About Rough Estimator!

Rough Estimator! exists because the difference between a good estimate and a wrong one is a wasted Saturday and a return trip to the supply yard. Cosyslabs built this site to be the calculator we wanted on our own job sites — accurate, fast, offline-ready, and free.

Works on a roof with no signal

Every calculator runs entirely in your browser. Install the site as an app (look for the install button) and it works offline — including new calculations, history, and favorites.

AI-empowered

Alex, our assistant in the corner, helps you pick the right tool and explains results. The same tools are exposed via an MCP endpoint at /mcp, so you can use them inside ChatGPT and Claude Desktop.

Open Calculator Standard

Our registry is open. See /standard/v1 for the JSON schema — embed our tools, fork the formulas, build your own.