Rain Barrel Calculator

1 inch of rain on 1,000 sqft of roof produces about 623 gallons. A 1,200 sqft roof with 40 inches of annual rainfall can collect nearly 30,000 gallons per year.

A 55-gallon barrel fills quickly — a 1,000 sqft roof fills it with just 0.1 inches of rain. For meaningful storage, consider 2-4 barrels or a 250-gallon cistern.

Rainwater collection is legal in most US states. Some states had restrictions but now allow up to 110 gallons. Check your state and local regulations.

The Rain Barrel Calculator is an online tool that lets you calculate rainwater collection potential from roof area with savings and garden coverage. It is part of NexTool's collection of free tools designed to help you work faster and more efficiently.

Using the Rain Barrel Calculator is simple: visit the tool page, enter your data or input into the provided fields, and get instant results. Follow the controls on the page. Some functions require sign-in or a paid plan; see Pricing for limits.

The Free plan includes 10 tool uses per day. Some features require an account or a paid plan. Check the controls on the tool page and Pricing for the applicable limits.

The Rain Barrel Calculator returns results based on the inputs and the tool methodology. Check assumptions, units and source dates. Treat projections as estimates. For critical decisions, always consult a qualified professional.

Yes, the Rain Barrel Calculator is fully responsive and works perfectly on smartphones, tablets, and desktop computers. Simply open NexTool in your mobile browser and navigate to the tool — no app download required.