Stringer Length Calculator - Find Length, Rise, Run & Steps

Last updated: 31 Jul 2025 | Author: Brij | Review By: Irshad

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Use our Stringer Length Calculator to quickly determine the correct length of a stair stringer. Includes formulas, example, and step-by-step explanation for accurate stair construction.

Total Rise (Vertical Height):

Total Run (Horizontal Length):

Tread Depth (Run per step):

inches

Riser Height (Rise per step):

inches

Number of Steps:

Stair Calculation Results

Stringer Length:

inches

Number of Steps:

Stair Angle:

degrees

Individual Step Rise:

inches

Individual Step Run:

inches

A stair stringer is the structural support that runs diagonally along the side of a staircase and supports the treads (steps). Calculating the correct stringer length is crucial for safe and stable stair construction.

Our Stringer Length Calculator helps you determine the diagonal length based on your total rise and run. This is especially useful for builders, DIYers, and contractors planning stairs for decks, porches, or interiors.

Formula to Calculate Stringer Length

The stringer length is the hypotenuse of a right triangle, where the total rise and total run form the other two sides.

$\text{Stringer Length} = \sqrt{(\text{Total Rise})^2 + (\text{Total Run})^2}$

Formula to Calculate Number of Steps

If you know the total rise and riser height:

$\text{Number of Steps} = \frac{\text{Total Rise}}{\text{Riser Height}}$

Formula to Calculate Tread Depth (if Total Run is known)

If you know the total run and number of steps:

$\text{Tread Depth} = \frac{\text{Total Run}}{\text{Number of Steps}}$

Example Calculation

Let’s calculate the stringer length for a stair with the following dimensions:

Total Rise = 36 inches
Total Run = 60 inches

Step-by-Step:

$\text{Stringer Length} = \sqrt{36^2 + 60^2} = \sqrt{1296 + 3600} = \sqrt{4896} \approx 69.97 \, \text{inches}$

So, the stringer length is approximately 70 inches.

Summary

The Stringer Length Calculator simplifies complex math for stair building, helping you:

Accurately measure and cut stair stringers
Determine step count, tread depth, and stair angle
Avoid errors during stair layout and construction

This tool is perfect for anyone designing stairs — from homeowners and DIYers to professional contractors.

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Stringer Length Calculator - Find Length, Rise, Run & Steps

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