How to use (3 steps)
- Choose an example or select the chamber (default: improved Neubauer) and counting scheme.
- Enter dilution factor and square counts (Live/Dead or Total).
- Click “Calculate” to see cells/mL, viability, and variability guide (auto updates if enabled).
Inputs (chamber, dilution, counts)
Results (cells/mL & viability)
Variability guide
| Square | Mean | SD | CV |
|---|---|---|---|
| Live | — | — | — |
| Dead | — | — | — |
| Total | — | — | — |
SD shows the population standard deviation across squares. CV = SD ÷ mean; a larger CV indicates greater between-square variation.
Counts by square (bar chart)
How it’s calculated
- Volume per square (mL) = area (mm²) × depth (mm) × 10−3
- cells/mL = (mean count ÷ volume per square in mL) × dilution factor
- Viability (%) = (Live ÷ (Live + Dead)) × 100 (Live/Dead mode)
Low/high-count guidance applies to the Improved Neubauer preset at 1 mm² and 0.1 mm depth. Other warnings are guides, not definitive conclusions.
FAQ
Why multiply by 10^4?
In an improved Neubauer chamber, the large square volume is 1e-4 mL, so the conversion factor is 10^4 (check the settings).
It says counts are low/high.
Low counts increase error and high counts are hard to count. Adjust dilution or the number of squares as needed.
How is viability calculated?
If you count live and dead separately, viability = Live/(Live+Dead)×100.
Does the share URL include counts?
Yes. If the URL gets too long, you can switch to sharing without data.
Is my data sent anywhere?
Calculations stay in this browser; this calculator does not upload counts. A data-inclusive share link embeds square labels and counts in the link, so anyone with the link can read them. Do not include confidential information or personal identifiers.
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