Reaction Rate Constant to Activation Energy Converter Calculate Activation Energy (Ea) from Rate Constants at two temperatures using the Arrhenius equation. Rate Constant k₁ (s⁻¹) at Temperature T₁ (K): Temperature T₁ (Kelvin): Rate Constant k₂ (s⁻¹) at Temperature T₂ (K): Temperature T₂ (Kelvin): Calculate Activation Energy (Ea) Download PDF