USPS packages can be dropped off at post offices, blue collection boxes, retail partners like Walgreens and Staples, or picked up free from your door. Each option has different weight limits and hours.
![USPS Certified Mail: Cost, Delivery Time, and How It Works [2026]](https://uploads.trackingadvice.com/2021/01/USPS-Certified-Mail-Service.jpg)
See what Certified Mail includes in 2026, what it costs on top of postage, how long it usually takes, and when Return Receipt is worth adding.
USPS bans some items outright — marijuana, gasoline, explosives — and restricts others with conditions. Lithium batteries, liquids, aerosols, and firearms each have specific rules. Publication 52 is the authoritative source.
USPS delivers packages Monday through Saturday, 8 AM to 8 PM. Transit times range from next-day (Priority Mail Express) to 2-8 days depending on service. Here is how each mail class compares in 2026.
USPS closes 11 federal holidays in 2026. No carrier delivery, no post office counter service. Priority Mail Express is the exception — it delivers on most holidays.
USPS targets 5 PM — in practice, carriers run to 8 PM on regular days and 9 PM during peak season. Priority Mail Express is the only service with a guaranteed delivery time.
