Calculate your egg incubation hatch date, lockdown day, and candling schedule from the set date, or work backward from a target hatch date.
Egg Incubation Hatch Date Formula
The calculator anchors every milestone to two facts: the day the eggs enter the incubator and the incubation period for the species. The core relationships are below.
Hatch Date = Set Date + Incubation Days
Lockdown Date = Hatch Date - Lockdown Lead
Set Date = Target Hatch Date - Incubation Days
Variables:
- Set Date is the calendar day the eggs are placed in a warm incubator (Day 0).
- Incubation Days is the species incubation period in whole calendar days (chicken 21, duck 28, quail 17, and so on).
- Hatch Date is the projected day external pipping begins.
- Lockdown Lead is the number of days before hatch that you stop turning and raise humidity (standard is 3).
- Lockdown Date is the day turning stops.
- Target Hatch Date is the day you want chicks to hatch when planning backward.
The forward mode adds the incubation period to your set date to return the hatch date, then subtracts the lockdown lead to find the lockdown day and counts 7 and 14 days from the set date for the candling checks. The reverse mode does the opposite: it subtracts the incubation period from a target hatch date so you know exactly when the eggs must go into the incubator. A likely hatch window of one day before to two days after the projected date is shown because real hatches rarely land on a single exact day.
Incubation Periods and Lockdown Days by Species
Use this table to confirm the incubation period and the day turning should stop. Lockdown day equals the incubation period minus three.
| Species | Incubation Days | Lockdown Day | Candle Days |
|---|---|---|---|
| Chicken | 21 | 18 | 7, 14 |
| Duck (domestic) | 28 | 25 | 7, 14 |
| Muscovy duck | 35 | 32 | 7, 14 |
| Turkey | 28 | 25 | 7, 14 |
| Goose | 30 | 27 | 7, 14 |
| Quail (Coturnix) | 17 | 14 | 7 |
| Quail (Bobwhite) | 23 | 20 | 7, 14 |
| Guinea fowl | 28 | 25 | 7, 14 |
| Pheasant | 24 | 21 | 7, 14 |
| Peafowl | 28 | 25 | 7, 14 |
| Pigeon | 18 | 15 | 7 |
| Emu | 50 | 47 | 7, 14 |
| Ostrich | 42 | 39 | 7, 14 |
Incubation periods assume a stable forced-air incubator held near 99.5 F. Actual figures vary slightly by breed and altitude.
The hatch date is only half of the planning problem. How long the eggs sat before you set them changes how many will hatch at all, which affects how many chicks you should expect on the date the calculator gives you. The table below shows the general effect of pre-set storage time on hatchability for chicken eggs held at proper storage conditions (55 to 65 F, high humidity).
| Storage Before Setting | Typical Hatchability | Note |
|---|---|---|
| 0 to 3 days | Highest (near peak) | Best window to set eggs |
| 4 to 7 days | Slight decline | Turn stored eggs daily |
| 8 to 10 days | Noticeable drop | Hatch may also run a day late |
| 11 to 14 days | Sharp drop | Expect fewer chicks |
| Over 14 days | Low | Not recommended for setting |
Storage time does not change the incubation period much, but eggs stored longer than a week often pip a day later than fresh eggs, so treat the hatch window as the more reliable target for older eggs.
Example Problems
Example 1: Chicken eggs. You set a batch of chicken eggs on April 1. The incubation period is 21 days, so the hatch date is April 1 plus 21 days, which is April 22. Lockdown is three days earlier on April 19 (day 18). Candling falls on April 8 (day 7) and April 15 (day 14). You should have the brooder ready by April 20.
Example 2: Planning backward for quail. You want Coturnix quail to hatch on May 27 for a fair. The incubation period is 17 days, so the set date is May 27 minus 17 days, which is May 10. Lockdown lands on May 24 (day 14), the same day as the second candling check, so candle first and then stop turning.
Frequently Asked Questions
Should I count from the day the egg was laid or the day I set it? Count from the day you set it in the incubator. Incubation only begins when the egg reaches incubation temperature. Eggs can be stored cool for several days before setting without starting to develop, so the lay date is not the start of the clock.
What does lockdown mean and why is it three days before hatch? Lockdown is when you stop turning the eggs, raise humidity, and stop opening the incubator. In the last three days the chick moves into hatching position and draws down the internal air cell, and turning or low humidity during this period causes malposition and shrink-wrapping. Three days is the standard lead for most poultry.
Why does the calculator show a hatch window instead of one exact day? Incubation biology is consistent but not perfectly precise. Temperature that runs slightly warm speeds development and slightly cool slows it, egg age adds a small delay, and a full clutch can take a day or two to finish hatching. The window from one day before to two days after the projected date is where most healthy hatches occur.
