Buffer solution calculator
pH of a buffer from K_a, [HA], and [A⁻] (Henderson–Hasselbalch).
Calculator
How to use
Buffer pH
$$\text{pH} = \text{p}K_a + \log_{10}\frac{[A^-]}{[HA]}$$
Best when both species are significant and you are not extremely dilute.
Educational use only. Double-check values for labs, homework, and exams.