RF Link Budget Calculator
EIRP and received level from power, gains, losses, and free-space path loss. Enter a direct path loss or let distance + frequency compute FSPL — results update instantly and the URL is shareable as-is.
Enter TX power, antenna gains, and a path loss (or distance + frequency) to see the budget.
Free-space estimate only — real paths add building penetration, clutter, and fade margin. Verify acceptance thresholds with your AHJ.
What this checks & why
A link budget chains every gain and loss between a transmitter and a receiver: EIRP = TX power + TX antenna gain − TX cable loss, then received level = EIRP − path loss + RX antenna gain − RX cable loss. It answers the field question “how hot is the signal when it arrives?” before anyone climbs a roof.
Free-space path loss (FSPL) is the textbook minimum loss over open air at a given distance and frequency — doubling the distance always costs about 6 dB. Real buildings lose more, so treat the received level here as a best case.