Estimate rate constants across temperatures with confidence easily. Compare scenarios using units, logs, and graphs. Download tables to share results with your team fast.
Choose single-point or sweep mode, then enter values. Temperature sweep builds a table for exporting.
The calculator uses the Arrhenius relationship: k = A · exp(−Ea / (R · T))
| A | Ea | Temperature | k |
|---|---|---|---|
| 1.20e13 1/s | 75 kJ/mol | 298.15 K | ~7.50e-1 |
| 5.00e10 1/s | 50 kJ/mol | 350 K | ~1.71e3 |
| 2.50e12 1/s | 90 kJ/mol | 450 K | ~9.15e1 |
Values are illustrative; your results depend on inputs and units.
Many reactions require molecules to pass an energy barrier before products form. As temperature rises, a larger fraction of molecules has enough energy to cross that barrier, so the measured rate constant often increases rapidly. This calculator translates that temperature sensitivity into a rate constant you can use in kinetic models, simulations, and lab calculations.
The pre-exponential factor A groups together collision frequency, orientation effects, and other influences that do not appear explicitly in the exponential term. Its units match the units of the rate constant, so a first‑order process typically uses s⁻¹, while bimolecular processes often use concentration‑based units.
Activation energy Ea controls how strongly k responds to temperature. Higher Ea makes the exponential term steeper, meaning small temperature changes can cause large differences in rate. The calculator accepts J/mol, kJ/mol, or eV per molecule and converts internally to J/mol.
The sweep mode builds a table of k(T) values over a range. This is helpful when you need to plan experiments, compare operating setpoints, or generate inputs for numerical solvers. You can export the sweep as CSV for spreadsheets or PDF for reports.
Many datasets are analyzed using the linearized Arrhenius form by plotting ln(k) versus 1/T. Reporting ln(k) and log10(k) also helps compare values that span multiple orders of magnitude. The calculator provides both for quick review.
If the reaction behaves as first order, the half-life is t1/2 = ln(2)/k. This is a convenient way to translate a rate constant into a time scale. When your process is not first order, treat this number as an approximate comparison rather than a strict prediction.
In many gas‑phase or solution reactions, Ea commonly falls between about 10–200 kJ/mol, while A for first‑order steps can range from roughly 108 to 1015 s⁻¹. If your output looks extreme, confirm unit choices, temperature conversion, and the sign of the exponent.
Good kinetic reporting includes the values of A, Ea, the temperature range, and the assumed mechanism. Exported tables from this calculator capture the inputs alongside computed results, helping you document modeling assumptions and reproduce analyses later.
The calculator uses k = A · exp(−Ea/(R·T)) with R in J/mol·K and T in kelvin. Ea is converted to J/mol from your selected unit.
Select K, °C, or °F, then enter temperatures in that unit. The tool converts values to kelvin internally, so the physics remains consistent.
Yes. Choose “eV/molecule” and enter Ea in electronvolts per molecule. The calculator converts to J/mol using the elementary charge and Avogadro’s number.
A units are displayed with k for clarity. The computation uses the numeric A value, so you should select units that match your reaction order and your intended interpretation.
At low T, the term exp(−Ea/(R·T)) can be very small, especially for large Ea. Verify you did not enter Ea in kJ/mol while selecting J/mol.
No. The shown half-life assumes first-order behavior: t1/2 = ln(2)/k. For other reaction orders or complex mechanisms, use it only as a rough comparison.
To keep pages responsive, the sweep is limited to 5000 rows. If you hit the limit, increase the step size or narrow the temperature range.
Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.