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

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## 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? **

- First, determine the total number of colonies on the plate. For this example, we will say there are 500 colonies.
- 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.
- Next, determine the volume of the DNA added to the mix. The total volume, in this case, is found to be 30 ul.
- 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.