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Guttering & Downpipe Calculator
Standing at the builders' merchant guessing how many brackets, unions and stop ends you need is a fast way to make three trips in one day. Enter your gutter run and downpipes, and get a plain parts list — lengths, brackets, outlets, clips and shoes — so you can order the lot in one go.
Estimates only. Bracket spacing and the exact fittings vary by system — half-round vs Ogee vs square — and by manufacturer. Always check the maker's fixing guide and round up.
Every figure here is a rule-of-thumb estimate. Buy a spare bracket or two and an extra union — offcuts and awkward corners have a way of eating fittings.
How many gutter brackets do I need?
As a rule of thumb, fit a support bracket roughly every metre along the run — so a 10-metre gutter needs about 10 brackets, plus one close to each stop end, outlet and joint. Closer spacing (600–800mm) is sensible in areas that get heavy snow or on longer, unsupported spans. This calculator uses your bracket-spacing figure (defaulting to 1m) and rounds up, but always follow the fixing guide for your specific gutter system, as half-round, Ogee and square profiles differ.
How far apart should downpipe clips be?
Downpipe (pipe) clips are typically fixed about every 1.8 metres, with a clip near every joint and at the top and bottom of the pipe — so a standard two-storey run of around 3.5m usually takes two or three clips per downpipe. This tool works out roughly one clip per 1.8m of total downpipe height and then adds one extra per pipe to cover the top and bottom fixings. On exposed or windy elevations, space them a little closer.
How much guttering do I need?
Measure the total length of eaves the gutter will follow, then divide by the length of each piece — UK guttering is usually sold in 2m or 4m lengths — and round up. You'll also need a union bracket at each join, a running outlet where each downpipe connects, a stop end at each open end of the run (normally two), and an external or internal angle at every corner. This calculator turns your run length and downpipe count into that full parts list so nothing gets forgotten at the merchant.
Does this tool store my details?
No. There's no sign-up and nothing to submit — every calculation runs entirely in your browser as you type. Nothing you enter is uploaded, saved or sent anywhere, so you can use it as many times as you like without leaving a trace.
Please note: this tool gives a guide or estimate only. It may not be 100% accurate and is not professional advice — always check the figures before you rely on them. Nothing you enter is uploaded — the calculation runs entirely in your browser.
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