What this is
Home Renovation Calcs is a small independent site of material calculators for home renovation work — paint, flooring, tile, concrete, mulch, gravel, wallpaper, insulation, decking, roofing, drywall, fence, stairs and brick.
Each calculator is paired with a written explanation of how the arithmetic works and what commonly goes wrong, because the number on its own is rarely the useful part. Knowing that a roof at 45° has 41% more surface than its footprint matters more than any calculator.
How it is built
Everything runs in your browser. There is no account system, no database and no upload endpoint — the figures you type are processed on your own device and are gone when you close the tab. The site is static files served from a CDN, which is also why it loads quickly on a phone with poor signal, which is where most people use it.
How it is funded
Advertising, and nothing else. Nothing on this site is a paid placement, no supplier has editorial input, and there are no affiliate links in the calculator results. Where a page says bulk delivery is cheaper than bags past a certain point, that is because it is, not because someone paid for the line.
Accuracy, and its limits
The arithmetic is checked and the rules of thumb are the standard ones used in the trade. But coverage figures vary between products, aggregate density varies with moisture, and building regulations differ by jurisdiction and change over time. Every page says where the estimate ends and where you need to check the packaging or your local building control.
If you find an error, please say so — corrections are welcome and get made. [email protected]