🧰 ToolPicoAll Tools →
⛽ Trip fuel cost calculator

Fuel Cost Calculator

Find your trip's gas cost from distance, your vehicle's MPG, and the current price per gallon. Round-trip, per-person split, regular vs premium vs diesel comparison, a two-route comparison, and monthly/annual cost — all in one free tool with instant, plain-English results.

Formula: (mi÷MPG)×$/gal Regular · Premium · Diesel Round trip & per-rider split 100% free
mi
One-way distance. Turn on round trip below to double it.
MPG
Miles your vehicle travels per gallon of fuel.
$
Enter today's pump price — prices change often, so this is never fixed.
🚦 Driving mix (optional)Blends city/highway MPG into an effective MPG
🏙️ City 50%🛣️ Highway 50%
Select a vehicle/fuel type below to blend its city/highway MPG — the effective MPG will auto-fill the field above.
Drive the same distance on regular, premium, and diesel and see which is cheapest per mile. Enter your own MPG and current price for each.
mi
⛽ Regular unleaded
MPG
$
⛽ Premium unleaded
MPG
$
🛢️ Diesel
MPG
$
Compare two routes (e.g. interstate vs. scenic route) side by side to see which one costs less in gas.
🅰️ Route A
mi
MPG
$
🅱️ Route B
mi
MPG
$
Estimate the monthly and annual fuel cost of a regular drive, like a daily commute.
mi/day
days
MPG
$
⚙️ Round trip, split by riders & vehicle type
people
Round tripAutomatically doubles the distance
Quick answer Fuel cost is found by dividing the distance by your vehicle's MPG to get the gallons needed, then multiplying by the price per gallon: Cost = (Distance ÷ MPG) × Price per gallon. For example, a car getting 32 MPG driving 300 miles at $3.49/gal uses about 9.4 gallons and costs about $32.72 — roughly $0.11 per mile.
—Cost per 100 miles
—Cost per mile
—Gallons per 100 miles
—CO2 per 100 miles
⛽ How do I get an accurate result? Accuracy depends on the values you enter. Price per gallon is never fixed — always enter today's pump price. MPG is most accurate when taken from your vehicle's real trip computer rather than the window-sticker rating; city driving and short trips typically use more fuel than the combined rating suggests. The CO2 estimate uses a fixed emissions factor per gallon (gasoline ≈ 19.6 lbs CO2/gal, diesel ≈ 22.4 lbs CO2/gal).
⛽ Fuel Cost Calculator — ToolPico ↗

What is fuel cost calculation, and how is it done?

A complete guide — with formulas and examples — to trip fuel cost, cost per mile, round trip, per-person splitting, and regular vs premium vs diesel comparison.

Fuel cost calculation means estimating, in advance, how much the gas for a trip will cost. It takes three inputs: the distance you'll drive (in miles), your vehicle's fuel efficiency (in MPG, miles per gallon), and the current price per gallon at the pump. This tool handles a single trip, a regular commute (monthly/annual), and lets you compare fuel types and two different routes side by side.

What is the fuel cost formula?

Quick answerCost = (Distance ÷ MPG) × Price per gallon. First divide the distance by your vehicle's miles-per-gallon rating to get the gallons you'll burn, then multiply by the current price per gallon. Cost per mile = Total cost ÷ Distance.
  • Gallons needed = Distance (mi) ÷ MPG
  • Total fuel cost = Gallons needed × Price per gallon
  • Cost per mile = Total cost ÷ Distance
  • Range from 1 gallon = your vehicle's MPG rating (that's the definition of MPG)

How many gallons and how much does 100 miles cost? (example table)

Quick answerGallons used for 100 miles equal 100 ÷ MPG. A car averaging 32 MPG uses about 3.1 gallons per 100 miles, costing about $10.90 at $3.49/gal — $0.109 per mile. The table below uses different distances at a constant 32 MPG and $3.49/gal.
Example trip cost (32 MPG · $3.49/gal)
DistanceGallons usedFuel costPer mile
50 mi1.6 gal$5.45$0.109
100 mi3.1 gal$10.90$0.109
200 mi6.3 gal$21.81$0.109
300 mi (typical road trip)9.4 gal$32.72$0.109
500 mi15.6 gal$54.53$0.109
1,000 mi31.3 gal$109.06$0.109

Note: the price per gallon in this table is only an example. Use the calculator above with your own current price and MPG for an exact result.

