Look on the bottom of your Dell. Most require either a 65 watt or a 90 watt input. Also note your model number. Then go to Office Depot, Staples, Office Max or Best Buy. They all have adapters. Either find your model on the back of an adapter, or get one with your plug in type and wattage output. The one thing I hate about the adapters you buy outside of Dell is the link is usually a special adapter for the input and can be lost easily. Also, the power adapters you buy at the store are often bigger and bulkier. They often cost close to $60-100 and are expensive.