Professional Stair Stringer Calculator
Calculate riser heights, tread depths, stringer lengths, and stair angles with real-time code compliance validation and an interactive live diagram.
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Input Dimensions Units
ft
in
in
in
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Live Stringer Diagram Calculated Results
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Framing Square Cut List | Step | Heel Position | Riser Height | Tread Depth |
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IRC R311.7 Code Reference Maximum Riser Height: 7¾″ (196 mm)
Measured vertically between leading edges of adjacent treads
Minimum Tread Depth: 10″ (254 mm)
Measured horizontally from nosing to nosing
Riser Uniformity: ≤ ⅜″ (9.5 mm) variance
Largest and smallest riser in a flight must not vary more than ⅜″
Nosing: ¾″–1¼″ projection if tread < 11″
Required when tread depth is less than 11 inches
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Material Estimate ⚠ Disclaimer: This calculator is a planning aid. Always verify results against your local building codes and regulations before construction. Consult a licensed professional for structural requirements.
How to Layout Stair Stringers
1
Measure Total Rise
Measure the vertical distance from the lower finished floor to the upper finished floor.
2
Calculate and Check Code
Enter details into our calculator to check if your riser height and stair angle comply with building codes.
3
Mark and Cut Stringer
Use the generated framing square heel positions to mark your cuts on a 2x12 lumber board.
Recommended Stair Angles and Ratios
Staircase design guidelines for optimal safety and walking rhythm.
Metric
Minimum
Maximum / Target
Ideal Stair Angle Range
30°
37° (Ideal)
Standard Riser Height Limit
4" (102 mm)
7.75" (196 mm)
Standard Tread Depth Limit
10" (254 mm)
12"+ (305 mm)
Riser + Tread Sum (7-11 rule)
17" (432 mm)
18" (457 mm)
Headroom Clearance
80" (2032 mm)
84"+ (2134 mm)