Fuel Cost / Trip Calculator
Estimate your trip's fuel cost, gallons needed, cost per mile, and CO2 emissions.
Last reviewed: April 2026This fuel cost calculator computes the total gasoline (or diesel) cost for a trip given trip distance, vehicle fuel economy, and pump price. Enter your trip details above; the sections below explain exactly how each result is derived, why EPA MPG numbers rarely match the real world, how to think about total cost of ownership beyond fuel alone, and how electric vehicles stack up on cost-per-mile against gas.
What This Calculator Does
The Core Fuel Cost Formula
Every trip's fuel bill follows the same simple identity: Total Cost = (Distance ÷ Fuel Economy) × Price per Unit. The calculator divides your trip distance by your vehicle's fuel economy to get the volume of fuel consumed, then multiplies that volume by the price per gallon (or per liter) to produce the dollar total. From that same calculation it derives two secondary metrics you actually use for budgeting: gallons (or liters) consumed and cost per mile (or per kilometer).
Units the Calculator Handles
The default U.S. display works in miles and U.S. gallons against a U.S. dollar price. For Canadian, U.K., and metric users, three conversions matter: an Imperial gallon equals 1.20095 U.S. gallons (4.546 liters vs. 3.785 liters), so MPG quoted in Imperial gallons looks ~20% higher than the same vehicle's U.S. rating. Liters per 100 km is the inverse-style metric used across Europe and is preferable for ranking vehicles because it is linear: half the L/100km means half the fuel. The conversion from MPG (U.S.) to L/100 km is L/100km = 235.215 ÷ MPG, so a 29-MPG sedan = 8.11 L/100km. A 5 L/100km efficient car = 47.0 MPG (U.S.).
What the Round-Trip Toggle Does
The round-trip toggle simply doubles the trip distance before the cost calculation runs. This matches real road-trip planning because the GPS one-way figure is usually what you have in hand, but you need to budget for fuel both directions. The calculator also surfaces CO2 emissions using the EPA's standard factor of 19.6 lb of CO2 per gallon of gasoline burned, which is useful for carbon-budget conscious travelers and for comparing internal combustion against EV alternatives.
How to Use It
Step-by-Step Inputs
Enter your trip distance as the one-way miles for the journey. If you're planning a round trip, enable the toggle rather than doubling the number manually — the calculator handles it and labels the result accordingly. Enter your vehicle's fuel efficiency in MPG. For best accuracy, use your real measured MPG averaged over the last 5–10 fill-ups rather than the EPA sticker number, because real-world driving conditions almost always diverge from the lab test (see the EPA discussion below). The four quick-select buttons (Sedan 25, Hybrid 30, Truck 15, EV Equivalent 50) cover common rough categories if you're shopping rather than driving a specific vehicle.
Setting a Realistic Fuel Price
Enter the current pump price per gallon as decimal dollars. National-average prices from EIA or AAA are a reasonable default if you're forecasting a trip across many states, but for accuracy, GasBuddy and similar route-aware apps will show the actual lowest prices along your planned highway corridor. Mid-trip price variation can swing a long road trip's fuel bill by 10–20% depending on which states you fuel up in (state fuel taxes vary by roughly $0.60/gallon between the lowest and highest).
Reading the Output
The calculator shows four primary results: total fuel cost, gallons (or liters) needed, cost per mile, and CO2 emissions. Cost per mile is particularly useful when comparing trips or vehicles — it normalizes the math so a 200-mile trip and a 2,000-mile trip can be ranked on equal footing. The shareable URL captures all four inputs, so you can bookmark a specific calculation or send it to a travel companion for review without having to re-enter anything.
Worked Example: 487-Mile Road Trip in a 29-MPG Sedan
- Trip distance (one-way)
- 487 miles
- Vehicle
- 2024 Honda Accord sedan
- Real-world MPG (highway)
- 29 MPG
- Fuel grade
- Regular unleaded (87 octane)
- Average pump price
- $3.42 / U.S. gallon
Step 1 — Compute Gallons Consumed
487 miles ÷ 29 MPG = 16.79 gallons. This is the total volume of fuel the sedan will burn over the one-way trip. Round up to 17 gallons if you want a buffer for traffic detours, weather, or finding the most convenient fuel stops rather than the cheapest ones.
