pH Calculator
Calculate pH and pOH from hydrogen ion concentration.
Quick answer: enter your details below and click Calculate pH — your result appears instantly, right here in your browser. Nothing you enter is uploaded or stored.
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How to use
- Enter hydrogen ion concentration in mol/L.
- Click Calculate pH.
- Read pH, pOH, and the classification.
About this tool
Enter the hydrogen ion concentration in mol/L. The tool takes the negative base-10 logarithm for pH, finds pOH from 14 minus pH, and labels the solution acidic, neutral, or basic. It assumes water at about 25 C, where pH plus pOH equals 14.
Frequently asked questions
Why is pH logarithmic?
Concentrations span many orders of magnitude, so a log scale keeps them readable.
Does temperature matter?
Yes. pH plus pOH equals 14 only near 25 C in water.