CalculatorCentrum

RF Link Budget Calculator

Work out received signal power and link margin from transmit power, antenna gains, path loss, other losses, and receiver sensitivity.

Other losses cover cables, connectors, and fade margin. Sensitivity is usually negative (e.g. −137 dBm for LoRa at SF12).
Received power–
Link margin–
Max allowable path loss–
Effective radiated power (EIRP)–

Link budget

A link budget adds up every gain and loss between transmitter and receiver to check whether the signal arrives strongly enough to be decoded. The spare headroom above the receiver's sensitivity is the link margin.

P_rx = P_tx + G_tx + G_rx − path loss − other losses

Link margin = P_rx − sensitivity

A positive margin means the link should close; designers typically want 10 dB or more to cover fading and real-world obstacles. The maximum allowable path loss is the loss at which the margin reaches zero — a handy figure for estimating range.

Related

Estimate the path loss first with thefree-space path loss calculator, or convert power units with thedBm to watts converter.

Related calculators