This depends on several mitigating factors, including but not limited to:

1. Whether or not you are going through a bank or a broker (Banks are typically quicker given they have fewer layers)

2. How solid a loan it is (A fringe or subprime loan will typically take longer than a full doc, 50% LTV, 800 FICO loan)

3. How busy a time of year it is for the underwriter

An average estimate would 2 to 4 weeks.

While some banks can turn out your loan in a matter of days, there is a reason for the standard 30 day escrow and that is to give adequate time for the borrower to achieve financing.