Hello Mario,
Most of the conventional financing is 45-50% DTI (Debt to Income Ratio). Assuming you have no debt take your gross income and take 45%-50% of that and put that towards your monthly mortgage payment. Make sure to give your self some buffer to include Tax, Insurance and HOA if applicable.
One formula we use to give you a quick glimpse of what you could hypothetically qualify for conventional loan is for example lets say you make 10k so take 45% of that to be conservative. Which is $4,500 payment and that should include all ofr your mortgage payment + Tax + ins. 4500/.007= 642,857 loan amount.
As for what rate it just all depends on your credit score and doing a soft pull can help you determined what rate you can possibly qualify for when speaking to a lender.
Hope this helps to give you an idea on how you can run rough numbers to see where you are in terms on how much you can qualify for.
@Albert Bui @Matthew Kwan