How do round-trip and per-person costs work?

Quick answerFor a round trip, double the distance; just turn on the round-trip switch in advanced settings. Per-person cost = Total cost ÷ Number of riders. For example, if 3 people split a $32.72 fill-up, each person owes about $10.91. Splitting fuel cost with passengers meaningfully lowers everyone's per-person expense.

Is regular, premium, or diesel cheaper per mile?

Quick answerIt depends on both price and MPG, not price alone. Diesel often costs more per gallon but frequently gets 15–25% better MPG, which can make it cheapest per mile overall. Premium usually costs 15–20% more per gallon without a matching MPG gain unless your engine specifically requires it, making it the most expensive option per mile in most cases. Use the "Fuel type" tab with your own MPG and current prices; the calculator highlights the cheapest option in green.

Don't forget: a more fuel-efficient vehicle (like a hybrid or diesel) may cost more upfront or need different maintenance. See the fuel-efficient vehicle payback calculator below to see how many miles it takes for a more efficient vehicle to earn back an extra purchase cost.

Popular fuel cost calculations

Ready-made calculations for commonly searched trips and scenarios. Click one to load it into the calculator automatically.

Related mini calculators: EV comparison, tank range & payback

Three extra calculators that help with fuel and vehicle decisions — all run in your browser, completely free.

🔌EV vs gas cost
Is an electric vehicle or a gas car cheaper for this distance? Compare cost per mile.
kWh
$
MPG
$
🛢️Tank & range calculator
How far does a full tank go, and how many fill-ups does a trip need?
gal
MPG
$
mi
🔋MPG upgrade payback
Is a more efficient (or hybrid) vehicle worth its extra cost? Find the break-even mileage.
$
MPG
MPG
$

Reference tables & practical figures

Citable data: common US road trip distances, typical MPG by vehicle type, fuel type comparison, and CO2 emissions per gallon.

Common US road trip distances (one-way, approximate highway miles)
RouteDistance

Distances are approximate highway figures and vary by route chosen. Click a row to load it into the "Trip cost" tab.

Typical MPG by vehicle type
Vehicle typeCityHighwayCombined
Compact car (gas)304034
Midsize sedan (gas)263630
Diesel car324538
SUV / crossover222925
Pickup truck182420
Hybrid454846
Electric (MPGe)115100108

Values are typical ranges; driving style, load, tire pressure, and climate control affect real-world MPG.

Fuel type general comparison
FuelTypical priceStands out for
Regular unleaded≈ $3.30–3.70/galLowest price, works in most vehicles
Premium unleaded≈ $3.90–4.40/galOnly needed for high-compression/turbo engines
Diesel≈ $3.60–4.00/galOften 15–25% better MPG on the highway
Electric (per kWh)≈ $0.12–0.22/kWhUsually the lowest cost per mile

Premium usually costs more per gallon than regular without a matching MPG gain in most engines.

Average CO2 emissions per gallon of fuel burned
Fuellbs CO2 / gallonExample (100 mi)
Regular gasoline≈ 19.632 MPG → ≈ 61 lbs
Premium gasoline≈ 19.6Same as regular per gallon burned
Diesel≈ 22.438 MPG → ≈ 59 lbs

Figures are widely used EPA average constants (fixed per gallon burned); actual emissions vary with fuel blend and engine efficiency.

Fuel cost & MPG terms glossary

Short definitions of the core terms used in fuel cost calculations.

