Stair Calculator

What is the Stair Calculator?

Calculate the number of steps, riser height and run for a staircase. Calculating the number of risers and treads helps build comfortable stairs that meet typical building code limits.

How to use the Stair Calculator

1. Enter your total rise, your target riser height, your tread depth.
2. Results update automatically as you type; you can also press Calculate.
3. Read the output: number of risers, actual riser height, total run, stair angle.
4. Use the 📊 chart to see the result visually, then copy or share it.

Formula and method

Worked example

With total rise = 108 in, target riser height = 7.5 in, tread depth = 10 in, the Stair Calculator returns number of risers: 15; actual riser height: 7.200 in; total run: 140.0 in.

Where the Stair Calculator helps in real life

You are building deck stairs with a total rise of 42 inches. The calculator shows how many steps you need and the exact riser height.

You are planning a basement staircase and want comfortable proportions. Checking riser and tread sizes helps avoid steep or awkward stairs.

Common mistakes to avoid

• Ignoring local building code limits.
• Making riser heights uneven.
• Forgetting headroom over the stairs.
• Measuring total rise from the wrong surface.

💡 Practical tip: Uneven step heights are a common trip hazard — keep every riser identical.

Tips for better results

• Check local codes before building.
• Keep every riser the same height.
• Measure total rise from finished floor to finished floor.

⚠️ Material estimates are approximate. Follow local building codes and manufacturer instructions.

Related tools