Stair Calculator - Rise Run Tread Steps Needed Online
Calculate riser height, stringer length, stair angle, and total run for any staircase given total rise and tread depth.
How to use this calculator
👉 Fill in the boxes below and your answer appears instantly — no maths needed, we do it all for you! 🎉
In plain English — what does this do?
📊 A helper for daily life! Things like working out your age, how much to tip, what a sale price is, or how long until your birthday. Quick and easy answers for real life!
The Stair Calculator helps you design a staircase by computing the riser height, total run, stringer length, and angle based on the total rise and your chosen number of steps and tread depth. It also checks whether the riser height falls within the recommended 7–7.75 inch range.
Riser Height
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Stringer Length
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Stair Angle
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Total Run
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Code Status
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What is Stair Calculator - Rise Run Tread Steps Needed Online?
The Stair Calculator helps you design a staircase by computing the riser height, total run, stringer length, and angle based on the total rise and your chosen number of steps and tread depth. It also checks whether the riser height falls within the recommended 7–7.75 inch range.
How to use it
- 1️⃣ Enter the total rise — the vertical distance from floor to floor in inches.
- 2️⃣ Enter the tread depth — the horizontal depth of each step (typically 10–11 inches).
- 3️⃣ Enter the number of steps.
- 4️⃣ Click Calculate to get the riser height, total run, stringer length, and stair angle.
- 5️⃣ Adjust the number of steps until the riser height falls between 7 and 7.75 inches for code compliance.
Formula
💡 See it in action — a real example
❓ Common questions
- What is the ideal riser height?
- Most building codes require risers between 7 and 7.75 inches. Consistent riser heights throughout the staircase are critical for safety.
- What is a stringer?
- The stringer is the diagonal structural board that supports the treads and risers. Its length tells you how long the lumber needs to be.
- What tread depth should I use?
- Residential codes typically require a minimum tread depth of 10 inches. A 10–11 inch tread combined with a 7–7.5 inch riser gives a comfortable staircase.
- What stair angle is comfortable?
- Comfortable stairs are typically between 30° and 45°. Steeper than 45° feels like a ladder; shallower than 30° takes up too much floor space.
- Does this account for tread nosing?
- No — this calculator uses the tread run depth only. If your treads have a nosing overhang (typically 0.75–1.25 in), add it to the tread depth for the actual tread width.