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Building a safe, comfortable staircase means keeping riser heights and tread depths within a narrow, code-friendly range.
This calculator finds the number of risers, actual riser height, total run, stringer length, and stair angle from your total rise and target riser and tread dimensions.
How it works
Enter the total rise (floor-to-floor height), your desired riser height, and your target tread depth. The calculator rounds to a whole number of risers, recalculates the exact riser height needed, and derives the total run and stringer length using the Pythagorean theorem.
- Enter total rise / floor-to-floor height (in).
- Enter desired riser height (in, typically 7–7.75).
- Enter tread depth (in, typically 10–11).
- Click Calculate to see your results.
Examples
108 in total rise
A staircase with 108 inches of total rise, targeting a 7.5 in riser and 10 in tread, needs 14 risers at 7.71 in each, with a stringer length of about 169 in.
Who should use it
- Planning a new deck, porch, or interior staircase before cutting stringers.
- Checking whether an existing staircase design meets a comfortable riser-to-tread ratio.
Industry applications
- Residential construction and carpentry
- Deck building and home renovation
Advantages
- Automatically rounds to a safe, whole number of risers.
- Calculates stringer length and stair angle alongside riser and tread dimensions.
Limitations
- Doesn't account for headroom clearance or landing requirements.
Common mistakes to avoid
- Designing risers taller than your local code maximum, which is both unsafe and likely to fail inspection.
- Forgetting that the top floor level itself doesn't count as an additional tread — the number of treads is always one less than the number of risers.
Best practices
- Always verify your final riser height and tread depth against your local building code before construction.
Tips
- A comfortable stair typically has riser height plus tread depth between 17 and 18 inches — a well-known rule of thumb among carpenters.