Generally speaking, yes! At least when it comes to USPS. If the current date is after the ship date on your postage, your package will still be accepted at your local Post Office. However, we don’t suggest waiting more than two or three days after you create your postage.
Be Careful Not to Ship TOO Far After the Ship Date
Heads up! It’s not uncommon for shipping carriers to raise postage prices over the course of a year (or sometimes sooner). In some cases, postage purchased at an earlier date may not be accurate for future dates. Therefore, we always recommend that you ensure you have the proper amount of postage before scheduling or dropping off a shipment. This is especially true if you decide to buy postage online and hold onto it for the future.