Feed Conversion Ratio Calculator
Feed conversion ratio FCR = feed used ÷ weight gained for a batch of animals or fish, its inverse feed efficiency, a mortality-adjusted FCR that counts the weight of animals lost, and the feed cost per kg or lb gained from your feed price.
Result…
How it's calculated
Weight gained = ending weight − starting weight FCR = feed used ÷ weight gained Feed efficiency = weight gained ÷ feed used = 1 ÷ FCR Mortality-adjusted FCR = feed ÷ (weight gained + weight of animals lost) Feed cost per unit gained = feed used × price ÷ weight gained
Feed conversion ratio is the mass of feed divided by the mass of gain it produced, so a ratio of 1.6 means 1.6 kg of feed (or 1.6 lb) for each kg (or lb) of live weight gained. Feed efficiency is the same comparison turned over. Because both sides are masses, the ratio is the same in any unit, as the Wikipedia article on feed conversion ratio notes. Animals that die or leave the batch ate feed too; counting their weight gives a mortality-adjusted FCR. The feed cost per unit gained multiplies the feed by your price and divides by the gain. Prices and targets vary by country, species and feed, so enter your own. 1 lb = 0.45359237 kg exactly.
Your numbers, step by step
About the Feed Conversion Ratio calculator
This feed conversion ratio calculator works out FCR for a batch of animals, birds or fish: the feed used divided by the live weight gained. Enter the head count and average weight at the start and the end, or the total batch weights, and the feed given over the period. It also shows feed efficiency, which is the same comparison turned over, and the mortality and removals rate. If some animals died or left the batch, you can add their weight to get a mortality-adjusted FCR, since they ate feed too. Add your feed price, per kg, per lb, per tonne or per short ton, to see the feed cost per kg or lb gained and the total feed bill. Weights work in kg or lb, and the ratio is the same in either. Each step uses your own numbers.
How to use it
- Pick the “Weight unit” and whether “Batch weights as” are a “Head count and average weight” or “Total weights”.
- Enter the “Animals at the start” and “Average starting weight”, then the “Animals at the end” and “Average ending weight”.
- To adjust for losses, set “Animals that died or were removed” to “Count their weight” and enter their total weight.
- Enter the “Feed used” over the period, and a “Feed price (optional)” with what the “Price is” per.
- Read the FCR, feed efficiency and the feed cost per kg or lb gained.
Worked example
A batch starts with 1,000 animals at 0.045 kg (45 kg in all) and ends with 970 at 2.5 kg (2,425 kg). Weight gained = 2,425 − 45 = 2,380 kg. With 4,000 kg of feed, FCR = 4,000 ÷ 2,380 = 1.68 and feed efficiency = 0.595. Counting the 30 kg of animals lost, the adjusted FCR = 4,000 ÷ 2,410 = 1.66. At a feed price of 0.5 per kg, feed costs 2,000 in all, or 0.84 per kg gained.
Updated
Questions people ask
How do I calculate feed conversion ratio?
Divide the mass of feed used by the weight the animals gained over the same period. The Wikipedia article on feed conversion ratio defines it as input mass divided by output, the inverse of feed efficiency.
Is a lower or higher FCR better?
Lower is better: it means less feed for each kg or lb of gain. Feed efficiency works the other way, so a higher figure is better.
What is a normal FCR for my animals?
It depends on the species, breed, age, diet, health and climate, so there is no single figure. Compare against your own past batches or the figures your feed supplier, breed company or adviser gives.
What is mortality-adjusted FCR?
It adds the weight of animals that died or were removed to the weight gained, because they ate feed before they were lost. It shows the feed conversion of the animals themselves, while the plain FCR shows what the batch delivered.
What mistakes skew the feed conversion ratio?
Counting feed delivered instead of feed eaten, so spilt or leftover feed inflates the ratio, and weighing a few animals that are not typical of the batch. Weigh a fair sample and subtract feed left in the bins. To compare prices per unit see the unit rate calculator.
What can this FCR result not tell me?
It does not judge animal health or welfare, or whether a cheaper feed with a higher FCR costs less overall. For feeding and health decisions, talk to a vet or livestock nutritionist, and check prices against your own supplier's.