Stair Calculator 🪜

How to Use the Stair Calculator

Select your measurement system (imperial or metric), choose automatic mode for optimal step calculation or manual mode to specify the number of steps. Enter the total rise (vertical height from floor to floor) and your desired tread depth. The calculator will provide complete stair dimensions including rise per step, total run, stringer length, angle, and building code compliance verification.

Understanding Stair Components

• Rise: The vertical height of each step (also called riser height).
• Run (Tread Depth): The horizontal depth of each step where you place your foot.
• Total Rise: The complete vertical distance from bottom floor to top floor.
• Total Run: The total horizontal distance the stairs will occupy.
• Stringer: The angled support beam that holds the stairs—stringer length is critical for material ordering.
• Number of Risers: Total vertical steps (one more than the number of treads).

Building Code Guidelines

Professional Tips

• The comfort formula (2R + T) should equal 24-25 inches (61-63.5 cm) for the most comfortable stairs.
• Consistency is critical—all risers and treads must be exactly the same height and depth.
• Always check local building codes, as requirements may vary by jurisdiction.
• For outdoor stairs, consider adding 1-2 degrees of slope to treads for water drainage.
• Steeper stairs (higher rise, shorter run) save space but are less comfortable and safe.