You could easily find out how many source words your text contains by using MS WORD function "WORD COUNT". You should have the text in MS WORD file or some other text type file. You need to copy and paste the text in a MS WORD file. Then you need to go to the MS WORD ribbon and find REVIEW. After clicking on REWIEW you need to watch to the left and find the function called WORD COUNT. Click on it and a small window will appear. There you can fund the needed information on the source words number of your file.
In short it looks like this:
MS WORD → REVIEW → WORD COUNT
How to calculate the number of source words of your order
Oct. 28, 2019