Step 2 — Compute Total Cost
16.79 gallons × $3.42/gallon = $57.42 total fuel cost. Cost per mile: $57.42 ÷ 487 miles = $0.118 per mile. CO2 emissions: 16.79 gallons × 19.6 lb/gallon = 329 lb of CO2, or about 149 kg.
Step 3 — Compare Against Other Vehicles
The same 487-mile trip in different vehicles produces dramatically different fuel bills, all else equal:
- 24-MPG SUV: 487 ÷ 24 = 20.29 gallons × $3.42 = $69.41 (cost per mile $0.143). About $12 more than the sedan.
- 52-MPG hybrid (Toyota Camry Hybrid or similar): 487 ÷ 52 = 9.37 gallons × $3.42 = $32.04 (cost per mile $0.066). Roughly $25 less than the sedan and $37 less than the SUV.
- 15-MPG full-size truck towing: 487 ÷ 15 = 32.47 gallons × $3.42 = $111.04. Over the course of a 10,000-mile/year commute the gap between the truck and the hybrid totals roughly $1,700/year in fuel alone.
Step 4 — Round Trip and Real-World Adjustments
For a round-trip cost, double the 487-mile distance and the fuel total: 974 miles, 33.59 gallons, $114.83 total. Note this is highway MPG only; if 100 miles of the route is dense urban traffic at a city-cycle rating of ~22 MPG, the actual gallons consumed will tick up by roughly 0.5–1 gallons and the cost by $2–$3. Cold-start fuel waste on a multi-stop trip with overnight pauses can add another 1–2% to the total.
Common Use Cases
Road Trip Budgeting
Multi-day road trips are the most direct application. Plug in the total route mileage from Google Maps, your vehicle's real measured MPG, and an average pump price along the corridor. For trips crossing multiple states, weight the fuel price toward the cheaper states where you'll fill up (Texas and Missouri typically run $0.30–$0.60 below California, for example). Add a 5–10% contingency for detours, traffic, and rest stops.
Rideshare and Delivery Driver Reimbursement Math
Uber, Lyft, DoorDash, and Instacart drivers can use the calculator to estimate raw fuel cost on a shift, which sits inside but is dwarfed by full IRS-mileage-rate ownership cost. A typical 8-hour rideshare day covering 150 miles in a 28-MPG sedan at $3.42 burns 5.4 gallons / $18.32 in fuel — but the true marginal cost per mile, factoring depreciation, tire wear, oil changes, and accelerated maintenance from city driving, is much closer to the IRS standard rate.
IRS Standard Mileage Reimbursement
For 2026 the IRS standard business mileage rate is $0.70 per mile (set annually by Revenue Procedure). A self-employed contractor reimbursing themselves at the IRS rate for the 487-mile trip in the worked example claims 487 × $0.70 = $340.90 — roughly 5.9× the raw fuel cost of $57.42. That spread is intentional: the IRS rate covers depreciation, insurance, registration, tires, repairs, and maintenance on top of fuel. Treat fuel cost as the marginal out-of-pocket spend and the IRS rate as the deductible representation of full operating cost.
Commute Cost vs. Public Transit Comparison
A 22-mile each-way commute (44 miles/day round-trip, 220 miles/week, ~10,560 miles/year) in a 25-MPG vehicle at $3.50/gallon costs roughly $1,478/year in fuel alone. Compare that to a $120/month transit pass ($1,440/year) and the two come out roughly even on fuel — but include parking fees, depreciation, and the IRS rate equivalence and driving costs 4–6× more in true total cost. This is the budget math that makes transit a strong choice in dense metros.
Comparing Two Cars Before Purchase
Plug in your annual mileage and compare two vehicles' MPG side-by-side. The difference between a 25-MPG and a 35-MPG vehicle driven 15,000 miles/year at $3.50/gallon is $600/year in fuel ($2,100 vs $1,500). Over a 7-year ownership period that's $4,200 — a useful number to set against any sticker-price premium for the more efficient vehicle.
