Frequently Asked Questions
Everything you need to know about the pH & pOH Calculator.
How does the pH & pOH calculator work?
Enter pH, pOH, [H+], or [OH-]; it calculates the other three using pH + pOH = 14 and [H+][OH-] = Kw.
Is it free?
Completely free, no sign-up, downloads, or limits.
Can I calculate pH from a strong acid's concentration?
Yes, using the strong acid/base concentration mode, which assumes full dissociation.
Does it work at temperatures other than 25°C?
Yes, you can adjust Kw for other temperatures instead of assuming the standard 10⁻¹⁴ value.
Does it handle scientific notation?
Yes, [H+] and [OH-] inputs and outputs support scientific notation.
What does the visual scale show?
Where your solution falls on the 0-14 acid-base spectrum, labelled acidic, neutral, or basic.
Does it work for weak acids or bases?
Not directly — weak acid/base pH depends on Ka/Kb equilibrium, which this tool doesn't model; it's for pH/pOH/ion conversions and strong acid/base concentrations.
What if I enter a negative concentration?
It's flagged as invalid, since concentrations can't be negative.
Is my data stored?
No; everything runs in your browser and isn't stored or sent anywhere.
Does it work on mobile?
Yes, fully responsive on all screen sizes.