Reviewed, sourced guidance

Calculate roof pitch from rise and run

Published 24 Sept 2026Reviewed 25 Sept 20262 min read

Direct answer

Roof pitch in degrees equals arctan(vertical rise divided by horizontal run). A rise of 3 m over a 4 m horizontal run is about 36.9 degrees.

Pitch is an angle. If you know the vertical rise and horizontal run, inverse tangent gives the angle in degrees.

Source-led homeowner information with its scope, limits and commercial status recorded.

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Produced by: My Roofing Calculator
Jurisdiction: UK-focused measurement information; permissions and building-control requirements are not assessed.
Page scope: A geometric explanation for pitch measured as rise over horizontal run.
Default subject: Pitched roof area, product-based quantity estimates, roof pitch and comparable quote scope.
Excludes: Roof inspection, survey or access planning; Structural, engineering or installation advice; Product selection or manufacturer endorsement; Contractor recommendation, ranking, referral or lead collection; Roofing work, quotations or guaranteed material quantities
Published: 2026-09-24
Reviewed: 2026-09-25
Commercial status: Information preview only. No roofing contractor is active, no lead capture runs, no enquiries are collected and no affiliate links are present.

The result does not establish a product’s minimum pitch, fixing design, exposure suitability or structural capacity.

Measure the vertical rise and its matching horizontal distance. Divide rise by run, then take the inverse tangent to get degrees.

A rise of 3 m and a run of 4 m gives arctan(0.75), or about 36.9 degrees.

Sources for this section: Marley, How to calculate roof pitch (observed 2026-09-25)

A calculated angle does not prove that a chosen tile or slate can be installed there.

Minimum pitch varies by the exact product, finish and headlap. Read the current technical data for that system.

Marley Duo Modern lists different minimum pitches by finish and headlap.
Separately, Marley recommends technical advice for Duo Modern slopes over 6 metres or sites in a severe exposure category.
Do not carry one manufacturer’s values across to another product.

Sources for this section: Marley, Duo Modern product data (observed 2026-09-25)

HSE describes roof work as highly dangerous and says roofs should be treated as fragile until a competent person confirms otherwise.

Use plans, ground-level measurements or a qualified surveyor. This calculator never asks you to climb onto a roof.

Sources for this section: Health and Safety Executive, Roof work (page updated 2026-06-05; observed 2026-09-25)