Your result
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Enter your values, then click Calculate result.How this calculator helps
This plate rolling calculator is a developed-length worksheet for a circular arc. Enter the finished inside radius, plate thickness, a neutral-axis factor established by your fabricator, the arc angle and a separate signed process allowance. It calculates the arc along the supplied neutral radius and keeps the allowance visible. Rolling behavior depends on material and process information that this worksheet does not model. The result does not choose a machine, predict springback or give roll positions. Use the geometry as one documented part of a fabricator-reviewed takeoff, with millimetres used consistently throughout.
How to use it
- 1
Verify inside radius, thickness, arc angle and the neutral-axis factor and allowance supplied for this fabrication scenario.
- 2
Enter the values in the displayed units and verify the source record or measurement basis.
- 3
Click Calculate result to submit the current inputs.
- 4
Read the labeled outputs with the methodology and checks. Input edits retain the previous result until Calculate is clicked again.
Formula and methodology
Neutral radius = inside radius + supplied factor × thickness. Arc length = neutral radius × angle × π/180. Illustrative developed length = arc length + signed process allowance.
The calculator applies the displayed arithmetic to the values entered on this device. It does not silently load a local tax rate, currency conversion or commercial assumption.
Worked calculation example
For 100 mm inside radius, 10 mm thickness, supplied factor 0.5 and 360° with no separate allowance: neutral radius is 105 mm and the arc is approximately 659.734457 mm. The factor is an input assumption, not a verified universal value.
How to interpret your result
For 100 mm inside radius, 10 mm thickness, supplied factor 0.5 and 360° with no separate allowance: neutral radius is 105 mm and the arc is approximately 659.734457 mm. The factor is an input assumption, not a verified universal value. Illustrative circular-arc development only. Supplied factor and allowance are not verified by the tool. No springback, roll load, machine setup, structural analysis or fabrication approval. Compare the main quantity with the separately labeled intermediate values before using it in another worksheet. Retain units, input basis and any selected convention with the result so it can be reproduced.
For different inputs or formulas, use Surface Area Calculator; Cylinder Volume Calculator; Drywall Calculator.
Related questions this calculator covers
- plate rolling calculator
Scenario comparison
| Scenario | What it shows |
|---|---|
| 360° with neutral radius 105 mm | approximately 659.734457 mm. |
| 180° on the same radius | half the full arc length. |
| Add 5 mm process allowance | final length increases by exactly 5 mm. |
Common mistakes to avoid
- Copying outside diameter into inside radius.
- Treating a default neutral-axis factor as process validation.
- Applying an allowance twice.
Convert angle to radians, establish the supplied neutral radius and multiply them. Compare full, half and quarter arcs for the same radius. Review the factor, allowance, drawing basis and tolerances with the fabricator; this arithmetic alone is not a production release.
Authoritative reference. OpenStax documents the circular arc identity. Neutral-axis factor and process allowance are user-supplied assumptions and are not established or certified by this reference. Reference reviewed 4 October 2026. Mohammad Qasim reviews the arithmetic and editorial scope; individual professional assessment is not performed.What can affect the result?
Inside radius must match the drawing basis
A drawing may specify inside diameter, outside diameter or a centerline dimension. This worksheet requires inside radius, so a diameter must first be divided by two and an outside dimension must not be copied without accounting for thickness. Write the measurement basis beside the calculation. For a full circular shell the angle is three hundred sixty degrees; for a partial arc it is the actual included angle. Conical and variable-radius parts require a different development.
Neutral-axis factor is independently supplied
The factor locates the modeled neutral radius within the plate thickness. A value of zero uses the inside surface, one uses the outside surface and one-half uses the thickness midpoint. The midpoint example is only a transparent geometry assumption. Material behavior, bend ratio and forming process can require a different established basis. Do not use the default as a production setting or assume that a familiar sheet-metal bending factor applies unchanged to plate rolling.
Arc angle and full circumference are distinct inputs
The tool converts degrees to radians before multiplying by neutral radius. A ninety-degree arc is one-quarter of the full circumference on the same supplied radius. A hundred-eighty-degree arc is one-half. These simple fractions make useful independent checks, but they do not identify where straight end portions or trimming zones start. If the fabrication drawing contains a circular section plus straight tangents, those lengths need a separate documented development rather than an angle adjustment.
Process allowance remains a separate signed quantity
An independently established trimming or process correction can be added as millimetres. A negative correction reduces the modeled length, and the tool rejects a non-positive final result. The field is not a percentage, a weld-gap recommendation or an automatic springback correction. Keep its source with the job record. If the drawing or supplied development already includes a correction, entering it again doubles the adjustment. Compare the unadjusted arc and the final developed length before release.
Geometry cannot validate the rolling process
Thickness, grade, mechanical properties, machine capacity, end preparation and welding requirements determine whether a part can be produced and accepted. The page has no rolling-force equation, residual-stress model, tolerance certificate or machine-setting output. A precise displayed decimal should not be mistaken for a precise finished radius. Have the responsible fabricator reconcile the chosen neutral-axis basis and allowance with the actual process, then confirm the finished part against the approved drawing and inspection requirements.
Privacy and browser processing
Values entered on this page are processed in the current browser session. SolvePilot does not require an account and does not receive the values entered into the calculator. Refreshing or closing the page clears the working values unless the browser itself restores a previous session. Avoid entering identifying or account information because the calculation needs summary values only.
Accuracy and verification
Accuracy depends first on input quality. Confirm definitions, scales, dates and source information before entering a value. Keep an independent record of any result used for planning because this page does not create an official statement or retain a calculation history.
Limits of this estimate
Illustrative circular-arc development only. Supplied factor and allowance are not verified by the tool. No springback, roll load, machine setup, structural analysis or fabrication approval. Results use the entered assumptions and do not verify their real-world applicability. Calculator inputs are processed locally by the browser interface. Avoid entering identifying records; save only the quantities and context necessary for your own review.
Sources and review information
Frequently asked questions
Does this predict springback?＋
No. It calculates a circular arc on a supplied neutral-axis basis and applies only your separate allowance.
Is a factor of 0.5 always correct?＋
No. It locates the modeled axis at mid-thickness. A fabricator must establish the appropriate process basis.
Can I enter diameter?＋
Convert a verified inside diameter to radius first. The field expects inside radius in millimetres.
Can allowance be negative?＋
Yes, when independently justified. The final developed length must remain positive.
Does this set the rolling machine?＋
No. Machine capacity, roll positions, forming sequence and acceptance tolerances are outside the worksheet.