📊 Gas Cost 利潤與成本計算機

The Gas Cost Calculator estimates how much fuel you'll burn — and how much it will cost — for any car trip. It works with US-style units (miles and miles per gallon), so it's ideal for drivers in the United States. You enter three values, and the tool instantly returns the total trip cost, the number of gallons used, and your cost per mile.

• Distance (miles): the total length of your trip in miles.
• Miles per Gallon (MPG): your vehicle's fuel efficiency — check your dashboard, owner's manual, or fuel-economy sticker.
• Gas Price (per gallon): the price you pay at the pump, in your local currency.

Behind the scenes the calculator uses three simple steps:

• Gallons used = Distance ÷ MPG
• Total cost = Gallons used × Gas price
• Cost per mile = Total cost ÷ Distance

In short, fewer miles per gallon or a higher pump price both push your total cost up, while a longer distance increases both the fuel used and the overall bill.

Say you're driving 300 miles in a car that gets 25 MPG, and gas costs $3.50 per gallon.

• Gallons used = 300 ÷ 25 = 12 gallons
• Total cost = 12 × 3.50 = 42.00
• Cost per mile = 42.00 ÷ 300 = 0.14 per mile

So this trip would cost about $42, or 14 cents for every mile driven.

The table below shows what the same trip costs at three different fuel economies and three different pump prices. All figures assume US gallons and use the calculator's formula:

These prices are illustrative round numbers chosen to bracket a plausible range — they are not current pump prices. Fuel prices change daily and vary widely by country, state and station, so replace them with the price you actually expect to pay. Costs are rounded to the nearest cent and cost per mile to three decimals.

Two patterns are visible in the numbers. First, cost per mile depends only on MPG and price, not on distance — the 100 mi and 1,000 mi rows at the same MPG and price share the same per-mile figure, and total cost scales linearly with distance. Second, the effect of fuel economy is proportional: going from 20 MPG to 40 MPG halves the fuel cost, while going from 40 MPG to 60 MPG cuts it by only a third more, because gallons burned varies with 1/MPG rather than with MPG itself.

The cost-per-mile figure this calculator reports is fuel only. It is simply the pump price divided by your MPG:

It does not include depreciation, tires, oil changes and other maintenance, insurance, registration, financing or lease payments, tolls, parking, or the cost of electricity if you drive a plug-in hybrid on battery for part of the trip. On most vehicles those non-fuel items together cost more per mile than the fuel does, so the number here is a lower bound on what a mile actually costs to drive.

That distinction matters most when comparing against a mileage reimbursement. In the United States, the IRS publishes a standard mileage rate for business use, set annually (it has been in the region of 65–70 cents per mile in recent years). That rate is deliberately a full-cost allowance covering depreciation, maintenance, insurance and fuel combined — it is not a fuel price. Comparing it with a fuel-only cost per mile of, say, $0.12 does not mean someone is being overpaid; the two figures measure different things. Other countries use their own schemes with different rules and amounts, so check the rate published by your own tax authority or employer rather than assuming the US figure applies.

Worked example: a round trip

Enter total distance, not one-way distance. A commute of 120 miles each way is a 240-mile entry. At 28 MPG and $3.60 per gallon:

That is 3.60/gal">30.86 of fuel, or about $0.129 per mile. Entering 120 instead of 240 would understate the trip by exactly half.

Reading the gallons figure

The gallons-used output is the one to compare against your tank. If the trip needs 8.6 gallons and the tank holds 14 gallons, the trip fits on one fill with margin. If a 1,000-mile drive at 30 MPG needs 33.3 gallons and the tank holds 14, that implies roughly two refuelling stops beyond the starting tank — useful for planning where and when you stop, and a reminder that usable range is less than tank capacity × MPG, since few drivers run a tank to empty. Gallons used is also the figure to check if you buy fuel in a different currency or unit partway through a trip.

MPG (miles per gallon)

Distance a vehicle travels per unit of fuel: miles divided by gallons consumed. Unless stated otherwise, MPG in this calculator means US MPG based on the US gallon (3.785 litres). Higher MPG means less fuel per mile.

EPA combined, city and highway ratings

Fuel economy labels published by the US Environmental Protection Agency for vehicles sold in the United States. The city rating reflects stop-and-go, lower-speed driving; the highway rating reflects steadier higher-speed driving; the combined rating is a weighted average of the two (55% city, 45% highway). For a long interstate drive the highway figure is the closer estimate; for mixed daily driving, use combined. Other markets publish their own ratings under different test cycles (for example WLTP in Europe), and those numbers are not directly interchangeable with EPA values.

Gallons used

Fuel consumed on the trip, calculated as Distance ÷ MPG. Compare it with your tank capacity to judge how many refuelling stops the trip needs.

Cost per mile (fuel-only)

Pump price divided by MPG — the fuel cost of driving one mile. It excludes depreciation, maintenance, insurance, tolls and every other running cost, so it is not a full cost of ownership per mile.

Pump price per gallon

The advertised price you pay at the station. In the United States this price already includes federal and state fuel taxes; in most other countries fuel is sold by the litre and tax treatment differs. Enter the price for the grade of fuel you actually buy, since premium typically costs more per gallon than regular.

L/100 km and Imperial MPG

Two other units that must be converted before being entered here. Litres per 100 kilometres is a consumption figure used across most of Europe and much of Asia; convert with US MPG = 235.215 ÷ (L/100 km). Imperial MPG, used in the UK, is based on the Imperial gallon (4.546 litres) and is therefore larger for the same vehicle: US MPG = Imperial MPG ÷ 1.201. A car rated 40 MPG (Imperial) is about 33.3 MPG (US). Entering an Imperial or L/100 km number directly will give a wrong result.

Fuel economy vs fuel consumption

Fuel economy (MPG) measures distance per unit of fuel — bigger is better. Fuel consumption (L/100 km, or gallons per 100 miles) measures fuel per unit of distance — smaller is better. They are reciprocals of each other, which is why equal MPG gains are not equal fuel savings: improving from 15 to 20 MPG saves about 1.67 gallons per 100 miles, while improving from 40 to 45 MPG saves only about 0.28 gallons per 100 miles.