Fuel Cost Calculator (Trip Total & Per Person)
Estimate trip fuel cost and per-person share
Fuel cost calculator FAQs
Does this use live fuel prices?
No. You enter the fuel price you pay locally so the estimate reflects your reality instead of a generic feed. That keeps the calculator fast, simple, and less likely to show stale numbers.
What if my car shows L/100 km but I drive in the US?
Switch the Units selector to metric. Labels change to km and L/100 km, but the math works exactly the same. You can drive in one country and still use the units your dashboard shows.
Can I include tolls, parking, or rental car costs?
Those vary too much to model automatically. A simple way is to mentally add them on top of the total fuel cost or slightly bump your fuel price to approximate those extras for a specific trip.
Do I have to think in USD?
No. The calculator shows amounts with a $ symbol by default, but the numbers work for any currency as long as your inputs (fuel price and any comparisons you make) are all in the same one.
How to use this fuel cost calculator for real-world trips
This fuel cost calculator is designed for quick, realistic trip planning. Instead of guessing whether a road trip will be “about fifty bucks each,” you plug in a few details and get a clear trip total and per-person share in one place. All of the math is visible and based entirely on your inputs, so it’s easy to sanity-check against your car’s display and fuel receipts.
1. Pick units and trip type
Start with the Units selector. US units (miles, mpg, gas price per gallon) are selected by default. If you’re used to kilometers and liters, switch to metric and the distance, efficiency, and price labels update automatically. Then choose whether you are planning a one-way drive or a round trip — round trips simply double the distance before calculating fuel use and cost.
2. Add distance and realistic car efficiency
Enter the one-way distance you expect to drive. For most trips you can rely on your navigation app’s distance. Next, add your car’s efficiency: in metric mode this is L/100 km (lower is better); in US mode it’s mpg (higher is better). Use real-world values if you have them — your car’s long-term average or trip computer is usually more honest than brochure numbers.
3. Enter the fuel price you actually pay
In the fuel price field, type the current price at the pump. You don’t need live feeds or public averages; what matters is what you’ll see on the receipt. The calculator treats that value as your base currency and shows all totals with a $ in the result. If you’re thinking in euros, pounds, or any other currency, just make sure your price input and any comparisons you make are all in that same currency.
4. Set the number of people in the car
Finally, add how many people are traveling. The calculator divides the total fuel cost by that number and shows the per-person share right in the result hero. It’s a simple way to keep things fair when one person covers fuel and others reimburse later.
5. Read the breakdown and copy the summary
After you hit Calculate, the hero highlights two key numbers: total trip fuel cost and per-person cost. Below it, you’ll see a short breakdown of trip distance, fuel used, efficiency, and price. The inline Copy summary button grabs a one-line text summary you can paste into a group chat, travel doc, or budgeting sheet so everyone sees the same estimate.
The calculator stays intentionally simple: no hidden assumptions, no live data calls, and no surprise unit changes. If gas prices spike, you load extra gear, or you change cars entirely, just tweak a single input and rerun the numbers. Over time, you can compare different vehicles, routes, or trip types using exactly the same structure.
How the fuel cost math works
The calculator uses straightforward fuel economy formulas, with a small difference between metric and US units. Let D be the one-way distance (miles or kilometers) and T be the trip type multiplier (1 for one-way, 2 for round trip).
Effective trip distance is:
Dtrip = D × T
For US units, you enter mpg and gas price per gallon. Total gallons are:
Gallons used = Dtrip ÷ mpg
Total fuel cost is:
Total cost = Gallons used × gas price per gallon
For metric units, you enter L/100 km and price per liter. Total liters are:
Liters used = (Dtrip × L/100 km) ÷ 100
Total fuel cost is:
Total cost = Liters used × fuel price per liter
If N is the number of people in the car, the per-person cost is simply:
Per-person cost = Total cost ÷ N
All outputs are displayed using a $ for consistency and rounded to two decimals. The math is simple enough to reproduce with a calculator, which makes it easy to cross-check against your car’s trip data after the drive.