🔬 Hemocytometer Cell Counting Calculator
Turn a hemocytometer count into cells per mL and a total cell number, accounting for your dilution (e.g. trypan blue) and suspension volume.
Cell density
(count ÷ squares) × 10⁴ × dilution
800,000 cells/mL
Total cells
density × volume
8.000e+6 in 10 mL
How the hemocytometer cell counting calculator works
Each large corner square of a hemocytometer holds 0.1 µL, so the cell density is the average count per square multiplied by 10⁴ and by your dilution factor: cells/mL = (total counted ÷ squares) × 10⁴ × dilution. Multiply by the suspension volume to get the total number of cells.
Pure geometry (the 0.1 µL square volume gives the fixed 10⁴ factor), no reference data, so it never goes out of date. Count at least 100 cells across the squares for a reliable average.
Frequently asked questions
How do you calculate cells per mL from a hemocytometer?
cells/mL = (total cells counted ÷ number of large squares) × 10⁴ × dilution factor. The 10⁴ comes from each large square holding 0.1 microlitres. If you counted 160 cells over 4 squares at a 2× dilution, that is (160/4) × 10⁴ × 2 = 8×10⁵ cells/mL.
Why multiply by 10,000?
Each large corner square of a Neubauer hemocytometer is 1 mm × 1 mm × 0.1 mm = 0.1 µL. To convert a count per 0.1 µL to a count per mL (1000 µL) you multiply by 10⁴.
How does the dilution factor work?
If you mixed your cells with an equal volume of trypan blue (a 1:2 dilution), the dilution factor is 2. You multiply by it because your count was of the diluted sample. Enter whatever dilution you made.
How many squares and cells should I count?
Count the four (or five) large corner squares and aim for at least 100 cells total for a reliable average, too few cells makes the estimate noisy. Enter the number of squares you actually counted.
How do I get the total number of cells?
Multiply the density (cells/mL) by the total volume of your cell suspension in mL. The tool does this when you enter a volume.
Does this measure viability?
Not directly, but if you count only live (unstained) cells after adding trypan blue, the density this gives is your live-cell density. Count live and total separately to get percent viability.
Which cells do I count on grid lines?
To avoid double-counting, use the standard rule: count cells touching the top and left boundary lines of a square, and skip those touching the bottom and right. Apply the same convention to every square so the average per square is unbiased.
How do I calculate percent viability?
Count total cells and, separately, the unstained (live) cells after trypan blue. Viability = live ÷ total × 100. For example, 90 unstained out of 100 total is 90% viability. Feed the live count into this tool to get live cells/mL directly.
What if my cells are clumped together?
Clumps bias the count because cells hide behind one another and a clump may be scored as one cell. Pipette or filter the suspension into a single-cell suspension before loading, spread it evenly under the coverslip, and re-count. If clumps persist, count each visible cell in a clump individually and note that the estimate is approximate.
How does this compare with an automated cell counter?
An automated counter (Coulter or image-based) reads a larger volume and removes human counting bias, so it is faster and often more reproducible. A hemocytometer needs no dedicated instrument, lets you see the cells and debris directly, and is the low-cost reference method, the same 10⁴ geometry underlies both, which is why this calculator matches what an automated device reports.