Edge Cases and Gotchas
Speed Has a Sharp Optimum
Fuel economy isn't constant — it peaks for most passenger cars around 50 mph and falls off sharply above 65. Aerodynamic drag rises with the square of velocity, so a vehicle that gets 35 MPG at 55 mph might drop to 28 MPG at 75 mph and below 25 MPG at 80 mph. The DOE estimates each 5 mph above 50 mph adds roughly $0.20/gallon equivalent in cost. Cruise control at 5 mph below the speed limit on highway stretches is one of the highest-ROI fuel-saving behaviors.
EPA's Two Numbers: City vs. Highway
Every EPA sticker lists separate city and highway MPG ratings derived from two different drive cycles. The composite number on the sticker is a 55/45 city/highway weighted average. For trip planning, use the rating closest to your actual route mix — interstate driving leans heavily toward the highway number, while a 20-mile urban commute is closer to the city figure. A 32 MPG combined sedan typically rates ~27 city / 36 highway.
Grade and Elevation Impact
Climbing significant elevation costs energy, and that energy comes from fuel. The Eisenhower Tunnel approach (Denver to summit, about 50 miles gaining 5,000 feet) can cost 15–25% MPG versus flat-road equivalent. Conversely, the descent recovers some of that energy through engine braking and reduced throttle. Over a balanced round-trip the net penalty is smaller, but for single one-way calculations toward higher elevations, knock 10–15% off your normal MPG.
A/C, Heat, and Climate Loads
Air conditioning typically costs 5–10% MPG in moderate use, 15–25% in hot stop-and-go conditions on small four-cylinder engines. Heating in a gas vehicle is essentially free (it uses waste engine heat), but defrost mode on most vehicles automatically engages A/C to dehumidify, so winter morning startups burn extra fuel too. EVs pay for cabin heat in range loss instead of MPG.
Cold-Start Penalty
Catalytic converters need to reach ~600°F before they operate efficiently, and the engine runs richer (more fuel per air mass) until coolant temperature reaches ~190°F. The first 5–10 minutes after a cold start can run at 30–50% lower MPG than a fully warmed engine. Multi-stop trips with cold restarts (such as errands rather than continuous travel) carry an outsized fuel penalty relative to a single longer trip covering the same total miles.
Premium vs. Regular: Price Differential vs. Real MPG Differential
Premium gasoline currently averages $0.50–$0.80/gallon above regular. For a vehicle that requires premium, no choice exists. For a vehicle where premium is recommended (not required), AAA's testing has shown 1–3% MPG and similar power gains on premium — usually not enough to offset the price premium. Vehicles labeled "regular fuel" gain nothing from premium and represent pure waste.
Towing: 30–50% MPG Drop
A half-ton pickup rated 22 MPG empty often delivers 12–14 MPG towing a 6,000 lb travel trailer at highway speed. Larger fifth-wheel trailers or boats pulled by full-size diesels can see similar percentage drops from already-lower baselines. The 487-mile trip in the worked example, if undertaken by a tow rig at 13 MPG and $4.20/gallon for diesel, totals 487 ÷ 13 × $4.20 = $157.36 — roughly 2.75× the sedan's bill for the same distance.
| Vehicle Class | Typical MPG | Gallons Used | Total Fuel Cost | Cost per Mile | CO2 (lb) |
|---|---|---|---|---|---|
| Full-size truck (towing) | 13 | 37.46 | $128.13 | $0.263 | 734 |
| Full-size truck (empty) | 18 | 27.06 | $92.55 | $0.190 | 530 |
| Mid-size SUV | 24 | 20.29 | $69.41 | $0.143 | 398 |
| Mid-size sedan | 29 | 16.79 | $57.42 | $0.118 | 329 |
| Compact car | 35 | 13.91 | $47.59 | $0.098 | 273 |
| Hybrid (Camry HV class) | 52 | 9.37 | $32.04 | $0.066 | 184 |
| Plug-in hybrid (gas mode) | 54 | 9.02 | $30.85 | $0.063 | 177 |
| EV (Tesla Model 3, gas-equiv.) | ~95 MPGe | n/a (122 kWh) | $19.52* | $0.040 | 0 (tailpipe) |
Beyond Pure Fuel: Total Cost of Ownership
Why the IRS Mileage Rate Dwarfs Fuel Alone
The IRS 2026 standard business mileage rate is $0.70 per mile — roughly 4–6× the typical fuel-only cost per mile of $0.10–$0.15. The gap exists because the IRS rate is meant to capture the full cost of operating a vehicle: depreciation, insurance, registration, tires, maintenance, repairs, and fuel. Studies by AAA's "Your Driving Costs" annual report break this down: for a typical sedan driven 15,000 miles/year, fuel is only about 18–22% of total operating cost; depreciation alone is roughly 40%, with insurance, maintenance, and tires making up the rest.
