Fault frequency calculator

Calculate bearing, gearbox, and machine defect frequencies.

Calculate critical fault frequencies for machinery diagnostics

Accurately calculate bearing defect frequencies, gear mesh frequencies, belt pass frequencies, and motor electrical frequencies with professional-grade calculators designed for vibration analysts. Enter your machine parameters including RPM, bearing geometry, gear tooth counts, or motor specifications to instantly determine the exact frequencies where faults will appear in your vibration spectra.

These free fault frequency calculators cover all major machinery types including rolling element bearings (BPFO, BPFI, BSF, FTF), simple and multi-stage gearboxes, epicyclic/planetary gears, blade/vane pass frequencies, belt drive systems, and induction motor electrical frequencies. Essential tools for setting up monitoring parameters, validating diagnostic findings, and training vibration analysts. Calculate fault frequencies instantly and improve your diagnostic accuracy.

Bearing Defect Frequency Calculator

Gearbox Calculator

Blade/Vane Pass Frequency

Belt Frequency Calculator

Motor Electrical Frequencies

Calculator usage notes

Bearing calculations:

Contact angle is 0° for most radial bearings

Use 15-25° for angular contact bearings

Check bearing manufacturer data for exact geometry

Results show fundamental frequencies - harmonics occur at multiples

Gearbox calculations:

GMF sidebands at shaft speeds indicate wear

Multi-stage: each stage has unique GMF

Planetary gears show complex frequency patterns

Hunting tooth frequency = shaft speed / LCM ratio

Belt & blade calculations:

Belt length auto-calculates from geometry

BPF harmonics indicate belt defects or tension issues

Blade/vane pass frequency = RPM × number of blades

Use for fans, pumps, compressors, turbines

Motor electrical frequencies:

2× line frequency (100/120 Hz) is most common

Slip frequency sidebands indicate rotor bar issues

Pole pass frequency relates to motor design

Use actual measured RPM for accurate slip calculation

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