Project Materials Calculator
Combine decking/flooring boards, drywall sheets, and gravel or topsoil fill into one project estimate, each with its own waste allowance and optional price, plus a combined cost total.
How it works
Each section uses the same math as its dedicated calculator: area (length × width) divided by material coverage, adjusted by (1 + waste % ÷ 100) and rounded up to a whole unit. Drywall subtracts door/window openings from gross wall area first. Gravel/topsoil fill converts length × width × depth into cubic feet (or cubic meters), then into bags and approximate weight using typical bag coverage and bulk density. Prices are optional per section — leave a price blank to exclude that section from the combined cost total.
Worked example
A 16 ft × 12 ft deck (16 sq ft/board, 10% waste) needs 14 boards. 40 ft of 8 ft wall with 40 sq ft of openings (32 sq ft/sheet, 10% waste) needs 10 sheets. A 20 ft × 10 ft bed of gravel at 3 in deep (0.5 cu ft/bag, 10% waste) needs 110 bags. Combined, that's 3 material lists and one project total.
Assumptions
- Each section is independent — areas, openings, and depths are not shared between sections.
- Board/sheet coverage, bag coverage, and bulk density are typical figures — check your specific product.
- This does not include framing, fasteners, tape/mud, or delivery charges — estimate those separately.
Reference
General construction measurement practices: International Code Council (ICC).
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Frequently asked questions
What does the project materials calculator combine?
Decking/flooring boards, drywall sheets, and gravel/topsoil fill — three independent waste-adjusted estimates in one workflow, with a combined cost total.
Do I have to fill in every section?
No — leave a section's price blank to exclude it from the combined total, and ignore sections your project doesn't need.
Why would I use this instead of the individual calculators?
It saves re-entering a unit system and waste percentage three times, and gives one combined project cost.