Marginal vs. Full Cost in Practice
For trip-by-trip decisions (do I drive or take transit?), the marginal cost is closer to fuel + a small wear premium — roughly $0.15–$0.20 per mile for most vehicles. For ownership decisions (should I keep this car or trade it for a more efficient one?), the full IRS-rate equivalent applies because depreciation, insurance, and maintenance are committed regardless of any specific trip. Mixing the two creates flawed budget math: claiming you "saved $200" on a road trip by driving instead of flying ignores the depreciation, tire wear, and increased insurance exposure that came with the extra 1,500 miles.
Maintenance Triggered by Mileage
Many maintenance items scale directly with mileage rather than time. Synthetic oil changes typically run $80–$120 every 7,500–10,000 miles ($0.01/mile). Tire replacement averages $800–$1,400 for a set every 40,000–60,000 miles ($0.020/mile). Brake pads run $150–$400 per axle every 30,000–60,000 miles. Add these to fuel and you reach roughly $0.20–$0.25 marginal cost per mile — still well below the full IRS rate, which factors in depreciation that dominates total cost.
Electric Vehicle Comparison
The kWh per 100 Miles Standard
EV efficiency is most cleanly expressed in kWh per 100 miles, the EV-world analog of L/100km. A Tesla Model 3 Long Range typically consumes 24–26 kWh per 100 miles in real-world mixed driving; smaller EVs like the Chevy Bolt or Hyundai Kona Electric land closer to 28–30 kWh/100mi; the Lucid Air at the efficient end achieves about 22 kWh/100mi. Heavier vehicles (Tesla Model X, Rivian R1T, Ford F-150 Lightning) climb to 35–50 kWh/100mi depending on payload.
Computing Cost per Mile for an EV
Cost per mile = (kWh per 100 mi ÷ 100) × $/kWh. A Tesla Model 3 at 25 kWh/100mi charged at the U.S. residential average of $0.16/kWh costs (25 ÷ 100) × $0.16 = $0.040 per mile, or $4.00 per 100 miles. The same Model 3 charged at a $0.43/kWh DC fast charger costs $0.108/mile — close to the 29-MPG sedan's fuel-only cost of $0.118 on gas.
The MPGe Formula
The EPA's MPGe (miles per gallon equivalent) label exists to let consumers compare EV efficiency to gas-vehicle efficiency on a familiar scale. The conversion uses the energy content of one U.S. gallon of gasoline (33.7 kWh) as the unit of equivalence: MPGe = 33,700 ÷ (Wh per mile), or equivalently MPGe = 33.7 × 100 ÷ (kWh per 100 miles). A 25 kWh/100mi EV: MPGe = 33.7 × 100 ÷ 25 = 134.8 MPGe. That's how the Model 3 LR earns its 132–138 MPGe EPA rating depending on year and configuration. To convert MPGe back to dollar terms, you have to know the local electricity price — the MPGe number alone doesn't capture cost the way an MPG-at-pump comparison does.
Putting EVs in Cost-per-Mile Context
At U.S. average prices ($3.50/gallon gas, $0.16/kWh electricity), a 25 kWh/100mi EV is roughly equivalent on cost-per-mile to a 95-MPG gas car burning $3.80/gallon fuel — far cheaper than any production gasoline vehicle. The picture changes meaningfully with charging choice: at $0.30/kWh peak utility rates the equivalent is closer to 50 MPG (still beating most gasoline vehicles), while at $0.43+/kWh public DC fast charging the equivalent drops to roughly 35 MPG (matching a small hybrid). The lesson: EVs are dramatically cheaper to fuel on home charging, modestly cheaper or break-even with hybrids on expensive public charging, and the typical driver who charges 80%+ at home captures the full savings.
