pH Calculator
pH and pOH from the hydrogen ion concentration of a solution.
Results
pH
4.0000
pH
10.0000
Concentration
1e-10
mol/L
What this tool does
The pH scale is logarithmic, so each whole step means a tenfold change in acidity: pH 4 is ten times more acidic than pH 5 and a hundred times more than pH 6. The pOH relationship assumes water at 25 °C.
Formula
pH = −log₁₀[H⁺] , pOH = 14 − pH
Variables
| Symbol | Meaning | Unit |
|---|---|---|
c | H⁺ concentration | mol/L |
PH | pH | — |
POH | pH | — |
OH | Concentration | mol/L |
Worked example
- H⁺ concentration0.0001 mol/L
- pH4.0000
- pH10.0000
- Concentration1e-10 mol/L
Limitations
- The formula assumes ideal conditions: no friction losses, no air resistance and no efficiency losses unless you enter them.
- The result is an estimate based only on the values you type. Real situations often include factors this calculator does not know about.