Quick answer
A backyard coop needs about 3 square feet of floor space per standard hen when the flock also has a run, plus about 8 square feet of run per bird. Six standard hens need roughly an 18 square foot coop (about 4 x 5 feet) and a 48 square foot run.
- Bantams: about 2 sq ft of coop and 4 sq ft of run per bird.
- Large breeds: about 4 sq ft of coop and 10 sq ft of run per bird.
- No run at all: plan on 8 to 10 sq ft of coop per bird.
- Give 5 to 10 inches of roost per bird and one nest box for every 4 hens.
How big should your chicken coop be? The answer depends on how many birds you keep, how big the breed is and whether they get outside every day. Use the calculator below, then check the tables for quick numbers.
Chicken coop size calculator
Enter your flock and get coop, run, roost, nest box and feeder sizes.
How much space does each chicken need?
University extension guides agree on a simple rule: the more time birds spend outside, the less coop space they need. Oregon State Extension recommends at least 3 square feet per bird when chickens have a run, and 8 to 10 square feet per bird when they never go outside.
Penn State Extension lists tighter minimums of 1 square foot inside for bantams, 1.5 for laying hens and 2 for large chickens, with 4, 8 and 10 square feet outside. We use the roomier numbers as our recommendation because extra space gives birds room to get away from each other.
| Breed size | Coop minimum (sq ft) | Coop recommended (sq ft) | Coop only, no run (sq ft) | Run (sq ft) | Roost per bird |
|---|---|---|---|---|---|
| Bantam | 1 | 2 | 6 | 4 | 5 in |
| Standard | 1.5 | 3 | 8 | 8 | 8 in |
| Large | 2 | 4 | 10 | 10 | 10 in |
What size coop do you need for 4, 6, 10 or 20 chickens?
This table assumes standard size hens with a run. Coop sizes are rounded up to common build or kit sizes.
| Hens | Coop floor | Coop size | Run | Roost bar | Nest boxes |
|---|---|---|---|---|---|
| 3 | 9 sq ft | 3 x 4 ft | 24 sq ft | 2 ft | 2 |
| 4 | 12 sq ft | 3 x 4 ft | 32 sq ft | 2.7 ft | 2 |
| 6 | 18 sq ft | 4 x 5 ft | 48 sq ft | 4 ft | 3 |
| 8 | 24 sq ft | 4 x 6 ft | 64 sq ft | 5.3 ft | 3 |
| 10 | 30 sq ft | 4 x 8 ft | 80 sq ft | 6.7 ft | 4 |
| 12 | 36 sq ft | 6 x 6 ft | 96 sq ft | 8 ft | 4 |
| 15 | 45 sq ft | 6 x 8 ft | 120 sq ft | 10 ft | 5 |
| 20 | 60 sq ft | 8 x 8 ft | 160 sq ft | 13.3 ft | 6 |
| 25 | 75 sq ft | 8 x 10 ft | 200 sq ft | 16.7 ft | 8 |
| 30 | 90 sq ft | 8 x 12 ft | 240 sq ft | 20 ft | 9 |
A flock of 6 standard hens fits a 4 x 5 foot coop with a run about 6 x 8 feet. If you plan to add birds later, build for the flock you will have in two years, not the one you have today. Our guide on how much space chickens need covers more layouts.
How much roost space do chickens need?
Chickens sleep shoulder to shoulder on a roost bar. Oregon State suggests 5 to 10 inches of bar per bird, set about 2 feet off the floor with 10 inches between bars. Penn State lists 6 inches per standard bird and 4 inches per bantam.
Penn State advises keeping perches low for large or meaty breeds like Brahmas and Jersey Giants, and never higher than 4 feet off the floor for any chicken. Oregon State suggests a roost about 1 foot off the ground for Silkies.
How many nest boxes do you need?
Plan on one nest box for every 4 hens, according to Oregon State and Oklahoma State Extension. Hens share boxes and often all pick the same favorite. A 12 x 12 x 12 inch box fits most standard breeds.
| Hens | Nest boxes |
|---|---|
| 2 | 2 |
| 4 | 2 |
| 6 | 3 |
| 8 | 3 |
| 10 | 4 |
| 12 | 4 |
| 16 | 5 |
| 20 | 6 |
Penn State recommends 2 nests for the first 4 hens, then one more for each additional 4, which is the formula our calculator uses. It also advises placing nests at least 2 feet off the ground and at least 4 feet from the roosts.
What else should you size before you build?
- Feeder: at least 3 inches of feeder space per bird so everyone can eat at once.
- Water: one nipple drinker for every 6 to 8 birds, set just above eye level.
- Ventilation: vents on one side, away from prevailing winds and not directly over the roost.
- Bedding: about 2 inches of clean pine shavings in each nest box.
Space matters more in cold climates, where birds spend more days shut inside. If you get long snowy winters, size the coop toward the coop only number for your breed. New to chickens? Start with our backyard chicken guide, and see what your flock saves with our egg price tracker.
How do the extension guides compare?
| Source | Coop space per bird | Run space per bird | Roost per bird | Nest boxes |
|---|---|---|---|---|
| Penn State | 1 to 2 sq ft | 4 to 10 sq ft | 4 to 6 in | 2 for first 4, then 1 per 4 |
| Oregon State | 3 sq ft (8 to 10 with no run) | Not listed | 5 to 10 in | 1 per 4 |
| Oklahoma State | 1.5 to 2 sq ft | 8 to 10 ft | Not listed | 1 per 4 |
Frequently asked questions
How big should a chicken coop be for 6 chickens?
Six standard hens need about 18 square feet of coop floor, such as a 4 x 5 foot coop, plus about 48 square feet of run. Without a run, plan on 48 to 60 square feet of coop.
How many square feet does a chicken need?
About 3 square feet inside the coop and 8 square feet in the run for a standard hen. Bantams need about 2 and 4, and large breeds about 4 and 10.
What size coop do I need for 10 chickens?
Ten standard hens need about 30 square feet of coop, such as a 4 x 8 foot coop, plus 80 square feet of run, 6.7 feet of roost bar and 4 nest boxes.
How many nest boxes do I need for 12 hens?
Four nest boxes. Plan on 2 boxes for the first 4 hens and 1 more for every additional 4.
Should I build a bigger coop than I need?
A little extra room is worth it if you plan to add birds later. Build for the number of hens you expect to keep in two years.
Do free range chickens need a smaller coop?
Yes. Birds that spend the day outside mainly sleep and lay in the coop, so about 3 square feet per standard bird is enough, and some guides allow as little as 1.5.
How we gathered this data: We compared poultry housing guidance from Penn State Extension, Oregon State University Extension and Oklahoma State University Extension in October 2026, then set our calculator to the roomier of the published numbers for each breed size.
