Hemocytometer Cell Count Calculator
Cell concentration from a hemocytometer count — with the dilution, trypan-blue viability, the total cells in your suspension and the volume that holds the number you need to plate.
Each large corner square of a Neubauer hemocytometer holds 0.
How the hemocytometer cell count calculator works
Each large corner square of a Neubauer hemocytometer holds 0.1 µL, so the average count per square × 10,000 is cells per milliliter of the loaded sample; multiply by the dilution you made (trypan blue is usually 1:1, a factor of 2). Dead cells take up the dye and are counted separately; viability is live over total. Count at least 100 cells across the squares for a reliable figure.
Formula: cells/mL = mean per square × dilution × 10⁴; viability = live ÷ (live + dead)
Worked examples
| Inputs | Live cells per mL | Note |
|---|---|---|
| Four squares averaging 50, 1:1 trypan blue | 1 × 10⁶ cells/mL | 1.0 × 10⁶ cells/mL, 96% viable |
| Undiluted count of 30 per square | 300 × 10³ cells/mL | 3.0 × 10⁵ cells/mL |
| Dense sample diluted 1:10 | 12.13 × 10⁶ cells/mL | 1.2 × 10⁷ cells/mL |
FAQFrequently asked questions
Which squares do I count?
The four large corner squares (each 1 mm × 1 mm × 0.1 mm deep = 0.1 µL) are standard for mammalian cells; the central square’s small grid is for smaller cells or dense samples. Count cells touching the top and left lines, not the bottom and right.
How many cells should I count?
At least 100 in total, ideally 200–500, for a coefficient of variation under 10%. Fewer than 20 per square means diluting less; more than 200 per square means diluting more.
What is a good viability?
Above 90% for a healthy culture; below 80% suggests over-confluence, harsh trypsinization or a problem with the medium. Freshly thawed cells often read 70–85%.
How does an automated counter differ?
It images and counts thousands of cells, so its precision is better, but it needs calibrating for cell size and its live/dead call depends on the dye and thresholds. The hemocytometer is the reference method.
Where these figures come from
- NCBI Bookshelf — Molecular Biology of the Cell — growth kinetics and molecular conventions
- National Human Genome Research Institute — the US genomics research institute
Last checked: September 2026. Formulas are the standard textbook forms; assumptions are stated on each page because they are where these models break.