Fuel consumption from fill-up calculator
Drive 450 km between two full tanks, put 36 litres back in, and your real consumption is 8 L/100 km, or 12.5 km per litre. Enter the odometer distance and the refill to check the burn rate in mixed units. Free in your browser.
- Free
- Runs in your browser
- No sign-up
- Your data stays on your device
Run — free
Worked example
- Distance
- 450
- Fuel
- 36
- Distance unit
- Km
- Distance km
- 450
- Distance mi
- 279.617
- Fuel unit
- L
This fuel consumption from fill-up calculator turns a real tank cycle into measured liters per one hundred kilometers. Enter the distance driven since the previous full fill-up and the fuel volume you put back to return the tank to full, and the engine applies the classic brim-to-brim identity: liters per one hundred kilometers equals fuel liters divided by distance in kilometers, times one hundred. The response also reports kilometers per liter and both US and imperial miles per gallon so you can compare handbook stickers, dashboards, and trip logs in mixed units. Optional fields let you supply miles and gallons when your odometer and pump are not metric; the path converts with exact international constants before computing. Small checks you may already know include four hundred fifty kilometers and thirty-six liters yielding eight liters per one hundred kilometers, and three hundred miles with ten US gallons yielding about thirty miles per gallon. The arithmetic is fully deterministic: no network, no sampling, and no date-dependent shortcuts.
What fill-up consumption tells you
Fill-up fuel consumption answers a practical measurement question: given how far you drove between two full tanks and how many liters (or gallons) the pump put back, what was the true burn rate over that cycle. Advertised economy and onboard computers are useful, but the brim-to-brim method is the field check that fleet managers, eco-driving coaches, and careful owners use when they want a number tied to the pump receipt and the odometer.
This calculator does not invent traffic, elevation, or load; it trusts the distance and refill volume you supply and applies a closed-form identity. If you need trip fuel volume from a known L/100km rating instead of measured consumption, use a trip fuel volume helper; if you only need to convert MPG to L/100km without a fill-up, use a fuel-economy unit converter. This page stays focused on the fill-up identity so worksheets, APIs, and browser demos share one stable contract.
Where fill-up L/100km checks fit in driving, fleets, and software
Private drivers meet this calculation when a full tank and a careful odometer note are the only honest way to check whether city congestion, highway cruise, or a roof box changed real burn rate versus the handbook sticker. Fleet operators batch the same formula across vehicles after depot fill-ups to flag high consumption, validate telematics, or coach drivers without trusting a single trip computer.
Travel and expense products call the contract from scripts when a user logs a refill receipt and an odometer reading and the app must show actual L/100km without shipping a full telematics stack. Students and driving instructors use it to connect the textbook idea of consumption rate with a concrete number from a weekend journey, including the classic four hundred fifty kilometers and thirty-six liters example that yields eight liters per one hundred kilometers.
Product and education tools use the dual liter-and-gallon plus MPG outputs when audiences mix metric and US customary units in the same classroom or marketplace. Pair it with trip fuel volume helpers when you plan future tanks from a known economy, and with fuel-economy converters when you only need unit translation, for a small lab of free, deterministic fuel tools.
What you can do with it
Track real tank efficiency
Log odometer delta and liters refilled at each full fill-up to measure actual L/100km over real mixed driving.
Fleet consumption audits
Batch depot fill-up volumes and distance driven per vehicle to flag high burn rates and validate telematics.
FAQ
What does the fuel consumption from fill-up calculator cost?
It is free in your browser on this page.
What happens if distance or fuel is zero or negative?
Zero or negative distance or fill-up volume is not meaningful for a consumption rate.
Does this tool estimate trip fuel needed from a rated economy?
No. It measures actual consumption from a completed fill-up cycle. For planned volume from a known L/100km or MPG, use a trip fuel volume calculator.
How do I measure a fill-up correctly?
Fill the tank to full and note the odometer. Drive normally, fill to full again and enter the distance since that first fill and the fuel the pump put back. This brim-to-brim method ties the figure to your receipt.
Can I enter miles and gallons?
Yes. Distance can be in kilometres or miles and fuel in litres, US gallons or imperial gallons, converted with exact constants. For instance, 300 miles on 10 US gallons comes out at about 30 miles per gallon.
Related tools
For developers — API access
Everything on this page is available programmatically. This section is for teams who want to wire it into their own systems; everyone else can just use the tool above.
API endpoint
Prefer to automate it? One authenticated POST creates the task; the result comes back by webhook or a signed link. The same capability also runs here on the web, by email and from Telegram — and soon from our app too.
