Feed conversion ratio calculator
A broiler flock that eats 3.6 kg of feed and gains 2.4 kg of live weight has an FCR of 1.5: one and a half kilos of feed per kilo of gain. Enter total feed and total gain in the same unit. Free in your browser.
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Worked example
- Feed consumed
- 3.6
- Weight gained
- 2.4
- Fcr
- 1.5
- Formula applied
- FCR = 3.6 / 2.4 = 1.5
Feed conversion ratio, or FCR, is the mass of feed an animal consumes divided by the live-weight it gains over the same period. A broiler flock that eats 3.6 kilograms of ration and puts on 2.4 kilograms of body weight has an FCR of 1.5: each kilogram of gain cost one and a half kilograms of feed. Lower ratios mean more of the diet became meat, which is why integrators, nutritionists, and farm managers track FCR by house, lot, or pond.
What feed conversion ratio means and how FCR is computed
Feed conversion ratio is the oldest efficiency identity in animal production: total feed consumed divided by total live-weight gained, with both masses already expressed in the same unit. Broiler companies quote FCR on a live-weight basis from placement to catch; pig finishers quote it from wean or from the start of finish to slaughter; aquaculture quotes it from stocking to harvest on wet-weight biomass.
Because the numerator and the denominator are masses, the ratio is dimensionless: 2.5 kilograms of feed per kilogram of gain is the same number as 2.5 pounds per pound. That is why this calculator does not convert units. A lower FCR is better: more of the ration became animal tissue.
Typical commercial bands sit near 1.4 to 1.8 for modern broilers, 1.0 to 1.6 for intensive salmon or tilapia, 2.4 to 3.5 for growing-finishing pigs, and 6 to 8 for feedlot cattle, but those bands are orientation, not a species key. The identity is not feed efficiency, which is the reciprocal gain over feed; it is not a dry-matter adjustment; it is not a calorie conversion; and it is not a mortality-corrected adjusted FCR. It evaluates the raw definition from two totals you already measured.
Where a feed conversion ratio calculator earns its keep
Nutritionists use a feed conversion ratio calculator at formulation time so a diet change is judged on kilograms of feed per kilogram of gain, not on bag price alone. A ration that is five percent cheaper but lifts FCR from 1.55 to 1.70 can cost more per kilogram of meat than the premium diet.
Integrators settle grower contracts on FCR against a standard, so a house that reports 2.4 tonnes of feed and 1.5 tonnes of gain needs a number that matches the mill, not a spreadsheet that silently swapped columns. Teaching labs use the same identity so students stop confusing FCR with feed efficiency: efficiency is gain divided by feed and is always less than one in livestock, while FCR is feed divided by gain and is usually greater than one.
Aquaculture technicians convert pond-level feed sheets and biomass samples into FCR before they compare a recirculating system with a cage site. Content sites that rank for feed conversion ratio calculator or fcr should not cannibalize a dog-food portion tool or a mass-unit converter: those queries want cups per day or a unit change, not the production ratio of feed to live-weight gain. Failed validation does not consume balance.
Pin fcr in tests, keep masses inside the declared ceilings, and you get the same 1.5 for 3.6 over 2.4 in a lecture notebook, an LMS plugin, and a settlement script.
What you can do with it
Broiler flock close-out
Enter total feed from the mill sheet and live-weight at catch to read FCR for the house before comparing it with the integrator standard.
Pig finisher settlement
Convert wean-to-finish feed deliveries and slaughter live-weight into FCR so the contract settlement matches the mill, not a swapped spreadsheet column.
Aquaculture pond check
Divide pond feed issued by biomass gained from stocking to sample, and compare recirculating and cage sites on the same dimensionless ratio.
FAQ
How is feed conversion ratio calculated?
FCR is total feed consumed divided by total live-weight gained over the same period.
Why is FCR undefined when weight gain is zero or negative?
Zero gain is division by zero. Negative gain is a loss of mass and would flip the sign of efficiency.
Do I need to convert kilograms and pounds first?
Yes if they differ. FCR is dimensionless only when both masses share one unit. Convert feed and gain to kilograms, or both to pounds, then send the two numbers. This calculator does not mix units.
Is feed conversion ratio the same as feed efficiency?
