What this calculator does
The Chicken Egg Incubation Calculator estimates when your eggs are due to hatch. You enter the date the eggs were placed in the incubator (the "set date") and choose the species, and the tool adds the typical incubation period to give you an expected hatch date plus a lockdown date for raising humidity and stopping egg turning.
How to use it
Select the date you set the eggs, pick the species from the list, then read the hatch date. Chicken eggs hatch in about 21 days. For other birds choose the matching option, or pick "Custom period" and type the exact number of days recommended for your breed.
The formula explained
The core calculation is simply $$\text{Hatch Date} = \text{Set Date} + N \text{ days}$$, where \(N\) is the incubation period for the species. For chickens \(N = 21\). The lockdown date — when you stop turning the eggs and increase humidity — is calculated as \(\text{Set Date} + (N - 3)\), so day 18 for chickens.
Worked example
You set a batch of chicken eggs on January 1, 2024. Adding 21 days gives a hatch date of January 22, 2024. Lockdown (day 18) falls on January 19, 2024. Mark these dates on your calendar and monitor the incubator's temperature (≈37.5 °C / 99.5 °F) and humidity throughout.
FAQ
Why didn't my eggs hatch on the exact day? Incubation time is an average. Cooler temperatures slow development and warmer temperatures speed it up, so eggs may hatch a day or two early or late.
What is "lockdown"? The last few days before hatching when you stop turning the eggs, lower handling, and raise humidity so chicks can pip and hatch successfully.
Can I use this for ducks, quail or turkeys? Yes. Choose the species in the dropdown, or enter a custom period — quail ~18 days, ducks ~28 days, Muscovy ducks ~35 days, geese ~30 days.
