pH Calculator

H⁺ concentration, pOH, and classification from a pH value.

Quick answer: Free online pH Calculator. Determine Hydrogen ion concentration and pOH values from simple pH numbers for chemistry tasks.

ClassificationNeutral
H⁺ concentration0 mol/L
OH⁻ concentration0 mol/L
pOH7
Example at this pHPure water

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Enter a pH value to instantly see the hydrogen ion concentration, hydroxide concentration, pOH, acid/base classification, and a real-world example at that pH level.

How it works

  1. Enter the numerical pH value (0 to 14).
  2. The engine automatically processes the logarithmic formulas for concentration.
  3. View the specific Hydrogen and Hydroxide ion concentration levels alongside acidity classes.

Frequently asked questions

What is the pH scale?

A logarithmic scale from 0 (most acidic) to 14 (most basic), measuring hydrogen ion concentration. Each step is a 10× change.

Why is the scale logarithmic?

Hydrogen ion concentrations span 14 orders of magnitude — from 10 mol/L at pH 0 to 10⁻¹⁴ mol/L at pH 14. Logarithms compress this range.

What is the pH of blood?

Normal blood pH is tightly regulated at 7.35–7.45. Values outside 6.8–7.8 are life-threatening.

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