Use this calculator to build a simple receive-side link budget in dB without leaving the page.
Inputs
This topic also has a deeper guide and a printable reference pack, so you can move from the live answer into the method, assumptions, and worked examples without leaving the topic cluster.
These are the main values the calculator uses. Keep the units consistent and, where relevant, match the assumptions explained in the related guide.
Unit: dBm
Use the absolute transmit power level at the start of the budget chain.
Unit: dBi
Enter the transmit-side antenna gain if it belongs in the budget.
Unit: dBi
Enter the receive-side antenna gain using the same convention.
Unit: dB
Use the main path-loss term, often from FSPL or a broader propagation estimate.
Unit: dB
Use this field for feeder, connector, or other losses that are not part of the main path term.
Use this page when you already know the main gains and losses in a radio link and want a quick received-power estimate.
The main result is estimated received power in dBm. The supporting value shows the combined gains before losses are subtracted.
If a transmitter outputs 30 dBm, both antennas add 12 dBi of gain, path loss is 110 dB, and miscellaneous losses are 2 dB, the page combines those terms directly in decibels to estimate received power.
This calculator assumes the gains and losses you enter are already in compatible dB units. It does not estimate fade margin, interference, noise floor, or receiver sensitivity.
Link budgets are easier to audit in logarithmic units because gains and losses can be added and subtracted directly instead of converted repeatedly.
Estimate the line-of-sight path loss between two points from the distance and frequency you enter.
Estimate received power from transmitter power, antenna gains, distance, and frequency using the free-space Friis relationship.
Use the Watts to dBm Calculator for quick watts to dbm estimates in RF, radar, and communications work.
Use the dBm to Watts Calculator for quick dbm to watts estimates in RF, radar, and communications work.