RF EIRP Calculator dBm / W

EIRP (dBm) = Tx power (dBm) + Antenna gain (dBi) – cable loss (dB)

e.g., 30 dBm (1 W)
dBi
dBi (isotropic)
dB
insertion loss (positive dB)
dB
misc. loss / margin
EIRP 38.00 dBm
EIRP (linear): 6.31 W

EIRP [dBm] = Ptx[dBm] + G[dBi] – L[dB] (losses include cable + other) 1 W = 30 dBm
Last Updated: 09-04-2026

EIRP Calculator – Effective Isotropic Radiated Power

The EIRP Calculator helps you determine the total radiated power of a transmitter system after considering antenna gain and transmission losses. EIRP (Effective Isotropic Radiated Power) is a critical parameter in RF planning, telecom network design, satellite communication, and wireless system analysis.

Whether you are working in LTE, 5G, microwave links, or Wi-Fi deployment, calculating EIRP ensures regulatory compliance and proper coverage planning.

What is EIRP?

Effective Isotropic Radiated Power (EIRP) represents the total power radiated by an antenna in a specific direction compared to an ideal isotropic antenna.

It includes:

EIRP tells us how strong the signal effectively radiates into space.

EIRP Formula

$$ \text{EIRP (dBm)} = \text{Tx Power (dBm)} + \text{Antenna Gain (dBi)} - \text{Cable Loss (dB)} $$

$$ \text{EIRP (W)} = 10^{\frac{\text{EIRP(dBm)} - 30}{10}} $$

EIRP formula diagram with transmitter power antenna gain and cable loss explanation

EIRP (dBm) = Tx Power (dBm) + Antenna Gain (dBi) - Cable Loss (dB)

How to Use EIRP Calculator

  1. Enter Transmitter Power (in dBm, W, or mW)
  2. Enter Antenna Gain (in dBi)
  3. Enter Cable Loss (in dB)
  4. Add optional extra losses if needed
  5. Click calculate to get EIRP in dBm and Watts

EIRP Calculation Example

Let’s calculate EIRP with real values:

  • Transmitter Power = 30 dBm
  • Antenna Gain = 6 dBi
  • Cable Loss = 2 dB

EIRP = 30 + 6 - 2 = 34 dBm

Convert to watts:

EIRP ≈ 2.51 Watts

What is EIRP in Telecom?

Effective Isotropic Radiated Power (EIRP) is the total power radiated by an antenna in a specific direction, compared to an ideal isotropic radiator.

It is a key parameter used in:

  • 5G and LTE network planning
  • Wi-Fi signal strength analysis
  • Satellite communication systems
  • RF link budget calculations

FAQ on EIRP Calculator

What is a good EIRP value?

A good EIRP depends on the application. For Wi-Fi, it is usually below regulatory limits, while telecom networks use higher values for better coverage.

EIRP in dBm represents the effective radiated power in logarithmic scale, combining transmitter power, antenna gain, and losses.

How do you calculate EIRP?

EIRP = Transmitter Power (dBm) + Antenna Gain (dBi) − Cable Loss (dB)

Why is antenna gain added in EIRP?

Antenna gain focuses energy in a direction, increasing effective radiated power compared to an isotropic antenna.

What is difference between ERP and EIRP?

EIRP is referenced to an isotropic antenna, while ERP is referenced to a dipole antenna (ERP is ~2.15 dB lower than EIRP).