Choose an assay method and enter your measurements. Review calculated titer, endpoint notes, and unit details. Download CSV and PDF reports for records today.
| Dilution | Plated volume (mL) | Plaques (Rep 1) | Plaques (Rep 2) | Plaques (Rep 3) | Average | Estimated PFU/mL |
|---|---|---|---|---|---|---|
| 1e-6 | 0.1 | 38 | 41 | 41 | 40.00 | 4.0000e+8 |
| 1e-7 | 0.1 | 4 | 2 | 3 | 3.00 | 3.0000e+08 |
Viral titer reporting depends on whether you need infectivity, genomes, or binding activity. Plaque assays yield PFU/mL, most reliable when plates fall near 10–100 plaques and replicates agree. Endpoint dilution methods estimate TCID50/mL for viruses without clear plaques, but they require a series spanning near 100% positive to near 0% positive wells. qPCR outputs genome copies per mL and is often 10–10,000× higher than infectious units, reflecting noninfectious particles and free nucleic acid. Hemagglutination provides HA units per mL and is best treated as a comparative metric across batches.
PFU/mL is calculated from average plaques divided by dilution and plated volume. Precision improves with three or more replicates, consistent adsorption time, and the same overlay concentration. A tenfold dilution error shifts titers by one log, so recording factors in scientific notation reduces transcription mistakes. If plaque counts are too high to separate or below your lab limit of detection, repeat with adjusted dilutions and document the threshold used.
For TCID50, use a fixed wells-per-dilution design such as 6, 8, or 12 wells. Reed-Muench interpolation assumes a monotonic decline in positivity with dilution. If positives show reversals, review scoring criteria, plate layout, and contamination controls. Tightening the step size from 10-fold to 3.16-fold (half-log) can improve endpoint resolution, but it increases plate count and pipetting burden.
The calculator converts copies per reaction into copies per mL by scaling for template volume, total elution volume, extracted sample volume, and any dilution before amplification. Report extraction input and elution volumes alongside copies/mL, because different kits shift recovery. When comparing runs, include the standard curve efficiency range (often 90–110%) and the no-template control outcome to support confidence.
CSV exports suit electronic lab notebooks and batch summaries, while the PDF report captures a timestamped snapshot of inputs and outputs. Store the assay method, inoculum volume, and dilution scheme with each titer, and note deviations such as edge effects or delayed readout. Consistent metadata enables trend tracking across passages, storage conditions, and process changes. Keep raw worksheets and plate photos when available for review.
Enter the numeric factor used in the calculation, such as 1e-6 for a 10^-6 dilution, or 0.000001.
qPCR measures genomes, including noninfectious particles and free nucleic acid. Infectious assays count only functional units, so genome copies per mL are commonly higher.
Your dilution series did not cross 50% positivity. Repeat using a wider range, or adjust starting dilution and step size so you capture both high and low positivity.
Use the actual inoculum volume applied to the monolayer, commonly 0.1 mL. If you used a different volume, enter that value for accurate scaling.
HA reflects binding and agglutination activity, not necessarily infectivity. It can correlate within a controlled system, but it should not replace PFU or TCID50 for potency decisions.
Yes. Both CSV and PDF outputs include your selected method, entered parameters, and computed results, supporting traceability for lab documentation and review.
Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.