Stair Stringer Calculator
Calculate riser height, tread depth, and stringer length.
Tool Interface
Stair Stringer Calculator
Calculate riser height, tread depth, total run, stringer length, and stair angle.
How to use
Measure the total vertical rise from the lower floor to the upper floor surface. Enter your target riser height and tread depth, then press Calculate. The tool gives you the step count, exact riser height, total run, stringer board length, and angle. Reset restores the example values.
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About This Tool
Frequently Asked Questions (FAQ)
What does the stair stringer calculator show?
Enter the total rise floor to floor, your target riser height and tread depth. It calculates the number of steps, actual riser height and the full stringer layout.
What is a comfortable riser height?
Most building codes cap risers around 7 to 8 inches. A rise near 7 inches with an 11 inch tread feels comfortable for most people.
What is the 2R plus T rule?
The classic comfort formula: twice the riser plus the tread should land between 24 and 26 inches. The calculator helps you hit that range.
How many stringers do I need?
Typically one stringer per 16 inches of stair width — a 3-foot stair needs at least three. Wider stairs need more for support.
Is the stair stringer calculator free?
Yes. It is free to use with no signup and no limits.