How to use the chicken coop size calculator
- Enter the number of hens you plan to keep.
- Enter the coop space per hen and the run space per hen in square feet. The boxes start with example values that you can change.
- Optionally enter a planned coop width in feet to find the length that the coop area needs.
- Read the coop area, the run area and the total.
Formula
Coop area = hens x coop space per hen
Run area = hens x run space per hen
Coop length = coop area / planned width
The space per hen is a number you choose. It is not a standard.
Six hens at 4 and 10 square feet each
With 6 hens at 4 square feet each in the coop, the coop floor is 6 x 4 = 24 square feet. At 10 square feet each in the run, the run is 6 x 10 = 60 square feet. Together they need 84 square feet of ground.
If the coop is 4 feet wide, a 24 square foot floor needs a length of 24 / 4 = 6 feet. Change the space per hen and every figure scales in proportion.
Space per hen is your choice
The tool multiplies the flock size by the space you enter. The starting values are examples so that the page shows a result, and they are not a recommendation or a standard. Breed, climate, how many hours birds spend outside and local rules all affect what you want, so check what applies where you live before building.
Many places have rules about animals, setbacks and structures. A quick call to your local office or a look at your homeowner association rules can save a rebuild.
From area to a build plan
Floor area is only the start. Nest boxes, roosts, doors, feeders and ventilation all take planning that this arithmetic leaves out. To price materials, the square footage calculator and the fence calculator help with the run, and the annual pet cost calculator covers ongoing costs.
For feed storage and forage planning, the hay needs calculator does a similar daily and total calculation.
Assumptions and limits
- Space per hen is an example number that you choose, not a standard.
- The same space is used for every hen.
- Nest boxes, roosts, doors and ventilation are not modeled.
- Local rules and the needs of your birds are for you to check.
Frequently asked questions
How big should a chicken coop be?
The tool does not say. It multiplies your flock by the space per hen that you enter. At the example 4 square feet each, 6 hens need 24 square feet.
How do I calculate the size of a run?
Multiply the number of hens by the run space per hen. At 10 square feet each, 6 hens need 60 square feet.
Do I need to check local rules?
Yes. Many areas have rules about keeping hens and building structures, so check with your local office or association.
What does the planned width do?
It turns the coop floor area into a length. A 24 square foot floor that is 4 feet wide needs to be 6 feet long.