SettingsSettings for this calculationUS
The number of full-length deck boards you already have.
Count only full, usable boards — don't include damaged boards or short offcuts.
The length of the deck boards you have on hand.
All boards are assumed to be the same stock length.
Maximum deck area coverable
113 sq ft coverable
This is a theoretical maximum assuming every board is used at full length with zero cut waste — real installs lose some material to end trimming and layout offsets, so the practical coverage will be somewhat less.
- Total linear footage on hand
- 240 ft
- Effective coverage width per board (incl. gap)
- 5.63 in
They open the calculator with your figures already in it
Reverse Decking Material Solver: 113 sq ft coverable — shown in imperial, US market. The link sets both, so the result they see is the one on your screen.
Show calculation logicHide calculation logic
How this was calculated
Formula source(s)
- Inverts the standard decking coverage formula: instead of area → boards needed, this solves boards on hand → maximum coverable area, using the same 5.625 in effective board-plus-gap width as the Deck Board Calculator.
Inputs used
- Deck Boards On Hand
- 20
- Board Length
- 12 ft
Intermediate steps
- Total linear footage on hand
- 240 ft
- Effective coverage width per board (incl. gap)
- 5.63 in
Confidence note: This is a theoretical maximum assuming every board is used at full length with zero cut waste — real installs lose some material to end trimming and layout offsets, so the practical coverage will be somewhat less.
What this calculation does not cover
- The area assumes every board is spent end to end, and on a deck a leftover only counts if it lands on a joist. Butt joints in decking bear on a joist, usually a doubled or sistered one, so the tail cut off a 12 ft (3.7 m) board on a 13 ft (4 m) run is worth nothing unless a joist happens to sit under both of its ends, and a piece shorter than two joist bays cannot be fixed down at all. This maximum is reachable only where the run in the board direction divides into the board length you own.
- Laying the boards diagonally moves both terms at once. A 45-degree lay lengthens the span between bearings, so most decking drops its rated joist spacing from 16 in (406 mm) to 12 in (305 mm) on the diagonal and many composites go tighter still, while every row now begins and ends on a triangular offcut that fits nowhere else. The same stack covers noticeably less deck, over a frame that has to be built closer.
Estimated cost — your price
This site holds no price list for this material — local prices vary too much to publish honestly. Enter your supplier's price and the result is costed with it.
Computed in your browser — nothing you enter is uploaded. Presented in US customary units and US trade terminology. Where a formula follows a published standard, that standard and its edition are cited beside it on this page; where none governs, the page says so. Local amendments override model codes — verify against the code in force where you build.
Sources checked 2026-09-06 · in the site-wide review of 2026-09-06 · v1.0.1
Regulatory standards & verification citations1
- Inverts the standard decking coverage formula: instead of area → boards needed, this solves boards on hand → maximum coverable area, using the same 5.625 in effective board-plus-gap width as the Deck Board Calculator.
Cite this page
Your workspace
Most jobs need more than one number. Add the calculators you need next and they open right here, underneath this one — your figures stay on screen and nothing is lost to a page change.
Tools and safety for this job
To frame joists and a deck. Generic types, no brands, no prices.
Protection this work requires
- Hardwood dust is a recognised carcinogen: extract at the tool and wear a P2/N95 respirator when cutting or sanding indoors.
- Saws, grinders and breakers run above 85 dB, where hearing damage accumulates and does not recover: defenders or plugs for every cut, not just the long ones.
- Boards, blocks and bagged material cause most lasting back injuries on small sites: two people or a lifter for full sheets, and never a bag on one shoulder up a ladder.
- Most fatal falls on small jobs are from under three metres: use a tower or a ladder tied at the top, and never work off the top two rungs.
Show the 7 tools this job needsHide tools
Essential
Circular saw
Claw hammer
Cordless drill/driver
Spirit level
Tape measure
Recommended
Impact driver
String line and pins
Also needed as materials: circular saw blades, drill and driver bits, impact driver bits.
what each carpentry tool is for, and the spec that decides which to buy where one does.