Loading Calculator...
Please wait a moment
Please wait a moment
Design custom staircases by calculating stringer dimensions, step rise and run, and material requirements. Perfect for builders, contractors, and DIY projects.
2×12 lumber = 11.25 in
Typical: 2-3 stringers (2 for narrow, 3 for wide)
Let us know if this calculator was useful
1723 people found this calculator helpful
A stair stringer (or carriage) is the diagonal structural support that holds the steps of a staircase. Stringers are the angled boards that run along the sides (and sometimes middle) of the stairs, with notches cut to hold the treads (the steps you walk on) and risers.
Most residential staircases use 2-3 stringers made from 2×12 lumber. The stringer angle typically ranges from 30° to 38° for comfortable stairs, with rise and run dimensions following building codes.
Key Components:
Place the framing square on the stringer with the rise measurement on the vertical leg and run measurement on the horizontal leg.
Rise + Run = 17" to 18"
Example: 7.5" rise + 10.5" run = 18" (good design)
Important Safety Notes
For stairs up to 36" wide, use 2 stringers. For wider stairs (up to 48"), use 3 stringers. Very wide stairs (over 48") may need 4 stringers. More stringers provide better support and less bounce.
30° to 35° is most comfortable for residential stairs. This provides a good balance between rise and run. Steeper stairs (35-38°) are more compact but less comfortable. Angles below 25° are rarely used in homes.
Yes, but 2x10 provides less margin for error in notching and may not support treads as well. If rise or run is large, the notches will be deeper, reducing the stringer's strength. 2x12 is recommended for most situations.
This is common. Distribute the remainder across all steps (a fraction of an inch per step) rather than making one step taller. All steps must be the same height for safety and comfort.
Yes, in almost all jurisdictions. Stairs must meet building codes and be inspected. Interior or exterior, residential or commercial - permits are required. Check with your local building department.
In modern terminology, these terms are often used interchangeably. Technically, a stringer is the main support beam with notches, while a carriage or "housed stringer" has a groove routed into it rather than notches cut out. Notched stringers are more common in residential construction.
Building codes require a minimum of 80" of headroom measured vertically from the stair nosing to any obstruction above. This ensures people won't bump their heads while climbing.
Not recommended. Pressure-treated lumber is for exterior/ground contact use only. Use standard construction lumber for interior stairs. It's safer, more attractive, and easier to finish.
Check out 6 similar construction converters