Understanding pH and How It Is Calculated
pH is a measure of how acidic or basic a solution is. The scale runs from 0 to 14, with 7 being neutral. Values below 7 are acidic; above 7 are basic (alkaline). pH is a logarithmic scale — a solution with pH 4 is ten times more acidic than pH 5 and 100 times more acidic than pH 6.
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Formula
pH Calculator
Calculate pH from hydrogen ion concentration [H⁺] or from pOH.
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Worked Example
Given:
Related Calculators
FAQs
What does a change of 1 pH unit mean?
Because pH is logarithmic, a change of 1 unit represents a 10-fold change in hydrogen ion concentration. Stomach acid at pH 1.5 is about 100,000 times more acidic than pure water at pH 7.
What is the relationship between pH and pOH?
At 25°C, pH + pOH = 14. pOH measures hydroxide ion concentration. Both describe the same acid-base balance — if pH is 3, pOH is 11.
Why is pH important in everyday life?
pH affects swimming pool safety, soil quality, food preservation, and human health. Blood pH must stay between 7.35–7.45 for normal function. Rainwater naturally has pH ~5.6 due to dissolved CO₂.