Stair Calculator
Calculate the height and width of the steps and their number.
Tip: The golden rule: 2 × riser + tread = 63 cm (e.g. 17.5 cm × 28 cm).
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About this digital tool
The stair calculator finds how many steps you need to cover a given height and shows the real dimensions of each. Enter the total height between two floors, the width of the stair, the desired height of one step (riser) and its depth (tread).
The number of steps is the total height divided by the desired height, rounded up; then the real height of each step is calculated by dividing the total height by the number of steps. The tool also gives the total horizontal length, the length of the sloped run and the estimated volume of concrete. It warns you if the real height falls outside the 15–20 cm range. It serves builders, junior architects and owners planning a staircase.
How to use
- Enter the total height to be covered, in metres.
- Enter the width of the stair in metres.
- Enter the desired riser height and tread depth of one step, in cm.
- Read the number of steps, the real height, the horizontal length and the concrete volume.
Frequently asked questions
How high should a step be?
Optimal height: 16–19 cm. Tread: 25–30 cm. The formula 2h + t ≈ 63 cm ensures comfort when climbing.
How is the number of steps calculated?
Divide the total height by the height of one step and round up. For 2.7 m and an 18 cm step it comes to 15 steps, with a real height of 18 cm. Then the tool recalculates the real height so that the steps are equal.
What does the formula 2 × riser + tread show?
It is a practical rule for comfort: twice the riser plus the tread depth should be about 63 cm. For example 17.5 cm riser and 28 cm tread give 63 cm. Use it to check whether a stair is comfortable.
Why does the tool warn me about the step height?
The warning appears when the real step height falls below 15 cm or above 20 cm, because very low or very high steps are uncomfortable and unsafe. Change the desired height until you get within this range.