Buffer pH Calculator
Our mixtures & solutions calculator computes bufferp hcalculator accurately. Enter measurements for results with formulas and error analysis.
Formula
pH = pKa + log([A-]/[HA])
The Henderson-Hasselbalch equation calculates buffer pH from the pKa of the weak acid and the logarithm of the ratio of conjugate base [A-] to weak acid [HA] concentrations.
Frequently Asked Questions
How do I choose the right buffer for my experiment?
Select a buffer whose pKa is within 1 pH unit of your target pH, because buffers work most effectively in this range. Common buffer systems include acetate (pKa 4.76) for pH 3.8-5.8, phosphate (pKa 7.2) for pH 6.2-8.2, and Tris (pKa 8.1) for pH 7.1-9.1. Consider whether the buffer components might interfere with your experiment, such as phosphate buffers precipitating calcium ions. Also check temperature sensitivity, as Tris buffer pH changes significantly with temperature while phosphate is more stable.
Why does a buffer resist pH changes?
A buffer resists pH changes because it contains both a weak acid (HA) and its conjugate base (A-) in significant amounts. When strong acid is added, the conjugate base neutralizes it: A- + H+ becomes HA. When strong base is added, the weak acid neutralizes it: HA + OH- becomes A- + H2O. This consumes the added acid or base without significantly changing the [A-]/[HA] ratio, keeping the pH relatively stable. The buffer fails when one component is depleted, which is why buffer capacity depends on concentration.
How accurate are the results from Buffer pH Calculator?
All calculations use established mathematical formulas and are performed with high-precision arithmetic. Results are accurate to the precision shown. For critical decisions in finance, medicine, or engineering, always verify results with a qualified professional.
Is my data stored or sent to a server?
No. All calculations run entirely in your browser using JavaScript. No data you enter is ever transmitted to any server or stored anywhere. Your inputs remain completely private.
Can I use Buffer pH Calculator on a mobile device?
Yes. All calculators on NovaCalculator are fully responsive and work on smartphones, tablets, and desktops. The layout adapts automatically to your screen size.
What formula does Buffer pH Calculator use?
The formula used is described in the Formula section on this page. It is based on widely accepted standards in the relevant field. If you need a specific reference or citation, the References section provides links to authoritative sources.