Conduit bending practice problems with answers
By Andrew ·
Quick answer
These conduit bending practice problems cover the basics: offsets, shrink and 90° marks. Work each one on paper first, then open its answer to check. Key formulas: distance between bends = offset height × multiplier, shrink = height × shrink per inch, and a 90’s mark = stub length − deduct. At 30° the multiplier is 2.000.
Practice problems
Work each problem on paper first, then open the answer. Answers are rounded to 1/16".
Problem 1
An offset is 4" high and bent at 30°. How far apart are the bends, and how much does the conduit shrink?
Show the answer
- Distance between bends
- 8"
- Shrink
- 1 1/16" (1.07")
Problem 2
An offset is 6" high and bent at 45°. How far apart are the bends, and how much does the conduit shrink?
Show the answer
- Distance between bends
- 8 1/2" (8.49")
- Shrink
- 2 1/2" (2.49")
Problem 3
An offset is 3" high and bent at 22.5°. How far apart are the bends, and how much does the conduit shrink?
Show the answer
- Distance between bends
- 7 13/16" (7.84")
- Shrink
- 5/8" (0.6")
Problem 4
An offset is 5" high and bent at 10°. How far apart are the bends, and how much does the conduit shrink?
Show the answer
- Distance between bends
- 28 13/16" (28.79")
- Shrink
- 7/16" (0.44")
Problem 5
A stub-up must be 14" to the back of the 90, and the bender deducts 5". Where is the mark?
Show the answer
- Mark the conduit at (from the stub end)
- 9"
Problem 6
A stub-up must be 18" to the back of the 90, and the bender deducts 6". Where is the mark?
Show the answer
- Mark the conduit at (from the stub end)
- 12"
Problem 7
An offset is 8" high and bent at 30°. How far apart are the bends, and how much does the conduit shrink?
Show the answer
- Distance between bends
- 16"
- Shrink
- 2 1/8" (2.14")
Problem 8
An offset is 10" high and bent at 60°. How far apart are the bends, and how much does the conduit shrink?
Show the answer
- Distance between bends
- 11 9/16" (11.55")
- Shrink
- 5 3/4" (5.77")
Problem 9
A stub-up must be 24" to the back of the 90, and the bender deducts 8". Where is the mark?
Show the answer
- Mark the conduit at (from the stub end)
- 16"
Problem 10
An offset is 12" high and bent at 45°. How far apart are the bends, and how much does the conduit shrink?
Show the answer
- Distance between bends
- 17" (16.97")
- Shrink
- 5" (4.97")
How to work each problem
- Read the bend, the angle and the measurements, and draw a quick sketch.
- Write the formula before you put numbers in it.
- Work it out and round to the fraction the problem asks for.
- Ask whether the answer is reasonable, then open the answer to compare.
The formulas to know
Multiplier = 1 ÷ sin(angle)Shrink per inch = tan(angle ÷ 2)Mark for a 90 = stub length − deductA worked example
- Offset height
- 6"
- Angle
- 30°
- Multiplier
- 2.000
- Shrink per inch
- 0.268
- Distance between bends
- 12"
- Shrink
- 6 × 0.268" per inch of height
- Trade rule of thumb
- 2 × height, and 1/4" per inch
Basic problems like this one test whether you can pick the right multiplier, read a measurement off the right edge, and keep track of units. A 90 problem tests the deduct instead: a 1/2" EMT hand bender typically takes 5", so the mark goes that far short of the stub length.
What the problems test
- Multiplier choice. A smaller angle gives a bigger multiplier. A 10° offset needs far more room than a 45° one.
- Shrink. The conduit gets shorter as the offset deepens; the amount grows with the angle.
- Deduct. Subtract it from the stub length for the mark. Do not add it.
- Fractions. Work in sixteenths and keep the same units from start to finish.
How to study with them
- Do a few every day rather than all of them at once.
- Say the formula out loud as you write it; it sticks faster.
- Redo any problem you missed after a day or two, without looking at the answer.
- Once the basics feel easy, move on to the mixed worksheet and the exam-style set.
How to check your answers
- The distance between bends is always longer than the offset height.
- A bigger angle means a smaller multiplier and more shrink per inch.
- Work it a second way, such as with the trade’s rounded rule, and see that the two agree closely.
- Check against the BendMate offset calculator. It uses your bender’s real radius, so its marks run slightly smaller than the textbook; switch to the multiplier method to match the problems exactly.
Keep a note of each mistake and what caused it. After a few sessions the same two or three errors will show up, and those are the ones to drill.
Get the marks for your bender
BendMate works this out from your bender’s radius and deduct, flags a bend that won’t work, and shows you every mark.
Common questions
Are the answers to these practice problems included?
Yes. Each problem hides its answer until you open it, so you can work it first and check afterward.
Which formulas do I need for conduit bending problems?
Multiplier = 1 ÷ sin(angle), shrink per inch = tan(angle ÷ 2), and the mark for a 90 = stub length − deduct. The rest follows from those.
Why does BendMate give a slightly different answer?
BendMate works from your bender’s real centerline radius, while textbook problems treat each bend as a sharp corner. Switch to the multiplier method and the numbers agree.