Feed Conversion Ratio Calculator
Enter feed intake and weight gain to compute the feed conversion ratio (FCR) and feed efficiency (FE), evaluating how efficiently livestock and aquaculture convert feed into body mass.
Input Data
Results
At a glance:Feed conversion ratio (FCR) measures how efficiently an animal converts feed into body mass: FCR = feed intake ÷ weight gain. It is a dimensionless ratio (feed and gain must use the same unit); a lower value means less feed is needed for the same growth, i.e. higher efficiency and lower cost. Its reciprocal is feed efficiency FE = gain ÷ feed = 1 ÷ FCR, the gain per unit feed. FCR is a core metric for the economics and environmental footprint of aquaculture and livestock farming.
Formula
Feed conversion ratio: FCR = feed intake ÷ weight gain.
Feed efficiency: FE = weight gain ÷ feed intake = 1 ÷ FCR.
Lower FCR is better; FCR = 1.75 means 1.75 kg feed per 1 kg gain.
$$FCR = \dfrac{\text{feed intake}}{\text{weight gain}}$$$$FE = \dfrac{\text{weight gain}}{\text{feed intake}} = \dfrac{1}{FCR}$$How to Use
- Record total feed intake (dry weight) and net weight gain over the farming period, in the same unit.
- Enter feed and gain; the right panel shows FCR and feed efficiency FE instantly.
- Compare with species norms: a high FCR suggests feed waste or health/environment issues to review.
Typical feed conversion ratios (FCR) for common farmed animals
| Species | Typical FCR | Note |
|---|---|---|
| Tilapia / catfish (fish) | 1.2 – 1.8 | High aquatic efficiency, ectotherms use less energy |
| Broiler chicken | 1.5 – 2.0 | Modern breeding greatly lowered FCR |
| Pig | 2.5 – 3.5 | Rises with growth stage |
| Beef cattle | 6.0 – 10.0 | Ruminants have the highest FCR |
Values are general industry ranges; actual results vary with breed, feed formula, water/air temperature, and management.
Case Studies
Broiler batch feed efficiency
A broiler batch ate 3.5 kg feed over the period; weight rose from 0.05 kg to 2.05 kg, a gain of 2.0 kg.
FCR = 3.5 ÷ 2.0 = 1.75; feed efficiency FE = 2.0 ÷ 3.5 ≈ 0.5714.
That is 1.75 kg feed per 1 kg gain, a good level for poultry.
Low-FCR advantage in aquaculture
A catfish pond fed 1.6 kg feed and the fish gained 1.0 kg.
FCR = 1.6 ÷ 1.0 = 1.6; FE = 1.0 ÷ 1.6 = 0.625.
FCR below that of broilers reflects high feed-to-meat efficiency of aquatic animals, a reason local Hong Kong farming is cost-competitive.
FAQ
Is lower or higher FCR better?
Lower is better. FCR is feed ÷ gain, the feed needed per unit of growth; the smaller the number, the more efficient the feed use and the lower the cost per kg gain. For example FCR 1.5 saves feed over 2.0. Its reciprocal, feed efficiency FE, is the opposite — higher is better.
Does FCR have units?
No units, provided feed and gain use the same unit (both kg or both g). Mixing kg feed with g gain makes the number 1000× off and meaningless. This calculator requires the same unit for both to yield a correct dimensionless ratio.
Why is cattle FCR much higher than fish?
Cattle are ruminants and homeotherms, spending large energy on body-temperature maintenance and activity, and fibre fermentation in the rumen loses energy, so FCR often reaches 6–10. Fish are ectotherms and save energy in water, with FCR as low as 1.2–1.8 — a main reason aquaculture is environmentally efficient.
Should feed be dry or wet weight?
Use a consistent basis; practice favors feed dry weight, because wet feed varies greatly in moisture and distorts results. When comparing feeds, convert both to a dry-matter (DM) basis, or high-moisture feed will appear to have a higher FCR.
How does FCR relate to feed cost?
Feed is typically 60–70% of total farming cost, and FCR directly sets how much feed money per kg gain. Lowering FCR (better formula, controlled temperature, fewer diseases) significantly cuts cost and reduces waste and carbon footprint — a key indicator of farming economy and sustainability.
Related Tools
References
Content review: Calculatorism Science Team. Results are for reference only; please refer to the relevant authorities for the official figures.