The tool calculates the thermal noise floor of a radio receiver.

Enter the:

- Temperature in either Kelvin or Celsius
- Bandwidth
- Noise Figure in dB

**Formula**

**Noise Floor _{dBm} = 10*Log_{10}(kTB/(1 mW)) + NF**

where,

- T = Temperature in Kelvin
- B = Bandwidth in Hz
- k = Boltzmann’s constant
- NF = Noise Figure

**Noise Floor of a Radio Receiver**

In a radio receiver, the noise floor is the level below which a signal will not be detected. In practice, a signal has to be a few dB higher before it can be detected. This level is called the Minimum Detectable Signal level.

**Example Noise Floor Calculation**

Let’s calculate the noise floor of a LoRa receiver system.

For a temperature of 25^{o}C, 125 kHz Bandwidth and a noise figure of 10 dB, the noise floor is **-113 dBm**. Increasing the antenna cable length will directly impact the noise figure and increase the noise floor.