Where do these multipliers come from?
Each multiplier is the exact trigonometric identity 1/sin(angle) for the standard trade bend angles (5 deg through 60 deg) -- public-domain geometry, not a licensed table.
Conduit Offset/Bend Calculator
Conduit offset-bend developed length using the standard trade bend-angle multiplier table.
Bend the conduit at undefined° for a — in travel.
Conduit offset/bend inputs
Standard trade bend angles, using the standard 1/sin(angle) multiplier table at the two-decimal values printed on the bender.
Bend the conduit at undefined° for a — in travel.
Bend at
Conduit offset/bend estimate
Warnings
- ERROR Enter an offset rise greater than zero.
- ERROR Select a standard bend angle.
Detail values
Assumptions
- Bend angle: Not selected
- Multiplier: Not available until a bend angle is selected
Included: travel (distance between bends), shrink (run length lost to the offset).
Not included: labor, verification against manufacturer or local-code specifics beyond the reference table used, material waste from cutting.
Formula details
- Travel: offsetRise x multiplier(bendAngle)
multiplier = 1 / sin(bendAngle), carried at the two-decimal values printed on a bender's multiplier chart so this mark and the bender's agree; travel therefore runs up to about 0.1 in short of the unrounded figure on a 24 in offset at 60 deg. Travel is the centre-to-centre distance between the two bends, not the arc length of either bend.
- Shrink: travel - sqrt(travel^2 - offsetRise^2)
Same right triangle as the multiplier; equivalently offsetRise x tan(bendAngle / 2). Derived from the travel above, so it carries that same two-decimal rounding and needs no table of its own.
Material List
About this calculator
Enter the offset rise and select a standard bend angle to get the developed (bent) conduit length.