pKa Calculator
Calculate pKa from a given Ka value.
Amortization schedule
| # | Payment | Principal | Interest | Balance |
|---|---|---|---|---|
Showing first 12 of months.
Growth over time
| Year | Invested | Value |
|---|---|---|
Introduction
pKa Calculator — Calculate pKa from a given Ka value. Enter Ka to get an instant, accurate result.
Formula
pKa = −log₁₀(Ka), the negative base-10 logarithm of the acid dissociation constant.
Step-by-step
- Enter the Ka.
- Click Calculate to see your result instantly.
Real-world example
Example: With Ka = 0.0000174, the pKa Calculator gives P Ka: 4.7595.
Frequently Asked Questions
How does pKa relate to acid strength?
A lower pKa means a stronger acid (larger Ka); a higher pKa means a weaker acid.
How is pKa used in the Henderson-Hasselbalch equation?
It's the reference point: pH = pKa + log₁₀([A⁻]/[HA]), so when acid and conjugate base concentrations are equal, solution pH equals pKa.
What inputs does the pKa Calculator need?
You'll need to provide: Ka. All fields use sensible defaults, so you can see a working example immediately and then adjust the values to match your own numbers.
How accurate is the pKa Calculator?
The pKa Calculator applies the formula exactly as calculated — pKa = −log₁₀(Ka), the negative base-10 logarithm of the acid dissociation constant. — so results are precise for the inputs you provide. Accuracy depends on entering correct, realistic input values.
Is the pKa Calculator free to use?
Yes, the pKa Calculator is completely free, requires no signup, and runs instantly in your browser.
About the pKa Calculator
The pKa Calculator uses a real, verifiable formula — pKa = −log₁₀(Ka), the negative base-10 logarithm of the acid dissociation constant. — so results are accurate every time, not an approximation.