Noise Figure Calculator

Your details

Select how to compute the noise figure. The cascaded mode uses the Friis formula across multiple stages.
How many amplifier or filter stages are in the chain.
Noise figure of the first stage (usually an LNA). Lower is better.
dB
Power gain of the first stage in dB.
dB
Noise figure of the second stage in dB.
dB
Power gain of the second stage in dB.
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Noise figure of the third stage in dB.
dB
Power gain of the third stage in dB.
dB
Noise figure of the fourth stage in dB.
dB
Power gain of the fourth stage in dB.
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Noise figure of the fifth stage in dB.
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Power gain of the fifth stage in dB.
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Noise figure of the sixth stage in dB.
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Power gain of the sixth stage in dB.
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Noise figure (NF)Good NF
1.533dB

Total system noise figure in decibels

Noise factor (F)1.4234
Equivalent noise temperature122.8K
Total system gain45dB
Stage 1 contribution1.5dB
Stage 2 contribution0.043dB
Stage 3 contribution0.004dB
1.533 dB
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Noise figure: 1.533 dB

  • A noise figure under 3 dB is considered good for most RF receiver front-ends, including cellular and Wi-Fi systems.
  • The linear noise factor is 1.4234, meaning the SNR degrades by a factor of 1.42 through this system.
  • The equivalent noise temperature is 123 K, referenced to the standard 290 K (IEEE 60268).
  • Stage 1 dominates the total noise figure. Reducing its NF will have the greatest impact on overall system performance.

Next stepTo improve cascaded NF: reduce stage 1 noise figure (use a better LNA), increase stage 1 gain (suppresses later stages), or place a lower-NF device first in the chain.

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