Bacterial Growth Sample Capacity Estimator

1. Enter available culture volume
Use the total volume that can actually be allocated to the planned samples.

2. Set volume per sample
Enter the culture aliquot required for one complete sample or replicate.

3. Add a reserve allowance
Use a percentage to hold back volume for pipetting loss, dead volume, QC, or repeats. Enter 0 if no reserve is needed.

4. Review whole-sample capacity
The calculator rounds down because a partial remaining aliquot cannot make a complete sample.

5. Check leftover volume
Use the breakdown to see how much usable culture remains after preparing the maximum whole-sample count.

Reserved volume = available volume × reserve %

Usable volume = available volume − reserved volume

Sample capacity = floor(usable volume / volume per sample)

Leftover = usable volume − sample capacity × volume per sample

Where:

• Available volume and volume per sample are in mL.
• Reserve % is entered as a percent and converted to a decimal.
• floor means round down to the nearest whole sample.

Assumptions: All samples are assumed to use the same culture volume and the reserve is taken from the available volume before samples are counted.

What the result means

The main result is the maximum number of complete equal-volume samples that fit after the reserve allowance.

This is a volume capacity estimate; confirm concentration, sterility, and protocol-specific minimum volumes separately.

Given:

• Available culture = 84 mL
• Volume per sample = 2.5 mL
• Reserve = 8%

Calculation:
Reserved = 84 × 0.08 = 6.72 mL
Usable = 84 − 6.72 = 77.28 mL
Capacity = floor(77.28 / 2.5) = 30 samples
Leftover = 77.28 − 30 × 2.5 = 2.28 mL

Result:
30 complete samples, with 2.28 mL usable volume left

The reserve is protected first, then only fully supplied samples are counted.