About HomeCostMath

HomeCostMath is a small, independent website with free calculators for home and yard projects. It answers the question that comes before almost every project: how much do I need to buy?

Buying too little means a second trip to the store and, with paint or tile, a risk of not matching the first batch. Buying too much wastes money on materials that end up in the garage. A few honest measurements and the right formula solve both problems, and that is what each calculator here does.

How the calculators work

Every calculator shows the formula it uses and walks through a worked example, so you can check the result yourself. The default values, such as how far a gallon of paint goes or how much concrete an 80 lb bag makes, come from the figures manufacturers print on their products and from rules of thumb widely used in the trades. When a number is an approximation, the page says so and lets you change it.

The calculators run entirely in your browser. The measurements you type are not sent to us or saved.

What the calculators are not

We are not contractors or engineers, and the results are estimates for planning and shopping. Products differ, and every house is a little different. For structural work such as footings, foundations or driveways, follow your local building code and get advice from a licensed professional.

How the site is paid for

The calculators are free to use. To cover the costs of running the site, we may show advertising. Ads never change the results of a calculator.

Corrections and suggestions

If you spot a mistake, or there is a calculator you would like us to build, we would like to hear from you. Visit the contact page.