Gutter Size Calculator
Get an indicative gutter profile for your roof. Enter the catchment area draining to the gutter, the correct size depends on roof area, pitch and local rainfall, so use this as a guide to confirm with a roof plumber.
How we estimate this
Gutter sizing under AS/NZS 3500.3 depends on the roof area draining to it, the roof pitch and your local rainfall intensity. A standard domestic quad or D-gutter suits most homes, large or steep roofs and high-rainfall areas need higher-capacity or box gutters.
Pricing reviewed: November 2026.
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Pricing reviewed November 2026. Indicative Australian costs, not a quote.
Understanding gutter sizes in Australia
Gutter sizing under AS/NZS 3500.3 depends on the roof area draining to it, the roof pitch and your local rainfall intensity. A standard domestic quad or D-gutter suits most homes, large or steep roofs and high-rainfall areas need higher-capacity or box gutters.
Box gutters (hidden gutters between roof sections) carry a lot of water and must be designed with overflow provisions, an overflowing box gutter can flood inside the building, so these are an engineered item, not a guess.
Frequently asked questions
What size gutter do I need?
It depends on the roof area draining into it, the pitch and your local rainfall. A standard quad or D-gutter suits most homes, large or steep roofs need high-capacity or box gutters. Confirm with a roof plumber.
What is a box gutter?
A box gutter is a wide, hidden gutter, often between roof sections or behind a parapet. It carries a lot of water and must be engineered with overflow provisions, because an overflow can flood inside the building.
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