MPG (miles per gallon)The distance a vehicle travels per gallon of fuel — the standard US fuel-efficiency rating.
Price per gallonThe current pump price of fuel. It changes often, so you always enter today's price.
Cost per mileTotal fuel cost divided by distance driven — the best figure for comparing vehicles or fuel types.
Round tripDriving to a destination and back; distance (and cost) roughly doubles versus one-way.
Per-person costTotal trip fuel cost divided by the number of people sharing the ride.
Gallons per 100 milesThe inverse of MPG; a more linear way to compare fuel savings between two vehicles.
Tank rangeThe distance a full tank can cover, equal to tank size (gallons) × MPG.
City / highway / combined MPGEPA ratings for stop-and-go driving, steady highway speeds, and a blended average of both.
MPGe"Miles per gallon equivalent" — used to compare an EV's energy use to a gas car's fuel economy.
CO2 emissionsCarbon dioxide released per gallon of fuel burned; a fixed chemical constant for a given fuel.
Payback periodHow many miles or months of fuel savings it takes for a more efficient vehicle to earn back its extra cost.
kWh (kilowatt-hour)The unit used to measure electricity used by an EV — the electric equivalent of a gallon.

In-depth guides

Detailed answers to the most commonly asked fuel cost questions.

How much does a 300-mile road trip cost in gas?

A 300-mile trip in a car averaging 32 MPG burns 300 ÷ 32 = 9.4 gallons. At a pump price of $3.49/gal, that's 9.4 × 3.49 ≈ $32.72 in gas — about $0.109 per mile. On a round trip (600 miles total), that amount roughly doubles to about $65.44.

A less efficient truck at 20 MPG would burn 15 gallons for the same 300 miles, costing about $52.35 — over 60% more, even at the identical price per gallon. This is why MPG, not just the price at the pump, drives most of the cost difference between vehicles. Enter your own distance, MPG, and current price above for an exact number.

Is diesel or regular gas cheaper per mile?

It depends on the combination of price and MPG. For example, over 300 miles: regular at 32 MPG and $3.49/gal costs about $32.72 ($0.109/mi); diesel at 38 MPG and $3.85/gal costs about $30.39 ($0.101/mi) — cheaper overall thanks to better mileage, even with a higher price per gallon. Premium at 33 MPG and $4.15/gal costs about $37.73 ($0.126/mi) — the most expensive of the three in this example, since the higher price isn't offset by a big enough MPG gain.

The exact winner always depends on your vehicle's real MPG and the prices at your local stations, which is why the "Fuel type" tab lets you plug in your own numbers instead of relying on a single rule of thumb.

Practical ways to improve your MPG

The biggest factors affecting MPG (and therefore cost) are tire pressure (underinflated tires increase fuel use), steady highway speeds, unnecessary cargo weight, aggressive acceleration and braking, and engine maintenance (like a clogged air filter). Keeping tires properly inflated, driving smoothly, and staying current on maintenance can each add a few percent to your MPG.

On the highway, driving at a steady 55–65 mph is noticeably more efficient than stop-and-go city driving or speeds above 70 mph, where aerodynamic drag rises sharply. Using your vehicle's real trip-computer MPG (rather than the window-sticker rating) in the calculator gives a more accurate result than a catalog figure.

Add this calculator to your site (embed code)

Embed the fuel cost calculator on your own website for free. Copy the code below into your HTML — the tool runs in a simplified view and links back to this page as its source.

The embedded tool has a fixed layout; you can adjust the height value to fit your site. No ads or personal data, runs entirely client-side.

