This method will introduce a formula to extract milliseconds from time in Excel. Please do as follows:

1. Select a blank cell besides the first time cell, enter the formula =RIGHT(TEXT(A2, "hh:mm:ss.000"),3)/1000 (A2 is the first time cell in the list) into it, and then drag the Fill Handle down to the range as you need.

Now you will get the calculation results showing as time with milliseconds as above screenshot shown.

2. Keep selecting the calculation results, and click Home > Number Format box > General to convert the times to general numbers.

So far, you can see milliseconds are extracted from each time cell as below screenshot shown:

This method will introduce Kutools for Excel’s Extract Text utility to extract milliseconds from each time easily.

1. Select the time data, and click Kutools > Text > Extract Text.

2. In the opening Extract Text dialog box, type .* into the Text box, and click the Add button; In the Extract list only check the new added extract field, and click the Ok button. See screenshot:

And then the second Extract Text dialog box comes out. Please specify the first cell of destination range, and click the OK button.

So far the milliseconds have been extracted from each time cell. See screenshot:

How to show time with milliseconds in Excel?