๐ค๏ธ Weather
Rainfall Calculator
Rainfall depth sounds abstract until it is turned into volume, and the numbers grow fast: one inch of rain over a thousand square feet is more than six hundred gallons. That is exactly the calculation behind sizing a rain barrel or a drainage soakaway.
How it works
Rainfall depth
Catchment area
Depth unit
Area unit
Harvestable share (roof runoff)
Water volume
Water volume
Water volume
Water volume
Harvestable water
55 gallon barrels full
Frequently asked questions
How do I use the Rainfall Calculator?
Fill in the fields above โ the result recalculates instantly as you type. Everything runs in your browser, so the values you enter are never collected or stored.
Is this calculator free?
Yes. It is completely free, requires no account, and works on phones, tablets and desktops.