What is the perfect size when looking for a pressure cooker to buy online? The truth is that what works for some people will not work for everyone else. There are two classic standards though – four quarts and 6 quarts. It depends on your necessities. How large is your family? How much food do you normally prepare? Do you have enough storage too? Generally speaking, specialists recommend the six quart standard as a minimum. If your budget is generous and you have a regular family, opt for a slightly higher size. Keep in mind that a pressure cooker is normally filled to 67% only.