The minimum rules
For homes under $500,000 the minimum is 5% of the price. Between $500,000 and $1.5 million you pay 5% on the first $500,000 and 10% on the rest. At $1.5 million or more the minimum is 20%.
What changes at 20%
Below 20% down your mortgage needs default insurance. The premium is added to your loan and ranges from about 2.8% to 4% of the mortgage, depending on how much you put down.
Keep a cushion
Closing costs such as land transfer tax, legal fees and moving usually add 1.5% to 4% of the price. Plan for those before you stretch your down payment.