How It Works
This calculator works in 4 steps.
Enter the stock concentration
Type C₁ for the single source stock.
List the targets
Type every concentration needed, in any order.
Enter the volume per tube
Type the final volume for each tube, such as 1 mL.
Read the independent volumes
The calculator returns stock and diluent volume for each tube and flags transfers under the minimum.
The Formula
The formula applies C₁V₁ = C₂V₂ to each target with the same stock.
V₁ᵢ = C₂ᵢ × V₂ / C₁V_dᵢ = V₂ − V₁ᵢV_stock = Σ V₁ᵢ- C₁:
- Common stock concentration
- C₂ᵢ:
- Target concentration of tube i
- V₂:
- Final volume per tube
- V₁ᵢ:
- Stock volume for tube i
From a 1,000 µg/mL stock, 1 mL of 50 µg/mL takes 50 µL stock and 950 µL diluent. 1 mL of 5 µg/mL takes 5 µL stock.
Conversion Table
The conversion table lists stock and diluent volumes for 7 independent targets from a 1,000 µg/mL stock at 1 mL each.
| Target | DF | Stock volume | Diluent volume |
|---|---|---|---|
| 500 µg/mL | 2 | 500 µL | 500 µL |
| 250 µg/mL | 4 | 250 µL | 750 µL |
| 100 µg/mL | 10 | 100 µL | 900 µL |
| 50 µg/mL | 20 | 50 µL | 950 µL |
| 10 µg/mL | 100 | 10 µL | 990 µL |
| 5 µg/mL | 200 | 5 µL | 995 µL |
| 1 µg/mL | 1,000 | 1 µL | 999 µL |
The total stock for all 7 tubes is 916 µL.
What Is the Parallel Dilution Calculator?
The Parallel Dilution Calculator is a tool that prepares each concentration independently from the same stock, so no tube depends on another tube. Every concentration uses its own C₁V₁ = C₂V₂ calculation from the original stock.
Parallel dilution (independent dilution) prevents error carry-over. A pipetting mistake in one tube affects only that tube. The trade-off is that low concentrations need small stock volumes, so the calculator flags any transfer below the user's minimum pipette volume.
Common Uses
There are 5 main uses of this calculator.
Calibration standards
Analysts prepare each standard from a certified stock to avoid compounded error.
Regulated methods
GLP and GMP labs prepare standards independently, when the method requires it.
Uneven concentration sets
Users prepare non-geometric sets such as 1, 2, 5, 20, and 75 µg/mL.
Drug screening plates
Researchers prepare dose levels independently for parallel testing.
Error isolation
QC teams trace an outlier to 1 tube without retesting the whole series.