How to Calculate CAC on a Cash Basis

Some of the common issues you see with people calculating CAC so one of the things I see is the confusion between am I using fully loaded cells and marketing expenses or I'm doing this more as an incremental variable kind of CAC ratio. Some startups dump a lot of cost in a GNA which messes up not only your P&L benchmarking because GNA looks really high but it also messes up your sales and marketing percent of revenue calculation. So personally as something of a purist I would correct it once which is to accelerate the commissions on a cash basis and leave it the rest of it as a gap expense basis meaning the rent for the sales team is included in the calculation