The cost to overnight a letter using USPS Priority Mail Express starts at about $31.40 if purchased at a Post Office, with lower rates available (around $27.20) if you buy postage online through services like Click-N-Ship

. This service guarantees overnight delivery. Prices can vary based on the weight and destination zone of the letter, but for a typical letter weighing up to half a pound, expect to pay around this amount. Other carriers like FedEx and UPS offer overnight options as well, but their prices generally start higher, often $50 or more depending on the service level and destination

. In summary:

• USPS Priority Mail Express overnight letter: starting at about $31.40 retail, $27.20 online
• FedEx and UPS overnight letter services typically cost $50 and up
• Exact price depends on weight, destination, and whether you purchase postage online or at retail