pH Calculator

Calculate pH, pOH & Ion Concentrations

Calculate pH from ion concentrations or vice versa. Get pOH, H⁺ and OH⁻ concentrations, and acid-base classification.

Calculate pH

Enter pH value (typically 0-14)

Key Formulas

pH = -log[H⁺]

pOH = -log[OH⁻]

pH + pOH = 14

[H⁺] × [OH⁻] = 10⁻¹⁴

Important Note

This calculator is for educational purposes. For precise measurements, use calibrated pH meters and proper laboratory techniques.

About pH

pH is a measure of the acidity or alkalinity of a solution. It is defined as the negative logarithm of the hydrogen ion concentration.

The pH scale ranges from 0 to 14, with 7 being neutral. Values below 7 are acidic, and values above 7 are alkaline (basic).

pH Scale:

  • 0-3: Strongly Acidic
  • 3-7: Weakly Acidic
  • 7: Neutral
  • 7-11: Weakly Alkaline
  • 11-14: Strongly Alkaline

Applications

pH measurement is crucial in many fields:

  • Water quality testing and treatment
  • Agriculture and soil management
  • Food and beverage production
  • Swimming pool maintenance
  • Medical and biological research
  • Chemical manufacturing
  • Aquarium and fishkeeping

pH Scale Reference

pHClassificationExamples
0-2Strongly AcidicBattery acid, Stomach acid
3-6Weakly AcidicLemon juice, Vinegar
7NeutralPure water
8-10Weakly AlkalineBaking soda, Seawater
11-14Strongly AlkalineBleach, Drain cleaner