Free calculators for the questions every homeowner and DIYer actually types into Google — how many bags, how many yards, how many gallons — each one showing the formula it used, not just a number in a box.
Start with the Concrete Bag CalculatorSlabs, footings and post holes → cubic yards and 40/60/80 lb bag counts, with a waste allowance.
Concrete Cubic Yards Calculator — ready-mix yardage for bigger pours.
Mulch Calculator — bags and cubic yards by bed size and depth.
Paint Calculator — gallons by room, walls, coats and coverage.
Bags, cubic yards, blocks, fence-post holes, gravel and sand.
Mulch, topsoil, gravel driveways and pavers.
Paint, tile, shower tile, drywall and flooring.
Board feet, deck boards, stairs and BTU sizing for rooms and garages.
Three rules run this site. 1. Every calculator prints its formula on the page — check our math before you trust it. 2. Inputs like bag yields come from published manufacturer data sheets, not vibes. 3. Results are planning estimates and are labelled as such; when a ready-mix truck or a professional is the smarter answer, the page says that too.
The first ten calculators, in build order: Concrete Bag Calculator (live) · Concrete Cubic Yards · Mulch · Paint · Tile · Shower Tile · Gravel · Board Foot · BTU (room & garage) · Fence Post Concrete. Followed by sand, topsoil, pavers, drywall, roofing, decking, blocks, stairs, square footage and flooring calculators.