Postage

Postage is the fee charged by a postal service to deliver mail and packages. It can refer to the price itself, the stamps or labels used to show payment, or the system of prepaying for mailing. The concept emerged in the 19th century with the introduction of adhesive postage stamps, beginning with Britain's Penny Black in 1840, standardizing prepayment and enabling widespread mail service. Since then, postage rates have been structured by class, weight, and distance, with domestic mail often priced differently from international mail. Common categories include first-class (or standard), second-class, and airmail or air services, with surface mail for ground transport.

Payment is typically evidenced by an adhesive stamp affixed to the item or by a prepaid indicia or meter stamp produced by the sender or business. In many countries, customers can also purchase online postage labels or use postage meters for bulk mail. International mail generally requires postage to be paid according to agreements set by the Universal Postal Union, with rates varying by country and service level.

Postage due refers to items for which insufficient postage was paid and the recipient is charged the deficit. Postal authorities may use stamps, labels, or electronic records to indicate outstanding fees. The rate structures often reflect weight tiers, zone or distance, and service speeds, with additional charges for certified mail, insurance, or tracking.

Today, postage is supported by physical stamps, digital e-postage, and tracking systems. While the role of stamps endures for many individuals and collectors, automated and online services increasingly facilitate prepayment and rapid processing of mail and parcels.