Deck · updated 2026
Deck Boards Calculator
Ordering deck boards is an area-to-linear conversion with a waste factor — get it wrong and you are either short on a Saturday or returning $300 of lumber. This deck boards calculator takes your deck’s dimensions and board width, accounts for the drainage gap between boards, and returns the exact board count (with 10% waste), total linear feet, and a screw estimate based on joist spacing. Boards are assumed to run the length of the deck in full-length pieces.
Boards run this direction — usually parallel to the house
Longer boards mean fewer butt joints — match your deck length when possible
Show the math
Area = 16 × 12 = 192.0 sq ft
Effective board width = (5.5 + 0.25 in gap) ÷ 12 = 0.48 ft
Linear feet = 192.0 ÷ 0.48 = 400.7 ft
Boards = 400.7 ÷ 16 ft = 26 × 1.1 (waste) = 29 (rounded up)
Joists = (16 × 12 ÷ 16 in spacing) + 1 = 13
Screws ≈ 29 boards × 13 joists × 2 = 754.0
What the numbers mean
The calculator converts your measurements into a practical purchase quantity using a documented coverage or spacing assumption.
Any whole-unit quantity is rounded up so the result does not leave you short during the project.
Use the cost range as a planning baseline and confirm the final quantity, availability, and delivery charge with your local supplier.
2026 material prices
| Material | 2026 average price | Note |
|---|---|---|
| 5/4×6×16 pressure-treated deck board | $12.00 – $20.00 / board | Per board, retail |
| 5/4×6×16 cedar deck board | $30.00 – $48.00 / board | Per board, retail |
| Deck screws, 5-lb box (~350 screws) | $35.00 – $50.00 / 5-lb box | Per box |
Material prices: Phase 2 2026 national-average guide, Sep 2026. Local prices vary. 2026 U.S. national averages. Prices vary by region and retailer — confirm locally before buying.
Pro tips
- Leave a ¼-in gap between boards for drainage — tight boards trap water and rot from below.
- Plan butt joints to land on joists, and stagger them — never line up joints in adjacent rows.
- Buy 10% extra for a simple rectangle, 15% if you have angles, stairs, or a picture-frame border.
- Let boards acclimate on-site for a few days before installing, sticker-stacked with airflow.
- Pre-drill near board ends to prevent splitting, especially with cedar.
- A 16×12 deck needs about 29 sixteen-ft boards and roughly 750 screws — that is two trips in most pickups, so plan delivery.
Common questions
Frequently asked questions
How many deck boards for a 16×12 deck?
About 29 sixteen-ft boards (5.5-in wide, ¼-in gap, 10% waste) — roughly 401 linear feet of decking.
How many screws for a deck?
About 750 for a 16×12 deck — 2 screws per joist per board across 13 joists at 16-in spacing.
What gap between deck boards?
¼ inch for wood (drainage and expansion); follow the manufacturer’s spec for composite, usually ⅛–¼ in.
Which direction should deck boards run?
Perpendicular to the joists — usually parallel to the house, so the long dimension has no butt joints.
12-ft or 16-ft boards?
Match the board length to your deck length when possible — fewer butt joints means a cleaner look and less waste.
How much waste should I add?
10% for simple rectangles; 15% with angles, stairs, or picture-frame borders.
Related calculators
Planning estimates only. Prices are 2026 U.S. national averages and vary by region — confirm with your local supplier before buying.