Offset multiplier and shrink chart

Every offset, kick and four-point saddle comes back to two numbers per angle: the multiplier (distance between bends per inch of depth) and the shrink (length lost per inch of depth). Here they are, both as the bender makers print them and as exact trigonometry.

Last reviewed Nov 14, 2026 · Sources at the end of the page

Multiplier and shrink by angle

Why the published and exact numbers differ

Bender makers round the multiplier to one decimal so it can be done in your head: 6.0 instead of 5.76 at 10°, 1.4 instead of 1.414 at 45°, 1.2 instead of 1.155 at 60°. At 30° there's no difference — sin 30° is exactly ½. The shrink column is rounded the other way: the textbook values (1/16″, 3/16″, ¼″, ⅜″, ½″) sit a little under the pure geometry of tan(θ ÷ 2), which ignores the bend radius.

In practice: at 22½°, 30° and 45° the two columns land within a sixteenth or two on normal offsets. At 10° and 60° they drift apart on deep offsets — on a 6″ offset at 60°, 6 × 1.2 = 7.2″ but 6 × 1.155 = 6.93″. Bend one on scrap and trust your bender. BendBoss uses the exact multiplier and the published shrink values.

Speed table: distance between bends / shrink

How to use the chart

1. Measure the offset depth — how far the conduit has to move over.
2. Pick the angle (30° unless space forces otherwise).
3. Depth × multiplier = distance between your two marks.
4. Depth × shrink per inch = how much to add to your measurement when bending toward an obstruction.

The same two numbers drive kicks (one bend, multiplier only), four-point saddles (two offsets) and rolling offsets (true offset first, then the chart). The parallel-offset shift uses tan(θ ÷ 2) too.