Drybench Calc.
Master mix calculator with overage and dead volume
Per-reaction and total volumes for a shared master mix and per-well additions, with overage and the extra dead volume of your mix vessel.
Per-reaction volumes for a shared master mix and the additions made to each well, scaled by the number of reactions with your overage and the extra dead volume of your mix vessel. Concentration lines take a stock and a final concentration in the same family (molar, mass or fold); one diluent balances the reaction. Nothing is rounded up behind your back.
Worked example: a 20 µL qPCR reaction
Thermo Fisher's TaqMan Fast Advanced Master Mix user guide (MAN0025706 revision B, pp. 12–13, read 10 October 2026): per 20 µL reaction, 10 µL of 2X master mix, 1 µL of 20X assay and 7 µL of water in the shared mix, then 2 µL of template in each well; its 10 percent overage; 16 reactions. Computed when this page is built by the calculators' engine.
| Component | Added | Per reaction (µL) | Total (µL) |
|---|---|---|---|
| TaqMan Fast Advanced Master Mix | In the shared mix | 10 | 176 |
| TaqMan Assay | In the shared mix | 1 | 17.6 |
| Nuclease-free water | In the shared mix | 7 | 123.2 |
| cDNA template or water (NTC) | To each well | 2 | 32 |
Shared mix to prepare: 316.8 µL, 17.6 reactions' worth.
Open this mix in the calculators
Worked example
- Batch = reactions × shared volume per reaction × (1 + overage) + the vessel's extra dead volume; each shared line scales by batch ÷ shared volume.
- A line added to each well (the template here) scales by the reaction count only; the overage and dead volume apply to the shared mix.
Method
- Master mix preparation. Volume balance and C1V1 = C2V2; protocol-specific overage and user-supplied single-vessel dead volume. Thermo Fisher MAN0025706 B pp. 12–13; INTEGRA dead-volume technical note, read 9 October 2026.Checked against exact rational volume balance (Python 3.11.15) on 14 cases to nine significant figures (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.
- The 2 µL pipetting flag and the 0.5 percent DMSO flag are bench rules of thumb, not instrument specifications.