Pre-exponential Factor Calculator

Calculate the Arrhenius pre-exponential factor (A)

About Pre-exponential Factor

The pre-exponential factor (A), also called the frequency factor, represents the frequency of molecular collisions with correct orientation for reaction.

Typical values:

  • Unimolecular reactions: 10¹² - 10¹⁴ s⁻¹
  • Bimolecular reactions: 10¹⁰ - 10¹¹ M⁻¹s⁻¹

A includes both the collision frequency (Z) and steric factor (p): A = p × Z

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Editorial Note

MyCalcBuddy Editorial Team

This page is maintained as an educational calculator reference.

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Formula Source: Chemistry: The Central Science

by Brown, LeMay, Bursten

🔄Last reviewed: May 2026
✓Formula checks are based on standard references and internal QA review.