How It Works
This calculator works in 4 steps.
Enter the step factor
Type the factor per step.
Enter the final volume per tube
Type the volume each tube must hold after the series is complete.
Enter the tube count and overage
Type the number of tubes and the overage percent, such as 10%.
Read the diluent volumes
The calculator returns diluent per tube, total diluent, and total with overage.
The Formula
The formula sets the per-tube diluent equal to the final volume kept per tube and multiplies by the tube count.
V_d = V_keepV_t = V_keep / (F − 1)V_total = n × V_d × (1 + overage)- V_d:
- Diluent volume per tube
- V_keep:
- Volume each tube holds at the end
- n:
- Number of tubes
- overage:
- Extra fraction, such as 0.10
A tenfold series of 6 tubes that each keep 900 µL needs 900 µL diluent per tube, 5.4 mL in total, and 5.94 mL with 10% overage.
Conversion Table
The conversion table shows per-tube and total diluent for 6 serial plans, with 10% overage in mL.
| Factor | Diluent per tube | Tubes | Total diluent | Total + 10% |
|---|---|---|---|---|
| 2 | 100 µL | 8 | 800 µL | 0.88 mL |
| 10 | 900 µL | 6 | 5,400 µL | 5.94 mL |
| 5 | 200 µL | 7 | 1,400 µL | 1.54 mL |
| 3 | 150 µL | 10 | 1,500 µL | 1.65 mL |
| 10 | 90 µL | 8 | 720 µL | 0.792 mL |
| 4 | 300 µL | 5 | 1,500 µL | 1.65 mL |
What Is the Serial Dilution Diluent Calculator?
The Serial Dilution Diluent Calculator is a tool that returns the diluent volume for each stage of a serial dilution and the total diluent for the whole series. The calculator works from the step factor and the volume each tube must hold at the end.
Diluent volume per tube is the amount pre-filled before any transfer. The total, plus an overage, sets the reservoir or bottle volume. The calculator adds a default 10% overage for reservoir dead volume and pipetting loss, and the user can change the overage.
Common Uses
There are 5 main uses of this calculator.
Buffer preparation
Users prepare enough assay buffer for all dilution tubes in one batch.
Dilution blank filling
Microbiologists fill 9 mL saline or peptone blanks ahead of plating.
Reservoir loading
Technicians load a multichannel reservoir with the total plus overage.
Broth budgeting
MIC labs calculate broth per panel and per day.
Batch scheduling
Lab managers plan diluent production across many series.