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Stairs Calc
Free stair calculators

Plan code-compliant stairs in seconds

A suite of free, instant stair calculators — plan a full staircase, size stringers, estimate concrete, cost or carpet, and check every dimension against code.

Checks IRC, IBC, OSHA & ADA Live 3D model & cut list Imperial & metric
16 steps 33.2°
Meets IRC 2021
Your stairs

Finished floor to finished floor.

Stairs Calc rounds to a whole number of equal risers and keeps them within code.

The depth you step on, not counting the nosing.

Stringer mount
Railings
Left side
Right side

Top of the rail above the nosing line. Codes target 34–38".

A guard fills the side with your chosen infill — balusters, glass, cable, or horizontal bars. Renders live in 3D and is included in the .obj export.

Advanced inputs
Risers

Open risers leave a gap between treads — drawn live in the diagram. Some codes (ADA) require closed risers.

// 2D ELEVATION

Steps (risers)

16

15 treads

Riser height

7 3/16"

183 mm

Tread run

11"

279 mm

Stringer length

16' 8 15/16"

5.104 m

Stair angle

33.2°

Very comfortable

Total run

13' 8 3/4"

4.185 m

Min stairwell opening

10' 11 13/16"

3.348 m

Recommended board

2x12

throat 5 1/4"

Board to buy

17' 8 15/16"

5.409 m

Comfort

90 / 100

Very comfortable

  • Blondel pass
  • Rise + Run pass
  • Ideal angle pass

Want the full tool with cut list, print and share? Open the Stairs Calculator →

All stair calculators

Stairs Calculator Enter one measurement — your total rise — and get a complete, code‑compliant stair layout with a 3D diagram, stringer cut list, and printable template. Free, instant, in inches or millimeters. Stair Stringer Calculator Get the exact stringer length, throat depth, recommended board size, and a step‑by‑step cut layout with framing‑square settings — then print a full‑scale template. Stair Rise and Run Calculator Turn one total‑rise measurement into equal risers and runs that meet code — with the comfort rules (2R+T and Rise+Run) checked for you. Deck Stairs Calculator Enter your deck height and get a complete, code‑compliant deck‑stair plan — risers, treads, stringers, and real lumber tread options (5/4×6, 2×6, 2×12). Stair Angle Calculator Enter rise and run to get the exact stair angle in degrees and slope — and see instantly whether it falls in the comfortable 30–37° range. Stairs with Landing Calculator Break a tall staircase into two safe flights with a landing — Stairs Calc splits the rise, sizes each flight, and checks the maximum rise between landings. L‑Shaped & U‑Shaped Staircase Calculator Design quarter‑turn (L), half‑turn (U) and winder stairs — Stairs Calc sizes each flight, lays out the turn, and checks winder treads at the walkline. Spiral Staircase Calculator Enter your floor‑to‑floor height and diameter to get tread count, tread angle, rotation and headroom — with the IRC spiral‑stair limits checked automatically. Baluster Spacing Calculator Enter your railing length and spindle width to get the number of balusters, the exact even gap and center‑to‑center spacing — checked against your code’s 4‑inch sphere rule. Stairwell Opening Calculator Find the minimum floor-opening length your stairwell needs for code headroom — from your rise, run and floor thickness — with a 2D section showing the clearance line and a live code check. Concrete Stairs Calculator Get the concrete volume for your steps in cubic yards, cubic meters and bags — using the waist‑slab method (structural slab plus step noses) with a builder's 10% waste allowance. Stair Carpet Calculator Enter your number of steps and step size to get the runner length and carpet yardage you need — including the nosing wrap for waterfall or cap installations. Handrail Length Calculator Get the handrail length for your stairs — the sloped grip run plus the code-required top and bottom extensions — with mounting height and grip diameter checked against your building code. Stairs Cost Calculator See what your stairs will cost — a clear, line‑by‑line estimate of materials and labor, per step and in total, for wood or composite builds. Stairs Square Footage Calculator Get the total surface area of your stairs — treads, risers, stringer sides and the sloped wall — for ordering flooring, paint or tile. ADA Ramp Calculator Enter your total rise and target slope to get the ramp length, run, number of switchback runs and landings, and clear width — each checked against the ADA §405 accessibility limits. Calories Burned Climbing Stairs Calculator See how many calories you burn on the stairs — by weight, time and pace, with per‑step and per‑flight numbers and a flights‑to‑miles estimate.

Why Stairs Calc

Instant answer

No submit button — a valid, code-compliant stair appears on first paint and updates as you type.

Code-aware

Every dimension is checked live against IRC, IBC, OSHA, ADA and four international codes, with the exact section cited.

Beautiful 3D

A true-to-scale 3D model is the centerpiece, with a fast 2D elevation that prints and shares.

One artifact out

Turn any calculation into a shareable link, a printable cut sheet, or a downloadable image in one tap.

Written by the Stairs Calc team. Methodology and code references: see our methodology.

Last reviewed 2026-06-20 against IRC 2021/2024

Stairs Calc gives accurate geometry and checks it against published building-code limits, but results are estimates for planning. Codes are adopted and amended locally and change over time. Always confirm dimensions against your local adopted code and a licensed professional before you build.