thumb|Seal of the former [[United States Post Office Department|U.S. Post Office Department (1792–1971), predecessor to the United States Postal Service]]
The system for mail delivery in the United States has developed with the nation. Rates were based on the distance between sender and receiver in the nation's early years. In the middle of the 19th century, rates stabilized at one price regardless of distance. Rates were relatively unchanged until 1968 when the price was increased every few years by a small amount. Adjusted for inflation, the cost of a first-class stamp has been steady. The seal of the Post Office Department showed a man on a running horse, even as railroads and, later, motorized trucks and airplanes moved mail. In 1971, the Post Office became the United States Postal Service, with rates set by the Postal Regulatory Commission, with some oversight by Congress. Air mail became standard in 1975. In the 21st century, prices were segmented to match the sorting machinery used; non-standard letters required slightly higher postage.
Postal rates to 1847
Initial United States postage rates were set by Congress as part of the Postal Service Act signed into law by President George Washington on February 20, 1792. The postal rate varied according to "distance zone", the distance a letter was to be carried from the post office where it entered the mail to its final destination. Rates were adopted in 1847 for mail to or from the Pacific Coast and in 1848 for mail sent from one place in the west to another place in the west. There were double and triple rates as a letter's size increased. Ship fees were also added (i.e., mail to Hawaii). The ship fee, including the ship rate on letters for delivery at the port of entry, were on a per letter basis, rather than weight. The United States issued its first postage stamps in 1847. Before that time, the letters' rates, dates, and origins were written by hand or sometimes in combination with a handstamp device.
United States Postal Service
The Postal Reorganization Act of 1970 established the postage rates, which have been set by the Postal Regulatory Commission.
Historical and current postage rates
{| class="wikitable"
|+United States domestic first-class & postcard rates, 1863–present (USD)
|-
! Date Introduced !! Letters <br /> !! Packages<br /> !! Additional <br />
! Postcard rate
!International rate (letters)
! Comments
|-
| July 1, 1863 || .06 <br /> ||.06|| .06 <br /> ||.06
| || .02 per half ounce in drop boxes
|-
| October 1, 1883 || .04 <br /> || .04 || .04 <br /> || .04
| ||
|-
| November 2, 1917 || .03 || .03 || .03 || .02
| ||Wartime Emergency Rate
|-
| July 1, 1919 || .02 || .02 || .02 || .01
| || Dropped back by Congress
|-
|April 15, 1925
|.02
|.02
|.02
|.01 (stamped cards)<br />.02 (postcards)
|
|
|-
| July 1, 1928 || .02 || .02 || .02 || .01
| ||
|-
| July 6, 1932 || .03 || .03 ||.03 || .01
| ||
|-
| January 1, 1952 || .03 || .03 || .03 || .02
| ||
|-
| August 1, 1958 || .04 || .04 || .04 || .03
| ||
|-
| January 7, 1963 || .05 || .05 || .05 || .04
| ||
|-
| January 7, 1968 || .06 || .06 || .06 || .05
| ||
|-
| May 16, 1971 || .08 || .08 || .08 || .06
| ||
|-
| March 2, 1974 || .10 || .10 || .10 || .08
| ||
|-
| September 14, 1975 || .10 || .10 || .09 || .07
| || Last surface mail rate
|-
| December 31, 1975 || .13 || .13 || .11 || .09
| || All domestic first class & postcards by airmail
|-
| May 29, 1978 || .15 || .15 || .13 || .10
| || A Stamp Used
|-
| March 22, 1981 || .18 || .18 || .17 || .12
| || B Stamp Used
|-
| November 1, 1981 || .20 || .20 || .17 || .13
| || C Stamp Used
|-
| February 17, 1985 || .22 || .22 || .17 || .14
| || D Stamp Used
|-
| April 3, 1988 || .25 || .25 || .20 || .15
| || E Stamp Used
|-
| February 3, 1991 || .29 || .29 || .23 || .19
| || F Stamp Used (also 4 cent F makeup rate stamp)
|-
| January 1, 1995 || .32 || .32 || .23 || .20
| || G Stamp Used (also 3 cent G makeup rate stamp)
|-
| January 10, 1999 || .33 || .33 || .22 || .20
| || H Stamp Used (also 1 cent H makeup rate stamp)
|-
| January 7, 2001 || .34 || .34 || .21 || .20
| ||Nondenominated Stamps Used
|-
| July 1, 2001 || .34 || .34 || .23 || .21
| || Nondenominated Stamps Used
|-
| June 30, 2002 || .37 || .37 || .23 || .23
| || Flag and Antique Toy Stamps Used
|-
| January 8, 2006 || .39 || .39 || .24 || .24
| || Lady Liberty Flag Stamp Used
|-
| May 14, 2007 || .41 || 1.13 || .17 || .26
|.69 (Can & Mex)<br />.90 (rest of world) || Price change announced February 10, 2009
|-
| April 17, 2011 || .44 || 1.71 (3 oz) || .20 (letters)<br />.17 (packages) || .29
|.80 (Can & Mex)<br />.98 (rest of world)
|-
| January 22, 2012 || .45 || 1.95 (3 oz) || .20 (letters)<br />.17 (packages) || .32
|.85 (Can & Mex)<br />1.05 (rest of world)
|-
| May 31, 2015 || .49 || 2.54 (3 oz) || .22 (letters)<br />.20 (packages) || .35
|1.20 || 2.54 (3 oz) || .21 (letters)<br />.20 (packages) || .34
| 1.15
| 2.67 (3 oz)
|.21 (letters)<br />.18 (packages)
|.34
|1.15
|3.50 (4 oz)
|.35
|1.15
|.55
|
|.15 (letters)
|.35
|1.20
|
|-
|January 24, 2021
|.55
|
|.20
|.36
|1.20
|Price change announced October 9, 2020
|-
|August 29, 2021
|.58
|
|.20
|.40
|1.30
|USPS notice post-dated September 16, 2021
|.60
|
|.24 (letters)
|.44
|1.40
|Price change announced April 6, 2022
|-
|January 22, 2023
|.63
|4.75-5.25 (zone-based)
|.24 (letters)
|.48
|1.45
|Price change announced October 7, 2022; new non-machinable surcharge: 40 cents
|-
|July 9, 2023
|.66
|
|.24 (letters)
|.51
|1.50
|Price change announced April 10, 2023
|-
|January 21, 2024
|.68
|
|.24 (letters)
|.53
|1.55
|Price change announced October 6, 2023
|-
|July 14, 2024
|.73
|
|.28 (letters)
|.56
|1.65
|Price change announced April 9, 2024
|-
|July 13, 2025
|.78
|
|.29 (letters)
|.61
|1.70
|Price change announced April 9, 2025
|}
Historical trend
thumb|450px|Actual and inflation-adjusted first-class postage rates in the U.S.
Plotting the data in the previous table yields the adjacent graph. The dark area shows the actual price of the stamp, while the light area shows the price adjusted for inflation in 2019 U.S. cents.
This plot shows that, despite the nominal rise in the price of a first-class stamp, the inflation-adjusted real cost of a stamp has stayed relatively stable. Since at least the early 1980s, the price of a stamp has closely followed the consumer price index. The large jumps in the early 1900s are because a change by a single penny was large compared to the price of the stamp. For example, the price increase from $0.02 to $0.03 on July 6, 1932, was a 50% increase in price.
Historical notes
Domestic parcel post service was adopted in 1913, 25 years after the Post Office had agreed to deliver international parcel post packages pursuant to the Universal Postal Union treaty and various bilateral agreements with other nations: