If you want to upload a big file but are not sure how it will be split into smaller pieces (chunks), this is the solution for you. 

Binary Split & Merge is a browser extension that allows you to split the input file into several smaller pieces. It has a built-in segment generator that allows you to find the desired number of chunks and also provides an option for changing the segment size.

After choosing the desired segment size, you can drag a file in the app UI (top section) and click on the - Download - button. You can also combine small file pieces by dragging them in the app UI (top section) and adjust the final file type and extension. Then click on the - Merge & Download - button.