The doubling time is the time taken by your cells to double in number. Why don’t you calculate the doubling time yourself?
Use the cells that are already in culture. Avoid using those cells that have been recently thawed form liquid nitrogen.
Count the number of cells that you plate with the help of hemocytometer. Let us say the starting number of cells (at the beginning) is X. Propagate the cells as you normally do in routine cell culture practice. The next time when you have to split them, count them again. Let us say this time the number is Y.
To calculate the doubling time, use the formula given below
Doubling Time = [ T × ( ln2 ) ] / [ ln (Y / X) ] where T = Time in any units
For instance,
Say on Day 0, your count was 2 × 10^6 cells. Three (3) days later, your count was 16 × 10^6 cells.
Please note that the cells should be in the log phase of growth to calculate doubling time properly, so it is necessary not to allow the cells to reach confluency.