What is the pH Calculator?
Calculate pH and pOH from the hydrogen ion concentration.
Enter hydrogen ion concentration [H⁺] and the pH Calculator returns pH, pOH and solution is. Results update as you type, and nothing you enter leaves your device.
How it is calculated
pH = −log₁₀[H⁺]
pOH = 14 − pH at 25 °C
How to use it
- Enter hydrogen ion concentration [H⁺] in mol/L.
- Read pH in the results panel. It updates as you type.
- Change any value to compare scenarios, or use Share to send the result as a link.
Worked example
Common questions
What formula does the pH Calculator use?
It uses: pH = −log₁₀[H⁺]; pOH = 14 − pH at 25 °C.
What do I need to use the pH Calculator?
You need hydrogen ion concentration [H⁺]. Sensible starting values are filled in so you can see how it works straight away.
Is the pH Calculator free, and is my data stored?
It is free with no sign-up. The calculation runs in your browser, so the values you enter are not sent to or stored on our server.