Multifamily- How do I estimate rent?

[Elisa Sacchetti]

I found a quadruplex with 8 bed 8 bath, so each unit is 2 bed 2 bath. I found it on the MLS and it said that estimate rent is $1000, but on the BP rental estimator it estimated $2175 at a low confidence level. Hypothetically does this mean, the whole property will rent for $1000-2000 per month, so each unit is $500? OR does this mean each unit is $1000-2000 per month so total rental per month is 4X what it says on BP or on the MLS? Just want some clarification, so I do the math correctly. Thank you!