Calculate the stock reagent and diluent volumes needed to prepare a working buffer. Enter stock concentration, desired final concentration, final batch volume, and an optional excess allowance. The calculator applies C₁V₁ = C₂V₂ and reports the practical preparation volumes plus the amount of active solute delivered.
The main result is the stock-solution volume required for the adjusted preparation volume.
Add diluent to reach the final volume rather than assuming liquid volumes are perfectly additive when the protocol requires volumetric preparation.
To make 500 mL of 50 mM buffer from a 1000 mM stock with 5% excess, prepare 525 mL total. Use 26.25 mL stock and approximately 498.75 mL diluent.
The preparation is impossible by dilution alone; use a stronger stock or add solute by another validated method.
It is a planning estimate. For precise work, add diluent until the solution reaches the final calibrated volume.
No. Convert both concentrations to the same unit before calculating.
It compensates for dead volume and transfer loss when a minimum usable batch volume is required.
No. If pH adjustment materially changes volume, prepare below final volume and bring to volume afterward.
| Variable | Meaning | Unit |
|---|---|---|
| C₁ | Stock concentration | mM |
| C₂ | Target concentration | mM |
| V₁ | Required stock volume | mL |
| V₂ | Adjusted final volume | mL |