Viral Titer (PFU/mL) Calculator
Calculate viral titer in plaque-forming units per milliliter (PFU/mL) from plaque assay counts. Essential for virology research, vaccine production, and viral vector quantification.
Viral Titer (PFU/mL)
intermediateCalculate viral titer from plaque assay results
Formula
PFU/mL = plaques / (dilution × volume)
How It Works
A plaque assay is the gold standard for quantifying infectious viral particles. Each plaque represents one infectious virus that lysed a cell and spread to neighboring cells.
PFU/mL = Plaques Counted / (Dilution × Volume Plated)
Example
Counted 50 plaques at 10⁻⁵ dilution, plating 0.1 mL:
PFU/mL = 50 / (10⁻⁵ × 0.1) = 50 / 10⁻⁶ = 5.00 × 10⁷ PFU/mL
Frequently Asked Questions
How many plaques should I count per plate?
For accurate results, count plates with 20-200 plaques. Too few plaques = low statistical confidence. Too many = plaques may merge and give inaccurate counts.
What is the difference between PFU and TCID50?
PFU (plaque-forming units) directly measure infectious particles. TCID50 measures the dilution at which 50% of cells are infected. Roughly, 1 PFU ≈ 0.7 TCID50 units, but the relationship depends on the virus and cell type.