Ka to pKa calculator

Free online Ka to pKa Calculator – Easily convert the ka value to pKa, Enter the Ka values then click the calculate button.

pKa value:
pKa to Ka calculatorAll Chemistry Calculator

Ka to pKa formula

The formula to convert from Ka to pKa is:

pKa = -log(Ka)


  • pKa = pKa is the negative logarithm of Ka
  • Ka = Ka (acid dissociation constant) measures the strength of an acid in solution

How to convert ka to Pka

If you know the value of Ka for a particular acid, you can calculate its pKa using the above formula.

Example – Acetic acid(CH3COOH) with a given Ka value of 1.8*10^(-5). calculate the pKa for acetic acid

Given values, Ka = 1.8 * 10^(-5)

Use this formula, pKa = -log(Ka)

pKa = -log(1.8 * 10^(-5)) = 4.7447

so, the pka of acetic acid is approximately 4.744