MPG to L/100km converter
30 US miles per gallon is 7.84 litres per 100 km, and the same rating appears in imperial mpg and km per litre at once. Compare US, UK and European figures on one scale. Free in your browser.
- Free
- Runs in your browser
- No sign-up
- Your data stays on your device
Run — free
Worked example
- Fuel-economy magnitude to convert
- 30
- Input fuel-economy unit
- mpg_us
- Output fuel-economy unit
- l_100km
- Result
- 7.8404861111
- Mpg us
- 30
- Mpg imp
- 36.0284977651
- Km per l
- 12.7543112229
Drivers, fleet managers, and importers constantly need a trustworthy MPG to L/100km converter when sticker ratings cross the Atlantic or the English Channel. United States window stickers quote miles per US gallon, United Kingdom and many Commonwealth listings quote miles per imperial gallon, and almost every European Union and ISO datasheet quotes liters per one hundred kilometers as a consumption figure. Those three scales do not share a simple multiply-by-constant story because L/100km is inverted: lower is thriftier, while higher MPG or km/L is thriftier.
How MPG, imperial MPG, km/L and L/100km relate
Fuel economy can be stated as distance per volume or as volume per distance. Miles per gallon and kilometers per liter are distance-per-volume measures: a larger number means the vehicle travels farther on each unit of fuel. Liters per one hundred kilometers is a volume-per-distance measure: a larger number means more fuel is burned for the same trip, so thriftier cars show smaller L/100km values.
Converting between the two families therefore requires an inversion, not only a unit factor. This converter first maps every input into kilometers per liter using fixed constants. One international mile is exactly one point six zero nine three four four kilometers.
One United States liquid gallon is exactly three point seven eight five four one one seven eight four liters, the volume of two hundred thirty-one cubic inches. One imperial gallon is exactly four point five four six zero nine liters.
From those definitions the US MPG to km/L factor is one point six zero nine three four four divided by three point seven eight five four one one seven eight four, and the imperial MPG to km/L factor is one point six zero nine three four four divided by four point five four six zero nine. A value already in km/L is the bridge itself. A value in L/100km becomes km/L by dividing one hundred by the amount.
Once the bridge value is known, converting outward is the reverse: multiply or divide by the same factors, or take one hundred over km/L for L/100km. Amounts must be finite and strictly positive; zero and negative figures fail early with invalid input rather than inventing infinity or a negative consumption.
What you send and what you get back
Send three fields. The field amount is a finite number strictly greater than zero, or a string that parses to such a number. The field from is the unit of that amount, and the field to is the unit you want as the primary result.
Matching is case-insensitive and tolerant of spaces, hyphens, and slashes. Classic checks include thirty US MPG into L/100km near seven point eight four, twelve L/100km into km/L of about eight point three three, and forty imperial MPG into US MPG by the gallon-size ratio alone. Wire the free browser form for quick sticker comparisons, then call the identical contract from scripts when you need bulk fleet normalization.
Where an MPG to L/100km converter shows up in real work
Cross-border car listings constantly mix US MPG, UK MPG, and European L/100km on the same comparison page; marketplaces that normalize every listing into one column avoid misleading shoppers who treat twenty-eight MPG as comparable to twenty-eight L/100km. Fleet managers importing vehicles or reading telematics exports need a single oracle that turns mixed manufacturer CSV columns into one reporting unit before ranking routes or leasing options.
Travel and road-trip planners who estimate liters needed for a European itinerary from a US-rated car must invert MPG into L/100km before multiplying by distance over one hundred. Automotive journalists and review sites cite both EPA-style MPG and WLTP-style L/100km, and they need reproducible numbers rather than spreadsheet drift between editors. Engineering classrooms teaching unit conversion and inverse consumption use this path as a concrete bridge problem with exact legal definitions of the mile and both gallons.
If you later need trip fuel cost from price per liter, tank range from tank volume, or CO₂ intensity from emission factors, treat those as separate search intents and landings rather than overloading this MPG to L/100km converter page.
What you can do with it
Cross-border car listing normalization
Map US MPG, UK imperial MPG, and EU L/100km columns into one comparable rating so marketplace filters never mix inverted consumption with distance-per-volume figures.
Fleet telematics and lease reporting
Bulk-convert mixed manufacturer economy fields into a single unit for route scoring, residual-value models, and board reports without spreadsheet formula drift.
Road-trip fuel planning
Turn a US MPG sticker into L/100km, then multiply by European route distance to estimate liters needed before booking ferries or long mountain stages.
FAQ
Why is L/100km inverted relative to MPG?
