How to use it
- Enter total rise in centimeters
- Enter total run in centimeters
- Enter the number of risers
- Click calculate and read the three results
What it does – The Stair Calculator takes the total vertical rise, total horizontal run, and the number of risers you plan, then instantly shows the rise per step, the tread depth, and the rise‑to‑tread ratio.
Why it matters – Correct rise per step ensures comfortable, code‑compliant stairs, while adequate tread depth prevents trips. The ratio lets you see if the stair geometry follows the classic 2 : 1 rule that many builders use for safety and ergonomics.
How to read the results – Rise per Step is the vertical height of each riser. Tread Depth is the horizontal surface you step on; remember the top landing isn’t a tread, so treads = risers‑1. Rise‑to‑Tread Ratio compares the two numbers; a ratio around 0.5–0.6 is generally comfortable. Use these numbers to order stair components or adjust your design before any material is cut.
Pro tips
- Add 1 cm to each tread depth for cutting waste
- Round rise per step to the nearest half‑centimeter for easier framing
- Order a few extra risers in case of breakage
- Double‑check that risers‑1 equals the number of treads you’ll cut
Real-life examples
- A homeowner planning a new staircase wants to ensure each step meets local code limits
- A contractor needs quick numbers to quote stair components for a remodel
- An architect checks the rise‑to‑tread ratio while drafting a building plan
Case study
John, a DIY homeowner, entered a 250 cm total rise, 300 cm run, and 12 risers. The calculator gave him a 20.8 cm rise per step and 27.3 cm tread depth, confirming a safe 0.76 ratio. He adjusted the design, ordered the correct lumber, and finished his staircase without re‑cuts.