No. Feed efficiency is gain divided by feed, usually a fraction below one. FCR is the reciprocal: feed divided by gain, usually above one. This calculator returns FCR, not efficiency.
What is a good feed conversion ratio?
Lower is better. Typical commercial ranges are about 1.4 to 1.8 for modern broilers, 2.4 to 3.5 for growing-finishing pigs and 6 to 8 for feedlot cattle, but treat these as orientation only.
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/bio/fcr \
-H "Authorization: Bearer $KIT_KEY" \
-H "Content-Type: application/json" \
-d '{"feed_consumed":3.6,"weight_gained":2.4}'const res = await fetch("https://api.kit.forhosting.com/bio/fcr", {
method: "POST",
headers: {
"Authorization": `Bearer ${process.env.KIT_KEY}`,
"Content-Type": "application/json"
},
body: JSON.stringify({
"feed_consumed": 3.6,
"weight_gained": 2.4
})
});
const { task_id } = await res.json();import os, requests
res = requests.post(
"https://api.kit.forhosting.com/bio/fcr",
headers={"Authorization": f"Bearer {os.environ['KIT_KEY']}"},
json={
"feed_consumed": 3.6,
"weight_gained": 2.4
},
)
task_id = res.json()["task_id"]<?php
$res = file_get_contents("https://api.kit.forhosting.com/bio/fcr", false, stream_context_create([
"http" => [
"method" => "POST",
"header" => "Authorization: Bearer " . getenv("KIT_KEY") . "\r\nContent-Type: application/json",
"content" => '{"feed_consumed":3.6,"weight_gained":2.4}',
],
]));
$task = json_decode($res, true);body := bytes.NewBufferString(`{"feed_consumed":3.6,"weight_gained":2.4}`)
req, _ := http.NewRequest("POST", "https://api.kit.forhosting.com/bio/fcr", body)
req.Header.Set("Authorization", "Bearer "+os.Getenv("KIT_KEY"))
req.Header.Set("Content-Type", "application/json")
res, _ := http.DefaultClient.Do(req)Example request
{
"feed_consumed": 3.6,
"weight_gained": 2.4
}Example response
{
"task_id": "tsk_a1b2c3d4e5f6a1b2c3d4e5f6",
"type": "bio.fcr",
"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 | 1000000000000000 |
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 feed conversion ratio calculator applies that definition exactly: FCR equals feed_consumed divided by weight_gained, using the same mass unit on both sides so the quotient is dimensionless. It rejects a zero or negative gain rather than dividing by zero or reporting a negative efficiency.
What feed conversion ratio means and how FCR is computed
You must send feed_consumed and weight_gained already expressed in one mass unit — kilograms, pounds, tonnes, or grams — and the API returns fcr as feed_consumed divided by weight_gained. Zero or negative weight_gained is rejected because FCR is undefined when the herd did not gain, or lost, mass over the period you are scoring.
Input contract, response shape, and error behaviour
Keep both masses inside the declared limits so the division stays finite. POST a JSON body with two required finite numbers. feed_consumed is the total mass of feed eaten over the period, with aliases feed, total_feed, feed_intake, and feed_kg. It must be a finite non-negative number; a negative ration is not a consumption total and is rejected with invalid_input that names the field. Zero feed with a positive gain is mathematically allowed and returns fcr equal to zero, even though a real barn would treat that as a data error rather than a triumph of efficiency. weight_gained is the total live-weight increase over the same period, with aliases gain, weight_gain, live_weight_gain, and gain_kg. It must be a finite positive number. Zero gain and negative gain, a loss of mass, are the distinctive failures of this calculator: FCR would divide by zero or flip sign, so the request is rejected rather than inventing an efficiency. Both fields may arrive as JSON numbers or as decimal or scientific strings. Missing required fields, empty strings, non-finite values, and magnitudes above the declared ceiling fail with invalid_input. Those failures are not billed. On success the body echoes feed_consumed and weight_gained, returns fcr as the dimensionless ratio, and fills formula plus formula_applied so a notebook can print the substitution next to the answer. Example: feed_consumed 3.6 and weight_gained 2.4 yield fcr 1.5. Example: feed_consumed 250 and weight_gained 100 yield fcr 2.5.
Technical questions
What does the feed conversion ratio calculator cost?
The browser tool is free. API requests use prepaid KIT balance at $0.002 per successful call; invalid input is not billed.