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Fuel Cost Calculator

Estimates the fuel needed for a trip and its cost from distance, fuel consumption in litres per 100 km and the price per litre, with the cost per person when it is shared.

When to use

You want to budget a road trip or commute, or split fuel money between passengers, and know the car's consumption in L/100 km.

Do not use when: Your consumption is in mpg or km/L (convert it first with fuel-economy), or you need total ownership costs such as tolls, wear or depreciation.

Formula

fuel_liters = distance_km × fuel_consumption_l_per_100km / 100; total_cost = fuel_liters × fuel_price_per_liter; cost_per_person = total_cost / passengers; cost_per_km = total_cost / distance_km; mpg_us = 235.215 / L_per_100km

Inputs

Parameter	Type	Unit	Required	Description
`distance_km`	number	km	yes	Trip distance in kilometres (enter the round-trip distance for a return journey). Range: > 0, ≤ 100000
`fuel_consumption_l_per_100km`	number	L/100 km	yes	Average consumption in litres per 100 km. Range: > 0, ≤ 100
`fuel_price_per_liter`	number	per L	yes	Price per litre in your currency. Range: ≥ 0, ≤ 100
`passengers`	integer		default 1	Number of people sharing the fuel cost, driver included. Range: ≥ 1, ≤ 100

Outputs

Output	Type	Unit	Description
`fuel_liters`	number	L	distance × consumption / 100.
`total_cost`	number		fuel_liters × price per litre.
`cost_per_person`	number		total_cost / passengers.
`cost_per_km`	number	per km	total_cost / distance_km.
`equivalent_mpg_us`	number	mpg (US)	235.215 / (L/100 km), for reference.

Example

350 km at 7.5 L/100 km, 1.85 per litre, 2 people: {"distance_km":350,"fuel_consumption_l_per_100km":7.5,"fuel_price_per_liter":1.85,"passengers":2} → {"fuel_liters":26.25,"total_cost":48.56,"cost_per_person":24.28,"cost_per_km":0.139,"equivalent_mpg_us":31.4}

1200 km at 6.2 L/100 km, 1.60 per litre: {"distance_km":1200,"fuel_consumption_l_per_100km":6.2,"fuel_price_per_liter":1.6} → {"fuel_liters":74.4,"total_cost":119.04,"cost_per_person":119.04,"cost_per_km":0.0992,"equivalent_mpg_us":37.9}

GET https://tttkmbb.com/api/v1/calculate/fuel-cost?distance_km=350&fuel_consumption_l_per_100km=7.5&fuel_price_per_liter=1.85&passengers=2

Machine access

API: GET https://tttkmbb.com/api/v1/calculate/fuel-cost (query parameters) or POST with a JSON body {"inputs": {...}}
Schema: https://tttkmbb.com/api/v1/calculators/fuel-cost · Markdown: https://tttkmbb.com/everyday/fuel-cost.md · JSON definition: https://tttkmbb.com/everyday/fuel-cost.json
MCP: server https://tttkmbb.com/mcp, tool run_calculator with calculator_id="fuel-cost"
OpenAPI operationId: calculate_fuel_cost
Freshness: static. Authentication: none. Rate limit: fair use (see rate limits).

Sources

US DOE / EPA – fueleconomy.gov Trip Calculator (government)
Fuel economy in automobiles – unit conversions (Wikipedia) (reference)

FAQ

I know my car's mpg, not L/100 km. What do I enter?

L/100 km = 235.215 / mpg (US gallons) or 282.481 / mpg (UK imperial gallons). 30 US mpg is about 7.84 L/100 km.

Does real consumption match the manufacturer figure?

Usually not; highway driving, load, speed and air conditioning change consumption by 10–30%. Use a measured average from recent fill-ups if you have one.

Related calculators

Fuel Economy Converter — Convert mpg or km/L to L/100 km first.
Bill Split Calculator — Split any shared cost, with an optional tip.