Call it from your stack
curl -X POST https://api.kit.forhosting.com/travel/l100km-from-fillup \
-H "Authorization: Bearer $KIT_KEY" \
-H "Content-Type: application/json" \
-d '{"distance":450,"fuel":36}'const res = await fetch("https://api.kit.forhosting.com/travel/l100km-from-fillup", {
method: "POST",
headers: {
"Authorization": `Bearer ${process.env.KIT_KEY}`,
"Content-Type": "application/json"
},
body: JSON.stringify({
"distance": 450,
"fuel": 36
})
});
const { task_id } = await res.json();import os, requests
res = requests.post(
"https://api.kit.forhosting.com/travel/l100km-from-fillup",
headers={"Authorization": f"Bearer {os.environ['KIT_KEY']}"},
json={
"distance": 450,
"fuel": 36
},
)
task_id = res.json()["task_id"]<?php
$res = file_get_contents("https://api.kit.forhosting.com/travel/l100km-from-fillup", false, stream_context_create([
"http" => [
"method" => "POST",
"header" => "Authorization: Bearer " . getenv("KIT_KEY") . "\r\nContent-Type: application/json",
"content" => '{"distance":450,"fuel":36}',
],
]));
$task = json_decode($res, true);body := bytes.NewBufferString(`{"distance":450,"fuel":36}`)
req, _ := http.NewRequest("POST", "https://api.kit.forhosting.com/travel/l100km-from-fillup", body)
req.Header.Set("Authorization", "Bearer "+os.Getenv("KIT_KEY"))
req.Header.Set("Content-Type", "application/json")
res, _ := http.DefaultClient.Do(req)Example request
{
"distance": 450,
"fuel": 36
}Example response
{
"task_id": "tsk_a1b2c3d4e5f6a1b2c3d4e5f6",
"type": "travel.l100km_from_fillup",
"status": "queued",
"_links": {
"result": "/tasks/tsk_…/result"
}
}The API is asynchronous: the call returns a task_id immediately and the result arrives by webhook. Polling is capped at 1 req/s per task.
Pricing
Published price — no tokens, no invented credits. A failed task is never charged.
Errors
| HTTP | Code | Meaning |
|---|---|---|
401 | unauthorized | Missing or invalid API key. |
402 | insufficient_balance | Your balance doesn't cover the task price. |
404 | unknown_type | That task type doesn't exist. |
429 | rate_limited | Too many requests. Use the webhook instead of polling. |
Technical notes
Zero or negative distance or fuel is rejected with invalid_input because a non-positive tank cycle does not define a consumption rate.
What fill-up fuel consumption means and what the response contains
The response echoes the normalized distance and fuel inputs, the resolved distance_unit and fuel_unit, distance in both kilometers and miles, fuel in liters plus US and imperial gallons, the primary metric l_per_100km, the reciprocal km_per_l, mpg_us and mpg_imp, the precision used, a method tag fillup_l100km, and a compact formula string for audits. There is no Monte Carlo path and no live map feed: the engine either builds finite economy figures inside the supported numeric range or rejects the input with invalid_input. Rejected cases include missing distance or fuel, non-finite values, magnitudes above the documented ceiling, and any non-positive distance or fuel volume, because dividing by zero distance or scaling with a negative refill is not a valid tank measurement.
How distance and fuel are read and how units stay consistent
Optional leading plus signs and scientific notation on numeric strings are allowed when they parse as finite decimals; embedded spaces, hex prefixes, and non-numeric tokens are rejected with a clear message so a bad cell does not become a wrong consumption rate. The preferred fields are distance for the odometer delta since the last full fill-up and fuel for the volume refilled to full, but aliases such as dist, trip_distance, odometer_delta, liters, volume, refilled, and amount are accepted so spreadsheets, query strings, and typed forms can reuse the same contract. distance_unit selects kilometers or miles and defaults to kilometers; fuel_unit selects liters (default), US gallons, or imperial gallons so a US pump receipt and a metric odometer can still produce a correct L/100km figure. After validation the engine converts distance into both kilometers and miles using the exact international mile, converts fuel into liters using three point seven eight five four one one seven eight four liters per US gallon and four point five four six zero nine liters per imperial gallon when needed, then computes l_per_100km as fuel liters over distance kilometers times one hundred. From the same intermediate values it derives km_per_l as distance kilometers over fuel liters, and both mpg figures as miles over gallons. An optional precision field, with aliases decimals and dp, chooses how many decimal places to expose, defaulting to four and capped at fifteen so JSON goldens stay stable. Pair the free browser run on this page with the priced API when you need the identical mathematical result inside an automated pipeline without re-implementing gallon constants yourself.
Where fill-up L/100km checks fit in driving, fleets, and software
On this page the work runs entirely in your browser; through the API each successful lookup costs $0.002, failed validation is not charged, and nothing is stored after the response returns. That split — free interactive exploration and a priced, identical API — matches the rest of the KIT tier-A catalog and lets you move from a dashboard demo to an automated pipeline without changing the mathematical result.
Integration use cases
Deterministic fixtures for apps
Generate reproducible l_per_100km, km_per_l, and MPG fields for expense tools, eco-driving demos, and CI assertions.
Technical questions
How is L/100km computed from a fill-up?
With distance in kilometers and fuel in liters, l_per_100km = (fuel_liters / distance_km) × 100. That is the classic brim-to-brim method.
Can I enter miles and US gallons?
Yes. Set distance_unit to mi (or miles) and fuel_unit to gal_us. The response still includes l_per_100km, km_per_l, and imperial MPG.