Just a quick post to share a handy BIAB water calculator I found and like using. There are several out there but I found this one easy to use and gave me spot on volume results. It also shows what the total volume of the mash will be including grain and water which makes it easy to figure out if it will fit in your kettle, great for us small batch brewers.
https://www.easycalculation.com/other/embedded_biab-calculator.php
Small Batch Home Brewing 