Work out what driving actually costs — per trip, per month, and per year — in miles or kilometers, with an optional split between passengers.
Switching converts distance, economy, price per unit, and tank size. Currency is separate.
An estimate based on the economy and price you enter. Real consumption varies with traffic, speed, weather, load, tire pressure, air conditioning, and driving style. Fuel prices change daily. The result covers fuel only; it does not include maintenance, insurance, tires, tolls, parking, depreciation, or currency conversion.
Driving 36 mi per trip, 5 times a week, covers 9,360 mi a year. At 30 MPG and $3.65 per gal, that is $1,139 in fuel — about $94.90 a month.
Fuel burned follows directly from distance and economy; price then turns it into money. Change any one box and the next moves with it. Splitting between passengers divides the fuel bill only.
| Period | Distance | Fuel | Fuel cost |
|---|---|---|---|
| One round trip36 mi · 1.2 gal | 36 mi | 1.2 gal | $4.38 |
| One week180 mi · 6 gal | 180 mi | 6 gal | $21.90 |
| One month780 mi · 26 gal | 780 mi | 26 gal | $94.90 |
| One year9,360 mi · 312 gal | 9,360 mi | 312 gal | $1,138.80 |
Months are the annual figure divided by 12; weeks assume 52 weeks a year. Per-person figures divide fuel only — not maintenance, insurance, or depreciation.
A US gallon is 3.785 liters and a mile is 1.609 kilometers. Economy converts with L/100km = 235.215 ÷ MPG, which is why the two numbers move in opposite directions: a higher MPG is better, a lower L/100km is better.
A 36-mile round-trip commute, five days a week, in a car that gets 30 MPG. Gas costs $3.65 a gallon and the tank holds 12 gallons.
| Item | Treatment | Why it matters |
|---|---|---|
| Fuel burned while driving | Included | Based on the economy figure you enter, not the window sticker. |
| Round trip and weekly frequency | Included | One-way distance is doubled, then multiplied by 52 weeks. |
| Splitting between passengers | Included (fuel only) | Useful for carpools; everyone shares the fuel bill equally, including the driver. |
| Tank range and fill-ups | Included when you add tank size | Range per tank and cost per fill-up make the annual total concrete. |
| Maintenance, tires, insurance | Not included | These costs continue whether you drive or not, and vary widely by vehicle. |
| Depreciation and financing | Not included | Depreciation is often the largest per-mile cost of ownership. |
| Tolls, parking, congestion charges | Not included | Add them separately for a full door-to-door cost. |
| Traffic, idling, AC, speed, weather | Not included | Real consumption can be 10–30% higher than a steady test figure. |
| Changing fuel prices | Not included | The calculator holds your price constant across the year. |
Calculate fuel costs per trip, week, month, and year in miles/MPG or km/L/100km. Split costs between passengers and see tank range and fill-up cost.
Fuel is the most visible recurring cost of driving, but most people only see it as a series of card taps at the pump. Multiplying a single fill-up by the number of fill-ups per month hides how much the commute actually costs — and how sensitive that number is to distance, traffic, and fuel prices. This calculator turns the guesswork into a per-trip, weekly, monthly, and annual figure, then lets you stress-test it: what happens if gas rises 25%, if you move ten miles farther out, or if you trade a 20 MPG vehicle for one that gets 35? A typical US commuter driving 36 miles round trip five days a week at 30 MPG burns about 312 gallons a year; small changes in any input move that total by hundreds of dollars.
In US units the core formula is straightforward: gallons used = distance ÷ MPG, and cost = gallons × price per gallon. Annual fuel = round-trip distance × trips per week × 52 ÷ MPG. In metric units the same journey is measured as liters = distance × L/100km ÷ 100, and cost = liters × price per liter. The tool stores the unit system and converts every value when you switch, so you never have to re-enter the trip. One US gallon is 3.785411784 liters and one mile is 1.609344 kilometers; fuel economy converts through L/100km = 235.214583 ÷ MPG. Because the two economies are reciprocal, a switch does not change the physical trip, only the units used to describe it.
The result covers fuel purchased for the trips you describe, using the price and economy you enter. It does not include maintenance, tires, insurance, depreciation, tolls, parking, or financing — those are ownership costs rather than fuel costs, and for a new car depreciation alone often exceeds the annual fuel bill. It also assumes steady economy: cold starts, idling in traffic, air conditioning, hills, and highway speeds above the efficiency sweet spot can all increase consumption. If you want a conservative budget, use a slightly lower MPG than the sticker or a slightly higher price than today’s, and compare the result with your actual credit-card spending over a couple of months.
The per-person split makes carpooling concrete: a 36-mile round trip at $4.38 of fuel becomes $2.19 each when two people share, and the annual saving scales with every extra passenger. The distance and economy charts show which lever matters more in your situation — for a long commute, a few MPG can beat a small change in route, while for a short one, combining trips is usually the bigger win. Tank range and fill-up cost help with planning: they tell you roughly how many fills a year to expect and what each stop costs at current prices. Finally, remember that this is an estimate for budgeting, not a quote: fuel prices vary by station and region, and winter blends, ethanol content, and driving style all shift real-world results.
Fuel cost per trip = distance ÷ fuel economy × fuel price. In US units, a 36-mile round trip at 30 MPG uses 1.2 gallons; at $3.65 per gallon that is $4.38. In metric units the same idea uses liters: distance × (L/100km ÷ 100) × price per liter. The calculator applies the round-trip multiplier when you enable it, then multiplies by trips per week and 52 weeks for the annual figure.
Enter the one-way distance — the calculator doubles it when “Round trip” is on. If you commute 18 miles each way, enter 18 and leave round trip on; the tool uses 36 miles per trip. Turn round trip off for a one-way journey. Getting this wrong doubles or halves every downstream figure, so it is the first thing to check if a result looks off.
EPA estimates come from standardized laboratory cycles, while real driving includes cold starts, traffic, hills, air conditioning, roof racks, and high speeds. Short trips are the biggest gap: a cold engine can burn 20–30% more fuel for the first few miles. Heavy acceleration and sustained speeds above roughly 60 mph also reduce efficiency quickly. Use your own tank-to-tank average if you track it, or lower the EPA combined rating by 10–20% for a realistic estimate.
L/100km = 235.215 ÷ MPG. The two measures are inversely related, so 30 MPG is about 7.84 L/100km and 50 MPG is about 4.70 L/100km. When you switch units in this calculator it performs that conversion automatically, along with miles to kilometers, gallons to liters, and price per gallon to price per liter, so the resulting trip cost stays consistent.
Enter the number of people sharing the vehicle including the driver. The calculator divides the per-trip and annual fuel cost by that number and shows a per-person figure. It splits fuel only — tolls, parking, maintenance, and rental fees are not included — so agree on those separately if you are carpooling or road-tripping with friends.
Range = tank capacity × fuel economy (or ÷ L/100km × 100 in metric), which estimates how far a full tank takes you before reserve. Fill-up cost = tank capacity × price per unit, the cost of refueling from empty. Real range is a little lower because you rarely run the tank completely dry and because efficiency varies; treat the number as a planning ceiling, not a guarantee.
Yes. The calculator is free, needs no account, and runs entirely in your browser. Your distances, fuel prices, and vehicle details are never uploaded or stored on a server, and switching units or clearing the form only changes local state. Nothing about your commute is sent anywhere.
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