Activation Energy Calculator
Determine activation energy from rate constants measured at two temperatures.
About Activation Energy Calculator
Two rate constants at two temperatures determine the activation energy uniquely. Enzyme-catalysed reactions have lower barriers than the uncatalysed equivalents, which is precisely how catalysis accelerates them. Activation energy predicts how sensitive a process is to temperature control, which drives both reactor design and shelf-life estimation.
Formula
Activation Energy
Ea = R ln(k₂/k₁) ÷ (1/T₁ − 1/T₂)
- Ea
- Activation energy in joules per mole
- R
- Gas constant, 8.314 J/mol·K
Worked example
With the default values below, Activation Energy Calculator returns Activation Energy of 69.9946. Change any input above and every figure here is recalculated in your browser.
Inputs used
- Rate constant at temperature 1minimum 0
- 0.001
- Temperature 1minimum -272 C
- 25 C
- Rate constant at temperature 2minimum 0
- 0.0025
- Temperature 2minimum -272 C
- 35 C
Results
- Activation Energy
- 69.9946 kJ/mol
- Activation Energy
- 69,994.6 J/mol
- Ratio of the Rate Constants
- 2.50000
- Pre-Exponential Factor
- 1,830,296,154.415172
- Classification
- Typical chemical reaction barrier
Step by step
- 1Values used
- 2Activation Energy
- 3Activation Energy= 69.9946 kJ/mol
- 4Activation Energy= 69,994.6 J/mol
- 5Ratio of the Rate Constants= 2.50000
- 6Pre-Exponential Factor= 1,830,296,154.415172
- 7Classification= Typical chemical reaction barrier
Assumptions and limits
- The result is derived only from the 4 inputs listed above. Anything not among them is not part of the calculation.
- In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
- Figures are rounded for display to 6 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.
How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.
Frequently Asked Questions
How is Activation Energy calculated?
Ea = R ln(k₂/k₁) ÷ (1/T₁ − 1/T₂) Two rate constants at two temperatures determine the activation energy uniquely. Enzyme-catalysed reactions have lower barriers than the uncatalysed equivalents, which is precisely how catalysis accelerates them.
Why does Activation Energy matter?
Activation energy predicts how sensitive a process is to temperature control, which drives both reactor design and shelf-life estimation.
What values do I need to enter?
This calculator takes 4 inputs: Rate constant at temperature 1, Temperature 1, Rate constant at temperature 2, Temperature 2. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.