22.5 Degree Offset Math, Chart and Minimum Depth

By Blissom · Updated 2026-11-04

Layout values: check them against your own bender, on scrap first.

Every 22.5° offset, marked from the endConduit Bending Calculator for Android · $7.99 one time · offline · no ads

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Formula: travel, shrink and advance

travel = depth × 2.6  ·  shrink = depth × 3/16"  ·  advance = depth ÷ tan 22.5°

• Travel is the distance between bend marks, measured along the pipe. Some textbooks call it the hypotenuse.
• Shrink is how much shorter the conduit reaches after the offset. Add it when you are measuring to something past the offset.
• Advance is how far the offset moves along the wall, about 2.41 × depth. Use it to check the offset fits between two obstructions.

22.5° chart with shoe check

Sticker math to the nearest 1/16". The last column shows which hand-bender sizes can make that depth as two separate bends.

Shoe check uses 2 × R × (1 − cos 22.5°) with the centerline radii of Klein 51606 (1/2", 4-5/8"), Klein 51607 (3/4", 5-1/2"), Greenlee 842AH (1", 6-1/2"). It is an estimate for those shoes only.

Worked marks: 3/4" EMT, 3" deep

A 3" offset on 3/4" EMT must be finished 48" from the cut end, for example to drop behind a beam flange.

1. Travel: 3" × 2.6 = 7-13/16".
2. Shrink: 3" × 3/16" = 9/16".
3. First mark: 48" + 9/16" − 7-13/16" = 40-3/4" from the end.
4. Second mark: 40-3/4" + 7-13/16" = 48-9/16".
5. Bend: 22.5° on the first mark, rotate the pipe a half turn, 22.5° on the second. Sight it for dog-leg.

Same method on the other sizes:

2.6 vs 2.613

The cosecant of 22.5° is 2.6131. Stickers drop it to 2.6. Lay out with 2.6, bend two true 22.5° bends, and the offset lands at 99.5% of the depth you wanted:

Below a foot of depth the gap is lost in the tolerance of a hand bend. On a 24" offset it is worth spacing with 2.61, or just bending each side a hair past the sight line.

How shallow can a 22.5° offset be?

This is the first sticker angle where the shoe, not the arithmetic, sets the lower limit. The two arcs need room before a straight section exists between them:

• 1/2" EMT (Klein 51606, 4-5/8" radius): about 11/16" minimum.
• 3/4" EMT (Klein 51607, 5-1/2" radius): about 13/16" minimum.
• 1" EMT (Greenlee 842AH, 6-1/2" radius): about 1" minimum.

So a 22.5° offset is out for most box offsets, and on 1" EMT anything under an inch should drop to 10°. Above those depths 22.5° is the tightest gentle offset you can bend, which is why it shows up in cramped ceilings and panel tops.

22.5° in saddles

Half of 45 is 22.5, and that is where this angle overlaps with saddle work. A 3-point saddle with a 45° center bend uses two 22.5° outer bends; guides lay those outer marks out at depth × 2.5 from the center and move the center mark 3/16" per inch. A 4-point saddle is two offsets back to back, and 22.5° is a common pick for both when the pipe has to step over something wide like a duct without adding much to the bend count.

Each 22.5° offset adds 45° toward the 360° limit. A 4-point saddle at 22.5° is 90°, the same as a single 90.

Choosing 22.5° over 10° or 30°

The same 3" offset at three angles:

Against 10°, 22.5° needs well under half the travel. Against 30° it costs only 1-13/16" more pipe between bends but spends 15° less of the run's bend budget, and the wire feels it less. Choose 30° instead when the depth is near the shoe minimum or when you want doubling instead of multiplying by 2.6.

Bend accuracy at 22.5°

With the marks 7-13/16" apart, the depth is that spacing times the sine of whatever you really bent:

Judging 22.5° by eye against the shoe's angle marks is where most of that error comes from. When the offset has to land in a fitting, put an angle finder or a level with a degree scale on the pipe before you let off the handle.

Sources: NEC 2023 358.24 and Chapter 9, Table 2; Klein Tools Conduit Bender Guide (stub take-up, offset multipliers and shrink, saddles). Method.

Questions electricians ask

Every 22.5° offset, marked from the end

• Marks from the end of the pipe with the shrink already in
• Tells you when the depth is too shallow for your shoe
• Any angle you like, not just 22.5°, with exact or sticker math
• Shoe-radius correction and offline use on site

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