Free Link Budget Calculator

Professional RF planning tool. Calculate EIRP, FSPL and Expected RSSI.

Global Link Parameters

MHz

Common: 2400, 5180-5825, 24000, 60000

km

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A Site A (Access Point / Tx)

dBm
dBi
dB

B Site B (Station / Rx)

dBi
dB

Expected Rx Level

-56.69 dBm
Link Quality excellent

Detailed Metrics

Total EIRP (Site A)
46 dBm
Free Space Loss (FSPL)
121.69 dB
Total Antenna Gain
38 dBi

Understanding Link Budgets

A link budget accounts for all of the gains and losses from the transmitter, through the medium (free space, cable, waveguides, fiber, etc.) to the receiver in a telecommunication system.

The Formula

Rx Power = Tx Power + Tx Gain - Tx Loss - FSPL + Rx Gain - Rx Loss

EIRP

Equivalent Isotropically Radiated Power. The amount of power that a theoretical isotropic antenna would emit to produce the peak power density observed in the direction of maximum antenna gain.

Why use the ISPbox Calculator?

Our Free Link Budget Calculator is designed for Wireless ISPs (WISPs) who need a quick, accurate alternative to complex vendor tools like Ubiquiti AirLink, Mikrotik Link Calculator, or Mimosa Design Tool.

  • Vendor Neutral: Works with any hardware (Ubiquiti airFiber, Mimosa B5, Mikrotik NetMetal, Cambium PTP).
  • Multi-Frequency: Supports 2.4 GHz, 5 GHz, 24 GHz, and 60 GHz bands.
  • Professional Metrics: Calculates Free Space Path Loss (FSPL) and System Operating Margin.