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pH Calculator

Calculate pH, pOH, and hydrogen ion concentrations for acids and bases.

pH Calculator

Enter in decimal or scientific notation

pH Scale Guide

pH Scale (0-14)
Acidic (0-7)Neutral (7)Basic (7-14)
Acidic Solutions (pH < 7)

Higher [H+] concentration. Examples: lemon juice (pH 2), vinegar (pH 3)

Neutral Solutions (pH = 7)

Equal [H+] and [OH-]. Example: pure water at 25°C

Basic Solutions (pH > 7)

Higher [OH-] concentration. Examples: ammonia (pH 11), bleach (pH 13)

💡 Key Formulas

  • • pH = -log[H+]
  • • pOH = -log[OH-]
  • • pH + pOH = 14
  • • Kw = [H+][OH-] = 1 × 10⁻¹⁴