Stair Calculator

Building Up: A Guide to the Stair Calculator

Constructing a staircase is a task that requires precision and careful planning. The safety and comfort of a stairway depend on the consistent and correct dimensions of its two main components: the risers (the vertical part of each step) and the treads (the horizontal part you step on). Building codes in most regions dictate very specific rules for these dimensions to ensure the stairs are not too steep, too shallow, or uneven, all of which can be serious tripping hazards. This stair calculator is a fundamental tool for carpenters, architects, and DIY enthusiasts to simplify the most critical part of stair design: determining the number and height of the risers.

By entering the total vertical distance the staircase needs to cover (the 'total rise'), this calculator instantly provides the number of risers required and the exact height of each riser, ensuring they are all identical. It uses a common building standard that aims for a comfortable riser height of around 7 inches. This automates the essential math, helping you lay a safe and compliant foundation for your stair project.

The Basic Principles of Stair Design

• Total Rise: This is the total vertical height from the finished floor of the lower level to the finished floor of the upper level. This is the single most important measurement.
• Riser Height: The height of a single vertical step. For comfort and safety, this is typically between 7 and 7.75 inches. All risers in a flight of stairs must be equal in height.
• Tread Depth: The horizontal depth of a single step. Building codes usually require a minimum of 10 inches.
• Number of Risers: This is calculated by dividing the total rise by a target riser height (e.g., 7 inches) and rounding to the nearest whole number.
• Actual Riser Height: The total rise is then divided by the calculated number of risers to get the precise, uniform height for each step.