Worked example
At pH = pKa, acid and base each contribute 50% of total buffer moles. At pH one unit above pKa, the base/acid ratio is 10; one unit below, it is 0.1.
Buffer preparation
Buffer Calculator — pH, Concentration, Volume, and Preparation Recipe
Choose a cataloged buffer and plan a Henderson–Hasselbalch reagent split using solids, stocks, or a titration estimate.
Calculations run locally in your browser. Values are only placed in a URL when you choose “Copy Shareable Link.”
How to use
- Choose a buffer and keep target pH within its useful range.
- Enter total concentration, final volume, temperature, and preparation mode.
- Verify reagent forms and stock strengths, calculate, then review every instruction and note.
Validation and limitations
Stock recipes are blocked when required stock volume exceeds final volume. pKa values use catalog temperature interpolation. Solid molecular weights are intentionally blank where hydrate or reagent form is ambiguous. Table-only systems are available in the pH explorer but excluded here.
Safety
This is a calculation aid, not a validated SOP. Confirm chemical identity, purity, hydration, temperature, ionic strength, compatibility, hazards, and final pH with appropriate lab controls and a calibrated meter.
Save recipes, then run the protocol.
Use RayCrest Lab Calculator on iPhone, iPad, and Apple Watch for saved recipes and timers.