FCR calculator (feed conversion ratio)
The FCR calculator divides the feed fed by the live weight gained: 1,800 lb of feed for a gain from 500 to 1,500 lb gives an FCR of 1.8. A lower number means the animals turn feed into body weight more efficiently. In the second mode it works out the feed needed for a planned gain.
Example: Calculate: FCR from feed and weight gain · Feed fed in the period 1,800 · Live weight at start 500 · Live weight at end 1,500 · Weight unit: lb → Feed conversion: FCR 1.80 (feed ÷ weight gain). Source: Mississippi Agricultural & Forestry Experiment Station, Information Sheet 1364 (E. H. Robinson, M. H. Li, August 2015): Feed Conversion Ratio for Pond-Raised Catfish – FCR = feed ÷ live weight gain, 1.8 in research ponds, farm FCR (feed ÷ fish sold) about 2.5 as five-year mean, salmon/trout 1.0–1.2, losses as main cause of FCR above 2 (read 10.10.2026). Updated: .
How it is calculated
FCR = feed fed ÷ live weight gain, both in the same unit and over the same period. Mississippi State University defines the feed conversion ratio this way: a measure of how efficiently an animal converts feed into body mass, “determined by dividing the weight of feed fed by live weight gain over some time interval”. The lower the FCR, the less feed each pound of gain takes. Feed efficiency is the inverse: gain ÷ feed.
Feed and gain at different FCRs
| FCR | Feed for 1,000 lb gain | Gain from 1,000 lb feed |
|---|---|---|
| 1 | 1,000 lb | 1,000 lb |
| 1.2 | 1,200 lb | 833 lb |
| 1.5 | 1,500 lb | 667 lb |
| 1.8 | 1,800 lb | 556 lb |
| 2.5 | 2,500 lb | 400 lb |
Example: a pond holds 500 lb of fish at the start and 1,500 lb at the end, and 1,800 lb of feed went in. The gain is 1,000 lb, the FCR 1,800 ÷ 1,000 = 1.8, the feed efficiency 55.6 %.
What FCR values are typical?
Figures from the same information sheet on farmed fish: catfish grown to about 1.5 lb in research ponds routinely reach an FCR of 1.8 or less, and tilapia are similar. Atlantic salmon and rainbow trout are usually about 1.0 to 1.2, as are young catfish fingerlings. On commercial catfish farms the FCR measured as feed fed ÷ fish sold averaged about 2.5 over five years. Values for poultry, pigs or cattle differ by species, age and feed – compare like with like.
Why the farm FCR is often higher
Since FCR is based on weight gain, anything that affects gain changes it: feed, feeding, genetics, environment, health, size and body composition. Mississippi State names fish deaths as possibly the major cause of FCRs above 2 – feed eaten by animals that die never shows up as sold weight. Lowering the FCR from 2.5 to 2.0 means 20 % less feed for every pound produced.
For shares and ratios see the percentage calculator and the proportion calculator.
Frequently asked questions
How do you calculate FCR?
Divide the feed fed by the live weight gain over the same period. 1,800 lb of feed for 1,000 lb of gain gives an FCR of 1.8.
Is a lower or higher FCR better?
Lower. An FCR of 1.2 means 1.2 lb of feed per pound of gain; at 2.5 the same gain needs more than twice as much feed.
What is a good FCR for fish?
According to Mississippi State, catfish in research ponds reach 1.8 or less, salmon and rainbow trout about 1.0 to 1.2. The farm-level average for catfish was about 2.5.
What is the difference between FCR and feed efficiency?
Feed efficiency is the inverse: gain ÷ feed. An FCR of 1.8 equals a feed efficiency of 55.6 %.
How much feed do I need for a planned gain?
Multiply the gain by the expected FCR. 1,000 lb of gain at FCR 1.8 needs 1,800 lb of feed.
Sources and legal basis
As of: · Editorial policy
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