What is the ideal rise and run for stairs?

The ideal rise (vertical height of each step) is 7-7.75 inches, and ideal run (horizontal depth) is 10-11 inches. The 7-11 rule creates comfortable, code-compliant stairs. Total rise/run must follow local building codes.

How do I calculate the number of steps needed?

Measure total height from floor to floor. Divide by your desired rise (typically 7.5 inches). Round to nearest whole number—this is your number of steps. Divide total height by number of steps to get actual rise per step.

What is the 18-inch rule for stairs?

The sum of one rise plus one run should equal 17-18 inches for comfortable stairs. For example, 7" rise + 11" run = 18". This creates an ergonomic stride and is used to validate stair design safety.

What are building code requirements for stairs?

Codes vary by location but typically require: minimum 36" width, maximum rise 7.75", minimum run 10", handrails 34-38" high, maximum variation between steps of 3/8". Always check local codes before building.

Everyday

Stair Calculator

Calculate rise, run, and stringer length for stairs.

Total Rise (inches)Vertical distance from floor to floor

Target Tread Depth (inches)Standard is 10-11 inches

Enter total rise

How to Use This Calculator

Measure Total Rise

Measure the total vertical height from finished floor to finished floor. This is the total rise your stairs must overcome. Be precise—errors multiply across all steps.

Enter Desired Step Dimensions

Input your preferred rise per step (7-7.75 inches recommended) and run per step (10-11 inches recommended). The calculator will determine if these create code-compliant stairs.

Calculate Number of Steps

The calculator divides total rise by your desired step rise to determine number of steps needed. It then calculates actual rise and run dimensions that work with whole numbers of steps.

Review Stringer Dimensions

Check the calculated stringer length, total run, and individual step dimensions. Verify all measurements meet local building codes before cutting stringers. Consider headroom clearance throughout.