pH Calculator

pH from [H⁺] and reverse — with pOH, [OH⁻] and temperature.

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See how it works

Watch a quick simulation of this tool in action — no file needed.

How to use pH Calculator

Follow these steps — everything happens instantly in your browser.

  1. 1

    Step 1. Pick a mode: '[H⁺] → pH' or 'pH → [H⁺]'.

  2. 2

    Step 2. Enter the value (e.g. 1e-7 mol/L for [H⁺], or 7.0 for pH).

  3. 3

    Step 3. Optionally adjust the temperature (default 25 °C) to update Kw.

  4. 4

    Step 4. See pH, pOH, [H⁺], [OH⁻] and the pH scale indicator update instantly.

Why use this tool

Frequently asked questions

Everything you might want to know about ph calculator.