How the calculator works
The calculator multiplies commonly cited per-bird minimums by the number of hens:
| Per hen | Bantam | Standard | Large breed |
|---|---|---|---|
| Coop floor | 2 sq ft | 4 sq ft | 6 sq ft |
| Run | 5 sq ft | 10 sq ft | 15 sq ft |
| Roost bar | 8 in | 10 in | 12 in |
| Nest box (inside) | 10 × 10 in | 12 × 12 in | 14 × 14 in |
- Nest boxes: one for every four hens, rounded up.
- Ventilation: about 1 square foot of opening for every 10 square feet of coop floor. That is a rule of thumb; hot, humid climates need more.
- Suggested footprint: the smallest common size that holds the floor area, such as 4 × 6 or 6 × 8 ft, because those dimensions work well with 4 × 8 sheet goods and standard lumber.
Standard hens are the usual laying breeds, such as Leghorns, Rhode Island Reds and Plymouth Rocks. Large breeds include Brahmas, Jersey Giants and Cochins. Bantams are miniature breeds or miniature versions of standard breeds.
If your hens free-range during the day, they still need the full coop to sleep and lay in, and the run becomes optional. If they live in a coop and run, the run is part of the minimum. Hens that will be shut in the coop for long stretches, through a hard winter for example, are happier with more floor than the minimum.
Use the Meters toggle for square meters and centimeters.
Chicken coop size chart
Minimums for standard-size hens. For bantams, halve the coop floor and the run; for large breeds, multiply them by 1.5.
| Hens | Coop floor | Suggested coop | Run | Roost bar | Nest boxes |
|---|---|---|---|---|---|
| 3 | 12 sq ft | 3 × 4 ft | 30 sq ft | 30 in (2.5 ft) | 1 |
| 4 | 16 sq ft | 4 × 4 ft | 40 sq ft | 40 in (3.3 ft) | 1 |
| 5 | 20 sq ft | 4 × 6 ft | 50 sq ft | 50 in (4.2 ft) | 2 |
| 6 | 24 sq ft | 4 × 6 ft | 60 sq ft | 60 in (5 ft) | 2 |
| 7 | 28 sq ft | 4 × 8 ft | 70 sq ft | 70 in (5.8 ft) | 2 |
| 8 | 32 sq ft | 4 × 8 ft | 80 sq ft | 80 in (6.7 ft) | 2 |
| 9 | 36 sq ft | 6 × 6 ft | 90 sq ft | 90 in (7.5 ft) | 3 |
| 10 | 40 sq ft | 6 × 8 ft | 100 sq ft | 100 in (8.3 ft) | 3 |
| 11 | 44 sq ft | 6 × 8 ft | 110 sq ft | 110 in (9.2 ft) | 3 |
| 12 | 48 sq ft | 6 × 8 ft | 120 sq ft | 120 in (10 ft) | 3 |
| 13 | 52 sq ft | 6 × 10 ft | 130 sq ft | 130 in (10.8 ft) | 4 |
| 14 | 56 sq ft | 6 × 10 ft | 140 sq ft | 140 in (11.7 ft) | 4 |
| 15 | 60 sq ft | 6 × 10 ft | 150 sq ft | 150 in (12.5 ft) | 4 |
Example: six standard hens in a coop and run
- Coop floor: 6 × 4 sq ft = 24 sq ft, which a 4 × 6 ft coop covers exactly.
- Run: 6 × 10 sq ft = 60 sq ft, for example 6 × 10 ft.
- Roost bar: 6 × 10 in = 60 in, such as one 5 ft bar or two 30 in bars.
- Nest boxes: 6 ÷ 4 = 1.5, rounded up to 2.
- Ventilation: 24 sq ft ÷ 10 = 2.4 sq ft of openings.
Tips before you build
- Build for the flock you will have. Many keepers add birds after the first season, so a size up is cheaper than a second coop.
- Use hardware cloth, not chicken wire, on windows, vents and the run. Chicken wire keeps chickens in but does not keep raccoons and other predators out.
- Put vents high, above the roosts, so air moves out without blowing across sleeping birds.
- Keep roosts above the nest boxes. Hens sleep on the highest perch, and you want them off the boxes at night.
- Plan for cleaning. A door you can step through, or a wall or roof that opens, makes mucking out a small coop far easier. A droppings board under the roosts saves a lot of scrubbing.
- Feeders and waterers take floor space. If you hang them inside the coop, size up so they don't eat into the hens' minimum.
- Check local rules first. Ordinances and HOA covenants can cap the number of hens, ban roosters, require a permit or set distances from property lines and neighbors' homes.
Frequently asked questions
How big of a coop do I need for 6 chickens?
Six standard-size hens need at least 24 square feet of coop floor, which fits a 4 × 6 ft coop, plus a run of at least 60 square feet. Six bantams need about 12 square feet of coop, and six large breeds such as Brahmas about 36.
How many square feet does each chicken need?
A commonly cited minimum is 4 square feet of coop floor per standard hen, 2 per bantam and more, about 6, for large breeds. In the run, plan on about 10 square feet per standard hen. More room than the minimum means less pecking and squabbling.
How many nest boxes do I need for my chickens?
One nest box for every four to five hens is plenty, because hens take turns and often all want the same box anyway. Standard hens use boxes about 12 inches square; bantams can use smaller ones and large breeds need bigger ones.
How much roosting space do chickens need?
Give each standard hen about 10 inches of roost bar, bantams about 8 and large breeds about 12. Put the roosts higher than the nest boxes so the hens don't sleep, and leave droppings, in the boxes.
Can free-range chickens live without a run?
Yes, as long as they have a secure coop to sleep in at night and somewhere sheltered by day. A run is still handy for days when predators are around, the weather is bad or you are away and need them shut in.
Do I need a permit to keep backyard chickens?
It depends on where you live. Many cities, counties and homeowners associations limit flock size, ban roosters or set how far a coop must sit from property lines. Check your local code or call your planning or zoning office before you build.
Last updated October 17, 2026.