Calculate the bacterial transformation efficiency. Enter the # of colonies per plate, and the total ng of DNA plated into the transformation efficiency calculator below.

Transformation Efficiency Formula

The following formula can be used to calculate the bacteria transformation efficiency. 

x = y/z*100
  • Where x is the transformation efficiency (transformants/ng of DNA)
  • y is the # of colonies on the plate
  • z is the total ng of DNA plated

To calculate the transformation efficiency, divide the number of colonies on the plate by the total ng of DNA, then multiply by 100.

Transformation Efficiency Definition

What is a transformation efficiency? Transformation efficiency is defined as the efficiency by which biological cells can take up extracellular DNA and express genes encoded by it.

What does a transformation efficiency tell us? Transformation efficiency can be used to tell us how well the transformants of a cell can absorb DNA from outside the cell and express the genes of the DNA that was absorbed in its own makeup.

What affects transformation efficiency? A transformation efficiency depends on the competence of the cells that are absorbing the extracellular DNA.

Transformation Efficiency Example

How to calculate a transformation efficiency?

  1. First, determine the total number of colonies on the plate. For this example, we will say there are 500 colonies.
  2. Next, determine the concentration of DNA used in the transform. In this problem, the concentration is 50ug/ul. These are units of micrograms and microliters.
  3. Next, determine the volume of the DNA added to the mix. The total volume, in this case, is found to be 30 ul.
  4. Finally, calculate the transformation efficiency. Using the formula, the transformation efficiency is found to be: # of colonies/(concentration of DNA*(volume of DNA*1000)) = 500 / (50*(30*1000)) = 0.00033333333 transformants/ng.