Transformation Efficiency

What this is for: Transformation efficiency in CFU/µg from the colonies on your plate, the DNA amount and the fraction of the recovery plated.

The formula: TE (CFU/µg) = colonies ÷ fraction plated ÷ DNA (µg)

How to use:

Enter the colonies counted on the plate.
Enter the DNA used (ng) — note this is in ng, e.g. 10 pg is 0.01 ng.
Enter the total recovery volume (µL), the volume plated (µL), and the dilution of the cells plated (1 if undiluted).
Read the total transformants in the recovery and the transformation efficiency in CFU/µg.

TE (CFU/µg) = colonies / DNA (µg) × (total recovery volume / volume plated). Example: 150 colonies from 10 pg plasmid, 100 µL plated of a 1 mL recovery → 1.5e8 CFU/µg.

Colonies counted on the plate

DNA used (ng)

Total recovery volume (µL)

Volume plated (µL)

Dilution of cells plated (1 = undiluted)

Total transformants in recovery (CFU)

TRANSFORMATION EFFICIENCY (CFU/µg)

Prefer to work offline or keep a copy? The download link is right below.
Download the Transformation Efficiency workbook (.xlsx)

Notes & limits (from the workbook): TE (CFU/µg) = colonies / DNA (µg) × (total recovery volume / volume plated). Example: 150 colonies from 10 pg plasmid, 100 µL plated of a 1 mL recovery → 1.5e8 CFU/µg.