Gutter Calculator — Roof Guttering 2026

The gutter length equals the sum of the roof eaves — the edges along which water runs off. For a typical gable roof these are the two longer edges. Measure the length of each eave and add them up. The calculator takes the given eaves length as the required gutter length.

A common rule is one downpipe per about 10–12 m of gutter or per about 70–100 m² of roof area. The calculator counts one pipe per 12 m of eaves, rounded up. For 30 m of eaves that gives 3 downpipes. Too few pipes cause the gutters to overflow.

Brackets are fitted as standard every 50 cm, i.e. two per running metre of gutter. This spacing provides adequate rigidity and prevents the gutter from sagging under the weight of water, snow or ice. The calculator counts one bracket per 0.5 m, rounded up — for 30 m that is 60 brackets.

Cost depends on the material. PVC gutters are about PLN 25–45/rm, coated steel PLN 45–80/rm, and titanium-zinc or copper PLN 90–200/rm. Add downpipes, brackets, corners and outlets. Complete guttering for a typical house is roughly PLN 3,000–8,000 in material plus labour.

PVC gutters are the cheapest, light and corrosion-resistant, but less resistant to frost and UV (lifespan 15–25 years). Coated steel gutters are more durable and stiffer (25–40 years), slightly more expensive. Titanium-zinc and copper are premium options lasting 50+ years. The choice depends on budget and looks.

Gutters are fitted with a slight fall toward the downpipes, usually 2–5 mm per metre of length (0.2–0.5%). Too little slope causes standing water and deposits, too much an unsightly look and overly fast runoff. The fall is set by mounting brackets at different heights.

The calculator counts the main elements: gutter (by eaves length), downpipes (allowing for building height) and brackets. The price per running metre of gutter should cover typical accessories. We do not separately price corners, outlets, end caps, leaf guards and clips — in practice add about 10–20% for these.

The gutter size is matched to the roof slope area. For small roofs (up to about 75 m² of slope) a 100–120 mm gutter is enough, for medium (75–125 m²) 125–150 mm, and for large roofs 150 mm and more. An undersized gutter cannot keep up with water during downpours.

Yes — gutters should be cleaned at least 1–2 times a year, ideally in autumn after leaf fall and in spring. Blocked gutters overflow, which leads to flooding of the facade and foundations. Fitting mesh or gutter guards limits leaf build-up and reduces cleaning frequency.

The calculator gives an indicative material cost based on average market prices in Poland 2026 and typical rules (pipe per 12 m, brackets per 0.5 m). It does not account for roof shape, dormers, corners, accessories or labour. Set the final quote from a roof design and contractor offer.