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Free stair stringer calculator & stair calculator. Calculate stringer dimensions, materials needed, and installation costs. Our calculator uses carpentry industry standards to determine accurate measurements and cost estimates for stair construction.
Last updated: February 2, 2026
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Number of Steps
15
Stringer Length
161.44"
Stringer Angle
42°
Material (Board Feet)
37.84
Recommendation
Good stair proportions. Stringer design meets safety and comfort standards.
Stringer length
√(Rise² + Run²)
Calculate the actual length of stringer board needed
Stringer angle
arctan(Rise ÷ Run)
Determine the angle of the stringer for proper installation
Board feet
Length × Width × Thickness
Calculate lumber requirements for stringer construction
Cost per board foot
$8 - $12
Estimate total project costs including materials and labor
Code requirements
Riser: 4-8.25"
Verify stair dimensions meet safety and building code standards
Number of steps
Rise ÷ Riser Height
Determine optimal number of steps for safe stair design
For a 108" rise × 120" run stair with 7.5" risers:
Stringer Length
161.2"
Stringer Angle
42.0°
Our stair stringer calculator uses carpentry industry standards and geometric principles to determine accurate stringer dimensions and material requirements. The calculation applies carpentry industry standards to ensure precise measurements and cost estimates for stair construction.
Stringer Length = √(Rise² + Run²)Stringer Angle = arctan(Rise ÷ Run)Number of Steps = Rise ÷ Riser HeightBoard Feet = Length × Width × Thickness ÷ 144These formulas ensure accurate stringer calculations for safe stair construction. The calculations follow standard carpentry principles and building codes.
Shows stringer geometry, angles, and cutting layout
Stair stringer calculations are based on carpentry industry standards and building codes. These standards ensure safe stair construction and proper material usage. Professional carpenters use these calculations for accurate stringer cutting and installation.
Need help with other carpentry calculations? Check out our stud calculator and beam calculator.
Get Custom Calculator for Your BusinessResult: 161.2" stringer length, 42.0° angle, 15 steps
Total material needed: 37.8 board feet for 2 stringers.
96" rise × 80" run, 8" risers
124.8" length, 50.2° angle
120" rise × 180" run, 6" risers
216.3" length, 33.7° angle
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Suggested hashtags: #StairCalculator #Carpentry #Construction #DIY #Calculator