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Buffer Preparation Sample Capacity Estimator

The Buffer Preparation Sample Capacity Estimator calculates how many complete samples can be supported by a known volume of prepared buffer after reserving a chosen percentage for dead volume, priming, repeat work, or other planned losses. It is useful before assays, washes, extractions, or other protocols where each sample consumes a predictable amount of buffer.

The result is intentionally conservative when a reserve is entered: only usable buffer is divided by the per-sample requirement, and the sample count is rounded down to a whole number. The calculator also reports the estimated leftover usable buffer after supporting that many complete samples, which can help decide whether another preparation batch is needed.

Buffer availability

mL
mL
%
Result
—
Complete samples supported
Usable buffer volume—
Reserved buffer—
Usable buffer left over—

1. Enter prepared buffer volume
Use the amount of buffer available for the planned work.

2. Enter buffer per sample
Include the total expected consumption for one sample across the relevant protocol steps.

3. Set a reserve allowance
Use this optional planning margin for dead volume, priming, repeats, or transfer losses.

4. Review complete sample capacity
The calculator rounds down so only fully supported samples are counted.

5. Check leftover usable buffer
The remainder shows how much of the usable, non-reserved volume is left after the complete sample count.

Usable buffer = Prepared buffer × (1 − Reserve % / 100)
Complete sample capacity = floor(Usable buffer / Buffer per sample)
Leftover usable buffer = Usable buffer − (Capacity × Buffer per sample)

Where:

  • Prepared buffer = total available buffer volume
  • Reserve % = planned percentage withheld from capacity
  • Buffer per sample = volume consumed by one complete sample

Assumptions: Every sample is assumed to use the same buffer volume, and sample capacity is rounded down to a whole number.

What the result means

After holding back 8%, the available buffer is sufficient for 38 full samples with 6 mL of usable buffer remaining.

Use the result as a planning or calculation aid and confirm protocol-specific assumptions before laboratory use.

Given

  • Prepared buffer = 750 mL
  • Buffer per sample = 18 mL
  • Reserve allowance = 8%

Calculation
Usable buffer = 750 × (1 − 0.08) = 690 mL
Capacity = floor(690 / 18) = 38 samples
Leftover = 690 − (38 × 18) = 6 mL

Result
38 complete samples.

Interpretation
After holding back 8%, the available buffer is sufficient for 38 full samples with 6 mL of usable buffer remaining.

Why is sample capacity rounded down?

A partial remaining volume cannot support another complete sample at the stated per-sample requirement, so the result counts only fully covered samples.

What should be included in buffer per sample?

Include all buffer consumed by the sample for the workflow you are planning, including repeated washes or transfers when applicable.

Is reserve allowance the same as measured dead volume?

Not necessarily. It is a planning percentage; you can choose it to represent known dead volume plus any additional operating margin.

Can I set reserve to zero?

Yes. With a zero reserve, all entered buffer volume is considered available for sample capacity.

How is this useful for batch preparation?

Compare the supported sample count with the planned batch size. If capacity is lower, increase prepared buffer or reduce per-sample use only if the protocol permits it.