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Roofing Calculators · reviewed September 1, 2026

Roof Pitch Multiplier Calculator

Convert a roof pitch such as 4/12, 6/12, or 12/12 into the slope multiplier used to turn horizontal footprint area into sloped roof area.

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Enter your measurements and calculate.
Worked example

Example

A 6/12 pitch has a multiplier of about 1.118 and an angle of about 26.6 degrees.

References

Sources & assumptions

Last reviewed September 1, 2026. Defaults are starting points; product-specific inputs are editable wherever coverage varies.

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FAQ

Common questions

What is the multiplier for a 6/12 roof?

Approximately 1.118.

What is a 12/12 roof angle?

45 degrees.

What do I multiply by the pitch factor?

Multiply the horizontal projected area by the factor to estimate sloped surface area on a simple roof.