Estimate boards, joists, posts, beams, rails, stairs, fasteners, waste, and budget. Plan purchases more clearly. Build stronger deck lists before buying for every project.
| Input | Example Value | Purpose |
|---|---|---|
| Deck size | 20 ft × 14 ft | Finds area, board rows, and framing length. |
| Board size | 5.5 in wide, 16 ft long | Controls deck board quantity. |
| Joist spacing | 16 in on center | Estimates joist runs and hangers. |
| Beam layout | 2 lines, 2 plies | Estimates built-up beam boards. |
| Waste | 10% | Adds cutting and selection allowance. |
Area: deck length × deck width.
Deck board rows: deck width ÷ ((board width + board gap) ÷ 12).
Deck boards: board rows × boards per row × waste factor.
Joist runs: (deck length × 12 ÷ joist spacing) + 1.
Beam boards: beam lines × beam plies × pieces per beam line × waste factor.
Posts: beam lines × ((deck length ÷ post spacing) + 1).
Total cost: materials subtotal + miscellaneous allowance + sales tax.
A good deck estimate starts with clear dimensions. Measure the planned platform length and width. Then confirm board direction before buying materials. Deck boards usually run along the long side. Joists normally run across the shorter span. This calculator follows that common layout. It also lets you change every major assumption.
Wood boards are sold in stock lengths. A perfect drawing rarely matches those lengths. Cuts, splices, knots, and damaged ends create waste. Gaps also affect the number of deck board rows. Wider gaps may reduce board count slightly. Narrow gaps may add another row. The waste setting protects the order from shortages.
The calculator estimates joists, beams, rim boards, posts, and concrete bags. Joist count depends on deck length and spacing. Beam boards depend on beam lines, plies, and stock length. Post count depends on post spacing along each beam. Rim boards follow the outside perimeter. These quantities help you prepare a full framing list.
Many decks need guards, rails, balusters, and stairs. Enter only the railing length you plan to build. Leave it at zero for ground level decks without guards. Stair materials use step count, stair width, tread depth, and stringer spacing. These values estimate tread boards and stringers. Local codes may require extra handrail parts.
Material prices can change often. Use current supplier prices for each item. The tool separates subtotal, miscellaneous allowance, tax, and final budget. Miscellaneous allowance is useful for blocking, flashing, sealant, connectors, and delivery. It is not a substitute for engineering review.
Treat the output as a planning list. Check span tables before choosing lumber sizes. Verify footing depth, guard height, stair rules, and fastener type. Compare the list with your drawings. Then export the results for supplier quotes. A careful material list saves trips, reduces waste, and keeps the build organized from layout to final inspection.
Review every line with the supplier. Confirm available board lengths before checkout. Ask about crowned joists, treated lumber grade, and approved connectors. Keep a small reserve for field changes. Store boards flat and dry. Recount delivered bundles before cutting. Mark waste pieces for blocking. Label longer offcuts for safe reuse.
It estimates deck boards, joists, beams, posts, rim boards, railing parts, stair materials, screws, hangers, concrete bags, waste, tax, and total project cost.
No. It creates a planning list. Always confirm spans, beam sizes, footings, loads, guards, and connections with local code rules or a qualified professional.
The calculator divides deck width by board coverage width. Coverage includes board width plus gap. It then multiplies rows by boards per row and waste allowance.
Waste covers trimming, damaged ends, knots, short cuts, layout changes, and mistakes. Many deck projects use five to fifteen percent waste.
Yes. Enter the railing length you need. Set it to zero when railing is not part of the project or will be priced separately.
Joist runs are based on deck length and joist spacing. Each run is divided by the joist stock length, then waste is applied.
Beam boards use beam lines, plies per line, deck length, stock length, and waste. This suits common built-up wood beam planning.
Yes. It estimates stair stringers and tread boards from step count, stair width, tread depth, board size, and stringer spacing.
Use current local supplier prices. Material prices vary by species, treatment level, size, grade, fastener type, and delivery location.
Yes. After calculation, use the CSV or PDF button above the result table to save the material list for quotes.
Suppliers may use different stock lengths, package counts, board grades, railing systems, or connector rules. Compare assumptions before ordering.
Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.