pH Calculator
Convert between hydrogen ion concentration and pH in either direction and see the full acid base picture. pH is defined as the negative base ten logarithm of the hydrogen ion concentration in moles per liter, so a concentration of 1e-7 gives a neutral pH of 7 at room temperature. Enter a concentration to get the pH, or enter a pH to recover the concentration, and this tool also reports pOH and the hydroxide ion concentration using the relationship that pH plus pOH equals 14. It then classifies the solution as acidic, neutral or basic. This is a staple for chemistry students, lab work and water testing. Everything is computed locally in your browser, so your numbers stay private and results appear the moment you type.
How to use pH Calculator
- Choose whether to enter a hydrogen ion concentration or a pH value.
- Type the value you know.
- Read the pH, pOH, hydroxide concentration, and acid or base classification.
Frequently asked questions
How is pH calculated from concentration?
pH equals the negative base 10 logarithm of the hydrogen ion concentration in moles per liter, so pH is minus log of [H+].
How are pOH and hydroxide concentration found?
pOH equals 14 minus pH at 25 degrees Celsius, and hydroxide concentration is 10 to the power of negative pOH.
How does it classify acid versus base?
A pH below 7 is acidic, exactly 7 is neutral, and above 7 is basic, based on the standard scale at 25 degrees Celsius.
What is pH Calculator?
Convert between hydrogen ion concentration and pH in either direction and see the full acid base picture. pH is defined as the negative base ten logarithm of the hydrogen ion concentration in moles per liter, so a concentration of 1e-7 gives a neutral pH of 7 at room temperature.
Is pH Calculator free to use?
Yes. pH Calculator is completely free, with no sign-up and no usage limits.
Does pH Calculator work in a web browser?
Yes. pH Calculator runs in any modern web browser. There is nothing to download or install.
Is my data private with pH Calculator?
Yes. pH Calculator runs entirely on your device in your browser, so nothing you enter is uploaded to a server.
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