Lenders want to see that you’d be able to make your mortgage payments even if you temporarily lose your income. As you shop around, you’ll find that lenders may have vague or unwritten policies for how much emergency savings you need to have. Generally speaking, it’s a good idea to have at least 2 months’ worth of expenses in highly liquid savings.
Lenders measure reserves based on the number of times you would be able to make your mortgage payment if you were unable to work or otherwise bring in income. While 2 months is often the baseline, more may be required depending on the loan program.