# How do I calculate the takeoff for a 45 degree elbow joint?

I'm trying to install a 45° elbow joint in PVC. I've found several suggestions online, but frankly, they are incomprehensible to me and seem contradictory of one another:

Is there a straightforward way to calculate the takeoff?

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Wouldn't it depend on the particular fitting being used? – DA01 Apr 26 '13 at 18:02
Such ratio calculations may give you an approximately useful value, but there are variations between manufacturers, and of course fittings. I wouldn't trust anything if real accuracy is needed except actually measuring or using the manufacturer's dimension tables. – bcworkz Apr 26 '13 at 21:56

First, a definition of "take off": The length of pipe to be removed (taken off) such that a pipe and a fitting make a specific length. The term is a concept shorthand used by pipefitters and plumbers. This is not the same as a material takeoff, which is a list of all materials needed for a project.

Take-offs in general are specific to pipe construction (PVC, copper, etc.) and is a function of diameter.

As suggested by bcworkz, tables for a given diameter and style of pipe are the best method for an accurate measurement.

The formula (listed in your link) .625 x pipe size (don't use the 25.4 factor, unless you are using millimeters) should give you a ballpark for a 45 fitting.

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Thanks Daniel. The unit is (inch) according to the unit of pipe diameter (D)and any pipe diameter is applicable in formulas. (The Picture is only geometrical prove to have a better perspective). See below picture with more details.

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Hi, Jalal. Thanks for the improvements, but we prefer that you edit an answer to improve it, rather than creating a new, improved answer. I've marked your other answer as a duplicate. (And, I condensed the image a bit.) – Daniel Griscom Jul 2 at 12:16