Free Ion Product of Water Calculator
Calculate the ion product of water (Kw) from hydrogen ion and hydroxide ion concentrations, or find one concentration given the other and Kw.
M
M
Kw
0.0000
pKw14.00
Kw vs Hydrogen Ion Concentration [H⁺]
Ion Product of Water
Formula
Kw = [H⁺] × [OH⁻]
At 25°C, Kw = 1.0 × 10⁻¹⁴, meaning:
Example Calculation
Pure water at 25°C has [H⁺] = 1.0 × 10⁻⁷ M and [OH⁻] = 1.0 × 10⁻⁷ M.
- 01Kw = [H⁺] × [OH⁻]
- 02Kw = (1.0 × 10⁻⁷)(1.0 × 10⁻⁷)
- 03Kw = 1.0 × 10⁻¹⁴
- 04pKw = 14.0
Frequently Asked Questions
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