About Sumshed

Free, accurate project calculators for people who'd rather measure twice than shop three times.

Sumshed exists because of a familiar moment: standing in a hardware store aisle, phone in hand, trying to figure out whether two gallons of paint is enough — and finding only clunky calculators buried under ads, or forum answers from 2011. We thought DIYers deserved better.

Sumshed is built and maintained by Anthony Hudson. Every calculator on this site starts with a real question from a real project.

Our methodology

Every calculator on Sumshed follows the same rules:

• Formulas are shown, not hidden. Each tool explains exactly how it computes your result, directly under the calculator.
• Numbers come from primary sources. Coverage rates, material dimensions, and standards are taken from manufacturer specifications and industry standards — not copied from other websites.
• Everything is dated. Each tool displays when its data was last verified, and we review rates annually or when standards change.
• Estimates round toward "enough." Our buying suggestions round up sensibly, because running out mid-project costs more than a spare quart.

Found an error or a rate that's out of date? Tell us — corrections are reviewed within days and noted on the affected tool.

How Sumshed is funded

Sumshed is free to use and supported by advertising. Ads never influence our formulas, data sources, or recommendations. We don't accept payment to feature or favor any product or brand in our calculators.