A wok is perfect for stir-frying, steaming, braising, boiling and other cooking methods. Most models of this ancient Chinese cooking utensil are made with thin steel that easily transfers heat; they can have a flat or round bottom (a flat wok is easier to handle on modern stoves), one or two handles and a lid. Woks come in many sizes; the best size depends on your stove arrangement, burner power and cooking needs.
A small wok can measure just 12 inches in diameter and can be useful for smaller portions or for stoves where you have other pots and pans at work. You can easily transport small woks to kitchen-equipped hotel suites or on a camping trip, where they can be used over a campfire or on a barbecue grill. Remember that a shallow, small wok will heat up fast, so don't leave it empty over the heat for any length of time.
A standard-size wok measures 14 inches in diameter and fits snugly over the gas ring or electric coil of a modern stove. This is the ideal size for family meals; remember that the depth of the wok also controls the amount of food you can fry in it. Many standard-sized woks come with double handles for ease of lifting and handling. The website Food Service Warehouse also matches wok size with BTU rating of your stove; a 12- to 15-inch wok requires a minimum 12,000 BTUs of burner power.
Slightly larger 16-inch woks are sufficient for most households. The website Thai Food and Travel recommends a rating of at least 10,000 BTU for a wok this size. It will take slightly longer for a 16-inch wok to heat up; also, cast-iron woks of any size take longer than steel woks. It's important to heat the wok well before cooking; oil in the pan should be at the point of smoking before you add the ingredients. If your wok is not heating up sufficiently, it's too big for your burner.
Larger woks can measure 2 feet or more in diameter and are useful for restaurants that need to prepare large portions. They are commonly not just for large stir-fry portions but also to boil water for rice or to prepare soups. If you are cooking for six people or more, use a larger wok. There should be plenty of room between the food in the wok and the rim. If you overfill a smaller wok with ingredients, the dish will not cook evenly and it will take much longer for the wok to reach an ideal temperature.