About this site

What the site is

Paints Calculator has 64 calculators for the questions that come up before, during and after a painting job: how much wall, ceiling and trim paint a room takes, how much stain a deck or a fence needs, how many rolls of wallpaper to buy, how long the work will take, what it costs to do yourself or to hire out, and, for contractors, how to turn hours and materials into a bid. They are written for homeowners and DIY painters planning a job, and for painters and estimators who want a quick, checkable figure.

We built one site for the topic because the questions are connected. The quantity depends on the coats, the coats depend on the colour and the primer, the time depends on the doors and the trim, and the cost depends on all of them. Each calculator answers one question well and links to the next one you are likely to ask, and the guides explain the inputs that move the answer most.

How the calculators are built

Each calculator is a small program with an explicit formula, listed on its page under "How we calculate this". The same code produces the example result shown when the page loads, the result you get when you press Calculate, and the worked examples in the text, so the three can never disagree. Before a calculator is published it is run against a set of test cases with known answers, including unit conversions, and it is published only when they all pass.

The default figures come from public sources: coverage, drying times and film thickness from the technical data sheets of the major paint, primer, stain and finish manufacturers; production rates from contractor estimating references; prices from dated published cost surveys and the Bureau of Labor Statistics; unit conversions from NIST. Each calculator's assumption table says which figure was used and when it was last checked; the methodology page lists the sources in one place, and the reference tables collect the figures themselves.

Who writes it

The site is written and maintained by its publisher, with AI writing tools used to draft and to check text, and with every number, formula and claim reviewed by a person before it goes up. We say this plainly because readers deserve to know how what they read was made. The editorial policy sets out the rules we follow, how corrections are handled, and how advertising is kept separate from content.

What the site does not do

• It does not ask you to sign up, and it keeps nothing you type into a calculator. The arithmetic runs in your browser.
• It does not take money from the companies whose products its calculators touch, and it does not recommend specific products.
• It does not claim precision it does not have. Where a figure is an estimate, the page says so and says how wide the uncertainty is.

Contact

Found a result that looks wrong, a source that has changed, or a calculator you wish existed? Use the contact form or write to contact@paintscalculator.com. Reports of errors are checked first and answered.