Enter your Signal and Noise values, choose your Type of SNR, and this Signal-to-Noise Ratio (SNR) Calculator gives you the SNR in decibels alongside the Simple Ratio and Linear SNR — so you can see exactly how cleanly your signal rises above the noise.
SNR
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Simple Ratio
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Linear SNR
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SNR is a measure of the strength of the desired signal compared to the background noise level. It indicates how much the signal stands out above the noise floor and is typically expressed in decibels (dB).
A good SNR depends on the application. For audio, 60+ dB is excellent, 40-60 dB is good, and below 20 dB is poor. For digital communications, 20+ dB is typically required for reliable transmission.
For power measurements: SNR(dB) = 10 × log₁₀(Signal Power / Noise Power). For voltage measurements: SNR(dB) = 20 × log₁₀(Signal Voltage / Noise Voltage). For dB values: SNR(dB) = Signal(dB) - Noise(dB).
Power SNR uses a factor of 10 in the formula while voltage SNR uses a factor of 20. This is because power is proportional to voltage squared, so the 20 log₁₀ formula accounts for this relationship.
Common noise sources include thermal noise, shot noise, flicker noise, electromagnetic interference, quantization noise in digital systems, and environmental factors like temperature fluctuations.
Yes, SNR can be negative when the noise level exceeds the signal level. A negative SNR indicates that the signal is weaker than the noise, making it difficult to detect or extract useful information.
CD audio requires ~96 dB, professional audio ~120+ dB, FM radio ~50-70 dB, digital communications ~20+ dB, and medical imaging systems often require 40+ dB for quality diagnostics.
Higher SNR allows for higher data rates, better signal quality, and more reliable communication. Low SNR can cause errors, reduced bandwidth capacity, and require error correction techniques.