Rain garden sizing calculator
PRORain garden area for the runoff you're capturing.
Short answer: Garden area = drainage area × soil factor. 500 sq ft roof × 0.2 (sandy) = 100 sq ft garden. Enter your measurements above and the rain garden sizing calculator returns the quantity, unit conversions and an estimated cost instantly, in imperial or metric — no sign-up needed.
What do you need to measure?
What is the answer?
Rain garden area
100 sq ft
Recommended depth
4–8 in
How does the rain garden sizing calculator work?
Garden area = drainage area × soil factor.
What does a worked example look like?
500 sq ft roof × 0.2 (sandy) = 100 sq ft garden.
What do people ask most?
›How far from the house?
At least 10 ft from foundations.
Which garden calculator should you use next?
Where can you learn more?
Read field notes on estimating and materials, or browse every calculator we make.
What should you read before you order materials?
Field notes from real jobs that explain the numbers behind this calculator.
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