pOH Calculator
Enter a hydroxide ion concentration to instantly calculate pOH and derive the corresponding pH value.
Hydroxide Ion Concentration
Enter [OH-] in mol/L. Accepts decimals or scientific notation (e.g. 1e-5).
Quick examples
Enter a concentration and click Calculate to see results.
pOH
—
pOH = -log10([OH-])
pH
—
pH = 14 − pOH (at 25 °C)
pH Scale (0–14)
0 (Acidic)
7 (Neutral)
14 (Basic)
Marker shows computed pH position on the scale.
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Summary
Enter a hydroxide ion concentration to instantly calculate pOH and derive the corresponding pH value.
How it works
- Enter the hydroxide ion concentration [OH-] in mol/L (e.g. 0.001 or 1e-5).
- The tool applies pOH = -log₁₀([OH-]) to compute pOH.
- pH is then derived using pH = 14 - pOH (at 25 °C, standard conditions).
- The acidity or basicity of the solution is labeled automatically.
- Copy any result with one click for use in reports or assignments.
Use cases
- Verify pOH and pH calculations for chemistry homework or exams.
- Check acid-base equilibrium values in lab reports.
- Convert between [OH-] concentration and pH quickly.
- Understand whether a solution is acidic, neutral, or basic.
- Teach or learn the relationship between pOH and pH.
- Cross-check titration endpoint pH values.
Frequently Asked Questions
Last updated: 2026-06-18 ·
Reviewed by Nham Vu