Losing your Social Security card is more common than you'd think, and in most cases it's fixable without a trip to a local office. If you already know your Social Security number, you may not even need a physical replacement card at all — many institutions accept the number itself for verification purposes. * If you do need a new card, the fastest method is applying online through a my Social Security account. To qualify for the online option, you need to be a U.S. citizen, at least 18 years old, and have a U.S. mailing address (military and diplomatic addresses count). You also have to live in a state that shares its records electronically with SSA for this specific purpose — not every state does, so online replacement isn't guaranteed to be available everywhere. * If you don't meet the online requirements — you're under 18, don't have a qualifying address, or your state isn't set up for electronic sharing — you'll need to call 800-772-1213 to schedule an appointment at a local Social Security office or card center instead. * Whichever method you use, you'll need to provide proof of both identity and U.S. citizenship. As with an original application, SSA only accepts original documents or copies certified directly by the agency that issued them — notarized copies and regular photocopies are rejected. * Once your request is processed, the replacement card arrives by mail in 5 to 10 business days, and like the original application, replacement is completely free.