Offset Bending Calculator — Multipliers & Shrink
Who this is for: For electricians kicking conduit over obstructions — ducts, doorframes, pipes — who want the multiplier spacing and the shrink number before the first bend, not after the dogleg.
Not the right tool for: Segmented and 4-point saddles — those use developed-length layouts, not the two-mark multiplier · Concentric (nested) offsets — each radius bends on its own spacing
Enter the offset rise and pick an angle — get the distance between marks from the multiplier table and the shrink to add back.
Quick answer: Distance between offset marks = rise × multiplier: 10° ×6.0, 22.5° ×2.6, 30° ×2.0, 45° ×1.4. Shrink per inch of rise: 1/16", 3/16", 1/4", 3/8". A 6" offset at 30° = marks 12" apart, shrink 1-1/2" — add the shrink back or the far end lands short.
How far the run must shift sideways.
| All angles — for a 6" rise | 10° | 22.5° | 30° | 45° |
|---|---|---|---|---|
| Marks apart / shrink | 36″ / 3/8″ | 15.6″ / 1 1/8″ | 12″ / 1 1/2″ | 8.4″ / 2 1/4″ |
| Formula | marks apart = rise × multiplier |
|---|---|
| Multipliers | 10° ×6.0 · 22.5° ×2.6 · 30° ×2.0 · 45° ×1.4 |
| Shrink / inch of rise | 10° 1/16" · 22.5° 3/16" · 30° 1/4" · 45° 3/8" |
| Example | 30°, 6" rise → marks 12" apart, shrink 1-1/2" |
| Technique | Bend A to angle, spin 180°, bend B same angle opposite |
| Status | Hand-bender teaching reference (Benfield take-ups, multipliers and shrink), compiled September 2026. Brand shoes vary — the chart stamped on your bender wins. Factory elbows, hydraulic and mechanical bender work are different methods. |
How do offset multipliers work?
An offset is two equal bends in opposite directions that shift the run sideways by the rise while staying parallel. The distance between the two pencil marks is rise × multiplier, and every angle has its own number: 10° = 6.0, 22.5° = 2.6, 30° = 2.0, 45° = 1.4. A 6" offset at 30° marks 12" apart (6 × 2.0); at 45° the same offset needs only 8.4" (6 × 1.4) but shrinks more. Shrink is the run length the pair of bends consumes — per inch of rise: 1/16" at 10°, 3/16" at 22.5°, 1/4" at 30°, 3/8" at 45°. That 6", 30° offset shortens the run 1-1/2", so the far end lands 1-1/2" closer unless you add it back. Technique: bend the first mark to angle, spin the conduit 180° without letting it twist, and bend the second mark to the same angle the other way — both bends in the same vertical plane or the offset dogs.
Common uses
- Kicking a run over a duct, doorframe or crossing pipe
- Landing conduit on a box that sits off the run's line
- Choosing between a shallow 22.5° and a tight 45° in a cramped corner
- Adding shrink to a measured stick so the far box still lands flush
Why shrink happens
The conduit through an offset travels up-and-over a diagonal path, and a diagonal is longer than the straight line it replaces — but the run's horizontal span shrinks by the amount the bends fold up. Multiplier charts bake the geometry in: at 30° the pure-geometry tangent spacing is about 1.73 × rise, and the field multiplier of 2.0 adds the bend-radius allowance the hand bender actually needs. That's also why brand charts differ slightly and why this site states the teaching-standard set: consistency with what's stamped on most benders and taught in every apprenticeship class, with the shrink table that keeps your overall length honest.