Crowded chickens are stressed, peck each other and get sick, so poultry extension services recommend minimum space per bird. Bantams (miniature breeds) need about half the space of standard hens. These are minimums – free-ranging birds can manage with less run, and birds confined all winter need more coop.
How to use the Chicken Coop Size Calculator
- Standard-size hens
- Bantams
Results update as you type, and every field accepts the units shown in its menu.
How it works
Enter the number of standard-size hens and bantams. The calculator adds up the space each needs inside and in the run, the length of perch and the nest boxes, and suggests a square coop size.
Tips for an accurate estimate
- Take measurements at floor level and at the ceiling – walls and rooms are often slightly out of square.
- Use the manufacturer’s coverage, spacing and installation data when it differs from the typical values here.
- Keep a little extra of every finish material for touch-ups and repairs later.
- Check local building codes and permits before structural, electrical, plumbing or gas work.
Common mistakes to avoid
- Sizing heating or cooling equipment by area alone when insulation, windows and climate make a big difference.
- Buying too little paint, stain or flooring and ending up with mismatched batches.
- Overlooking the extra material for steps, railings, gables and trim.
Inputs explained
| Field | What to enter |
|---|---|
| Standard-size hens | A number |
| Bantams | A number |
What each result means
- Coop floor area = (4×[Standard-size hens] + 2×[Bantams])×0.09290304
- Square coop side = sqrt([Coop floor area])
- Run area = (10×[Standard-size hens] + 4×[Bantams])×0.09290304
- Roost length = (10×[Standard-size hens] + 6×[Bantams])×0.0254
- Nest boxes = ceil(([Standard-size hens] + [Bantams])÷4 – 0.000001)
Example values
How the main result changes when Standard-size hens changes and everything else stays at the example values above:
| Standard-size hens | Coop floor area (ft²) |
|---|---|
| 3 | 12 |
| 4.5 | 18 |
| 6 | 24 |
| 7.5 | 30 |
| 9 | 36 |
| 12 | 48 |
Formula
Coop = 4 ft² × standard + 2 ft² × bantamRun = 10 ft² × standard + 4 ft² × bantamRoost = 10 in × standard + 6 in × bantamNest boxes = ceil(hens ÷ 4)Worked example
Inputs — Standard-size hens: 6; Bantams: 0.
Results — Coop floor area = 24 ft²; Square coop side = 4.9 ft; Run area = 60 ft²; Roost length = 5 ft; Nest boxes = 2.
Frequently asked questions
How big should a coop be for 6 chickens?
At least 24 ft² inside (e.g. 5 × 5 ft) plus a 60 ft² run.
How many nest boxes do hens need?
One box for every 4–5 hens; they will share.
How much roost space per chicken?
8–10 in per standard hen and about 6 in per bantam.
What formula does the Chicken Coop Size Calculator use?
Coop = 4 ft² × standard + 2 ft² × bantam.