Chicken Coop Size Calculator
Chicken Coop Size Calculator
The honest coop maths, adjusted for your birds’ size. Enter your flock and get coop and run area, roost length and nesting boxes — and see how many birds the ready-made coop sizes really hold.
Standard: 3.5 sq ft coop and 10 sq ft run per bird. These are comfortable, commonly recommended figures — not the tight legal minimums factory farms use. More space always means a calmer, healthier flock.
Ready-made coop sizes
Your flock needs
How it works
Space per bird depends on bird size, following the allowances used in university extension poultry guides: bantams 2 sq ft coop / 6 sq ft run, standard breeds 3.5 sq ft / 10 sq ft, and large breeds 4.5 sq ft / 12 sq ft. Multiply by your flock size for the totals. Roost length is 10 inches per bird, and nesting boxes work out at one per four hens.
A word of honesty about minimums: some sources quote 2–3 sq ft per bird indoors, and factory standards go lower still. Those figures assume birds spend nearly all day outdoors and are managed commercially. Backyard keepers who size to 3.5–4 sq ft indoors see calmer flocks and far less feather-pecking — which is why this calculator plans around the comfortable figures and labels them as such. Planning a flock from scratch? Work out how many chickens you actually need first, then come back and size the coop.
Chicken coop size chart (standard breeds)
| Chickens | Coop (3.5 sq ft/bird) | Coop in m² | Run (10 sq ft/bird) | Run in m² | Roost length | Nesting boxes |
|---|---|---|---|---|---|---|
| 2 chickens | 7 sq ft | 0.7 m² | 20 sq ft | 1.9 m² | 1.7 ft | 1 |
| 4 chickens | 14 sq ft | 1.3 m² | 40 sq ft | 3.7 m² | 3.3 ft | 1 |
| 6 chickens | 21 sq ft | 2 m² | 60 sq ft | 5.6 m² | 5 ft | 2 |
| 8 chickens | 28 sq ft | 2.6 m² | 80 sq ft | 7.4 m² | 6.7 ft | 2 |
| 10 chickens | 35 sq ft | 3.3 m² | 100 sq ft | 9.3 m² | 8.3 ft | 3 |
| 12 chickens | 42 sq ft | 3.9 m² | 120 sq ft | 11.1 m² | 10 ft | 3 |
| 20 chickens | 70 sq ft | 6.5 m² | 200 sq ft | 18.6 m² | 16.7 ft | 5 |
| 30 chickens | 105 sq ft | 9.8 m² | 300 sq ft | 27.9 m² | 25 ft | 8 |
| 50 chickens | 175 sq ft | 16.3 m² | 500 sq ft | 46.5 m² | 41.7 ft | 13 |
Frequently asked questions
How many square feet per chicken in a coop?
For standard breeds, plan on 3.5–4 sq ft of coop floor per chicken; bantams need about 2 sq ft and large, heavy breeds about 4.5 sq ft. Anything under about 2 sq ft per standard bird invites stress, feather-pecking and disease, whatever the seller of a flat-pack coop claims.
How much run space do chickens need?
10 sq ft of outdoor run per standard chicken is the widely used recommendation (6 sq ft for bantams, 12 for large breeds). Birds that free-range for much of the day can manage with less run, because the run is not their only outdoor space.
How many chickens fit in a 4 × 8 ft coop?
A 4 × 8 ft coop has 32 sq ft of floor. At 3.5 sq ft per standard bird that houses 9 chickens comfortably — not the 16–20 some sellers advertise, figures that assume factory-farm minimums. At bantam rates (2 sq ft) it fits 16; at large-breed rates, 7.
How much roost space does a chicken need?
Allow 10 inches (about 25 cm) of roost bar per bird — more in hot climates, where birds spread out to cool down. For 10 hens that is just over 8 ft of roost, which can be split across two parallel bars.
How many nesting boxes do I need?
One nesting box per 4 hens is plenty — hens happily share, and most flocks use one or two favourite boxes whatever you provide. Ten hens need 3 boxes; twenty hens need 5.
Is a bigger coop always better?
Within reason, yes. Extra space reduces bullying, keeps litter drier and means birds cope better on days they stay inside (storms, snow, flock-downs). The main cost of oversizing is money and cleaning time, not the birds' welfare — nobody's flock ever suffered from too much room.