Springback Calculator
Calculate springback angle and required over-bend compensation from material properties and bend geometry.
About this calculator
This calculator estimates sheet-metal springback -- the amount a bent part relaxes back toward its original shape after the forming force is removed -- using a simplified, single-term version of the classic elastic-recovery relationship: Springback Factor = (Inside Bend Radius x Yield Strength) / (Elastic Modulus x Material Thickness). A higher Yield Strength means the material stores more elastic energy at the same bend, so it springs back MORE (springback percentage increases); a higher Elastic Modulus or a thicker material resists elastic deformation more, so both REDUCE springback. The calculator multiplies this factor by the Desired Bend Angle to estimate the Springback Angle, then adds that back to get the Required Over-Bend Angle -- the angle to actually program into the press brake so the part relaxes to the target angle after release; Required Over-Bend Angle always rises when Desired Bend Angle rises, since a bigger target angle needs a proportionally bigger compensation. Springback Factor itself does not depend on Desired Bend Angle at all -- it is purely a property of the material and bend geometry.
It applies the full cubic elastic-recovery relationship Ri/Rf = 4x^3 - 3x + 1 (where x is the Springback Factor), not just its leading term, and converts the resulting radius ratio into an angle ratio by conserving bend-arc length. That relationship is only physical up to a Springback Factor of 0.5, at which point the sheet springs completely flat; above about 0.35 the calculator says so explicitly in the Recommendation rather than quoting a number. Treat every result as a starting estimate for die design, not a substitute for a first-article test: real springback also depends on tooling, lubrication, and bend method (air bending vs. bottoming vs. coining), none of which this calculator models. The Recommendation field escalates from "standard tooling" at low springback percentages up through "coining, bottoming, or radius compensation" and "multi-stage forming" as the estimated springback grows past 5%, 10%, and 20%.
Inputs
Results
Required Over-Bend Angle
90.45°
How to Use This Calculator
- Enter the desired final bend angle (degrees).
- Set material thickness and inside bend radius.
- Enter yield strength and elastic modulus in MPa from the material data sheet — if your data sheet gives the modulus in GPa, multiply by 1,000 (steel 200 GPa = 200,000 MPa).
- Review the springback angle (degrees), the overbend angle to use in the press brake program, and the Compensated Die Radius to cut into the tool.
- Test a sample part and measure actual springback -- adjust the overbend angle iteratively for tight tolerances.
How the result changes with Desired Bend Angle
| Desired Bend Angle | Required Over-Bend Angle |
|---|---|
| 45 | 45.23° |
| 68 | 68.34° |
| 135 | 135.68° |
| 180 | 180.9° |
What each input means
- Desired Bend Angle
- Target bend angle after springback, measured as the angle the flange turns THROUGH (a right-angle bracket is 90°). If your press brake is programmed in included/formed angle, subtract the Required Over-Bend Angle from 180 before entering it there.
- Material Thickness
- Sheet metal thickness.
- Inside Bend Radius
- Inside radius of the bend.
- Yield Strength
- Material yield strength in MPa (mild steel A36: 250; annealed 304 stainless: 205–310; quarter-hard 304: ~450; aluminum 3003-H14: 145, 5052-H32: 193, 6061-T6: 276). Temper matters more than alloy here — use the data sheet for your actual condition.
- Elastic Modulus
- Young's modulus in MPa, NOT GPa (steel: 200,000; aluminum: 69,000; copper: 117,000). A data sheet quoting GPa needs x1,000.
How this is calculated
Worked example, using the default values
- Identify Input Parameters5 parametersDesired Bend Angle = 90, Material Thickness = 1.5, Inside Bend Radius = 2, Yield Strength = 250, Elastic Modulus = 200000 = 5 input(s) provided
- Calculate Required Over-Bend AngleRequired Over-Bend Angle90.45 = 90.45
- Calculate Springback AngleSpringback Angle0.45 = 0.45
- Calculate SpringbackSpringback0.5 = 0.5%
Engine last updated . Checked against 2 independently-derived tests — how we verify calculators. Built by Paul Gunder, a software engineer, not a licensed financial, medical, or legal professional.
Frequently Asked Questions
Why does higher yield strength increase springback?
A higher-yield-strength material stores more elastic strain energy for the same amount of bending, and that stored elastic energy is exactly what relaxes back out once the forming force is removed. Doubling Yield Strength roughly doubles the calculated Springback Factor, since it enters the springback ratio directly in the numerator.
Why does a thicker material spring back less?
Material Thickness sits in the denominator of the springback ratio, so a thicker section resists elastic deformation more relative to its bend radius and springs back less for the same yield strength and elastic modulus. This is part of why thin sheet metal is notoriously harder to bend to a precise angle than heavy plate.
What does the Springback Factor number actually mean?
Springback Factor is the dimensionless ratio (Inside Bend Radius x Yield Strength) / (Elastic Modulus x Material Thickness) -- a value near 0 means almost no elastic recovery, while a larger value means more of the bend will relax back after forming. Neither the Springback Factor nor the Springback Percentage depends on the Desired Bend Angle -- the percentage is the springback expressed as a share of that angle, so the angle cancels out. Only the Springback Angle and the Required Over-Bend Angle in degrees scale with the angle you're targeting.
Is the Required Over-Bend Angle exactly what I should program into the press brake?
Use it as a first-pass figure, not a final tooling value -- and check your controller's angle convention first. This calculator works in bend-arc angle, so over-bending a 90-degree part means bending to 90.45 degrees; a press brake programmed in included/formed angle wants 89.55 for the same bend. Getting that backwards doubles the error instead of removing it. It also does not account for tooling geometry, lubrication, or bend method (air bending, bottoming, or coining) -- run a first-article bend and adjust the over-bend angle based on the measured result for tight tolerances.
What is the Compensated Die Radius, and why is it smaller than the radius I entered?
It is the radius to actually cut into the die so that the part relaxes to the inside radius you asked for. Because the bend opens up when the forming force is released, the radius also grows -- so the tool has to start tighter. It is your entered radius multiplied by the same elastic-recovery ratio the angle compensation uses, and it is always at or below the radius you entered, never above it.
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