Inbreeding Rate (ΔF) Calculator
Calculate the rate of inbreeding per generation (ΔF) from effective population size, and project inbreeding over time.
Inbreeding rate per generation ΔF = 1 ÷ (2 × Ne). Keep it below 1% per generation; above that, inbreeding depression (poorer fertility, growth and survival) builds up. Project it forward to see the long-term cost of a small breeding base.
Indicative planning figures based on published research averages. Local soil tests, varieties and weather change actual requirements — confirm with your agronomist or extension officer.
Livestock breeders and farm managers use the free Inbreeding Rate (ΔF) Calculator for an accurate answer in seconds — no formulas to remember, works offline at the farm.
About Inbreeding Rate (ΔF) Calculator
The rate of inbreeding (ΔF) tells you how fast relatedness — and the loss of vigour that comes with it — accumulates in a closed herd or flock. It depends only on effective population size: the smaller the breeding base, the faster inbreeding climbs. This tool gives ΔF per generation from your Ne and projects the cumulative inbreeding over the generations ahead, so you can see whether your breeding programme is genetically sustainable or heading for inbreeding depression.
How to use Inbreeding Rate (ΔF) Calculator
- 1Enter your herd/flock figures into the inputs.
- 2Read the headline result and the supporting breakdown.
- 3Apply the guidance in the note to your breeding decisions.
Why use Inbreeding Rate (ΔF) Calculator?
- ✓Uses the standard, citable animal-breeding formula
- ✓Clear inputs with sensible defaults
- ✓Instant result with the working shown
- ✓Free, fully in-browser and private
Frequently asked questions
What is a safe rate of inbreeding?+
Below about 1% per generation (ΔF < 0.01) is the widely-used safe ceiling. Above it, inbreeding depression — reduced fertility, slower growth, weaker immunity — accumulates noticeably. Conservation programmes aim for ΔF under 0.5%.
How do I reduce the inbreeding rate?+
Raise the effective population size: use more breeding males, rotate or exchange sires, avoid mating close relatives, and bring in unrelated breeding stock periodically. Even a modest increase in Ne sharply lowers ΔF.
Is this tool free and private?+
Yes — free, no sign-up, and all calculation runs in your browser, so it works offline at the farm and your data never leaves the device.
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