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Pinnacle Contractor Calculator

Stair Calculator

Calculate stair risers, treads, stringer materials, cut layout with angles, and labor — with IRC code checks and pre-code override for older homes.

This is an estimate, not a bid or contract. Every job has unique conditions — access, structure, moisture, code — that software cannot account for.

Use at your own risk. Pinnacle Designs, LLC is not liable for bids, losses, or code compliance based on calculator output. You are responsible for verifying all numbers before use.

Terms of Service (limitation of liability & your responsibilities)

Always verify local building codes. Supplier prices vary by region. Add waste for cuts, mistakes, and damaged material.

Typical residential stair code (IRC R311.7 — Stairways (typical US residential)):

  • Minimum tread depth: 10" (nosing to nosing). Without a nosing, many jurisdictions require 11".
  • Maximum riser height: 7.75" (62/8").
  • Minimum riser height: 4".
  • Uniformity: Risers and treads within a flight may vary no more than 0.375" (3/8").
  • Minimum clear width: 36" for interior residential stairs.
  • Headroom: 80" (6′-8″) minimum above tread nosing.

Local amendments vary. Pre-1970s and rural homes often pre-date current code — use custom dimensions when matching existing work.

Job Site Market (ZIP & Region)

Enter the job ZIP — not your shop — to load typical local labor and material defaults. Useful when bidding out of town or out of state.

Most U.S. ZIPs auto-select a region. Unknown ZIPs — pick the closest market manually.

Typical U.S. contractor rates, loaded ~5% above market average — adjust for your bid.

National Average — typical contractor labor ~$57.75/hr

Typical labor rates align with the national average.

Defaults load ~5% above typical market averages — a conservative benchmark when clients compare your bid. Edit any rate below for your actual numbers.

Regional defaults update labor, materials, markup, and tax in this calculator. Your job ZIP and region are saved across all calculators — change ZIP when you switch to a different job site.

Estimate — not a bid. This is an estimate, not a bid or contract. Every job has unique conditions — access, structure, moisture, code — that software cannot account for. Each job is unique. Final prices may vary based on site conditions, scope, materials, labor, and your local market. Use at your own risk. Pinnacle Designs, LLC is not liable for bids, losses, or code compliance based on calculator output. You are responsible for verifying all numbers before use. Full terms

Stair Dimensions

Floor to floor

Code max 7.75" — actual 7.385" with 13 risers

Code minimum 10" nosing to nosing (11" if no nosing)

Interior code minimum 36" clear width

Stringer & Tread Materials

Stringer Cut Layout

Hover or tap the i icons to learn each part · click drawing to zoom

7.39"rise10.00"run96.0"total rise120.0"total run
Click to zoom
Rise: 7.39"Run: 10.00"Notches: 12Board: 159.2" 2×12Floor cut: 38.7°Landing cut: 51.4°

Save stores this on your device · Add to Estimatesends material & labor lines to the Full Job Estimator

Material List / Shopping List

  • 2×12 Sawn Lumber Stringer
    3
  • Construction Pine / SPF — treads
    12
  • Risers
    13
  • Stringer board length
    159.2" each

Results Summary

Pricing RegionNational Average
Code StatusMeets typical IRC
Risers13
Actual Riser7.385"
Treads12
Tread Depth10.00"
Total Run120.0 in
Pitch Angle38.7°
Stringer Length159.2 in
Labor ÷ Material74%

Recommended Client Price

$1,543.28

Estimate — not a bid

Numbers from this tool are planning estimates only. They are not a contract, quote, binding bid, or professional advice. Every job carries its own challenges — hidden damage, tight access, moisture, local code, and scope details — that no calculator can see.

Each project is different. Access, existing conditions, code requirements, material choices, and your local market all affect the final price. Use these figures as a starting point — your actual price may vary.

By using this tool you agree you will not rely on it as a final bid without your own verification. See our Terms of Service for limitations of liability and your responsibilities.

Read full terms & conditions

Cost Breakdown

Materials$620.55
Labor$462.00
Overhead$108.26
Markup$238.16
Tax$114.32
Client Price$1,543.28
Profit (15.4% margin)$238.16
How this was calculated
  1. Risers = total rise ÷ desired riser height (rounded)
  2. Code check: tread ≥ 10", riser ≤ 7.75" (IRC R311.7)
  3. Stringer cut length & angles computed automatically
  4. Materials: pick stringer and tread/riser types
  5. Labor: hours × rate (adjusted for stringer complexity)

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Frequently Asked Questions

What is the minimum tread depth?
IRC R311.7.5.2 requires a minimum 10" tread depth (nosing to nosing) for residential stairs. Without a nosing, many jurisdictions require 11". Maximum riser height is 7.75".
How do I cut the stringers?
The Stringer Cut Layout shows rise, run, pitch angle, and framing-square settings for every tread — no trigonometry on the job site.
What if I'm matching an old staircase?
Enter the existing dimensions. When code warnings appear, choose Continue — Pre-Code / Existing Home to document that the design is intentional for a legacy build.

Stair Calculator — Risers, Treads & Stringers

Stair construction requires precise riser and tread dimensions that meet IRC code limits for residential work. Calculate total rise and run, stringer count, tread and riser lumber, landing framing, and install labor — with warnings when dimensions fall outside code ranges.

Whether you are building deck stairs, basement steps, or interior staircase framing, this tool helps you order the right lumber and price labor accurately. Pair with the deck calculator for multi-level outdoor projects.