Frequently asked questions

How do you calculate fuel cost for a trip?
Trip fuel cost is found with Cost = (Distance ÷ MPG) × Price per gallon. First divide the distance by your vehicle's MPG to get the gallons needed, then multiply by the current price per gallon. A car getting 32 MPG driving 300 miles at $3.49/gal uses about 9.4 gallons and costs about $32.72.
How many gallons does 100 miles use?
Gallons used for 100 miles equal 100 ÷ MPG. A car averaging 32 MPG uses about 3.1 gallons per 100 miles; a 40 MPG car uses about 2.5 gallons; a 20 MPG truck uses about 5 gallons. This is sometimes called gallons per 100 miles (GPM).
How do you calculate round-trip fuel cost?
Double the one-way distance, then apply the normal formula: Cost = (2 × Distance ÷ MPG) × Price per gallon. In the calculator, just turn on the round trip switch in advanced settings; the distance doubles automatically.
How far can you drive on one gallon of gas?
Exactly your vehicle's MPG rating — that's the definition of miles per gallon. A car rated at 32 MPG travels about 32 miles per gallon; a hybrid rated at 50 MPG travels about 50 miles per gallon. Real-world range varies with driving style and terrain.
Is diesel or regular gas cheaper per mile?
It depends on both price and MPG. Diesel often costs more per gallon but frequently gets 15–25% better MPG, which can make it cheaper per mile overall. Use the "Fuel type" tab with your own numbers to see which one wins per mile for your vehicle.
Is premium gas worth the extra cost?
For most vehicles, no. Premium typically costs 15–20% more per gallon than regular but doesn't meaningfully improve MPG unless the engine specifically requires it (high-compression or turbocharged engines). If your manual says "regular fuel recommended," premium usually raises your cost per mile without a matching efficiency gain.
How do you split a road trip's gas cost between passengers?
Per-person cost = Total fuel cost ÷ Number of riders. If a trip costs $32.72 in gas and 3 people split it, each person owes about $10.91. Fill in "Split between" in advanced settings and the calculator shows the per-person amount automatically.
How do you estimate monthly commuting fuel cost?
Multiply daily distance by days driven per month to get monthly miles, then apply the fuel cost formula. 30 miles a day for 22 days is 660 miles a month; at 32 MPG and $3.49/gal that's roughly $72/month, or about $864/year. The "Monthly / Annual" tab automates this.
Why isn't the gas price fixed in the calculator?
Gas prices change often — sometimes daily — so the price per gallon is never hardcoded. You always enter today's pump price, which keeps every result accurate and current instead of relying on an outdated number.
Can I calculate fuel cost in km and liters instead of miles and gallons?
Yes — use the metric/imperial toggle above the Trip Cost tab to switch to km, L/100km (or km/L), and price per liter. Your entries convert automatically, and the results stay accurate in whichever unit system you choose.
What is an effective MPG based on city/highway driving mix?
Fuel economy isn't linear between city and highway driving, so an effective MPG blends the two using the percentage of your drive spent in each. Use the driving-mix slider in the Trip Cost tab to set your City % / Highway % split — the calculator blends the reference city/highway MPG and fills in the effective MPG for you.

Methodology & sources

ToolPico's Fuel Cost Calculator is a free, independent tool. The calculation engine runs entirely in your browser with the standard formula: Cost = (Distance ÷ MPG) × Price per gallon. Cost per mile, gallons needed, per-person split, round trip, and the fuel-type/route/monthly comparisons are all derivatives of this base formula. No data is sent to a server.

Input data: distance, MPG, and price per gallon are entered by the user (the price is never fixed — it's always the current value you provide). CO2 estimates use fixed average emissions factors per gallon burned (gasoline ≈ 19.6 lbs CO2/gal, diesel ≈ 22.4 lbs CO2/gal), figures widely used by the EPA. Road trip distances are approximate highway figures. Last updated: July 21, 2026. Results are for informational purposes only and are not financial advice; actual cost varies with driving conditions and current prices.

🔗 Add this tool to your site

Copy the code below into your own site. The tool is free, always up to date, and runs entirely on your page. No sign-up required.

Preview →
⚡ Built with ToolPico · toolpico.com