ChemBench

pH Calculator

How acidic or basic is this solution?

A logarithmic scale for acidity

pH = −log₁₀[H⁺] compresses a huge range of hydrogen ion concentrations (spanning many powers of 10) into a simple 0-14 scale — each single pH unit represents a 10× change in acidity.

Why it's everywhere

pH governs which chemical reactions can occur in blood, soil, swimming pools, and industrial processes — human blood, for instance, is tightly regulated between pH 7.35 and 7.45, and even small deviations are medically dangerous.

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ChemBench

pH Calculator

How acidic or basic is this solution?

[H⁺] concentration (mol/L)

pOH: 10

What you entered

[H⁺] concentration (mol/L): 0.0001

1
pH = −log₁₀[H⁺]
−log₁₀(1.00e-4)= 4
2
pOH = 14 − pH
14 − 4= 10

Result

pH: 4

A pH of 4 is acidic.

A logarithmic scale for acidity

pH = −log₁₀[H⁺] compresses a huge range of hydrogen ion concentrations (spanning many powers of 10) into a simple 0-14 scale — each single pH unit represents a 10× change in acidity.