Bearing Defect Frequency Calculator
BPFO, BPFI, BSF and FTF for vibration analysis.
Lines at BPFO in the spectrum = outer-race spall; BPFI sidebanded at shaft speed = inner race. Quick fallback when geometry's unknown: BPFO ≈ 0.4×n×f, BPFI ≈ 0.6×n×f.
Formula
Bearing Defect Frequency Calculator is a free bearing frequencies for mechanical and machine-design engineers — instant, accurate and 100% client-side, with the governing formula and reference shown next to the result so the number can be defended, not just quoted.
About Bearing Defect Frequency Calculator
BPFO, BPFI, BSF and FTF for vibration analysis. The calculation implements BPFO = (n/2)f(1−d/D); BPFI = (n/2)f(1+d/D); FTF ≈ 0.4f (Vibration analysis — ISO 13373; Mobius training). Lines at BPFO in the spectrum = outer-race spall; BPFI sidebanded at shaft speed = inner race. Quick fallback when geometry's unknown: BPFO ≈ 0.4×n×f, BPFI ≈ 0.6×n×f.
How to use Bearing Defect Frequency Calculator
- 1Enter Shaft speed in rpm.
- 2Enter Rolling elements.
- 3Enter Ball diameter in mm.
- 4Enter Pitch diameter in mm.
- 5Read BPFO (outer race), BPFI (inner race), BSF (ball spin) instantly — no submit button needed.
Why use Bearing Defect Frequency Calculator?
- ✓Implements the standard formula — BPFO = (n/2)f(1−d/D); BPFI = (n/2)f(1+d/D); FTF ≈ 0.4f
- ✓Reference cited on-page: Vibration analysis — ISO 13373; Mobius training
- ✓Runs entirely in your browser — nothing uploaded, free forever
Frequently asked questions
What formula does the Bearing Defect Frequency Calculator use?+
It computes BPFO = (n/2)f(1−d/D); BPFI = (n/2)f(1+d/D); FTF ≈ 0.4f, per Vibration analysis — ISO 13373; Mobius training. The formula is displayed under the result.
What should I keep in mind when using this calculator?+
Lines at BPFO in the spectrum = outer-race spall; BPFI sidebanded at shaft speed = inner race. Quick fallback when geometry's unknown: BPFO ≈ 0.4×n×f, BPFI ≈ 0.6×n×f.
Is this suitable for machine design coursework?+
Yes — these are the exact Shigley/Machinery's-Handbook formulas, with the substitution shown step by step, so you can follow the worked example into your own calculation sheet.
Is the Bearing Defect Frequency Calculator free to use?+
Yes — completely free, no sign-up, no limits. It runs client-side in your browser, so inputs stay private and results are instant even on slow connections.
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