FFT Bin Resolution Calculator
Enter the known values and run the calculation.
Overview
Calculate spectral bin width from sample rate and record length for frequency-domain planning.
Use this tool to get FFT bin width from sample rate and record length. It also reports total capture time and the Nyquist limit for the chosen setup.
Use it when you need to know how far apart two tones can be before they collapse into the same bin, or how much record length you need before a spectrum becomes useful.
The math and how it's used
FFT bin width is sample rate / record length.
Capture time is record length / sample rate, and Nyquist frequency is sample rate / 2.
This is the quick planning relationship between sample rate, record length, and frequency-bin spacing.
It tells you how finely the FFT grid is spaced, not whether two tones are cleanly separable in practice. Window choice, coherent sampling, leakage, and averaging still drive what the spectrum actually looks like.
Practical note
Bin width is not the same thing as real-world ability to resolve two nearby tones. Windowing, leakage, averaging, and signal stability still matter.
This is the right first pass for acquisition planning. Use it before deciding whether the hardware, front end, or record length is the real limit.