Stair Railing Calculator

The Stair Railing Calculator takes the guesswork out of planning a stair railing system by calculating exactly how much material you need before you buy or build. Enter your stair's total rise, total run, number of steps, baluster width, maximum gap between balusters, post spacing, and handrail height to get your total railing length, total balusters needed, actual baluster spacing, handrail linear feet, and stair angle. Toggle Include Landing Railing to factor in material for top and bottom landings.

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Total vertical height from bottom to top of stairs

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Total horizontal length of the staircase

Total number of steps in the staircase

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Width of each individual baluster or spindle

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Maximum allowed space between balusters (typically 4" for safety)

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Distance between support posts along the railing

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Height of the handrail above the stair treads

Include railing for top and bottom landings

Results

Total Railing Length

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Total Balusters Needed

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Actual Baluster Spacing

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Handrail Linear Feet

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Stair Angle

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Frequently Asked Questions

How far apart should spindles be on a stair railing?

Spindles (balusters) should be spaced no more than 4 inches apart for safety, as required by most building codes. This prevents small children from getting their heads stuck between balusters.

What is the standard height for stair railings?

Standard stair railing height is typically 34-38 inches measured from the stair nosing. Most codes require a minimum of 34 inches and maximum of 38 inches for residential stairs.

How do I calculate the angle of my stairs?

The stair angle is calculated using the arctangent of the rise over run ratio. Typical stair angles range from 30-40 degrees, with 35-37 degrees being most comfortable for daily use.

Do I need railing on both sides of the stairs?

Building codes typically require handrails on at least one side for stairs with 4 or more risers. Stairs wider than 44 inches usually require railings on both sides.

What materials can I use for stair balusters?

Common baluster materials include wood, metal (iron, aluminum, steel), glass panels, and cable systems. The choice depends on your design preference, budget, and local building codes.

How do I measure my existing stairs for new railings?

Measure the total rise (vertical height), total run (horizontal length), count the number of steps, and measure individual tread depth and riser height. Also measure any landings that need railings.

What is the difference between open and closed stringer stairs?

Open stringers expose the ends of the treads, while closed stringers have solid sides that hide the tread ends. This affects how the railing attaches and the overall appearance.