About the Hemocytometer Cell Count Calculator
This hemocytometer cell count calculator converts the cells you count under the microscope into a cell concentration. Enter the live (unstained) and dead (blue-stained) cells counted, how many large squares you counted, and the dilution factor from mixing with trypan blue, and it returns viable cells per mL, total cells per mL and percent viability.
It is built for cell-culture work with a standard improved Neubauer chamber, where each large 1 mm × 1 mm square is 0.1 mm deep and so holds 0.1 µL (10⁻⁴ mL). Add the volume of your cell suspension to get the total number of viable cells, and a target number of cells to find how much suspension to pipette when seeding plates or flasks.
For a reliable count aim for roughly 100–300 cells across the squares you count, count both chambers if possible, and follow a consistent rule for cells touching the boundary lines (for example, count the top and left edges but not the bottom and right). If your chamber has a different depth or square size, change the volume factor.
With the default inputs, the viable cells per ml is 1,060,000. Change any value above to recalculate instantly.
How to use the hemocytometer cell count calculator
- 1Mix cells with trypan blue (often 1:1) and load the hemocytometer.
- 2Count live and dead cells in the large squares — typically the four corners.
- 3Enter both counts, the number of squares and the dilution factor.
- 4Add the suspension volume and how many cells you need to seed.
- 5Read cells/mL, viability and the volume to pipette.
Formula and method
Each large square of an improved Neubauer hemocytometer is 1 mm × 1 mm with a 0.1 mm chamber depth, so it holds 0.1 mm³ = 0.1 µL = 10⁻⁴ mL. Multiplying the average number of cells per square by 10⁴ therefore gives cells per millilitre in the loaded sample, and multiplying by the dilution factor (2 for an equal-volume trypan blue mix) corrects back to the original suspension.
Viable concentration uses only unstained cells because trypan blue is excluded by intact membranes. Total viable cells in the suspension = viable cells/mL × volume, and the seeding volume = target cells ÷ viable cells/mL.
- DF
- Dilution factor (total volume ÷ sample volume)
- 10⁴
- Chamber factor: 1 ÷ 0.0001 mL per large square
Worked examples
Four corner squares, 1:1 trypan blue
212 live cells over 4 squares is 53 per square. × 2 (dilution) × 10,000 = 1.06 × 10⁶ viable cells/mL. Viability = 212 ÷ 230 = 92.2%. Seeding 1 million cells needs 1,000,000 ÷ 1,060,000 = 0.943 mL.
Both chambers (8 squares), extra dilution
340 ÷ 8 = 42.5 live cells per square; × 10 × 10⁴ = 4.25 × 10⁶ cells/mL. With 5 mL of suspension you have 2.125 × 10⁷ viable cells, and 5 million cells is 1.18 mL.
Undiluted count, no dye
150 cells over 5 squares is 30 per square, so the suspension holds 30 × 10⁴ = 3.0 × 10⁵ cells/mL. Without a viability dye every counted cell is treated as live.
Frequently asked questions
How do you calculate cell concentration with a hemocytometer?+
Divide the number of cells counted by the number of large squares counted, multiply by the dilution factor, then multiply by 10,000 (because each large square holds 0.1 µL). The result is cells per mL.
Why multiply by 10,000?+
A Neubauer large square is 1 mm × 1 mm × 0.1 mm deep = 0.1 mm³, which is 0.0001 mL. Multiplying the average count per square by 1 ÷ 0.0001 = 10,000 converts it to cells per millilitre.
What dilution factor do I use with trypan blue?+
Mixing equal volumes of cell suspension and 0.4% trypan blue gives a dilution factor of 2. If you mixed 10 µL cells with 90 µL dye it is 10. Multiply factors if you diluted the cells beforehand.
What is a good cell viability?+
Healthy, log-phase cultures usually show more than about 90% viability by trypan blue. Values much below 80–85% suggest over-confluence, contamination or harsh handling, and many protocols require above 90% before experiments.
How many cells should I count?+
Aim for about 100–300 cells in total, roughly 20–50 per large square. Too few cells makes the count statistically noisy; too many makes it easy to miscount, so adjust the dilution.