GPM to LPM converter
One US gallon per minute is exactly 3.785411784 liters per minute, so a 10 GPM pump moves 37.85411784 LPM. Match a US pump curve, well pump or irrigation nozzle to a metric datasheet without the rough times-four shortcut. Free in your browser.
- Free
- Runs in your browser
- No sign-up
- Your data stays on your device
Run — free
Worked example
- Gpm
- 1
- Result
- 3.785411784 L/min
- Converted
- 3.785411784
- Lpm
- 3.785411784
- From unit
- gal/min
A GPM-to-LPM converter turns a US gallons-per-minute flow rate into the liters-per-minute scale used on pump nameplates, irrigation specs, laboratory peristaltic pumps, process piping data sheets, and international procurement documents. Approximate mental shortcuts such as “times four” are unnecessary here because the factor is exact by definition of the US liquid gallon in SI units—231 cubic inches with one inch exactly equal to 2.54 centimeters—not a survey constant that needs estimation.
Why GPM converts to LPM at exactly 3.785411784
Gallons per minute remain the everyday volume-flow unit across much of the United States for residential well pumps, fire-protection standpipes, spa and pool circulation, HVAC chilled-water loops, and agricultural irrigation nozzles, while liters per minute dominate international product datasheets, metric building codes, laboratory protocols, and most process-engineering standards outside US customary practice.
Installers comparing a US pump curve rated in GPM to a European manifold labeled in LPM, facility managers converting hydrant flow tests for metric reports, chemists sizing continuous feed into SI batch systems, and students solving unit-conversion homework all need a single reliable bridge from US GPM to LPM. That bridge is definitional rather than approximate: one US liquid gallon is exactly 231 cubic inches, and the international inch is exactly 2.54 centimeters, so one US liquid gallon equals exactly 3.785411784 liters.
Because both GPM and LPM use the same minute, the flow conversion is the same exact multiply—LPM equals GPM times 3.785411784—with no leftover uncertainty and no dependence on local survey factors or temperature corrections for the unit definition itself. This landing stays on the US liquid GPM path only.
It does not convert imperial (UK) gallons per minute, which rest on a larger gallon of 4.54609 liters and would mislead searchers who typed gpm to lpm for US plumbing or pump work, and it does not convert dry-measure flow or multi-unit hubs such as liters per second or cubic meters per hour.
Practical tips, checks, and related searches
Round-trip sanity checks are easy: convert one GPM and confirm you receive exactly 3.785411784 LPM after rounding, convert ten GPM and confirm 37.85411784 LPM, or convert zero and confirm zero. When teaching, show that dividing the published LPM by 3.785411784 recovers the original GPM within the same twelve-decimal rounding used for published fields. Stay inside the absolute range so the multiply cannot overflow into a non-finite result the solver must reject.
This landing targets people searching for gpm to lpm, convert gallons per minute to liters per minute, or an exact 3.785411784-factor flow calculator; it is not a general multi-unit flow hub, not an LPM-to-GPM primary form, not an imperial gallon path, and not a mass-flow or molar-flow converter. Prefer this capability when the input is already in US GPM and you only need LPM; if you must convert among many flow units in one call, use a broader flow-rate converter instead.
When comparing pump curves across regions, remember that this tool multiplies volume flow only and does not convert head, pressure, power, or efficiency—use dedicated converters for those quantities.
What you can do with it
Pump and irrigation datasheet bridging
Convert US GPM nameplate ratings to LPM for international tenders, manifold schedules, and irrigation nozzle charts that store capacity in metric units only.
Lab and process continuous feed
Turn GPM feed rates into LPM for peristaltic pumps, reactor makeup lines, and SI batch recipes that expect liters per minute in control logic.
FAQ
What formula converts GPM to LPM?
LPM = GPM × 3.785411784. One US liquid gallon is defined as exactly 3.785411784 liters, and both sides use the same minute, so the factor is exact for flow, not an estimate.
Does this convert imperial (UK) gallons per minute?
No. It converts US liquid GPM to LPM only. An imperial gallon is 4.54609 L and is not accepted as input on this landing.
Is the GPM to LPM converter free?
