A SMALL TOOL WITH ONE JOB
About Raincatch.
Raincatch is a focused entered-rainfall event calculator. It turns rainfall depth and connected horizontal catchment area into a transparent volume balance.
A capture fraction and a separate event-loss volume have distinct roles. Optional free-capacity comparison separates collection from the amount retained against your supplied headroom and the amount beyond it. Missing storage information remains unavailable.
The site does not retrieve rainfall, forecast weather, measure a tank, recommend system settings or evaluate water quality or installation. Local text and CSV reports keep the entered assumptions with the calculation.
Free to use
There is no subscription, checkout or account. The calculator is part of an independently operated collection of free planning tools. Each site focuses on one calculation so its assumptions stay easy to inspect.
How the tool is maintained
The calculation method is described in the worked guide. Automated checks cover conversion factors, example results and invalid inputs. A model can still miss a practical detail; use the guide to decide whether its assumptions fit your situation.
Corrections and questions
For a reproducible calculation problem or a privacy enquiry, use our shared portfolio contact. Include the inputs and expected result. No telephone call is needed.