Handrail Length Calculator
Handrail length, angle and baluster count for a staircase.
Enter your values
Enter the number of risers you are working with.
Enter the riser height in in.
Enter the tread depth in in.
Enter the extension each end in in.
Enter the max baluster gap in in.
Results update instantly as you type — no submit needed. Your values are remembered on this device, and the shareable link reopens the calculator with exactly these numbers.
- Handrail length
- 14.88 ft (178.62 in)
- Rail along stairs only
- 12.88 ft
- Stair angle
- 39.1 degrees
- Total rise / run
- 97.5 in / 120 in
- Balusters needed
- 30
Working
- 1sqrt(97.5^2 + 120^2) = 154.62 in of rail
Quick answer
Handrail length is the hypotenuse of total rise and total run, plus any required extensions at the top and bottom.
rail = sqrt(rise^2 + run^2) + extensions
At a glance
| What it does | Handrail length, angle and baluster count for a staircase. |
|---|---|
| Category | Home & DIY |
| Inputs needed | Number of risers, Riser height, Tread depth, Extension each end, Max baluster gap |
| Main output | Handrail length |
| Formula | rail = sqrt(rise^2 + run^2) + extensions |
| Cost | Free — no sign-up, no download |
How to use the Handrail Length Calculator
- 1Count the risers and measure one riser height and one tread depth.
- 2Add 12 inch extensions at the top and bottom if your code requires them.
- 3Space balusters so no 4 inch sphere can pass between them.
Inputs explained
- Number of risers
- Enter the number of risers you are working with.
- Riser height(in)
- Enter the riser height in in.
- Tread depth(in)
- Enter the tread depth in in.
- Extension each end(in)
- Enter the extension each end in in.
- Max baluster gap(in)
- Enter the max baluster gap in in.
Worked example
Using the values the calculator loads with:
Inputs
- Number of risers13
- Riser height7.5 in
- Tread depth10 in
- Extension each end12 in
- Max baluster gap4 in
Results
- Handrail length14.88 ft (178.62 in)
- Rail along stairs only12.88 ft
- Stair angle39.1 degrees
- Total rise / run97.5 in / 120 in
- Balusters needed30
- sqrt(97.5^2 + 120^2) = 154.62 in of rail
Frequently asked questions
What height should a handrail be?
Between 34 and 38 inches measured vertically from the tread nosing in most residential codes.
How many balusters do I need?
Enough that the clear gap never exceeds 4 inches - usually two per tread on a standard staircase.
What do I need to enter into the Handrail Length Calculator?
Just 5 values: number of risers, riser height, tread depth, extension each end, max baluster gap. Every field starts with a realistic example, so you can change one number at a time and watch the result update instantly.
How does the Handrail Length Calculator work out the answer?
Handrail length is the hypotenuse of total rise and total run, plus any required extensions at the top and bottom. It applies the formula rail = sqrt(rise^2 + run^2) + extensions and shows the working so you can check each step by hand.
Is the Handrail Length Calculator free, and do I need an account?
It is completely free with no sign-up, no download and no usage limit. Everything is calculated in your browser, so the numbers you type never leave your device.
Results are estimates for general information. For medical, legal, structural or financial decisions, confirm with a qualified professional.