CalcHub Pro

pH Calculator

Calculate pH, pOH, and ion concentrations for acids and bases. Enter any known value to find the others.

pH Calculations

Choose your input type and calculate the others

H⁺ Concentration (M)

OR

OH⁻ Concentration (M)

pH Theory & Formulas

Key Formulas:

pH = -log[H⁺]

pOH = -log[OH⁻]

pH + pOH = 14

[H⁺][OH⁻] = 1×10⁻¹⁴

pH Scale:

• 0-6.9: Acidic (more H⁺ ions)
• 7.0: Neutral (pure water)
• 7.1-14: Basic/Alkaline (more OH⁻ ions)

Common Examples:

• Lemon juice: pH ≈ 2
• Coffee: pH ≈ 5
• Pure water: pH = 7
• Baking soda: pH ≈ 9
• Household ammonia: pH ≈ 11

Important Notes:

• pH scale is logarithmic
• Each unit = 10× change in acidity
• Temperature affects pH
• Use scientific notation for concentrations