Signal to Noise Ratio Calculator
Calculate SNR and thermal noise floor.
SNR Requirements by Application
| Application | Minimum SNR | Quality |
|---|---|---|
| Voice (analog) | 30 dB | Intelligible |
| FM Radio | 20 dB | Good audio |
| WiFi (basic) | 10 dB | 54 Mbps |
| WiFi (fast) | 25 dB | 300+ Mbps |
| WiFi 6 (max) | 35 dB | 1024-QAM |
| Cellular LTE | 10-20 dB | Varies |
| Digital TV | 15 dB | Reliable |
Understanding SNR and Noise
SNR Formula
SNR (dB) = Signal Power (dBm) - Noise Power (dBm)
Higher SNR means better signal quality. SNR determines what modulation schemes can be used and ultimately the achievable data rate.
Thermal Noise Floor
N = kTB
k = Boltzmann constant, T = temperature, B = bandwidth
At 290K: -174 dBm/Hz
k = Boltzmann constant, T = temperature, B = bandwidth
At 290K: -174 dBm/Hz
This is the theoretical minimum noise in any system. Real receivers add additional noise (noise figure).