pH Calculator — Acid, Base, Neutral pH Online
Calculate pH from H⁺ concentration or pOH. Visual pH scale indicator with acidic/neutral/basic labels.
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Frequently Asked Questions
What is pH?
pH measures the acidity or alkalinity of a solution on a scale from 0 to 14. Below 7 is acidic, 7 is neutral, and above 7 is basic (alkaline).
How is pH calculated from H⁺ concentration?
pH = -log₁₀[H⁺]. For example, [H⁺] = 0.001 mol/L gives pH = -log(0.001) = 3 (acidic).
What is pOH?
pOH is the measure of hydroxide ion concentration. pH + pOH = 14 at 25°C, so they are directly related.
What are common pH values?
Battery acid: ~1, Lemon juice: ~2, Vinegar: ~3, Coffee: ~5, Pure water: 7, Baking soda: ~9, Bleach: ~13.