About ProjectCostKit
Who runs ProjectCostKit, how the calculators are built and checked, and where the numbers come from.
ProjectCostKit is a free set of calculators and cost guides for home projects. It is built for two kinds of people: homeowners who want to know how much paint, tile or concrete to buy before they go to the store, and the painters, handymen and contractors they hire, who need to price that work so it pays.
Who is behind it
ProjectCostKit is an independent site, run by a web developer who builds websites for small and home service businesses. It is not owned by a manufacturer, a retailer or a lead-generation company, and no brand pays to be mentioned.
How the calculators work
Every calculator follows the same rules:
- The formula comes from a primary source. Bag yields come from the concrete maker's data sheet. The grout formula is the one printed on the grout maker's technical sheet. Drywall screw spacing comes from the International Residential Code. Where a number is a rule of thumb rather than a published figure, the guide says so.
- The math is shown. Each calculator has a guide underneath with a worked example you can check by hand.
- Inputs are editable. Coverage rates, bag sizes and prices are pre-filled with typical values, and you can change all of them to match the product you are actually buying.
- Units work both ways. Every calculator runs in feet or meters and in dollars, pounds or euros.
Where the prices come from
Cost ranges come from published 2026 cost data, mostly Angi, along with manufacturer pages, government sources such as the US Bureau of Labor Statistics and the IRS, and trade suppliers. Each guide lists its sources at the end with links, and the date each source was last updated where it shows one.
Prices vary a lot by region, season and the specific job. Treat every range on this site as a starting point for a conversation with your supplier or contractor, not as a quote.
Corrections
If you find a mistake in a formula, a number or a guide, please email hello@projectcostkit.com. Corrections are made as quickly as possible, and the guide's "Updated" date changes when they are.
Contact
Questions, corrections or ideas for a new calculator: hello@projectcostkit.com. For website work for your contracting business, see websites for contractors.