Home / Pets / Chicken Coop, Run and Roost Size Calculator

Pets

Chicken Coop, Run and Roost Size Calculator

Calculate coop area, run area, roost length, nest boxes, and ventilation for a backyard chicken flock.

chicken cooprun sizeroost lengthnest boxesbackyard chickens

Chicken coop and run size calculator

Estimate coop floor area, run space, roost length, nest boxes, and ventilation from flock size.

Coop floor area
24 ft²
5 ft × 5 ft or larger
Outdoor run area
60 ft²
Predator-safe daytime space
Roost length
5 ft
Total linear roost bar
Nest boxes
2
At roughly 1 per 4 hens
Local rules, predator pressure, weather, breed behaviour, and sanitation can all change the ideal coop design.

What this estimate does and does not do

This calculator gives a backyard poultry space estimate using common husbandry rules of thumb. It is not animal welfare, veterinary, or building-code advice. Local regulations, predator pressure, heat, humidity, breed temperament, flock integration, sanitation, and how much time birds spend confined can all change the right design.

Formula used

coop area = birds × coop ft² per bird × confinement factor × climate factor
run area = birds × run ft² per bird × confinement factor × climate factor
roost length = birds × roost inches per bird / 12
nest boxes = ceil(birds / 4)
ventilation = birds × 1 ft² permanent ventilation rule of thumb

Breed-size rules used:

  • Bantam: 2.5 ft² coop, 7 ft² run, 8 inches roost per bird
  • Standard: 4 ft² coop, 10 ft² run, 10 inches roost per bird
  • Heavy: 6 ft² coop, 15 ft² run, 12 inches roost per bird

Worked example

For 6 standard hens with a daytime run in a mild climate:

coop = 6 × 4 = 24 ft²
run = 6 × 10 = 60 ft²
roost = 6 × 10 / 12 = 5 ft
nest boxes = ceil(6 / 4) = 2

Assumptions

  • The calculator uses square-footage rules, not a full coop design.
  • It assumes all birds can access usable floor and run space.
  • Mostly confined flocks get a larger multiplier because crowding increases stress and pecking risk.
  • Hot or wet climates need extra attention to ventilation, shade, drainage, and cleanliness.

Frequently asked questions

How much coop space does a standard chicken need?

A common backyard rule of thumb is about 4 square feet of indoor coop floor per standard chicken, plus about 10 square feet of outdoor run per bird.

How many nesting boxes do chickens need?

A common rule is one nest box for every 3–4 hens, although hens often share favourite boxes even when more are available.

How much roost space does each chicken need?

Standard hens commonly need around 10–12 inches of roost bar each. Heavy breeds need more, while bantams can use less.

Can this calculator guarantee good coop welfare?

No. Space is only one factor. Ventilation, predator protection, sanitation, shade, drainage, enrichment, local climate, and flock behaviour all matter.