One thing we do know: There is a rigid formula for survival. Whether a restaurant opens in hypercompetitive Manhattan or in California’s gold-rush dining scene, it has to make the same equation work: The costs of real estate, labor and food should add up to about 75 percent of its projected sales, leaving a profit margin of roughly 10 percent once smaller expenses are figured in.

A large restaurant group or chain may be able to skate below 10 percent because its volume is so high, but a chef who opens a starter full-service restaurant can end up in trouble if profits dip below that threshold.

To further break down the formula, a healthy restaurant aims to spend about 10 percent of its sales revenue on rent, utilities and other occupancy costs; 30 to 40 percent on labor, including payroll taxes and benefits; and 30 percent on food and beverages.

Because those three expenses account for most of a restaurant’s costs, we sought the best numbers we could find and compared them for three vibrant dining cities: New York, which has the nation’s largest roster of independent restaurants; Los Angeles, where the number of independents is growing; and San Francisco, a smaller, volatile market that has responded to restaurant closings with a real estate plan that enables start-ups to hedge their bets.

Here’s how the cities stack up, cost by cost.

Real Estate

Space in Manhattan and parts of Brooklyn can cost twice as much as in Los Angeles or San Francisco.

CoStar, the nation’s largest source of commercial real estate data, tracks more than 980,000 listings. Though they are not broken down by use, Joseph Sollazzo, an economist with the firm, created a rough category of “restaurant friendly” spaces for us: listings from 2,000 to 5,000 square feet, a popular range for independent full-service restaurants, that met criteria like “available for all uses” and “ventilation.”