Handyman Stair Calculator

This handyman stair calculator helps you quickly estimate stair dimensions like rise per step, total run, stringer length, and angle — so you can plan and build safely and efficiently.

What is a Handyman Stair Calculator?

It’s a simple tool that calculates key stair measurements based on your total rise (floor-to-floor height), number of steps, tread run, and mount type. It takes the guesswork out of stair design and ensures compliance with standard safety guidelines.

Why should I use a handyman stair calculator?

Using a stair calculator saves time, ensures accuracy, and reduces costly mistakes by helping you determine the correct number of steps for any project, meet building code requirements for riser height, tread depth, and stair angle, and provide accurate project estimates to clients.

How do you use this calculator?

To use this calculator and determine stair dimensions, follow these simple steps:

Enter Total Rise: Input the height from the lower floor to the upper floor.

Set Tread Run: Decide the tread depth you want for each step.

Choose Mount Type: Standard or Flush mount based on your design.

Add Tread Thickness: Helps calculate the bottom step height accurately.

Enter Number of Steps: Or leave blank to let the calculator auto-compute.

Get Instant Outputs: Total run, stringer length, bottom step rise, and angle

Formulas Used :

1. Auto Rise per Step:
Rise per Step = Total Rise / Number of Steps

2. Bottom Step Rise:
For Standard Mount:
Bottom Step Rise = Rise per Step
For Flush Mount:
Bottom Step Rise = Rise per Step – Tread Thickness

3. Total Run:
Total Run = Run per Step * Number of Steps

4. Stringer Length (Pythagorean Theorem):
Stringer Length = sqrt(Total Rise^2 + Total Run^2)

5. Stair Angle (in degrees):
Stair Angle = atan(Total Rise / Total Run) * (180 / π)

Example:

Inputs:

Mount Type: Standard

Tread Thickness: 1.5 in

Total Rise: 106 in (distance from lower floor to upper floor)

Number of Steps: 14

Rise per Step: Leave blank (calculator will auto-compute)

Run per Step: 10 in

Step-by-Step Calculation:

Auto Rise per Step = Total Rise ÷ Number of Steps
= 106 ÷ 14
= 7.57 in

Final Rise per Step

Since user left rise blank → 7.57 in

Bottom Step Rise (Standard mount → no subtraction)
= 7.57 in

Total Run = Run per Step × Number of Steps
= 10 × 14
= 140 in

Stringer Length = √(Total Rise² + Total Run²)
= √(106² + 140²)
= √(11236 + 19600)
= √30836
= 175.6 in (≈ 14.63 ft)

Stair Angle = atan(Total Rise ÷ Total Run) × 180 ÷ π
= atan(106 ÷ 140) × 180 ÷ 3.1416
= atan(0.7571) × 57.2958
= 37.1°

Final Outputs:

Rise per Step: 7.57 in

Bottom Step Rise: 7.57 in

Total Run: 140 in

Stringer Length: 175.6 in (14.63 ft)

Stair Angle: 37.1°