Deck calculator
Deck length and width, board width, the gap and the joist spacing. Boards, joists, fasteners and footings out.
Your numbers stay in this browser. Nothing is sent anywhere.
How it is figured
Rows of decking are the deck length in inches divided by the board width plus the gap. Each row is a board the width of the deck, so linear feet is rows times the width, plus five percent for cuts and the one that is bowed. Divide by the stock length you will buy.
Joists run the other way at 16 inches on center for straight-laid wood or composite, 12 for a diagonal pattern or the heavier composites. Count is the length in inches over the spacing, plus one. Screws: two per board per joist crossing. Hidden clips: one per crossing.
Footings here are a rough count at 6 foot beam spans and 8 foot joist spans; the real layout depends on the beam size and your code. The permit drawing decides it. The bid says who pulls the permit.
From the quantity to the bid
The calculator gives you the material count. The bid gives the customer one price and the scope in plain words, and keeps the count as your cost math. The how to bid deck jobs guide works the whole price with example numbers, and the decks proposal template is the layout. Materials at cost plus markup, labor at your rate, then the job price calculator adds them up and sets the deposit.
Questions contractors ask
How many deck boards for a 20x14 deck?
With 5.5 inch boards and a 1/4 inch gap: 42 rows at 14 feet, 588 linear feet, about 620 with waste, which is 39 boards at 16 feet.
12 or 16 inch joist spacing?
16 inches on center for wood and for most composite laid straight. 12 inches for composite laid diagonally or when the manufacturer says so for their thinner lines. The composite install guide is the law here.
How many screws per deck board?
Two at every joist. A 14 foot board over joists at 16 inches crosses 11 joists, so 22 screws. Hidden fasteners are one clip per crossing.
How do I bid a deck?
Frame, decking and railing at cost plus markup, labor by the day, the permit and any demo as lines, and composite and wood as two packages on the same bid. The <a href="/guides/how-to-bid-deck-jobs">deck bidding guide</a> prices a composite build.
The other tools
- Price book builder. Pick your trade, set what you pay yourself, your overhead and your margin. Every job in the book is priced with your rate, with the math showing. PDF and Excel.
- Hourly rate calculator. What to charge per hour, from what you want to take home, your overhead, and the hours you can bill.
- Markup vs margin calculator. Enter a cost and a markup, see the price and the real margin. Or go the other way.
- Job price calculator. Materials, labor, markup, and the deposit to ask for. The number that goes on the bid.
- Deposit calculator. Job price and the materials you buy first, out comes the deposit, the schedule, and the payment terms line for the bid.
- Concrete calculator. Slab, footing, or post holes to cubic yards and bags, with the order-over built in.
- Roofing calculator. Footprint and pitch to squares, bundles of shingles, rolls of underlayment, and waste.
- Drywall calculator. A room to sheets of 4x8 or 4x12, with the mud, tape and screws to finish it.
- Paint calculator. A room to gallons of paint for walls, ceiling and trim, by the coat, primer included if needed.
- Flooring calculator. Room size to square feet with waste and the number of boxes, for plank, tile or carpet.
- Fence calculator. A fence run to posts, rails, pickets and the concrete to set them.
- Mulch and soil calculator. Bed area and depth to cubic yards of mulch, soil or compost, and bags.
- Tile calculator. Area, tile size and pattern to tiles and boxes, waste included.
- Gravel calculator. Area and depth to cubic yards and tons of gravel, crushed stone or base.
- Estimate checker. Paste the bid you are about to send. A score out of ten and the exact lines it is missing.
- Invoice generator. Your business, the customer, the lines, tax, the deposit already paid. A clean PDF invoice, no account.
When the number is right, put it on an estimate the customer signs on their phone. Type the job and see it, no account needed. 30 days free, then $29 a month.