pH Calculator
pH from hydrogen ion concentration, or the reverse.
Enter your values
ⓘ Live results
Results
- pH
- 4
- pOH
- 10
- Classification
- Acidic
Quick answer
pH = -log10[H+].
pH = -log10[H+]
How to use the pH Calculator
- 1Enter the hydrogen ion concentration [H+] in mol/L.
- 2The calculator applies the negative log10 to find pH.
- 3Read the pOH and whether the solution is acidic, neutral or basic.
Worked example
Using the values the calculator loads with:
Inputs
- Hydrogen ion concentration [H+]0.0001 mol/L
Results
- pH4
- pOH10
- ClassificationAcidic
Frequently asked questions
What is a neutral pH?
Pure water at 25°C has a pH of 7, meaning [H+] = 1e-7 mol/L.
How does pOH relate to pH?
At 25°C, pH + pOH always equals 14.
About this calculator
- Built and reviewed by James Whitfield · How we build and test calculators
- Report an error
Results are estimates for general information. For medical, legal, structural or financial decisions, confirm with a qualified professional.