@Amanda Kroepfl A lot depends on what your are talking about when you mean multifamily. If you are looking at smaller commercial units like 10-20 units, then the BP rental calculator "may" work assuming you are funding the deal yourself. When you get into larger deals, especially syndicated deals, that calculator will not work. It was more meant for SFH and small MF deals. As mentioned by @Josh Edwards, I found the Michael Blanks SDA a good start for larger deals to learn the basics. Most groups make their own tools for underwriting though because how you come up with your business plan is unique to your strategy. If you are looking for something to learn from as you start off, I think the SDA is a good but I would read books like Multifamily Millionaire Vol. 2 by Brian Murray, The Definitive Guide to Underwriting Multifamily Acquisitions by Robert Beardsley and How To Analyze Big Apartment Buildings & Make Them Feel Small by John Stoeber (there are more, those are just a few) to further develop your underwriting skills. Learning and understand what goes on in the background of underwriting writing is very important as mentioned by @Account Closed After underwriting a few times, you will likely learn that you need a flexible solution that fits your needs rather than something off the self. If you are not a numbers person, it would be good to partner with someone that has that skill set. Best of luck on your RE journey!