Hemocytometer Cell Concentration Calculator – Online Tool
Each corner large square of a hemocytometer has a fixed volume of 0.1 µL (1 mm × 1 mm × 0.1 mm), so
Cell concentration (cells/mL) = average count per large square × dilution factor × 10⁴
10⁴ is the conversion factor from 0.1 µL to 1 mL.
Three common sources of error:
- Include trypan blue in your dilution factor. A 1:1 mix of cell suspension and 0.4% trypan blue gives a dilution factor of 2; multiply by any prior dilution steps.
- Count border cells on two sides only. By convention, count cells touching the top and left borders; exclude those on the bottom and right. Deviating from this causes a systematic overcount.
- Aim for 20–50 cells per large square for reliable results. Fewer than 20 increases sampling error; more than 100 makes cells easy to miss. In either case, adjust the dilution factor and recount.
Viability is calculated by trypan blue exclusion: dead cells stain blue, viability = live cells / (live cells + dead cells).
FAQ
Why multiply by 10⁴?
One large square has a volume of 0.1 µL = 10⁻⁴ mL; converting to per mL requires multiplying by 10⁴.
What dilution factor should I enter for a 1:1 mix with trypan blue?
Enter 2. If the cells were also diluted 5-fold before mixing, enter 10.
Related tools
Buffer Preparation Calculator (Henderson-Hasselbalch)
Given a target pH, calculate the acid-to-base component ratio and the mass of each component needed to prepare your buffer.
PCR Reaction Setup Calculator (with Multi-Sample Master Mix)
Calculate the volume of each component and water make-up from stock and final concentrations; supports batch master mix preparation for multiple samples.
DNA / RNA Copy Number Calculator (Plasmid Standards, qPCR, ddPCR)
Calculate copies/µL, copies per reaction, and single-copy mass from concentration and length; generate a standard-curve dilution series.
Buy me a coffee