EIRP Calculator — Effective Isotropic Radiated Power

Written by Great Medico

Updated September 25, 2026 •2 min read

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When you want a quick eirp — effective isotropic radiated power estimate, the formula matters as much as the final number. For eirp — effective isotropic radiated power, energy and power numbers are easiest to understand when you keep track of what is being stored, transferred, or normalized. This page converts the entered quantities into one focused result without adding unrelated assumptions.

What this calculator does

The EIRP Calculator — Effective Isotropic Radiated Power turns the physical quantities shown on the form into a focused eirp. It is designed for quick scenario checks while keeping the inputs and units visible, so you can change one quantity and immediately see how the modeled result responds.

How to use it

Start with the fields that drive the current calculation: Transmitter power, Antenna gain, Cable/system losses. Enter values in the units shown beside each field; the page converts supported units before applying the formula. Keep signs and angles consistent with the labels, then read the headline result together with any supporting metrics rather than copying the number without its unit.

How the calculation works

Effective isotropic radiated power is calculated as EIRP = Ptx × 10^[(G − L)/10], where G is antenna gain in dB and L is cable/system loss in dB. The page also converts the resulting power to dBW.

Example

Using the default example on the page (Transmitter power = 10 W; Antenna gain = 6 dBi; Cable/system losses = 1 dB), the calculator returns eirp of 31.622777 W. Change one input at a time and compare the direction of the change with the formula above; that is a quick way to catch a wrong unit, sign, or selected method before you rely on the number.

How to interpret the result

On the EIRP Calculator — Effective Isotropic Radiated Power, the eirp describes the energy, power, or normalized quantity produced by the stated relationship. When a squared speed or displacement appears in the formula, changes in that input have a nonlinear effect. Keep energy (joules), power (watts), force (newtons), and dimensionless ratios conceptually separate.

Limitations and notes

For the EIRP Calculator — Effective Isotropic Radiated Power, real losses, efficiency, heat, deformation, and time-varying behavior may sit outside the displayed relationship. Use the result for the stated model and keep separate any effects that the form does not ask you to enter. The most important inputs to verify here are Transmitter power, Antenna gain; an incorrect unit or an assumption outside those fields can move the result more than extra decimal places improve it.