Can't look at this from my phone but does it take into account the 2 bump outs on the kegs?
I have site gauges on my gear but I made the same thing for my buckets/carboys. This let's me know what my final yield was using a tape measure. Ahhh, math. So useful.
First they came for my Four Loko and I said nothing, then they came for my Double Imperial Espresso Stout.