pH to [H⁺]

Hydronium molarity from pH at 25 °C (Kw = 10⁻¹⁴).

Inputs

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Results

[H⁺] (mol/L)

0.00001778

pOH9.25

[OH⁻]0

How to Use This Calculator

Enter the pH value of your solution (range 0-14).
Review the hydrogen ion concentration [H+] in mol/L.
Check pOH (14 - pH) and hydroxide ion concentration [OH-] in mol/L.
pH < 7 is acidic, pH = 7 is neutral, pH > 7 is basic.
Use for chemistry homework, water quality analysis, or buffer preparation.

How the result changes with pH

pH	[H⁺] (mol/L)
-0.2	1.58489319
4.3	0.00005012
9.7	0
14	0

What each input means

pH: The pH value to convert. Acidic solutions are below 7, basic above 7. Neutral water is 7.0 at 25 C.

How this is calculated

Worked example, using the default values

Identify Input Parameters
pH = 4.75 = 1 input(s) provided
Calculate [H⁺]
[H⁺] = pow(10, -ph)
0.00001778279410038923 = 0.00001778279410038923
Calculate pOH
pOH = 14 - ph
9.25 = 9.25
Calculate [OH⁻]
[OH⁻] = pow(10, -poh)
5.623413251903491e-10 = 5.623413251903491e-10

Engine last updated July 26, 2026. Checked against 4 independently-derived tests — how we verify calculators.

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