Antenna Gain And Range Calculator

Work out antenna gain and range instantly with clear inputs, formula shown and shareable results.

About Antenna Gain And Range Calculator

Range comes from the link budget: transmit power plus both antenna gains minus receiver sensitivity, set against free-space path loss. Antenna gain is free power in both directions, which is why a pair of 9 dBi antennas adds 18 dB — equivalent to a 63-fold increase in transmit power — and why directional links reach far further than omnidirectional ones.

Formula

Link budget and range

budget = Tx + Tx gain + Rx gain - sensitivity; FSPL(dB) = 20log10(d_km) + 20log10(f_MHz) + 32.45; solve for distance

Worked example

With the default values below, Antenna Gain And Range Calculator returns Theoretical maximum range of 6,125.440. Change any input above and every figure here is recalculated in your browser.

Inputs used

Transmit poweraccepts -10–40 dBm: 20 dBm
Transmit antenna gainaccepts -10–40 dBi: 9 dBi
Receive antenna gainaccepts -10–40 dBi: 9 dBi
Receiver sensitivityaccepts -110–-30 dBm: -85 dBm

Results

Theoretical maximum range: 6,125.440 km
Total link budget: 123.0 dB
Effective radiated power: 29.0 dBm
Combined antenna gain: 18.0 dBi

Step by step

1Values used
2Link budget and range
3Theoretical maximum range= 6,125.440 km
4Total link budget= 123.0 dB
5Effective radiated power= 29.0 dBm
6Combined antenna gain= 18.0 dBi

Assumptions and limits

The result is derived only from the 4 inputs listed above. Anything not among them is not part of the calculation.
In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
Figures are rounded for display to 3 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

Why does gain count twice?

Antennas are reciprocal, so a directional antenna concentrates energy on transmit and collects more of it on receive. Both ends contribute their gain to the same budget.

Is the theoretical range achievable?

Rarely. It assumes clear line of sight with Fresnel zone clearance and no fade margin. Practical designs reserve 10 to 20 dB of margin for rain, multipath and obstruction.