RF Field Strength Calculator

Calculate the electric field strength (V/m) at any distance from an RF transmitter given power and antenna gain.

Transmitter Parameters

Quick Presets

Enter transmitter parameters and click Calculate

Formula Reference

E (V/m) = sqrt(30 × PEIRP) / d
PEIRP (W) = Ptx (W) × 10GdBi/10
S (W/m²) = E² / 377
E (dBuV/m) = 20 × log10(E × 106)
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Summary

Calculate the electric field strength (V/m) at any distance from an RF transmitter given power and antenna gain.

How it works

  1. Enter the transmitter output power in watts (W) or dBm.
  2. Enter the antenna gain in dBi (decibels relative to an isotropic radiator).
  3. Enter the distance from the antenna to the measurement point in meters.
  4. Click Calculate to apply the free-space formula: E = sqrt(30 * P_eirp) / d.
  5. The result shows electric field strength (V/m), power density (W/m²), and field strength in dBuV/m.
  6. Use the unit toggles to switch between watts/dBm and meters/feet.

Use cases

  • Estimate RF exposure levels near broadcast towers or base stations.
  • Verify compliance with ICNIRP or FCC RF exposure limits.
  • Design wireless link budgets and coverage zones.
  • Calculate antenna field intensity for EMC pre-compliance testing.
  • Determine safe working distances around high-power transmitters.
  • Convert between field strength units (V/m, dBuV/m, mW/m²).
  • Validate antenna range test setups and calibration distances.
  • Estimate received signal strength in RF propagation planning.

Frequently Asked Questions

Last updated: 2026-06-09 · Reviewed by Nham Vu