100km car for the same trip, while a 40 MPG car uses less fuel than a 20 MPG car but not exactly half. The math: doubling MPG halves consumption ONLY in fuel-per-distance terms, not linearly. L/100km is more honest about cost. Conversion: L/100km = 235.214583 / MPG_US. So 30 MPG = 7.84 L/100km, 50 MPG = 4.70 L/100km, 100 MPG (hybrid territory) = 2.35 L/100km. The asymmetry of MPG hides how much fuel a 12 MPG SUV burns compared to a 25 MPG sedan — the SUV uses roughly twice as much fuel per mile, but the MPG numbers don't visually shout that.
Because a UK (imperial) gallon is 4.54609 L while a US gallon is 3.785411784 L — about 20% larger. So a UK MPG figure ALWAYS looks better than the equivalent US MPG for the same real-world car. A car that does 30 MPG (US) does 36 MPG (UK), even though it's the same car burning the same fuel over the same miles. This trips up Americans reading UK car reviews and vice versa. Conversion shortcuts: UK MPG × 0.8327 = US MPG · US MPG × 1.2009 = UK MPG. The conversion to L/100km is different too: 235.214583 / MPG_US vs 282.480936 / MPG_UK. The UK officially uses MPG for everyday talk about cars (despite metricating most other things) and L/100km on official efficiency labels — pick the right unit when comparing reviews or import buyers' notes.
It's usually 10-25% too optimistic for real-world driving. The reasons depend on the test cycle. The US EPA cycle was reformulated in 2008 to be more realistic; even so, drivers commonly see 10-15% worse than the sticker on the highway and 15-25% worse in mixed driving. The European WLTP cycle (replaced NEDC in 2018) was specifically designed to close the gap, but real-world hybrids and small turbocharged engines still under-deliver — the WLTP cycle drives gently, and turbo engines burn extra fuel under any harder acceleration. Best practice: log your actual fuel-up data for a month (gallons or liters bought, miles or km between fills) and compute your true average. Most cars have a built-in trip computer showing a 'lifetime average' that's reasonably accurate after 5000 km. Use that number in this calculator, not the sticker.
EVs don't use gasoline, but the same trip math works once you swap units. Replace 'L/100km' with 'kWh/100km' (Europe standard) or 'MPGe' (US standard for energy equivalence). A typical 2026 EV uses 16-22 kWh/100km in mixed driving. At a US residential rate of $0.16/kWh, a 100 km drive at 18 kWh/100km costs $2.88 — versus a 25 MPG car at $3.50/gal that costs about $8.70 for the same distance. That's a 3× cost advantage for the EV on cheap residential electricity. Public DC fast-charging is more expensive ($0.40-$0.55/kWh in the US), which can erase the savings on long-distance trips. The MPGe equivalent uses 33.7 kWh = 1 gallon of gasoline (energy content basis), so an EV at 18 kWh/100km = 187 MPGe. This calculator works for EVs if you enter kWh/100km values and your local electricity rate in the consumption + price fields.
Gross fuel cost is the full price of all the fuel a trip burns. Incremental cost is what an additional trip adds beyond what you'd burn anyway (commuting, errands, etc.). For example: if you drive 12,000 miles/year regardless, an extra 500-mile weekend trip adds 500 miles of fuel cost — that's the incremental cost. For shared expenses (carpooling, ridesharing), incremental cost is what matters: you'd be driving anyway, so don't charge passengers for fixed costs like insurance and depreciation, just the marginal fuel. The IRS standard mileage rate for 2026 is $0.67/mile and includes depreciation, insurance, maintenance, and fuel — it's the gross cost, not the incremental. For Uber/Lyft drivers, the practical incremental cost is just fuel — typically $0.10-$0.15/mile for an efficient car at current prices, versus the $0.67/mile the IRS lets them deduct (which is structurally generous because most of the gap is depreciation of a vehicle they already own).
10-30% in fuel economy, sometimes more. The EPA's official guidance: aggressive driving (hard acceleration, late braking) costs 15-30% MPG on highways and up to 40% in stop-and-go city traffic. The mechanism: combustion engines have a small efficiency 'sweet spot' (typically 1500-2500 RPM at low load); flooring the throttle pushes the engine outside that range into rich-mixture territory. Brakes turn kinetic energy into heat that's gone; eco-driving captures that energy by anticipating and rolling. Hybrid cars amplify the difference because regen captures braking energy — aggressive driving costs hybrids more because braking energy is wasted as heat in the pads, not recovered. Practical numbers: a 30 MPG car that gets 21 MPG under aggressive driving means a $1,200 annual fuel bill becomes $1,720 — $520 you could save with no equipment changes. Eco-driving is the cheapest fuel-economy upgrade available.
Always use your real-world MPG when it's available. The sticker is a rated number based on a standardized test — useful for comparing cars but not for predicting your actual cost. Use the sticker only when planning to buy a car you don't own yet, and even then mentally discount it by 10-20% for real-world driving. To find your real number: (1) modern cars: check the trip computer's lifetime average or current tank average; (2) older cars: keep a fuel log for a month — record odometer at each fillup and gallons/liters purchased; (3) divide total distance by total fuel = your true L/100km or MPG. This single piece of data is the most important input to this calculator. A 28 MPG sticker car that actually delivers 24 MPG in your hands will cost you 17% more fuel than the sticker says — a $700/year error on typical US driving.
Indirectly — by letting you set whatever pump price you actually pay. The math is identical regardless of fuel type as long as you input the consumption and price for the specific fuel. Things to know: (1) diesel has 12-15% more energy per liter than gasoline, so diesel cars are typically rated lower L/100km than equivalent gasoline cars — but diesel is usually priced higher per liter, so total cost per km is close. (2) Premium gas costs 10-15% more than regular but only delivers measurable benefits in engines specifically tuned for it (most turbo and luxury cars). For cars rated for regular, premium is wasted money. (3) E85 (flex-fuel) is priced 15-25% lower than regular but contains 25-30% less energy, so MPG drops by roughly that amount — net cost per mile is often a wash or slightly more expensive. (4) Compressed natural gas (CNG) is sold by GGE (gasoline gallon equivalent) in the US; check whether your station prices by kg or GGE. Plug in your actual fuel's pump price and your car's measured consumption on that fuel, and the calculator gives you the correct trip cost.
FINANCIAL CALCULATORS22
WUTOOLS