Chicken Coop Calculator
Size a coop and run for your flock. Enter the number of chickens and space per bird, and see coop area, run area, nest boxes, roost length, ventilation and weekly feed.
| Detail | Result |
|---|---|
| Coop length at your width | 6 ft |
| Total roost length | 5 ft |
| Vent opening needed | 5 sq ft |
| Feed per week | 11 lb |
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How Chicken Coop Calculator Works
Four quick steps happen behind the screen every time you change a number.
Sizes the coop floor
Number of birds times the space per bird gives the floor area inside the coop.
Sizes the run
The same flock count is multiplied by run space to give the outdoor area.
Adds the fittings
One nest box per four hens, plus roost length per bird, covers rest and egg laying.
Estimates daily needs
Ventilation and feed are scaled from the flock count so you can plan ahead.
How to Use Chicken Coop Calculator
Five quick steps take you from a tape measure to a usable result.
- Count your flockInclude the birds you plan to add. Chickens need room as they grow.
- Set coop space per birdUse 4 square feet for standard hens and 2 for bantams.
- Set run space per birdTen square feet per bird gives them room to scratch and keeps the ground from turning bare.
- Enter your coop widthThis gives the length you need for the floor area.
- Read the full listUse the nest, roost and vent numbers to plan the inside of the coop.
Formula Used in Chicken Coop Calculator
These are the standard formulas behind every result, so you can check the numbers yourself.
Coop floor
Space is in square feet.
Nest boxes
One box serves about four hens.
Feed
An adult hen eats about a quarter pound a day.
Worked example
Six chickens at 4 sq ft each need a 24 sq ft coop, which is 4 ft wide by 6 ft long. The run needs 60 sq ft, there should be 2 nest boxes, 5 ft of roost and about 11 lb of feed each week.
Chicken Coop Size Chart
Coop floor, run and nest boxes for common flock sizes at 4 sq ft of coop and 10 sq ft of run per bird.
| Size | Coop, sq ft | Run, sq ft | Nest boxes |
|---|---|---|---|
| 3 chickens | 12 | 30 | 1 |
| 6 chickens | 24 | 60 | 2 |
| 10 chickens | 40 | 100 | 3 |
| 15 chickens | 60 | 150 | 4 |
| 20 chickens | 80 | 200 | 5 |
| 30 chickens | 120 | 300 | 8 |
Bantams need less space. Large breeds may need more.
Space per Bird Guide
Typical space targets by bird type. Use them to set the values in the calculator.
| Bird type | Coop space | Run space | Roost space |
|---|---|---|---|
| Bantam | 2 sq ft | 8 sq ft | 6 to 8 in |
| Standard hen | 4 sq ft | 10 sq ft | 10 in |
| Large breed | 5 sq ft | 12 sq ft | 12 in |
More space reduces stress and pecking.
Common Chicken Coop Mistakes
Four slips that throw off the result, and how to avoid them.
Building for today only
A flock tends to grow. Plan space for a few extra birds from the start.
Choking off the ventilation
Damp, stale air causes illness. Keep vents high above the roost, away from drafts.
Skipping the run
Birds need daylight and room to scratch. A coop alone is not enough for long periods.
Putting nest boxes too low
Boxes lower than the roost invite roosting inside them. Place them below the roost bar.
Tools You Must Know
One number is rarely enough for a yard project. These calculators pair well with this one.
Chicken Coop Calculator FAQs
Quick answers before you order materials.
How big should a chicken coop be?
Allow about 4 square feet inside the coop for each standard hen, and about 10 square feet outside in the run.
How many nest boxes do I need?
One box for every four hens is enough. Hens will often share a favourite box.
How much roost space does a chicken need?
About 10 inches per bird. Large breeds need closer to 12 inches.
How much ventilation does a coop need?
Plan about one square foot of vent opening per bird, placed high above the roost.
How much feed does a chicken eat?
An adult hen eats about a quarter pound of feed a day, or 1.75 lb a week.
Is the Chicken Coop Calculator free?
Yes. It is free to use, with no signup.
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