pH / pOH / Buffer
pH ↔ pOH ↔ [H⁺] ↔ [OH⁻]; Henderson–Hasselbalch buffer
About this tool
pH / pOH / hydronium / hydroxide converter at 25 °C, plus a Henderson-Hasselbalch buffer calculator.
pH section
Edit any of pH, pOH, [H⁺], [OH⁻]; the others update via K_w = 10⁻¹⁴ and pH + pOH = 14.
Buffer
pH = pK_a + log₁₀([A⁻]/[HA]). The buffer is effective within pK_a ± 1; the calculator flags out-of-range setups.