Common Mistakes and Misconceptions
Mistake 1: Using the EPA Sticker Number Verbatim
The EPA combined MPG is a useful comparison point between vehicles but rarely matches your actual driving. Most drivers achieve 85–105% of the EPA combined rating depending on driving style, route mix, climate, and vehicle age. For accurate trip planning, log your own MPG over 5–10 fill-ups and use that personal baseline.
Mistake 2: Comparing Cars by MPG Instead of Gallons per 100 Miles
MPG is non-linear: a 5-MPG improvement at the low end of the scale saves much more fuel than a 5-MPG improvement at the high end. Going 15 → 20 MPG saves 1.67 gallons per 100 miles; going 40 → 45 MPG saves only 0.28 gallons per 100 miles — six times less. When choosing between two efficient cars, the difference between 38 and 42 MPG is much smaller than the percentage suggests. The EPA introduced the gallons-per-100-miles label specifically to surface this distinction.
Mistake 3: Pricing a Trip on Fuel Alone
A 2,500-mile cross-country road trip at $0.12/mile fuel cost = $300. The full IRS-rate cost of that same trip = $1,750. Neither number is "wrong" — they answer different questions. If you're deciding whether to fly vs. drive on a one-shot basis, the marginal cost (fuel + a small wear premium) is the right comparison. If you're choosing a job that requires 25,000 additional miles per year, the full cost matters because depreciation, insurance, and maintenance scale with mileage too.
Mistake 4: Ignoring Currency and Unit Mismatches Internationally
Pricing fuel in U.S. dollars per U.S. gallon when traveling in Canada, the U.K., or continental Europe gives wrong answers. Canada and the U.K. price by liter; Europe prices by liter with a 15–25% VAT load on top of the wholesale figure. To convert a U.K. price quoted as £1.50/liter to U.S. dollars per gallon: £1.50 × 3.785 L/gal × $1.27/£ ≈ $7.21 USD/U.S. gallon — roughly double the U.S. price. Imperial-gallon MPG ratings on older British cars are also ~20% higher than the same vehicle's U.S. rating, which makes head-to-head comparison misleading without unit conversion.
FAQ: Fuel Cost Calculator Questions
How accurate are EPA MPG numbers?
EPA MPG ratings come from a standardized lab test using a dynamometer and a fixed drive cycle defined in 40 CFR Part 600. The agency tests two cycles — city (FTP-75) and highway (HWFET) — then applies a correction factor based on aggressive driving, A/C use, cold-start behavior, and high-speed cruising added during the 2008 methodology revision. Even after that correction, real-world fuel economy generally lands within ±15% of the sticker number, but specific drivers can deviate more sharply depending on terrain, traffic, vehicle age, and driving style. FuelEconomy.gov publishes user-submitted MPG data alongside every EPA sticker so you can compare your real-world average to other owners of the same model.
Why does my actual MPG differ from EPA?
The EPA test cycle peaks at 60 mph and averages closer to 48 mph, so any sustained driving above 65 mph immediately undercuts the rated economy because aerodynamic drag rises with the square of speed. Short trips also penalize you — a cold engine runs richer for the first 5–10 minutes, and catalytic converters need to reach 600°F before they operate efficiently. Aggressive acceleration, heavy A/C use, low tire pressure (every 1 PSI below spec costs roughly 0.2% MPG), cargo weight, roof racks, towing, and cold weather (winter blends contain less energy per gallon and engines take longer to warm) all compound. Logging actual fuel-economy over 5–10 fill-ups gives a much better personal baseline than any single EPA number.
Should I compare cars by MPG or cost per mile?
Cost per mile is the better single metric because MPG is non-linear — going from 15 to 20 MPG saves more fuel than going from 40 to 50 MPG over the same distance. The EPA introduced the gallons-per-100-miles label specifically to make this clearer, since at 15 MPG you burn 6.67 gallons per 100 miles while at 20 MPG you burn only 5 gallons (a 1.67-gallon savings), versus 2.5 vs 2.0 gallons for the 40-to-50 swap (just 0.5 gallons). For ownership decisions, extend this to total cost per mile including depreciation, insurance, maintenance, and fuel — that's roughly what the IRS standard mileage rate captures, and it's nearly always 3–6× higher than fuel alone.
