Determining how much webspace has been used.

I use Website X5 V8 Evolution. I have a few websites that I load to the free webspace allocated by my ISP. When I reach the limit of my webspace allowance, it just stops loading any updates until I reduce content from somewhere else.

Do you have any tools that will let me keep track of how much webspace has been used for pages created by Website X5 V8?

My ISP tells me that they don't have any such tool that would assist me.

Thanks

Alan C