pH Calculator
Fill in the values and the answer updates as you type.
How the pH Calculator works
pH = −log₁₀[H⁺] and pH + pOH = 14 at 25 °C. A concentration of 0.001 mol/L H⁺ gives pH 3. Each pH step is a tenfold change in acidity. Results assume a dilute water solution at 25 °C.
Inputs and results
The pH Calculator takes 2 inputs and gives 5 results.
What you enter
- You know — starts at Enter H+ concentration (mol/L). Choose from: Enter H+ concentration (mol/L), Enter pH and Enter OH- concentration (mol/L).
- Value — starts at 0.001.
What you get
- pH
- pOH
- H+ concentration (mol/L)
- OH- concentration (mol/L)
- Nature of the solution
pH Calculator FAQ
How do I use the pH Calculator?
Enter you know and value in the fields, then read ph, poh, h+ concentration (mol/l) and oh- concentration (mol/l) in the result panel. The answer updates as you type, and you can press Calculate or Enter to refresh it. Use “Copy link” to share your exact numbers with someone else.
What does the pH Calculator calculate?
Convert between pH, pOH, H+ and OH- concentration. It returns ph, poh, h+ concentration (mol/l) and oh- concentration (mol/l) from the 2 values you provide.
What values does the pH Calculator start with?
It opens with you know Enter H+ concentration (mol/L) and value 0.001 so you can see a working result straight away. Replace them with your own numbers, or press Reset to return to these starting values.
Is the pH Calculator free and private?
Yes. It is free, needs no account, and runs in your browser, so nothing you type is sent to or stored on our servers. See the Privacy Policy for details.
Can I rely on the pH Calculator for important decisions?
Treat the result as a well-rounded estimate. Real situations often have details a general calculator cannot know, so confirm important decisions with a qualified professional. See the Disclaimer for more.