Sending a standard letter from the United States to the United Kingdom requires specific international postage, which differs from domestic rates. International postage is calculated based on the mail class, the weight, and the size of the letter. For international First-Class Mail, the cost is a flat rate for the first ounce, provided it is a standard letter, regardless of the destination country.
Current International Letter Rate
The current First-Class Mail International rate for a standard 1-ounce letter to the United Kingdom is $1.65. This rate applies universally to all countries outside the United States, Canada, and Mexico.
A standard letter must be rectangular and no more than 11.5 inches long, 6.125 inches high, and 0.25 inches thick. The simplest way to cover this cost is by using a single Global Forever Stamp. This specialized stamp is designed to always equal the current 1-ounce First-Class Mail International price, covering the full $1.65 rate. Since the UK is included in the First-Class Mail International service, a single Global Forever Stamp is the direct answer for a standard letter.
Translating Value into US Stamps
While the Global Forever Stamp is the most straightforward solution, you can also use a combination of standard Domestic Forever Stamps and smaller denomination stamps to meet the $1.65 rate. The value of a Domestic Forever Stamp is currently $0.73, which is the cost of mailing a 1-ounce letter within the United States. Meeting the international rate requires carefully combining the value of multiple stamps.
To reach the $1.65 international rate, you would need two Domestic Forever Stamps, totaling $1.46. This leaves a remaining postage requirement of $0.19. The most economical combination is two Domestic Forever Stamps and an additional $0.19 worth of smaller denomination stamps, such as two 10-cent stamps and one 1-cent stamp. Exact postage is preferred, but overpaying by a few cents is acceptable.
Weight and Size Considerations
The base international rate of $1.65 covers a letter weighing up to 1 ounce. If your letter contains multiple pages, photos, or is printed on heavy cardstock, the cost will increase. First-Class Mail International letters have a maximum weight limit of 3.5 ounces.
A letter weighing over 1 ounce but up to 2 ounces costs $2.45, and a letter between 2 and 3 ounces costs $3.25. The price increases for each ounce or fraction thereof beyond the first ounce. If mail exceeds the 3.5-ounce weight limit, or if it is rigid, lumpy, or has an uneven thickness, it is categorized as a “large envelope” or “flat,” which starts at a higher base rate of $3.15. Weighing your letter before affixing postage is important to ensure it does not require additional postage upon arrival.
Simplest Mailing Options
For those who wish to avoid calculating stamp values or combining multiple small denominations, simple alternatives exist. Taking the letter directly to a United States Postal Service (USPS) post office counter is the simplest approach. The clerk can weigh the letter precisely, apply a postage label with the exact required amount, and ensure proper classification for international transit.
Alternatively, using the USPS website or an online postage provider allows you to print a label with the precise postage amount required. This method eliminates the need for physical stamps entirely, ensuring the correct $1.65 (or higher, based on weight) postage is paid with a single label.