Arrhenius Equation Calculator — k = Ae^(−Ea/RT)

The Arrhenius equation captures why reactions speed up with heat: only the fraction of collisions clearing the activation barrier react. Give A, Eₐ, and T to predict k — or invert it to find Eₐ from two rate constants' worth of data.

Arrhenius Equation Calculator — k = Ae^(−Ea/RT)

$k = Ae^{-E_a/RT}$

Solve for

Pre-exponential factor (A)

Unit

Activation energy (E_a)

Unit

Temperature (T)

Unit

Result unit

How to interpret the result

Worked check: A = 4.0×10¹³ s⁻¹, Eₐ = 103 kJ/mol, T = 300 K → k = 4.0×10¹³ × e^(−103/(0.008314×300)) ≈ 4.6×10⁻⁵ s⁻¹. A 10 K rise near room temperature roughly doubles most rates.

Assumptions

First-order units shown; A and k share whatever consistent units apply
Eₐ in kJ/mol with R = 0.008314 kJ/(mol·K)
A and Eₐ treated as temperature-independent