The browser tool is free and runs locally.
How many LPM is 10 GPM?
Ten US gallons per minute equal 37.85411784 liters per minute. The converter multiplies the flow by 3.785411784, so the same rule works for a garden hose, a pool pump or a hydrant test.
Can it give liters per second or cubic meters per hour?
No. It converts US gallons per minute into liters per minute only. For liters per second or cubic meters per hour, use a general flow converter, since those units change the time base as well.
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/conv/gpm-to-lpm \
-H "Authorization: Bearer $KIT_KEY" \
-H "Content-Type: application/json" \
-d '{"gpm":1}'const res = await fetch("https://api.kit.forhosting.com/conv/gpm-to-lpm", {
method: "POST",
headers: {
"Authorization": `Bearer ${process.env.KIT_KEY}`,
"Content-Type": "application/json"
},
body: JSON.stringify({
"gpm": 1
})
});
const { task_id } = await res.json();import os, requests
res = requests.post(
"https://api.kit.forhosting.com/conv/gpm-to-lpm",
headers={"Authorization": f"Bearer {os.environ['KIT_KEY']}"},
json={
"gpm": 1
},
)
task_id = res.json()["task_id"]<?php
$res = file_get_contents("https://api.kit.forhosting.com/conv/gpm-to-lpm", false, stream_context_create([
"http" => [
"method" => "POST",
"header" => "Authorization: Bearer " . getenv("KIT_KEY") . "\r\nContent-Type: application/json",
"content" => '{"gpm":1}',
],
]));
$task = json_decode($res, true);body := bytes.NewBufferString(`{"gpm":1}`)
req, _ := http.NewRequest("POST", "https://api.kit.forhosting.com/conv/gpm-to-lpm", body)
req.Header.Set("Authorization", "Bearer "+os.Getenv("KIT_KEY"))
req.Header.Set("Content-Type", "application/json")
res, _ := http.DefaultClient.Do(req)Example request
{
"gpm": 1
}Example response
{
"task_id": "tsk_a1b2c3d4e5f6a1b2c3d4e5f6",
"type": "conv.gpm_to_lpm",
"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.
Limits
max_abs | 1000000000000 |
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
Invalid or missing input fails with a clear invalid_input error instead of inventing a number.
How to call the API and what comes back
Absolute values must stay within the published limit of one trillion. Prefer bare numbers when you control the client; string numbers are accepted only when they match a strict finite numeric pattern without unit symbols, thousand separators, or currency marks attached to the value. Send a JSON body with one required finite number field named gpm. Aliases gallons_per_minute, gal_per_min, value, flow, flow_rate, and us_gpm are accepted so SDK clients and form posts can use the name that fits the product. On success the response echoes rounded gpm, sets lpm, result, and converted to the same rounded LPM magnitude, unit to the token L/min, from_unit to gal/min and to_unit to L/min, factor and lpm_per_gpm to 3.785411784, formula to the string lpm equals gpm times 3.785411784, message to a short English summary, and steps to an ordered array of substitution lines that show the exact US liquid definition applied to flow. Failed validation—missing fields, non-finite numbers, bare plus or minus signs, non-numeric strings, values outside absolute limits, or a non-finite converted result—returns invalid_input and is never charged. Pricing is a flat $0.002 per successful request with unit item and zero marginal unit price.
Practical tips, checks, and related searches
Failed tasks that return invalid_input do not consume prepaid balance, which keeps exploratory scripts cheap when learners deliberately omit gpm or pass text placeholders while debugging their client code.
Integration use cases
Homework and unit-test fixtures
Students and engineers convert classroom GPM values to LPM and pin golden JSON so browser and API arithmetic never drift.
Technical questions
Is the factor 3.785411784 exact for flow?
Yes. The US liquid gallon is exactly 231 cubic inches, and the international inch is exactly 2.54 cm, so 1 US gal = 3.785411784 L exactly. With the same minute on both sides, 1 GPM = 3.785411784 LPM exactly.
What happens on missing or non-numeric input?
The API returns invalid_input naming the problem (for example a missing gpm field). Failed tasks are not charged.