⚙️ RF Power Density & EIRP Calculator
Single or bulk — accurate far-field calculations
📡 Single Calculation
⚡ Bulk Upload / Paste
Drag & drop or click to upload .txt/.csv
Format: power_dBm,gain_dBi,distance_m,freq_MHz (optional)
📖 Understanding RF Power Density
What is RF Power Density? It quantifies the spatial concentration of electromagnetic power (W/m²). In the far-field region, the formula is S = EIRP / (4πr²), where EIRP = Pt × G (numeric). This calculator also computes Free-Space Path Loss (FSPL) = 20 log₁₀(d) + 20 log₁₀(f) + 32.44 dB (distance in km, f in MHz).
Example 1 (Cellular Tower): 40 dBm (10W) + 17 dBi gain → EIRP = 10 × 10^(1.7) ≈ 501W. At 50m distance: S = 501/(4π×2500) ≈ 0.0159 W/m² (1.59 mW/cm²). Safe distance for 10 W/m² limit: r = √(501/(4π×10)) ≈ 2.0m.
Example 2 (Wi-Fi AP): 20 dBm (0.1W) + 5 dBi gain → EIRP = 0.316W. At 2m: S = 0.316/(4π×4)=0.0063 W/m² (0.63 µW/cm²) — well below safety limits. Use this tool for compliance with ICNIRP, FCC OET-65, and site survey analysis.
Bulk mode accepts: power_dBm,gain_dBi,distance_m,freq_MHz or power_W,gain_num,distance_m,freq_MHz. All calculations run locally in your browser — private and fast.
EIRP (Effective Isotropic Radiated Power) relates to an isotropic antenna, while ERP (Effective Radiated Power) uses a half-wave dipole reference. EIRP = 1.64 × ERP (2.15 dB higher). This calculator focuses on EIRP, the standard for power density.
Far-field begins at distance > 2D²/λ (where D is antenna diameter). For most antennas above a few wavelengths, the formula S = EIRP/(4πr²) is valid. Near-field requires different models.
Yes, select the exposure limit (10 W/m² general public, 100 W/m² occupational). The safe distance computed helps RF safety planning. Always consult local regulations.