About Backyard Calc Hub

Backyard Calc Hub is a small independent site that builds free calculators for home gardeners, lawn owners and anyone planning a backyard project. Each tool is built to answer one practical question, such as how much soil a raised bed needs or how much fertilizer to put in a spreader.

How the tools are checked

• Every formula is written out on the tool's page, with a worked example you can repeat by hand.
• Recommended amounts, rates and timings come from university extension services and other primary sources, which are linked at the bottom of each page.
• The calculation code is covered by automated tests that check the worked examples.
• Each page shows the date it was last checked.

Found a mistake?

Please tell us. Corrections are made quickly and the page's "last checked" date is updated.