Drybench Calc product page
Drybench Calc.
Percent solutions: w/v, w/w and v/v
Grams or millilitres of solute for a percent solution on an explicit basis, with no density assumed and the make-up-to-volume step stated.
Percent solutions
Use measured inputs and your protocol’s targets. Save the exact setup or export a free preparation sheet.
For volume-based recipes, dissolve or mix and make up to the final volume. Density and chemical form are not guessed. Mass/volume cross-conversions and molarity are unavailable here.
Answer
10 g solute, made up to 200 mL (% w/v).
- Solute mass
- 10g
- Final volume to make up to
- 200mL
Planned calculation; no performed preparation is recorded.
Calculated setup
| Quantity or basis | Value |
|---|---|
| Percent basis | w/v |
| Specified percentage | 5 % w/v |
| Solute mass | 10 g |
| Final volume to make up to | 200 mL |
- Calculated setup only; this is not a performed preparation or measurement.
- Weight per final solution volume: grams solute per 100 mL. Dissolve and make up to the stated final volume; the solvent volume is not inferred from solute mass.
- No density-free conversion between mass and volume bases is performed. Such conversions need the applicable density and conditions; molarity additionally needs the relevant chemical form and molar mass.
Illustrative arithmetic only; no biological target or equipment setting is recommended.
Assumptions and qualifications
Open in the bench sheetThe bench sheet carries these inputs and offers the other calculators.
Worked example
- 5% w/v in 200 mL: 5 g per 100 mL of final solution, so 10 g of solute, dissolved and made up to 200 mL.
- 5% w/w in 200 g: 10 g of solute and 190 g of other material; the other material is a mass, not a solvent volume.
- 5% laboratory v/v in 200 mL: 10 mL of liquid solute, made up to 200 mL. This is not the IUPAC volume fraction, and mixed volumes need not add, so no diluent volume is given.
- No density is assumed (not even 1 g/mL), so a w/w percentage with a final volume, or any percentage to molarity, is refused rather than guessed.
Method
- Percent solutions on an explicit basis (w/v, w/w, laboratory v/v). w/v: g per 100 mL final solution; w/w: g per 100 g solution; laboratory v/v: mL per 100 mL final prepared solution, not the IUPAC constituent-volume fraction (IUPAC Gold Book V06643, read 10 October 2026).Checked against exact rational arithmetic (Python 3.13.16 fractions) on 8 cases, three of them refusals, to nine significant figures; refusals exact (10 October 2026).
Limits
- For research and education only, and not medical advice: the stock, dilution and buffer calculations here are not for dosing or clinical preparation.
- Percent solutions need an explicit basis (w/v, w/w or laboratory v/v); no density is assumed, so no basis converts to another or to molarity.