MPG and km/L measure distance per volume (higher is thriftier). L/100km measures volume per distance (lower is thriftier). The converter bridges through km/L and applies 100/(km/L) for L/100km.
What happens if the amount is zero or negative?
Fuel economy must be a finite positive number; zero or negative values are rejected rather than producing infinity or nonsense.
Is US MPG the same as imperial MPG?
No. The US liquid gallon is 3.785411784 L and the imperial gallon is 4.54609 L, so the same miles-per-gallon number represents different economy. Always set from and to explicitly.
What does it cost?
The browser tool is free and runs locally.
Can I see all four units in one go?
Yes. Besides the unit you ask for, the result shows the same rating in US mpg, imperial mpg, kilometres per litre and litres per 100 km, so one conversion covers a US sticker, a UK brochure and an EU datasheet.
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/fuel-economy-convert \
-H "Authorization: Bearer $KIT_KEY" \
-H "Content-Type: application/json" \
-d '{"amount":30,"from":"mpg_us","to":"l_100km"}'const res = await fetch("https://api.kit.forhosting.com/travel/fuel-economy-convert", {
method: "POST",
headers: {
"Authorization": `Bearer ${process.env.KIT_KEY}`,
"Content-Type": "application/json"
},
body: JSON.stringify({
"amount": 30,
"from": "mpg_us",
"to": "l_100km"
})
});
const { task_id } = await res.json();import os, requests
res = requests.post(
"https://api.kit.forhosting.com/travel/fuel-economy-convert",
headers={"Authorization": f"Bearer {os.environ['KIT_KEY']}"},
json={
"amount": 30,
"from": "mpg_us",
"to": "l_100km"
},
)
task_id = res.json()["task_id"]<?php
$res = file_get_contents("https://api.kit.forhosting.com/travel/fuel-economy-convert", false, stream_context_create([
"http" => [
"method" => "POST",
"header" => "Authorization: Bearer " . getenv("KIT_KEY") . "\r\nContent-Type: application/json",
"content" => '{"amount":30,"from":"mpg_us","to":"l_100km"}',
],
]));
$task = json_decode($res, true);body := bytes.NewBufferString(`{"amount":30,"from":"mpg_us","to":"l_100km"}`)
req, _ := http.NewRequest("POST", "https://api.kit.forhosting.com/travel/fuel-economy-convert", body)
req.Header.Set("Authorization", "Bearer "+os.Getenv("KIT_KEY"))
req.Header.Set("Content-Type", "application/json")
res, _ := http.DefaultClient.Do(req)Example request
{
"amount": 30,
"from": "mpg_us",
"to": "l_100km"
}Example response
{
"task_id": "tsk_a1b2c3d4e5f6a1b2c3d4e5f6",
"type": "travel.fuel_economy_convert",
"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
This capability accepts a positive fuel-economy amount with explicit from and to units, bridges through kilometers per liter using exact international definitions of the mile and both gallon sizes, returns the target result plus every supported unit in one JSON object, and rejects zero or negative values so a bad odometer export never looks like a valid rating.
How MPG, imperial MPG, km/L and L/100km relate
Because every step is deterministic floating-point arithmetic with no network call, no random seed, and no wall-clock timestamp, the same amount and units always produce the same JSON.
What you send and what you get back
Accepted labels include mpg_us for US miles per gallon, mpg_imp for imperial or UK miles per gallon, km_l for kilometers per liter, and l_100km for liters per one hundred kilometers, plus common aliases such as mpg, us_mpg, uk_mpg, imperial_mpg, lp100km, and liters_per_100_km. Missing fields, non-numeric garbage, NaN, Infinity, unrecognized unit strings, and non-positive amounts fail with invalid_input and are not charged. On success the response echoes the cleaned amount, the canonical from and to keys, the primary result in the to unit, and the same physical rating expressed as mpg_us, mpg_imp, km_per_l, and l_per_100km so a single call can feed US stickers, UK brochures, and EU datasheets. Bridge factors factor_from_km_l and factor_to_km_l appear for non-inverted units and are null when the corresponding side is L/100km. The formula string documents the mile and gallon constants, and method is always km_l_bridge. Pricing for successful API calls is the published base of $0.002 per item; validation failures do not consume prepaid balance.
Where an MPG to L/100km converter shows up in real work
Because this capability is a pure parse engine, API pricing is the published base of $0.002 per successful item and failed validation does not consume balance.
Technical questions
What units does this MPG to L/100km converter support?
US MPG (mpg_us), imperial/UK MPG (mpg_imp), kilometers per liter (km_l), and liters per 100 km (l_100km), including common aliases such as mpg, uk_mpg, and lp100km.