pKa and Ka Converter
Convert Ka and pKa and calculate conjugate-base Kb and pKb using an explicitly entered water ion product.
YOUR CALCULATION
Result
—
Calculation steps
Work through one step at a time or reveal the complete calculation. The steps use your current inputs.
How to calculate
Read a positive Ka or convert pKa using a power of ten. Calculate pKa as minus the base-ten logarithm. Divide the entered water ion product by Ka for Kb. Calculate the conjugate-base pKb from Kb.
pKa=−log10(Ka); Kb=Kw/Ka; pKb=−log10(Kb)
Worked example
With Ka=0.00001 and Kw=1e−14, pKa=5, Kb=1e−9 and pKb=9.
Assumptions and input details
The constants must use compatible activities or the same stated concentration approximation and temperature. Kw is an input rather than an automatic temperature correction. This converter does not solve a mixture or infer pH.
Using this calculator
Can I enter my own problem?
Yes. Replace the example values with your own inputs. The result, calculation steps, tables and applicable diagrams update from those inputs. Blank or invalid values clear the result; example values are never silently substituted for missing inputs.
Are the results exact?
Results use floating-point arithmetic and displayed rounding. Read the formula, assumptions and any stated data precision before interpreting the result.
Is my input uploaded?
The calculation runs in your browser. No account, file upload or external AI service is required. Inputs are not saved between page reloads.
Convert pH and ion concentrations or model a single strong or weak monoprotic acid/base. Include water autoionization instead of ignoring dilute-solution effects.
Calculate a real logarithm in any valid base, or raise that base to an exponent. Compare natural, binary and decimal logarithms and inspect the inverse relationship.
Compare a measurement with a reference or calculate symmetric percentage difference between two values.
Reserved advertising space.