How much can I really be approved for?

[Derek Luttrell]

Hello, 

This is my first post, and I'm here because I found the podcast off of Millennial Money Minutes. Before mapping out my actual plan, I need to know what I can actually be approved for, and I'm not sure which (if any) calculator online is most accurate. 

Here is my situation:

My goal is to buy either a 3-bedroom single family, or 5-br+ multi-family in a neighborhood just outside of downtown Chicago. My girlfriend and I will live in one bedroom/unit (the house will be in my name only, but she will pay her share in rent). I will then rent out the remaining bedrooms/units.

I can get a quality 3br home for $3-400k, and rent each room for around $800/month (girlfriend and I will share a room). Is anyone able to give me a glimpse of what I can be approved for? 

Gross pay: $8-11k/month (base of 60k, plus steady commission) 3yrs at current job

FICO: High 700s 

Cash: $40,000

Debt: Student loan minimum $100/month (no credit card debt)

Thank you!