This specific absorption rate calculator finds the SAR — the RF power absorbed per unit mass of tissue — from the conductivity, electric field, and tissue density. Enter the values above.
Formula
SAR = σ × E² ÷ ρ
- σ — tissue conductivity (S/m), E — field strength (V/m), ρ — tissue density (kg/m³)
Example
σ = 1 S/m, E = 10 V/m, ρ = 1000 kg/m³: SAR = 1 × 100 ÷ 1000 = 0.1 W/kg.
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Frequently Asked Questions
How do I calculate SAR?
Multiply tissue conductivity by the field strength squared, then divide by tissue density: SAR = sigma E squared / rho.
What units does SAR use?
Watts per kilogram (W/kg), the rate of RF energy absorbed per unit mass of tissue.
Why does SAR matter?
It sets safety limits for phones and RF devices, capping how much energy body tissue absorbs.