Rolling Offset / Pipe Offset Calculator
Calculate true offset, bend multiplier, travel and rotation for simple or rolling offsets. Work in decimal inches or feet + inches, with nearest 1/16-in display and optional user-entered takeout.
A geometry aid for pipe, conduit and similar field-layout work. Confirm the fitting or bender method for your project.
Rolling Offset / Pipe Offset Calculator
Calculate simple and rolling offset geometry, true offset, travel, rotation and optional user-entered takeout.
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Plumbing Estimating ServicesHow to use the rolling offset calculator
- Choose Simple Offset or Rolling Offset and your input units.
- Enter the single offset, or the perpendicular Rise and Roll dimensions.
- Select a bend angle: 15°, 22.5°, 30°, 45°, 60°, or Custom Angle.
- Enter the number of identical physical offsets. Add another specification for different geometry.
- If required, enable Takeout Adjustment and enter the start and end takeouts.
- Calculate and review decimal travel, nearest 1/16-in dimensions and project totals.
Rolling offset formula and travel
Rise and Roll are perpendicular components. The true offset is their combined straight-line displacement:
Multiplier = 1 ÷ sin(Bend Angle)
Travel = True Offset × Multiplier
For a simple offset, True Offset is the entered Offset. Bend angle is measured from the original run to the diagonal travel. The pipe travel calculator uses full trigonometric precision, not rounded field multipliers. Changing bend angle changes the offset multiplier and travel, while the required True Offset stays the same.
Worked example: 12-in Rise, 16-in Roll, 45°
√(12² + 16²) gives a 20-in True Offset. The multiplier is 1.414213562, rotation is 53.130102°, and geometric travel is 28.284271 in. Its nearest field fraction is 28 5/16 in.
Simple offset example
A 10-in Offset at 30° has a multiplier of 2 and 20-in Travel. For a precision example, 7.375 in at 22.5° gives 19.27180373… in, displayed as 19.271804 in and 19 1/4 in.
Rotation angle is different from bend angle
Rotation Angle = atan2(Roll, Rise), expressed in degrees. The convention is 0° entirely in the Rise direction and 90° entirely in the Roll direction. Rise 12 / Roll 16 gives 53.130102°. Swapping them retains the 20-in True Offset but changes rotation to 36.869898°. Rotation describes the orientation of the offset; it is not the selected fitting bend angle.
Decimal inches, feet + inches and field fractions
Use Decimal Inches or Feet + Inches: 28.5 in = 2 ft 4.5 in. Switching representations preserves the physical dimension, with decimal-inch geometry retained internally. Feet must be whole and nonnegative; the inches component must be at least zero and less than 12.
Field-friendly length results also show the nearest 1/16 in, using half-up rounding. For example, 28.284271 in becomes 28 5/16 in. Fractions are display only: calculations and project totals use full decimal precision.
Optional user-entered takeout
With 28.284271-in travel and 1.5 in entered at each end, adjusted travel is 25.284271 in / 25 5/16 in. The combined takeouts must be less than travel. The calculator does not invent fitting takeouts or retrieve fitting-center dimensions; use values appropriate to the actual fittings and layout.
Adjusted travel — takeout-enabled entries only sums only entries where Takeout is enabled. Total Geometric Travel includes every entry and remains the complete unadjusted project geometry.
Multiple and identical offsets
Quantity multiplies travel without changing individual geometry. Simple 10 in at 30°, Qty 2, contributes 40 in. Rolling 12/16 at 45°, Qty 3, contributes 84.852814 in. Together they produce 5 physical offsets / 124.852814 in / 124 7/8 in. Totals use unrounded values.
What this geometry tool does not calculate
Use it as a geometry aid for pipe, conduit and similar field-layout work. It does not size pipe/conduit, select fittings, supply automatic takeouts or fitting-center databases, provide conduit-bender shoe data, calculate conduit shrink or bending marks, calculate saddle bends or pipe pressure, design fabrication spools, calculate labor/pricing, or establish code compliance. Confirm the actual fitting and bender methodology for your work.
Frequently asked questions
What is a rolling offset?
A rolling offset combines displacement in two perpendicular directions, entered here as Rise and Roll.
How do you calculate a rolling offset?
Find √(Rise² + Roll²), then divide that True Offset by the sine of the bend angle to obtain geometric travel.
What is True Offset?
It is the combined displacement perpendicular to the original run. For a simple offset, it is the entered Offset.
How do you calculate Travel?
Multiply True Offset by 1 ÷ sin(Bend Angle). Optional start and end takeouts are subtracted separately.
What is the offset multiplier?
It is the reciprocal of the sine of the selected bend angle. This calculator retains full trigonometric precision internally.
What is the Rotation Angle?
It is atan2(Roll, Rise), measured from the Rise direction toward Roll. It describes orientation, not bend angle.
Can I use this for conduit?
Yes, for conduit rolling offset geometry. It does not provide bender-specific shrink, shoe data or bending marks.
Can I enter feet and inches?
Yes. Select Feet + Inches, enter whole feet and an inches component below 12, or use Decimal Inches.
How does the 1/16-in rounding work?
Displayed field fractions round to the nearest sixteenth, with halfway values rounded up. They do not feed back into calculations.
Does the calculator determine fitting takeout?
No. Takeout is optional and entirely user-entered. Obtain the correct dimensions for the fittings and method you are using.