pH Calculator
Calculate pH, pOH, and ion concentrations
0
7
14
Common Substances pH Reference
Click any substance to calculate its pH values
Battery Acid
pH 0
Stomach Acid
pH 1
Lemon Juice
pH 2.4
Vinegar
pH 2.9
Tomato Juice
pH 4
Coffee
pH 5.5
Milk
pH 6.5
Pure Water
pH 7
Blood
pH 7.4
Sea Water
pH 8.3
Baking Soda
pH 9
Milk of Magnesia
pH 10
Ammonia
pH 11
Bleach
pH 12.5
Drain Cleaner
pH 14
pH Formulas
pH = -log₁₀[H⁺]
pOH = -log₁₀[OH⁻]
pH + pOH = 14
(at 25°C)
[H⁺] × [OH⁻] = 10⁻¹⁴
(Kw at 25°C)