Free estimate — verify against local code before building
Deck Cost Calculator
See exact deck geometry, every allowance, and each whole stock or package rounding step.
What this calculator includes
Turn an approved deck layout into a transparent shopping estimate for joist and rim stock, ledger or freestanding framing, beam plies, support posts, decking, cylindrical footing concrete, decking fasteners, guards and stair stock. Edit every spacing, stock size, product yield, waste allowance and price. This calculator does not size structural members, footings, ledger or lateral connections, guards, stairs or attachment hardware.
How to use this deck cost calculator
- 01
Start with an approved framing concept
Enter overall length and width, attached or freestanding framing, joist spacing and stock length, beam lines and plies, and support-post spacing from a permit plan, adopted prescriptive path or qualified design.
- 02
Match the exact decking product
Enter face width, installed gap, stock length, waste, fasteners per joist intersection and package count from the selected decking instructions and actual package label.
- 03
Describe footings, guards and stairs
Use approved footing dimensions and concrete yield. Select the guard runs and enter rail, post and baluster assumptions. If stairs are included, enter the riser count and approved stringer and tread layout.
- 04
Replace example prices and review exclusions
Update unit prices from the selected store products, then verify every geometry, waste and whole-stock step. Add taxes, delivery, structural connector schedules, flashing, drainage, finishes, tools, labor and disposal separately.
Calculation sources and review
Primary references and formula assumptions are linked so you can verify them against the selected product, supplier, and adopted local requirements.
Internal formula review completed July 13, 2026. What this review covers
- 2024 International Residential Code, Section R507 - Exterior Decks (opens in a new tab)
Current model-code provisions for deck materials, design, footings, framing, connections, ledgers and vertical/lateral loads; local adoption controls.
- American Wood Council DCA 6 - Prescriptive Residential Wood Deck Construction Guide (opens in a new tab)
Illustrated wood-deck planning reference based on the 2015 IRC; use the current locally adopted code and approved plan for construction.
- 2024 International Residential Code, Chapter 3 - Building Planning (opens in a new tab)
Model-code planning provisions including guards, stairs, handrails, glazing and other safety conditions; local adoption controls.
Frequently asked questions
Does this calculator size deck joists, beams or footings?
No. It counts the spacing, stock lengths, beam lines, plies, posts and footing dimensions you enter. Safe sizing depends on species, grade, spans, loads, cantilevers, connections, soil, frost and locally adopted requirements.
How are deck boards rounded?
Rows are deck width divided by board face plus installed gap, rounded up. Each row is then rounded to enough full stock lengths to cross the deck length. Waste is applied to that layout-piece count before the final whole-board rounding.
How is deck-footing concrete calculated?
The entered footings are modeled as cylinders: count times pi times radius squared times depth. The editable irregular-placement allowance is then applied and volume is divided by the bag yield you enter. This does not determine required bearing area, frost protection or reinforcement.
Why does the guard estimate round each side separately?
A rail offcut is not assumed to turn a corner. The three-side preset rounds both side runs and the outside run independently, shares the two outside corner posts, and counts balusters within each run using the entered face and clear gap.
Does a stair rise below the entered maximum make the stairs compliant?
No. Uniform rise is only one check. Total run, tread depth, nosing, landings, headroom, width, handrails, guards, lighting, stringer capacity, footings and connections still require a complete approved design and inspection.