FullCalculator

Handrail Height Calculator

Stair Handrail

Calculate handrail height and post lengths for stairs

Deck / Balcony Guardrail

Determine guardrail requirements based on deck height above grade

Formula

Rail height measured vertically from nosing line | Post count = Perimeter / Spacing + 1

Frequently Asked Questions

What is the code-required handrail height for stairs?
Per the IRC (International Residential Code), stair handrails must be between 34 and 38 inches high, measured vertically from the stair nosing to the top of the handrail. Commercial stairs per IBC require 34-38 inch handrails plus a 42-inch guardrail if open on the side.
When is a guardrail required?
A guardrail is required when the walking surface (deck, balcony, landing) is more than 30 inches above the grade or floor below. Residential guardrails must be at least 36 inches high (IRC). Commercial guardrails must be at least 42 inches high (IBC).

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