RF Link Budget Calculator
Roll transmit power, antenna gains, and every loss into a received-power figure, then read the margin over your receiver's sensitivity — and whether the link closes.
Make the whole link balance
A link budget turns a wireless design into one honest number: does the signal arriving at the far end sit comfortably above what the receiver needs, or is it living on the edge? Every decision — a bigger dish, a lower-loss cable, more transmit power, a more sensitive radio — shows up as a few dB moved in or out of the margin, so you can see the cheapest way to close a marginal path.
Get the path-loss input from the Free-Space Path Loss Calculator, size the antenna gains with the Antenna Gain Converter, and translate transmit power between dBm and watts with the dBm to Watt Converter.
Frequently Asked Questions
What is a link budget?
A link budget is the running total of every gain and loss between a transmitter's output and a receiver's input, kept entirely in decibels. Received power = transmit power + transmit antenna gain + receive antenna gain − path loss − cable and connector loss − fade and miscellaneous losses. Comparing that received power against the receiver's sensitivity tells you whether the link works and with how much headroom.
What is link margin, and how much do I need?
Link margin is received power minus receiver sensitivity — how far above the demodulation threshold your signal lands. A positive margin means the link closes; a negative one means it does not. Because real signals fade with weather, motion, and multipath, engineers design in headroom: roughly 10 dB for a stable fixed link and 20 dB or more where fading is severe. This tool flags whether your margin is positive and shows its size.
Where do I get the path-loss number to enter?
For a clear line-of-sight link, start with free-space path loss from the distance and frequency — the companion Free-Space Path Loss Calculator gives it directly. For obstructed or non-line-of-sight paths, use a propagation model appropriate to the environment (it will be higher than free space), then enter that value here as the path loss.
Is the result a guarantee the link will work?
No. A link budget is a planning estimate built on the figures you enter — datasheet powers, catalogue antenna gains, and modelled path loss. Component tolerances, connector wear, interference, and real-world fading all move the true numbers. Use the margin to decide whether a design is worth prototyping, then confirm with a measured over-the-air test. This is educational, not engineering sign-off.
Planning estimate only, built from the figures you enter. Verify component specs from datasheets and confirm with a measured test. Not engineering or regulatory advice.