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Mechanical and material strength calculator

Use this mechanical and material strength calculator for bend allowance, beam deflection, section properties, axial stress, shaft torsion, torque, ratios and bearing rating life.

Method version 1.0.0 · Reviewed November 2, 2026 · Calculated on your device

Your calculation

Choose a specific mechanical or material calculation. Material names alone do not establish stiffness, strength or bendability; use documented properties for the actual grade and condition.

Choose a method, then enter your figures. Examples are illustrative, not recommended settings or rates.

What would you like to calculate?

Choose a method, then enter actual dimensions, operating conditions and sourced properties.

Unit system

Review the unit printed in each label. Changing this selector does not convert entries; Load example gives a matching converted example.

Sheet thickness (in / mm)

Measured thickness, not gauge designation.

Inside bend radius (in / mm)

Proposed formed inside radius; punch radius may differ.

Bend rotation from flat (degrees)

90 is a right-angle bend. Must be greater than zero and less than 180.

K-factor (0–0.5)

Neutral-axis location divided by thickness. Obtain from shop trials or validated supplier data; the example is not a recommended K-factor.

First outside mold-line leg (in / mm)

Outside distance to virtual sharp intersection, not inside flange or tangent length.

Second outside mold-line leg (in / mm)

Same outside mold-line convention as the first leg.

How this calculation works

Bend allowance = angle(rad) × (inside radius + K × thickness); elastic bending stress = M × c / I; shaft shear stress = T × r / J; basic bearing rating life L10 = (C/P)^p.

What information do I need?

Only fields for your selected method are required. Use consistent units and scope. Changing an entry method or unit system does not convert the numbers already entered. Previously calculated results are cleared when inputs change.

Input definitions and where to find them

What would you like to calculate?: Choose a method, then enter actual dimensions, operating conditions and sourced properties.
Unit system: Review the unit printed in each label. Changing this selector does not convert entries; Load example gives a matching converted example.
Cross-section shape: Ideal section dimensions; for rectangles, height is vertical and bending is about the horizontal centroid axis.
Beam support and load: Uniform load entry is total force on the whole span, NOT force per length.
Sheet thickness (in / mm): Measured thickness, not gauge designation.
Inside bend radius (in / mm): Proposed formed inside radius; punch radius may differ.
Bend rotation from flat (degrees): 90 is a right-angle bend. Must be greater than zero and less than 180.
K-factor (0–0.5): Neutral-axis location divided by thickness. Obtain from shop trials or validated supplier data; the example is not a recommended K-factor.
First outside mold-line leg (in / mm): Outside distance to virtual sharp intersection, not inside flange or tangent length.
Second outside mold-line leg (in / mm): Same outside mold-line convention as the first leg.
Supplier minimum inside R/t ratio: Supply the minimum for actual alloy, temper, thickness, grain direction and forming method. No universal material threshold is chosen.
Section / specimen width (in / mm): Horizontal width. For hollow sections use outside dimension.
Section / specimen vertical depth (in / mm): Vertical bending depth. Outside depth for hollow sections.
Outside diameter (in / mm): Round section outside diameter.
Uniform wall thickness (in / mm): Ideal wall thickness; no corner radii included.
Span or loaded length (ft / m): Beam: support span or free cantilever length. Axial/torsion: loaded length. Flexural test: distance between supports.
Applied force magnitude (lbf / N): Beam uniform cases require TOTAL load over span. Flexural test uses measured center load. Include relevant dead load yourself.
Young’s modulus E (psi / MPa): Use tensile elastic modulus for actual material and temperature, not yield strength.
Entered tensile yield strength (psi / MPa): Used only as a nominal stress/yield comparison; no code allowable stress or safety factor is selected.
Net loaded cross-sectional area (in² / mm²): Use actual net area at the section under consideration. No holes or stress concentrations are inferred.
Shaft outside diameter (in / mm): Uniform circular shaft.
Shaft inside diameter (in / mm): Zero for solid; otherwise less than outside diameter.
Shear modulus G (psi / MPa): Actual elastic shear modulus; do not enter Young’s modulus.
Shaft value to calculate: Shaft mechanical power only; electrical input power requires a separate efficiency conversion.
Known shaft rotational speed (RPM): Positive shaft speed.
Known shaft torque (lbf·ft / N·m): Positive mechanical torque magnitude.
Known mechanical shaft power (kW): Mechanical output/input at the same shaft, not electrical nameplate power.
Input shaft torque (lbf·ft / N·m): Torque magnitude; lb-force feet, not pound inches.
Input operating speed (RPM): Constant input shaft or bearing speed.
Driver teeth or pitch diameter: Use tooth counts for gears, matching pitch-diameter units for pulleys.
Driven teeth or pitch diameter: Same basis as driver. One stage only.
Entered transmission efficiency (%): Actual assumed power-transmission efficiency; greater than zero through 100.
Bearing type: Use the applicable bearing catalog rating method.
Catalog basic dynamic load rating C (lbf / N): Catalog dynamic rating, not static rating.
Equivalent dynamic bearing load P (lbf / N): Derive using the bearing catalog coefficients and actual radial/axial loads. This input is not automatically just the radial force.
Rectangular specimen width (in / mm): Measured specimen width at the tested section.
Rectangular specimen depth (in / mm): Measured bending depth.

Worked example

This example uses the initial method shown in the selector. Load an example in the form to try it.

Example inputs

What would you like to calculate?: bend
Unit system: us
Sheet thickness (in / mm): 0.125
Inside bend radius (in / mm): 0.1875
Bend rotation from flat (degrees): 90
K-factor (0–0.5): 0.33
First outside mold-line leg (in / mm): 4
Second outside mold-line leg (in / mm): 3

Example answer: Flat blank length = 6.73431966 in

Use the result well

Single bend only. Angle is rotation from flat: 90° is a right-angle bend. Legs are outside mold-line distances to the virtual sharp intersection. K is neutral-axis distance / thickness; obtain it from validated shop bend data. Tooling, grain, springback, bend sequence and tolerances are not inferred.

Use actual material, equipment and operating specifications. This is a stated-model calculation, not approval of a part, machine, lifting arrangement or structure. Verify units and assumptions before use.

Review the limits shown with each result. Browser arithmetic has finite precision; small differences may reflect rounding. Print or download important results before closing the tab. This workspace does not store projects online or replace an approved examination calculator, engineering design or professional judgment.

Method and sources

References support the stated mathematical concepts; the interface and implementation are original. Publishers do not endorse this site.