pH Calculator
Calculate pH, pOH and OH⁻ concentration from H⁺ (hydrogen ion) concentration in mol/L. Find out if a solution is acidic, basic or neutral.
How to use this tool
- Enter h⁺ concentration [h⁺] in the fields above.
- Results update instantly as you type — or click Calculate.
- Read your ph and the full breakdown beneath it.
pH is defined as pH = −log₁₀[H⁺]. A solution with [H⁺] = 10⁻⁷ mol/L is neutral (pH 7). Below 7 is acidic; above 7 is basic. pOH = 14 − pH at 25 °C.
Frequently asked questions
- What everyday substances have known pH values?
- Lemon juice ~2, coffee ~5, pure water 7, baking soda ~9, bleach ~12.
- Does pH change with temperature?
- Yes. Pure water at 25 °C has pH 7, but at 100 °C it has pH ~6.1 — still neutral because both H⁺ and OH⁻ concentrations rise equally.