Free online tool for real-time bidirectional conversion between pH and hydrogen ion concentration
This free online tool provides instant conversion between pH and hydrogen ion concentration [H⁺]. The calculator works in both directions - enter either value to get the corresponding conversion in real time.
pH is a logarithmic measure of the acidity or basicity of an aqueous solution. It is defined as the negative logarithm (base 10) of the hydrogen ion concentration:
Understanding the relationship between pH and [H⁺] is fundamental in chemistry, biology, environmental science, and many industrial processes. This calculator helps students, educators, researchers, and professionals make accurate conversions quickly.
The tool is completely free to use with no registration required. All calculations happen in your browser for maximum privacy and speed.
pH is a scale used to specify the acidity or basicity of an aqueous solution. It ranges from 0 to 14, with 7 being neutral. Solutions with a pH less than 7 are acidic, while solutions with a pH greater than 7 are basic.
[H⁺] represents the concentration of hydrogen ions in a solution, measured in moles per liter (mol/L). It is the key factor determining a solution's acidity. Pure water has a [H⁺] of 1×10⁻⁷ mol/L.
To convert pH to hydrogen ion concentration, use the formula: [H⁺] = 10-pH. For example, a pH of 3 corresponds to [H⁺] = 10⁻³ = 0.001 mol/L.
To convert hydrogen ion concentration to pH, use the formula: pH = -log10([H⁺]). For example, [H⁺] = 0.0001 mol/L corresponds to pH = -log(0.0001) = 4.
The logarithmic scale allows a wide range of hydrogen ion concentrations to be expressed with small numbers. Each whole pH value below 7 is ten times more acidic than the next higher value, and each whole pH value above 7 is ten times more basic.