Arrhenius Equation Calculator
Estimate rate constants across temperatures by leveraging activation energy data and optional pre-exponential factors.
If left blank, A is derived from the known rate constant.
Predicted k at target temperature
0.0033
Pre-exponential factor A
49,309,151.0202
How to Use This Calculator
Measure activation energy
Use experimental data or literature to obtain Eₐ in J/mol.
Provide a known rate constant
Enter a rate constant measured at a particular temperature to anchor the calculation.
Set the target temperature
Choose the temperature at which you want to estimate the rate constant.
Optionally input A
Supply a known pre-exponential factor or let the calculator derive it from the provided rate constant.
Formula
k = A e^(−Eₐ / (RT))
Rearranging using known k and T gives A = k e^(Eₐ/(RT)), enabling prediction of rate constants at other temperatures.
Example
Given Eₐ = 60 kJ/mol, k = 1.5×10⁻³ s⁻¹ at 298 K, and target 308 K, predicted k ≈ 3.0×10⁻³ s⁻¹.
Full Description
The Arrhenius equation describes how chemical reaction rates depend on temperature. Knowing activation energy and a single rate constant allows projection of rates at new temperatures.
This calculator makes the process straightforward for kinetics studies, process design, or lab planning, with optional entry of the pre-exponential factor for more precise modeling.
Frequently Asked Questions
Do temperatures need to be in Kelvin?
Yes. Kelvin ensures the exponential term is dimensionally correct. Convert °C to K before input.
What if I have multiple rate constants?
Use two to determine Eₐ (via the activation energy calculator), then predict others with this tool.
Can Eₐ vary with temperature?
Yes. The Arrhenius equation assumes Eₐ is constant over the range considered. Large temperature ranges may require more advanced models.
Is A always constant?
In Arrhenius theory it is treated as constant. Real systems may deviate slightly, especially near phase transitions.
What units should k have?
Use consistent units (typically s⁻¹) for k and the predicted rate constant. The formula preserves units.