How to know when formatting disk has finsihed - Ubuntu 16.04?

I had a similar situation where I right clicked a previously created partition on an external drive to reformat it. Once it had started there was no window of any sort to show the progress of the formatting. My solution was to open the Disk Utility which can easily be installed if it is not already available.

Once I opened Disk Utility I was able to select the partition being formatted and view the progress bar together with an estimation of the time remaining.

Note: when looking for Disk Utility amongst your apps only enter the term Disk as that is what it shows up as.

After a dialogue as comments, we can conclude

• "I right clicked on the drive icon in the task bar(Unity) and then I pressed format."

• Slow format on a USB 2 drive was selected for NTFS on 300 GB.

• This will last for between 2 and 3 hours, and there is no feedback during the process, except signs that the computer and target drive are busy.

• It was easy to see that the formatting was successful in the end.