Link Budget Calculator

Calculate a radio link budget to determine whether a wireless link will close by summing gains and subtracting losses.

dBm
dBi
dBi
dB
dB
dBm

Received Power

-63.0 dBm

Link Margin27.0 dB
Link Viable?1

Received Power vs Transmit Power

How a Link Budget Works

A link budget adds up all gains and subtracts all losses between transmitter and receiver to find the received power.

Formula

P_rx = P_tx + G_tx + G_rx - L_path - L_misc

Link Margin = P_rx - Receiver Sensitivity

A positive link margin means the link will work. Engineers typically design for 10-20 dB of margin to account for fading and environmental variation.

Example Calculation

30 dBm transmitter, 15 dBi antennas on each end, 120 dB path loss, 3 dB misc losses, receiver sensitivity -90 dBm.

  1. 01Received power: 30 + 15 + 15 - 120 - 3 = -63 dBm
  2. 02Link margin: -63 - (-90) = 27 dB
  3. 03Link is viable with 27 dB margin

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