While I use SpectraFoo for critical analysis, I’ve found the TT Dynamic Range Meter to be a terrific tool that works within any DAW in an insert slot. Put it n the last slot of your master section and enjoy: http://www.pleasurizemusic.com/es/es/download
What the TT Dynamic Range Meter adds, is measuring not only RMS, but this in relation to a top 20 of peaks. This means that it also gives a reasonable dynamic range for audio that has peaks to, say, -7 dB - or any other arbitrary level not being 0 dBFS. And - it looks great!