Stringer Calculator
A stair stringer is the structural support that runs along each side of a staircase, providing the framework that holds the treads and risers in place. Proper stringer calculation is essential for building safe, code-compliant stairs that can support the intended load while maintaining comfortable step dimensions.
The key measurements for stair stringer construction include the total rise (vertical distance from floor to floor), total run (horizontal distance the stairs will cover), individual riser height (vertical part of each step), and tread depth (horizontal part where you step). Building codes typically require riser heights between 4 and 7.75 inches, with tread depths of at least 10 inches for safety and comfort.
Accurate stringer calculations ensure that your stairs meet building codes, provide consistent step dimensions, and maintain structural integrity. The remaining width after cutting the stringer must be sufficient to support the load, typically requiring at least 3.5 inches of material remaining after the deepest cuts are made.
How to Use the Stair Stringer Calculator
Step 1: Enter Basic Measurements
Input the total rise (vertical distance from the bottom floor to the top floor) and total run (horizontal distance the stairs will span). These are the fundamental measurements that determine your stair layout. Measure carefully as these values directly affect all other calculations.
Step 2: Specify Step Dimensions
Enter your desired riser height (typically 7-8 inches) and tread depth (usually 10-11 inches). If you leave these fields empty, the calculator will automatically determine optimal dimensions based on your total measurements and standard building practices.
Step 3: Configure Stringer Details
Set the stringer width (common lumber sizes like 2×12 = 11.25 inches) and number of stringers needed. Most stairs require at least 3 stringers for proper support, with additional stringers needed for wider stairs or heavier loads.
Step 4: Review Calculated Results
Examine the calculated step configuration, stringer dimensions, and material requirements. Pay special attention to the structural check section, which indicates whether your design meets safety requirements for remaining material width after cuts are made.
Step 5: Verify Code Compliance
Check that your calculated dimensions comply with local building codes. The results include code compliance indicators and recommendations for adjustments if needed. Always consult local building authorities for specific requirements in your area before beginning construction.