Noise Temperature ↔ Noise Figure

Noise figure and equivalent noise temperature describe the same thing two ways. Satellite and radio-astronomy links quote noise temperature (kelvin); most RF datasheets quote noise figure (dB). Enter either one and this tool returns the other, the linear noise factor F, and — with a bandwidth — the added noise power the device contributes at its input. The reference temperature is the IEEE standard T₀ = 290 K.

Equations & Parameters ▸

\(F = 10^{NF/10} \qquad T_e = T_0\,(F-1) \qquad F = 1+\dfrac{T_e}{T_0} \qquad T_0 = 290\,\text{K}\)
\(P_{added} = k\,T_e\,B \quad(\text{referred to the input})\)

NF	Noise figure (dB). Enter this or the noise temperature.
T_e	Equivalent input noise temperature (K).
F	Linear noise factor (unitless), = 10^(NF/10).
B	Bandwidth (MHz), optional — gives the added noise power k·T_e·B.

Reference: IEEE Std 100; H. T. Friis, "Noise figures of radio receivers," Proc. IRE 32, 419 (1944). k = 1.380649×10⁻²³ J/K.

Inputs (enter NF or T_e)

Noise figure, NF

or fill Tₑ →

Noise temperature, T_e

← or fill NF

Bandwidth, B (opt)

MHz

For added power

Results

Equivalents

Noise figure NF—

Noise factor F—

Noise temperature T_e—

Added noise

Power k·T_e·B—

In dBm—

Diagram

📖 Learn about noise in RF systems →