Hip & Valley Converter
Convert hip and valley rafter lengths and angles between metric and imperial. Enter pitch and run in any system, get results in both. Free, no signup.
Rafter / Hip & Valley
Calculate rafter and hip/valley lengths from pitch and span
Plan-view distance from wall to ridge (one rafter)
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Hip & valley conversion — did you know?
Hip length metric vs imperial
A 6.31m hip (35°, 4m run) = 20.70ft. Standard US lumber: 22ft would cover it with waste. UK: 6.6m or 7.2m C24.
Backing angle in degrees and ratio
Backing angle is always in degrees (it is a bevel, not a slope). At 35° pitch: 24.2° backing. Convert to percentage: tan(24.2°) × 100 = 44.9%.
Side cut as a bevel angle
Side cut = arctan(cos(pitch°) ÷ sin(45°)). At 35°: 49.2°. This is set on a circular saw bevel gauge. In Imperial: same degrees — angles are unit-independent.
Why angles don't need conversion
Angles in degrees are the same in metric and imperial. Only linear measurements (lengths) need conversion. A 49.2° cut is 49.2° whether you measure the timber in mm or inches.
Formulas used
Hip length (metric→imperial)
feet = metres × 3.281
Hip length (imperial→metric)
metres = feet × 0.3048
Backing angle (always degrees)
backing = arctan(sin(pitch°) ÷ sqrt(2))
Side cut (always degrees)
side_cut = arctan(cos(pitch°) ÷ sin(45°))
Frequently asked questions
Do I need to convert backing angles?
No — angles in degrees are the same in metric and imperial. Only convert lengths (m↔ft).
How long is a 6.31m hip in feet?
6.31 × 3.281 = 20.70ft. Order 22ft lumber to allow for cuts and waste.
Can I calculate hip lengths in imperial?
Yes — toggle to Imperial. Enter hip run in feet; get hip length in feet. Switch to Metric for metres.
Is there a free hip and valley converter?
Yes — this converter handles lengths and angles in both unit systems, free.