How much does AC affect MPG?
Air conditioning draws 4–6 horsepower from the engine when the compressor cycles on, which translates to roughly a 5–10% MPG penalty for most passenger cars under normal summer use — higher in stop-and-go traffic and on very hot days. The Society of Automotive Engineers (SAE) and Oak Ridge National Laboratory have measured penalties as high as 25% in extreme conditions on small four-cylinder engines, where the A/C load is a larger fraction of total engine output. Driving with the windows down at speeds above roughly 45 mph creates enough aerodynamic drag to be comparable to A/C use, so at highway speed the A/C is usually the more efficient choice; below that, windows down wins. EVs pay the A/C cost in range loss rather than MPG, but the underlying physics is the same.
Is premium gas worth it?
Only if your vehicle's owner's manual or fuel door says premium is required. Vehicles tuned to run on 87-octane regular gain nothing from premium — the higher octane simply resists pre-ignition (knock) in high-compression engines, and a normally-aspirated low-compression engine cannot extract more energy from it. AAA's 2017 fuel study tested six 2016 vehicles designed for regular fuel and found no measurable performance, MPG, or emissions improvement when fed premium. Vehicles where premium is recommended (not required) can typically use regular without engine damage; the ECU retards timing slightly to prevent knock, which costs 1–3% MPG and a similar amount of horsepower — usually far less than the 50–80 cents per gallon price gap, so regular still wins economically. Vehicles where premium is required will run on regular under light load but can suffer detonation under heavy throttle, so don't ignore that label.
How do EVs compare on fuel cost?
EVs typically cost 60–75% less per mile in 'fuel' than a comparable gasoline vehicle at U.S. average electricity prices. A Tesla Model 3 consuming roughly 25 kWh per 100 miles at the U.S. residential average of $0.16/kWh costs about $4.00 per 100 miles — equivalent to a 95-MPG gas car at $3.80/gallon. The EPA's MPGe (miles per gallon equivalent) label uses the conversion 1 gallon of gasoline = 33.7 kWh, so a vehicle rated 132 MPGe is consuming 33.7 ÷ 132 = 0.255 kWh per mile, or 25.5 kWh per 100 miles. Real-world EV cost varies enormously with charging location: home charging on a $0.14/kWh tariff is cheap, public DC fast chargers at $0.43/kWh wipe out most of the savings versus a 30-MPG hybrid, and time-of-use rates make overnight charging significantly cheaper. Factor in your local kWh price and charging mix before assuming a flat 'EVs save 70%' figure.
What's the IRS mileage rate and what's it for?
The IRS standard mileage rate for business use is $0.70 per mile in 2026, set annually under IRS Revenue Procedure guidance and updated each December for the following calendar year. It is intended to cover the full cost of operating a vehicle for business — not just fuel, but also maintenance, repairs, tires, insurance, registration, and depreciation. Because it includes depreciation, the rate is roughly 4–6× higher than a typical fuel-only cost-per-mile figure (which for a 25-MPG car at $3.50/gallon is about $0.14/mile). Taxpayers can deduct the standard rate for business miles in lieu of tracking actual expenses; self-employed drivers should keep a contemporaneous mileage log per IRS Publication 463 to substantiate any deduction. The IRS also publishes separate (lower) rates for medical, moving, and charitable mileage.
How does towing affect fuel use?
Towing typically reduces fuel economy by 30–50% depending on trailer weight, frontal area, and grade. The two physics drivers are aerodynamic drag (which scales with frontal area and the square of speed) and rolling resistance from the additional tires on the trailer. A typical half-ton pickup rated at 22 MPG empty often drops to 12–14 MPG towing a 6,000 lb travel trailer at highway speed — and significantly worse on mountain grades where the engine spends extended time at high load. SAE J2807 is the modern tow-rating standard manufacturers use to certify maximum trailer weights, but those ratings cover safety and durability, not fuel economy. For accurate cost forecasting on a road trip with a trailer, use the towing MPG figure if your vehicle reports one (some newer trucks log it separately), or as a rule of thumb assume 60% of the empty highway MPG.