pH measures how acidic or basic a solution is, based on the concentration of hydrogen ions [H+] in it.
pH measures how acidic or basic a solution is, based on the concentration of hydrogen ions [H+] in it. A pH of 7 is neutral, below 7 is acidic, and above 7 is basic. This calculator converts between pH and [H+] concentration in either direction.
A solution has [H+] = 1×10⁻⁴ mol/L. pH = −log₁₀(1×10⁻⁴) = 4 — an acidic solution.
pH = −log10[H⁺], based on the hydrogen ion concentration in a solution.
It ranges from 0 (highly acidic) to 14 (highly basic), with 7 being neutral, on a logarithmic scale.
Hydrogen ion concentrations span an enormous range, so a log scale keeps the numbers manageable — each pH unit represents a 10x change in acidity.