Overview
What Is a pH Calculator?
This tool calculates pH from hydrogen ion concentration using the formula pH = -log[H+].
Calculate pH from hydrogen ion concentration.
This tool calculates pH from hydrogen ion concentration using the formula pH = -log[H+].
Useful for chemistry coursework involving acids, bases, and solution chemistry.
Input the [H+] concentration in mol/L.
The result updates automatically.
pH = -log₁₀[H+], where [H+] is the hydrogen ion concentration in mol/L.
pH values below 7 are considered acidic.
pH values above 7 are considered basic (alkaline).
pH 7 is neutral, the pH of pure water at 25°C.
Because hydrogen ion concentrations span an enormous range, a logarithmic scale makes the values more manageable and comparable.
This calculator computes pH from concentration - the reverse would use [H+] = 10^(-pH).
The pH scale typically ranges from 0 (highly acidic) to 14 (highly basic), though values outside this range are theoretically possible.
Yes, pH measurements can shift slightly with temperature, though 25°C is the standard reference condition.
No, calculations happen entirely in your browser.
Yes, completely free with no sign-up required.