Cell Viability Calculator
Enter absorbance readings from MTT, MTS, WST-1, or resazurin assays relative to a control.
Enter a known viability percentage to get health assessment and interpretation.
Results
How to Use the Cell Viability Calculator
Select the tab that matches your method. For Cell Counts, enter live and dead cell numbers from a hemocytometer. For Absorbance, enter optical density readings from a colorimetric assay. For % Input, enter an already-known percentage to get a health interpretation and application-specific recommendation.
Cell Viability Formula
For count-based methods (e.g. trypan blue exclusion):
For absorbance-based methods (e.g. MTT assay):
Viability Thresholds by Application
- General cell culture: ≥ 85% acceptable; ≥ 90% preferred
- Transfection: ≥ 90% strongly recommended for optimal efficiency
- Cryopreservation: ≥ 90% before freezing for good recovery post-thaw
- Cell-based assays (MTT, ELISA): ≥ 85% to avoid false results from dying cells
- In vivo injection: ≥ 95% required to minimize immune response and animal harm
Why Viability Matters
Low viability cultures release intracellular contents including proteases, lipases, and nucleic acids that can contaminate conditioned media and interfere with downstream assays. Dead cells also consume nutrients and produce toxic metabolites that accelerate further cell death in the culture vessel.
Tips for Accurate Viability Counting
- Use freshly prepared trypan blue (0.4% solution) — degraded dye may stain live cells.
- Count within 3 minutes of mixing with trypan blue to avoid false positives.
- A 1:1 dye ratio is standard; always factor this dilution into your concentration calculation.
- Aim for 100–300 total cells per hemocytometer count for statistical accuracy.
- For absorbance assays, run at least 3 replicates per condition and subtract background blank.