For pipefitters · fab shops · mechanical contractors
Rolling offsets,
right the first time.
Turn roll and set into true offset, travel, run and the exact cut length — with the fitting take-outs and weld gaps already subtracted. No chalk on the floor, no 1/16" guesswork.
Roll
12.000"
Set / rise
16.000"
Fitting
4" LR
Root gap
1/8"
Cut length
23.064"
1'-11 1/16"
Pipefitters
Standing at the vise with a roll and a set, needing the cut number now — not after the math on the wall.
Fab shops
Cut sheets that match the drawing. Every spool gets the same numbers and the same reference table.
Mechanical contractors
Give apprentices a tool that shows its work, so the travel and take-out get checked before the pipe is cut.
What it does
Job-site math, done properly.
True offset, travel and run
Roll and set in, and the calculator does the trigonometry the way it is taught on the job: travel = true offset ÷ sin(angle), run = true offset ÷ tan(angle).
Fitting take-outs deducted
Take-out is R × tan(angle ÷ 2) from the ASME B16.9 90° radius for your size, so the cut length is real pipe, not center-to-center guesswork.
Weld gap included
Root gap defaults to 1/8" and is editable. Both joints are deducted from the cut so the spool lands on dimension.
Any fitting angle
11.25°, 22.5°, 30°, 45°, 60° or a custom angle. Have the run and need the angle? Solve it backwards from a known run.
Built for the field
Fast, readable numbers on a phone in your pouch: every result in decimal inches and in feet-inches to the nearest 1/16".
Show your work
The isometric view draws the offset plane, the roll angle and the travel pipe, plus a worked check you can verify by hand.
Worked example
Roll 12", set 16", 45° elbows.
Two 4" long radius 45s, 1/8" root gaps. This is the whole calculation, in the order PipeFlow runs it.
True offset
√(12² + 16²) = 20.000"
Travel
20.000 ÷ sin 45° = 28.284" (×1.4142)
Run / advance
20.000 ÷ tan 45° = 20.000" (×1.0)
Take-out each
6.000 × tan 22.5° = 2.485"
Cut length
28.284 − 4.970 − 0.250 = 23.064" (1'-11 1/16")
Roll angle
atan(12 ÷ 16) = 36.87°
Cut sheet
23.064"
1'-11 1/16" — pipe between fittings
True offset
20.000"
1'-8"
Travel
28.284"
2'-4 5/16"
Run
20.000"
1'-8"
Take-out ea.
2.485"
2 1/2"
Every dimension is shown in decimal inches and in feet-inches rounded to the nearest 1/16", so it reads straight off a tape.
Pricing
One plan. Everything included.
Seven days free, then $12/month or $99/year. Cancel any time from your account.
PipeFlow Pro
Full calculator access
- Rolling offset, travel, run and cut length
- Long and short radius elbows, 1/2" to 30"
- Any angle from 11.25° to 60°, or solve from a run
- Editable weld root gap
- Decimal inches and feet-inches to 1/16"
- Isometric view and fitting reference table
Card required. Cancel before day 7 and you are not charged.
Questions
Next offset, do it once.
Start your 7-day trial and put the calculator in your pouch.