Mechanical Engineering Calculators

Beam Deflection Calculator

Calculate maximum deflection of a simply supported beam under a central point load.

Bearing Load Calculator

Calculate L10 bearing rating life in hours from dynamic load rating, equivalent load, and speed, with separate exponents for ball and roller bearings.

Belt Length Calculator

Calculate required belt length for an open belt drive from pulley diameters and center distance.

Bolt Torque Calculator

Calculate the tightening torque needed for a target clamp force from bolt diameter, preload, and nut factor K, with worked examples across common bolt sizes.

Engineering Safety Factor Calculator

Calculate the engineering safety factor from material yield strength and applied stress.

Euler Buckling Load Calculator

Calculate the critical Euler buckling load for a slender column based on material, cross-section, length, and end conditions.

Fatigue Life Calculator

Predict cycles to failure under cyclic stress using Basquin's equation from stress amplitude, fatigue strength coefficient, and exponent, with worked examples.

Flywheel Energy Calculator

Calculate stored kinetic energy in a rotating flywheel from moment of inertia or solid disk mass and radius, with worked examples showing the effect of speed.

Gear Design Calculator

Calculate gear ratio, output speed, and output torque from tooth counts, input speed, torque, and mesh efficiency, with worked examples for reduction ratios.

Hydraulic Cylinder Force Calculator

Calculate hydraulic cylinder output force from bore diameter and system pressure.

Moment of Inertia Calculator

Calculate the second moment of area (moment of inertia) for rectangular or circular cross-sections.

Natural Frequency Calculator (Spring-Mass System)

Calculate the natural frequency of an undamped spring-mass mechanical system.

Power Transmission Calculator

Convert between torque and power at a given rotational speed for shafts and drivetrains, with worked examples in kilowatts, horsepower, and newton-meters.

Pulley Ratio Calculator

Calculate belt pulley ratio and driven speed from driver and driven pulley diameters and driver rpm, with worked examples for step-up and step-down drives.

Shaft Diameter Calculator

Calculate the minimum solid shaft diameter for a given torque and allowable shear stress using the torsion formula, with a fully worked numeric example.

Shaft Keyway Size Calculator

Look up standard keyway width and depth dimensions for a given shaft diameter following common engineering conventions.

Spring Constant Calculator

Calculate spring constant from force and deflection, or predict it from helical coil geometry and shear modulus, with worked examples for both methods.

Stress Strain Calculator

Calculate stress, strain, or elastic modulus from force, area, and length change using Hooke's Law, with a worked example connecting all three quantities.

Thermal Expansion Calculator

Calculate the change in length of a material due to temperature change using the linear thermal expansion formula.

Thermal Stress Calculator

Calculate the internal stress developed when a material is fully constrained from thermal expansion or contraction.

Parts Fail Long Before They Break

Mechanical components rarely fail from a single overload event — they fail from repeated stress cycles below their breaking point, a process called fatigue, and predicting when that happens is central to safe design. These ten calculators cover load, stress, and mechanical design math.

Why a Small Stress Increase Costs So Many Cycles

Approximate cycles to failure by stress amplitude (illustrative S-N relationship) Lower stress amplitude: millions of cycles to failure. Moderate stress: hundreds of thousands of cycles. High stress: only thousands of cycles before failure. High stress Low stress Cycles to Failure (log scale) →
The classic S-N (stress vs number of cycles) fatigue curve — a modest reduction in operating stress can extend fatigue life by orders of magnitude. Calculated with the Fatigue Life Calculator.

This relationship is exactly why engineers build in a safety margin below the theoretical yield stress rather than designing right up to it — the fatigue life cost of running close to the edge is disproportionately steep compared to the material saved. Check your own loading scenario with the Fatigue Life Calculator and Stress Strain Calculator.

Popular Mechanical Engineering Calculators

  • Bolt Torque Calculator — calculates the torque needed to achieve a target bolt preload force.
  • Gear Design Calculator — calculates gear ratio and tooth parameters for a target speed reduction.
  • Spring Constant Calculator — calculates a spring's stiffness from force and displacement.

Related: Civil Engineering Calculators, Electrical Calculators.