pH Scale Simulator
Test everyday liquids and see pH, hydrogen and hydroxide ions, and acid or base.
Choose a liquid, or set the pH yourself, and dip the pH meter or the pH paper into it. Add water to dilute it and watch the H₃O⁺ and OH⁻ ions change. Every step on the pH scale is a factor of ten in acidity.
About the pH Scale Simulator
Free pH scale simulation. Pick lemon juice, coffee, water, soap or bleach, or slide to any pH, and see H+ and OH- concentrations, indicator colour and whether it is acidic or basic. Built for chemistry, the ph scale simulator runs instantly in your browser: change a setting or drag an object and the result updates at once, so you learn by trying things out rather than only reading about them.
Test everyday liquids and see pH, hydrogen and hydroxide ions, and acid or base. Use it to explore chemistry ideas at your own pace, then check what you found against the key ideas further down this page.
How to use the pH Scale Simulator
- Use the controls to change Liquid, Or set the pH yourself, Volume of liquid, Universal indicator colour, Show ions, and more. The simulation reacts instantly.
- Pick an option such as Water, Battery acid, Stomach acid, Lemon juice to switch modes or load an example.
- Press "+ 50 mL water", "Undo dilution", "Reset" to start, reset or change what is happening.
- Where you see a glowing handle, object, weight or atom, drag it with your mouse or finger. Everything responds in real time.
- Watch the readouts and graphs update as you experiment, and compare what you see with the key ideas below.
Things to try
- Compare lemon juice and bleach.
- Slide the pH to 7 and see the ions balance.
- Find a liquid with pH between 8 and 9.
- Note how [H⁺] changes per pH step.
Key ideas you can learn
- pH = −log₁₀[H⁺]. Each step down the scale is ten times more acidic.
- At 25 °C, pH + pOH = 14 and [H⁺] × [OH⁻] = 10⁻¹⁴.
- pH 7 is neutral, below 7 is acidic and above 7 is basic.
Where this is used in the real world
pH matters in swimming pools, soil for farming, blood chemistry, food safety and water treatment. Everyday products are labelled by pH.
Who is this simulation for?
Chemistry students from middle school to university, teachers who need a virtual demonstration, and anyone without access to a lab. It is safe, free and repeatable as many times as you like.
For teachers: project it on the board, let students predict what will happen, then run it together. For students: change one thing at a time and write down what changes.
Frequently asked questions
What does pH actually measure?
The concentration of hydrogen ions in a solution, on a logarithmic scale. Lower pH means more hydrogen ions and a stronger acid.
Why is a pH change of 1 such a big deal?
Because the scale is logarithmic. pH 3 has ten times more hydrogen ions than pH 4 and a hundred times more than pH 5.
Is the pH Scale Simulator free to use?
Yes. It is completely free, with no signup, no download and no ads inside the simulation. It runs in your web browser.
Does the pH Scale Simulator work on a phone or tablet?
Yes. It uses touch as well as the mouse, so you can drag objects with your finger. A larger screen makes the controls easier to see.