Rainfall Calculator
A rainfall calculator is a practical tool that helps you calculate how much rain falls on a given area over a specific period. By using rainfall data, roof size and roofing material, you can estimate how many litres of rainwater can be collected from your roof.
Collecting rainwater is becoming increasingly interesting for homeowners, property owners and anyone who wants to use water more sustainably. With a rainfall calculator, you can easily explore how to make use of rainwater instead of letting it run off.
How does a rainfall calculator work?
A rainfall calculator uses information about rainfall in a geographical area to estimate the potential amount of rainwater that can be collected.
The calculation is usually based on several factors:
- Rainfall: How much rain falls at the selected location.
- Roof area: The size of the roof in square metres.
- Roofing material: Different materials affect how much water can be collected.
- Water losses: Some water is lost through evaporation, splashing and other factors.
For example, 10 millimetres of rain falling on a 100-square-metre roof theoretically produces 1,000 litres of water. The amount actually collected is usually slightly lower, depending on the roof design and the efficiency of the collection system.
Why use a rainfall calculator?
A rainfall calculator gives you a better understanding of how much rainwater your property could capture. This can be particularly useful if you are planning to install a rainwater tank or want to reduce your use of mains water for irrigation.
Rainwater can be used to water gardens, crops and greenhouses, for example. With the right equipment, it can also be used for other purposes that do not require drinking water.
A rainfall calculator also helps you estimate a suitable rainwater tank size. By comparing rainfall across different periods, you can plan how much water to store for drier months.
How much rainwater can your roof collect?
An accurate calculation based on actual rainfall data for your address.
- 1. Enter your address or coordinates
- 2. Enter your roof area and roofing material
- 3. Get the full report instantly
Use the rainfall calculator here
With RainTact, you can use a rainfall calculator to estimate how much rainwater your roof can collect. This provides a useful basis for planning your rainwater harvesting.