Calculate sampling rate from samples and duration, find the Nyquist minimum for a signal frequency, or estimate recording time from a sample rate.
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Sampling Rate Formula
The calculator uses one of three formulas depending on the tab you select.
Find Rate (samples and duration known):
fs = N / t
Nyquist Minimum (highest signal frequency known):
fs_min = 2 * f_max
Find Duration (samples and rate known):
t = N / fs
- fs = sampling rate in samples per second (Hz)
- N = total number of samples collected
- t = total acquisition time in seconds
- f_max = highest frequency component in the signal (Hz)
- fs_min = minimum sampling rate that avoids aliasing
Nyquist gives the theoretical floor. In practice you sample 10 to 25 percent above 2 × f_max to leave room for an anti-aliasing filter rolloff. The duration formula assumes a constant rate and uniform spacing between samples.
Common Sampling Rates and Nyquist Limits
Reference values for matching a rate to an application or sanity-checking your result.
| Application | Typical Rate | Max Captured Frequency |
|---|---|---|
| Telephone voice | 8 kHz | 4 kHz |
| Wideband speech (VoIP) | 16 kHz | 8 kHz |
| CD audio | 44.1 kHz | 22.05 kHz |
| Studio / video audio | 48 kHz | 24 kHz |
| High-res audio | 96 / 192 kHz | 48 / 96 kHz |
| Vibration / ECG | 1 to 5 kHz | 500 Hz to 2.5 kHz |
| Ultrasonic sensors | 200 kHz to 1 MHz | 100 to 500 kHz |
| RF / SDR baseband | 2 to 20 Msps | 1 to 10 MHz |
| Highest Signal Frequency | Nyquist Minimum | Practical Rate (≈2.2x) |
|---|---|---|
| 100 Hz | 200 Hz | 220 Hz |
| 1 kHz | 2 kHz | 2.2 kHz |
| 10 kHz | 20 kHz | 22 kHz |
| 20 kHz | 40 kHz | 44 kHz |
| 100 kHz | 200 kHz | 220 kHz |
| 1 MHz | 2 MHz | 2.2 MHz |
Worked Example and FAQ
Example: You record a sensor and end up with 480,000 samples over 10 seconds. The rate is 480,000 ÷ 10 = 48,000 samples/s, or 48 kHz. That is enough to capture frequencies up to 24 kHz.
Why 44.1 kHz for CDs and not exactly 40 kHz? Human hearing tops out near 20 kHz, so the Nyquist minimum is 40 kHz. The extra 4.1 kHz gives the anti-aliasing filter room to roll off without affecting audible content.
What happens if you sample below the Nyquist rate? Frequencies above fs/2 fold back into the captured spectrum as aliases. They cannot be removed after sampling, so the only fix is a higher rate or an analog low-pass filter before the ADC.
Is higher always better? No. Doubling the rate doubles storage, bandwidth, and processing load. Pick a rate that covers your signal plus a margin, then stop.
How do you find samples if you know rate and duration? Multiply: N = fs × t. A 10-second recording at 44.1 kHz produces 441,000 samples per channel.
