The Rolling Offset calculator computes the run (R) and travel (T) lengths of a rolling offset based on the vertical (V) and horizontal (H) offsets and the fitting angles (fA) of the elbow fittings. This is also known as pipe rolling. 
INSTRUCTIONS: Choose units and enter the following:
- (V) Vertical Offset
- (H) Horizontal Offset
- (fA) Elbow Fitting Angle. (e.g. 22.5°, 30°, 45o, 60o, 90o)
Rolling Offset (R & T): The calculator returns the run (R) and travel (T) in inches. However, these can be automatically converted to other length units (e.g. centimeters or feet) via the pull-down menu.
The Math / Science
When running pipes or conduits, it is common to have to change the run of the line of pipes by using two equal angled elbow fittings (see diagram). The length of the run (R) and travel (T) created with the elbows and the length of pipe between them, can be calculated if one knows the vertical and horizontal offsets and the angle of the fitting. To compute the Rolling Offset Travel and Run (aka pipe rolling), the relationship between the travel length and the offsets is as follows:
` x = sqrt( V^2 + H^2)`
` T = x / cos (90 - fA)`
`R = sqrt(T^2 - x^2)`
where:
Note: vCalc allows for multiple units for both length (SI and English) and for angles (degrees and radians). The result will be in inches. However, this can automatically be converted to other length units (e.g. centimeters) with the pull-down menu.
Plumbing Calculators
- Rolling Offsets (Run and Travel) – The Rolling Offset
Rolling Offset Lengths 
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- Rolling Offset (run) - Equation to calculate the run (R) in the diagram above.
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