pOH Calculator Formula
Understand the math behind the poh calculator. Each variable explained with a worked example.
Formulas Used
pOH
poh_value = -log10(oh_conc)pH
ph_value = 14 - (-log10(oh_conc))Variables
| Variable | Description | Default |
|---|---|---|
oh_conc | Hydroxide Ion Concentration [OH-](M) | 0.01 |
How It Works
How to Calculate pOH
Formula
pOH = -log10([OH-])
And: pH + pOH = 14 (at 25 C)
Worked Example
[OH-] = 0.01 M.
oh_conc = 0.01
- 01pOH = -log10(0.01)
- 02pOH = 2
- 03pH = 14 - 2 = 12
Frequently Asked Questions
What is pOH?
pOH is the negative log of the hydroxide ion concentration. Like pH, lower pOH means more basic.
Why does pH + pOH = 14?
At 25 C, the ion product of water Kw = [H+][OH-] = 10^-14, so -log(Kw) = 14 = pH + pOH.
Is pOH commonly used?
Less than pH, but useful for base calculations and understanding the relationship between acids and bases.
Learn More
Guide
pH and pOH Guide
Understand pH, pOH, and the pH scale. Learn how to calculate pH from hydrogen ion concentration, the relationship between pH and pOH, buffers, and real-world applications.
Ready to run the numbers?
Open pOH Calculator