Decking Calculator

Estimate deck boards, linear length, fasteners, and cost.

Measurement guide

Measure the finished deck rectangle and enter actual board face width, gap, and purchasable board length.

Record each area separately, keep units consistent, and update the estimate with a final site measurement before ordering.

Assumptions and limitations

This estimates surface boards only. It excludes structural framing, stairs, picture frames, clips, span limits, code loads, and optimized butt-joint layouts.

Prices, tax, and delivery are user-entered planning figures, not supplier quotations.

Worked example

A 16 × 12 ft deck using 5.5 in boards with 0.25 in gaps requires roughly 26 rows across its width before waste and cut planning.

Frequently asked questions

What waste allowance should I use?

Simple rectangles often start at 5–10%; complex patterns, many cuts, or fragile material justify more based on the installation plan.

Why is the purchase quantity rounded up?

Packages and whole pieces usually cannot be bought fractionally, so purchasing rounds up while the exact quantity remains visible.

Can I order directly from this result?

Not without verification. Re-measure, check the product label, batch and stock, and confirm with the supplier or a qualified professional.

What does the cost estimate include?

Material cost uses the rounded purchase quantity, then adds entered labor, delivery, and tax; unlisted accessories are excluded.