# Decking Calculator

> Decking calculator: estimate deck boards and linear footage needed from deck dimensions, board width, gap spacing, and waste. Free, private, no signup.

- **Canonical URL:** https://boringtoolskit.com/decking-calculator/
- **Category:** Construction & Measurement
- **Evidence level:** authored-methodology
- **Reviewed:** July 26, 2026
- **Last verified:** 2026-10-12
- **Privacy:** Inputs and results stay in this browser unless the page clearly labels an external request.

## Worked example

A 20 x 12 ft deck with 5.5-inch boards and 1/8-inch gaps: 26 courses, 520 linear feet, 572 feet with 10% waste, or 48 twelve-foot boards.

## Common questions

### What is a decking calculator and how does it work?

A decking calculator is a free, browser-based tool that estimates the materials you need for your deck project. You input your deck dimensions and it calculates the square footage, board lengths, and fastener quantities, no signup required and all processing happens in your browser.

### Is my personal data safe when using a decking calculator?

Yes. This decking calculator runs entirely in your browser with no server-side data collection. No signup is needed, nothing is stored or transmitted, and your measurements stay private on your device.

### Can I use the decking calculator for any deck shape?

The standard decking calculator works best for rectangular decks. For L-shaped or irregular decks, break the area into rectangles, calculate each section separately, and add the totals together for an accurate material estimate.

## Sources

- [Calculation methodology](/methodology/)
- [Quality evidence and verification standard](/quality-evidence/)

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