pH Scale Visualizer
Drag the pH slider or tap a substance — and feel why each step on the pH scale is 10× the acidity.
Or tap an everyday substance
Neutral 💧
Each step on the pH scale = 10× the change in acidity (pH = −log₁₀[H⁺]).
Pure water
Pure water is neutral at exactly pH 7, where [H⁺] and [OH⁻] are equal at 1×10⁻⁷ mol/L. It's the balance point of the entire scale.
pH measures how acidic or basic something is, on a scale from 0 to 14, with pure water sitting neutral at 7. The secret is that pH is logarithmic: pH = −log₁₀[H⁺], the hydrogen-ion concentration. That tiny word "log" is the whole story — each step down the scale means 10× more acid. So lemon juice at pH 2 isn't a little more acidic than water — it's 100,000× more. Slide along the scale, watch the color shift from red to green to violet, and see the [H⁺] and [OH⁻] concentrations swing across fourteen orders of magnitude.
Sources & formulas
- pH = −log₁₀[H⁺]
- [OH⁻] = Kw / [H⁺], Kw = 1×10⁻¹⁴ (mol/L)² @ 25 °C
- en.wikipedia.org/wiki/PH
- usgs.gov — pH and water
Embed this tool
Embed this tool on your own site for free. An attribution link is included.