PipeMaster How to bend a 90 in EMT conduit: stub-up mark, deduct and gain
Subtract your bender's deduct (take-up) from the stub height and that's your mark: a 24" stub with a 5" deduct marks at 19". Check it by hand the first few times with any new bender. PipeMaster's free 90° / Stub-Up calculator does the subtraction in fractions or millimetres and throws in the gain for whatever radius you enter.
What take-up (deduct) means
A hand bender doesn't make a sharp corner — it sweeps. That curve eats into the stub, so marking the full stub height leaves the leg too tall. The deduct (take-up) is how much you subtract so the finished leg actually matches your tape.
The deduct depends on the bender's shoe, which is why most benders stamp it near the take-up mark, often an arrow. PipeMaster has no idea which bender you own, so it never fills this number in for you — you type it, every time.
EMT deduction chart (generic values)
PipeMaster's Bender Profiles list comes with six generic EMT profiles using these commonly published values. Your bender may differ from the chart, and when it does, the number stamped on your own tool wins, not this page.
| EMT trade size | Take-up / Deduct | Centerline Radius |
|---|---|---|
| 1/2" | 5" | 4" |
| 3/4" | 6" | 4 1/2" |
| 1" | 8" | 5 3/4" |
| 1-1/4" | 11" | 7 1/4" |
| 1-1/2" | 13" | 8 1/4" |
| 2" | 14" | 9 1/2" |
How to calculate the stub-up mark in PipeMaster
- Open 90° / Stub-Up from Calculators.
- Tap Height of the 90° Leg and enter the stub height, measured from the floor or surface to the back of the finished bend.
- Tap Deduct and type your bender's take-up. PipeMaster does not pull it from Bender Profiles; you copy it in.
- Enter the Centerline Radius of your bender if you also want the gain.
- Read Distance from End to Bend and mark the conduit that far from the end.
- Line the mark up with your bender's take-up mark and bend to 90°. Tap Save to keep the numbers in History.
Worked examples
| Height of the 90° Leg | Deduct | Centerline Radius | Distance from End to Bend | Gain |
|---|---|---|---|---|
| 24" | 5" | 4" | 19" | 1 23/32" |
| 18" | 6" | 4 1/2" | 12" | 1 15/16" |
| 500 mm | 127 mm | 102 mm | 373 mm | 44 mm |
Row one uses the generic 1/2" EMT values, row two the 3/4" ones. In millimetre mode PipeMaster keeps what you type to the nearest 1/32" internally and shows whole millimetres.
What is gain, and how do you calculate it?
Gain is the length a curved 90 saves compared with a square corner. The formula is gain = R × (2 − π/2), about 0.429 × the centerline radius, so a 4" radius gains 1 23/32".
You need it when two legs share one piece of conduit: the length required is both legs, each measured to the corner where they would meet, added together, minus the gain. Legs of 24" and 30" with a 4" radius need 24 + 30 − 1 23/32 = 52 9/32" of conduit.
Take-up vs gain
Take-up is subtracted from one leg to place a single mark before you bend. Gain is subtracted from the total when you work out how much conduit two legs need. Both come from the bender's radius, but they answer different questions.
Tips and common mistakes
- New bender? Bend a test 90, measure the stub and adjust the deduct you type until the result matches.
- Measure the stub to the back of the bend, not to the middle of the pipe.
- Draw the mark all the way around the conduit so you can still see it once it sits in the shoe.
- Keep foot pressure on the bender so the conduit does not kink or flatten.
Questions and answers
What is take up in conduit bending?
What is gain in conduit bending?
How to bend a 90 in 3/4 EMT?
Does PipeMaster fill in the deduct from my bender profile?
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