Cell Viability Calculator
Determine the health and percentage of viable cells in a population. Essential for checking cell health prior to transfection, freezing, or subculturing.
Viability counts
Input counts of live and dead cells.
Cell Viability Percentage
* A healthy culture typically has viability above 90%.
Expert Tip
When using Trypan Blue exclusion, count cells within 3-5 minutes of mixing, as cells will start to take up dye over time and artificially reduce the viability readout.
Methodology & Viability Formulas
Viability Equation
Viability percentage measures the fraction of intact, dye-excluding live cells out of the total population:
Trypan Blue Principle
Trypan Blue is a diazo dye that selectively colorizes dead tissues and cells blue. Live cells with intact cell membranes exclude the dye and remain translucent. Non-viable cells permit the dye to cross the membrane, coloring the cytoplasm deep blue under standard brightfield microscopes.
How to Calculate Cell Viability Percentages
Cell viability indicates the proportion of healthy, living cells in a population:
Perform Differential Count
Count live cells (which exclude dye like Trypan Blue) and dead cells (which stain blue).
Find Total Cells
Add live cells and dead cells together: Total Cells = Live Cells + Dead Cells.
Apply the Percentage Formula
Viability (%) = (Live Cells / Total Cells) × 100%.
Related Calculators
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Calculate cell concentration and total count from hemocytometer grid counts.
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Determine stock and diluent volumes needed for cell culture preparations.
Cell Doubling Time
Determine cell doubling kinetics over incubation periods.