Negative Log Calculator

Compute −log₁₀(x), as used for pH and pKa.

−log₁₀(x) 4

Formula: result = −log₁₀(x)

Step-by-step with your numbers:

1. Values used:

2. x = 0.0001

4. −log₁₀(x) = 4

Did we solve your problem today?

The negative logarithm turns very small numbers into convenient positive values — the idea behind pH.

The math behind it

result = −log₁₀(x). Smaller x gives a larger result; each factor of 10 changes it by 1.

−log₁₀(0.0001) = 4 (a hydrogen-ion concentration of 10⁻⁴ means pH 4).

Why use it for pH?

Concentrations span many orders of magnitude; the negative log compresses them into a 0–14 scale.