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DIY Cost Tools

DIY Cost Tools

Deck Screw Quantity Calculator

Estimate deck-board screws from board count, length, fastening spacing, and screws per crossing.

Whole number from 1 to 10000 boards.
Number from 0.5 to 100 ft.
Number from 4 to 48 in.
Whole number from 1 to 10 screws.
Number from 0 to 100 %.
Whole number from 1 to 10000 screws.

Enter values in the units shown. Empty fields, fractions, comma-formatted numbers, values outside the listed ranges, and non-finite values are rejected.

Screws to order
Whole boxes

How to use this calculator

  1. Measure the project or enter costs from a current quote or product label.
  2. Adjust the quantities, coverage, package size, and allowances to match your situation.
  3. Select Calculate, then check the method, worked example, and limitations below.

Formula and method

Crossings per board = ceiling(board length × 12 ÷ joist spacing) + 1. Multiply by boards and screws per crossing, then extras; round up boxes.

Whole packages and pieces are rounded up. Results disappear when an input changes until the new values are calculated.

Worked example

Deck boards 40 boards; Board length 12 ft; Joist spacing 16 in; Screws per crossing 2 screws; Extras 10 %; Screws per box 350 screws. Results: Screws to order 881 screws; Whole boxes 3 boxes.

The example uses the values initially displayed in the fields.

Limitations

Field boards, perimeter fastening, blocking, local code, and the fastener maker’s instructions can change counts.

Review and reference

Reviewed October 5, 2026. The default example, input boundaries, arithmetic, rounding, and invalid input behavior were checked. The method is explained on How Our Calculators Work; replace example inputs with measurements or current product specifications. This is a planning estimate.

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