FFT Bin Resolution Calculator

Summary

Enter a sample rate and FFT size to get the Hz-per-bin resolution and a full table of bin center frequencies.

How it works

1. Enter the sample rate in Hz (e.g. 44100 for CD-quality audio).
2. Enter the FFT size — must be a power of two (e.g. 512, 1024, 2048).
3. The tool divides the sample rate by the FFT size to get Hz per bin.
4. Bin center frequencies are listed from bin 0 (DC) up to the Nyquist bin (FFT size / 2).
5. Use the search box to filter the table to a specific frequency range.
6. Copy any value or export the full table as CSV.

Use cases

• Verify frequency resolution when designing audio equalizers or filters.
• Determine the minimum FFT size needed to resolve two closely spaced tones.
• Plan hop-size and window-size trade-offs in short-time Fourier transform (STFT) pipelines.
• Debug spectrum analyzers by confirming which bin a known test tone falls into.
• Teach DSP fundamentals — bin resolution is a foundational concept.
• Quickly look up the exact center frequency of a bin index when reading FFT output arrays.

Frequently Asked Questions