Data Source & Methodology
Calculations follow the classical hemocytometer method: the volume of one large square is 0.1 µL (10⁻⁴ mL). The concentration in cells/mL is \( \dfrac{\text{total cells}}{\text{squares counted}} \times \text{dilution factor} \times 10^{4} \). Reference protocols: Current Protocols in Cell Biology (Wiley), and Thermo Fisher Scientific application note “Cell Counting with Hemocytometers”.
Tips for Accurate Counts
- Mix the sample gently before loading to avoid settling.
- Focus on a consistent plane; count cells touching the top and left borders, skip bottom/right borders.
- Count at least four large squares (or more) and average the result for precision.
- Apply an appropriate dilution if the chamber is overcrowded.
Worked Example
Input: 500 cells counted in 4 squares, dilution factor 2.
Calculation: \( (500 / 4) \times 2 \times 10^{4} = 2.5 \times 10^{6} \) cells/mL.
Frequently Asked Questions
What does the 10⁴ multiplier represent?
Each large square on a standard Neubauer hemocytometer holds 0.1 µL. Multiplying by 10⁴ converts the average count per square to cells per milliliter.
Can I use this for yeast or bacterial cultures?
Yes. As long as you use the same counting rules and apply any dilution factor, the formula works for most cell suspensions.
How do I handle viability staining?
Count live and dead cells separately. You can run this calculator twice (once for each) and compute viability as live / total × 100.