Skip to main content
NIH Logo NIH Logo

Office of Research Services

Serving the NIH Community

International Mail

​Special care should be taken when using any of the international mail services identified below. A return address should be used on each piece of mail. Appropriate customs forms should be completed and securely attached to all parcels. Extra packing material is encouraged for international parcels. Before sealing international parcels place a separate sheet of paper with both the destination and the return addresses inside the parcel in case the shipping label becomes detached. Make sure both the destination and the return addresses are placed on the parcel directly in the center of the top side of the envelope/box, with large clear print.

Typ​​es of International/Foreign Mail

Global Expr​​​​e​​ss Guaranteed

An expedited premium international document and non-document mail service. It provides reliable, high-speed, date-certain service to locations in most countries and territorial possessions. This service is a partnership between the U.S. Postal Service and FedEx. The official USPS delivery time frame is from 1-3 days.

Express Ma​​​il Internat​​ional (Formerly Global Express Mail)

An on-demand type service equivalent to Domestic Express Mail Service. Mailable matter such as letters, documents and some merchandise may be sent to most foreign countries. The official USPS delivery time frame is from 3-5 days.

Priority M​​ail International

The equivalent handling of Domestic Priority Mail. The official USPS delivery time frame is from 6-10 days.

First Cla​​ss Mail​​ International

Includes post cards, letters, flats, letter packages – regular printed matter, books, periodicals and small packets. This service is equivalent to the Domestic First-Class and Package Services Mail. There are some differences from domestic mail in size or weight requirements (noted by *). There is no USPS official time frame for this mail class.

First Class Mail International Postcards:

    • Maximum length 6” - Minimum length 5-1/2” *
    • Maximum height 4-1/4” - Minimum height 3-1/2”
      • Maximum thickness 0.016” - Minimum thickness 0.007”

First Class Mail International Letters:

    First Classs Mail 
    • Maximum weight 3.5 ounces
    • Maximum length 11-1/2" - Minimum length 5-1/2” *
    • Maximum height 6-1/8” - Minimum height 3-1/2”
    • Maximum thickness 1/4” - Minimum thickness 0.00
      • If your letter exceeds any of the above factors it will be classified and priced as a large envelope (flat).

First Class Mail International Large envelopes (flats):

    First Class Large 
    • Maximum weight: 16 ounces*
    • Maximum height: 12" - Minimum height 6-1/8”
    • Maximum length: 15” Minimum length 11-1/2”
    • Maximum thickness: 3/4"
      • A large envelope that exceeds any of these dimensions will be classified and priced as a package (parcel). Large envelopes must also be flexible, rectangular and uniformly thick. A large envelope that exceeds 13 ounces is classified and priced as Priority Mail.

First Class Mail International Packages:

    • Maximum weight: 16 ounces*
    • Maximum weight: 16 ounces*
    • Maximum size no more than 36" in combined length + height + thickness*

Addressing In​ternational Mail

When preparing mail to be sent to international countries, the following address format is necessary to insure delivery:

Delivery A​​​d​dress

    Recipient's Name
    Recipient’s Street Address
    Recipient’s Postal Delivery Code, City, or Province
    Recipient’s Country Name in CAPITAL letters

    Sample Delivery Address

    Dr. K.B. Loo
    45 Kane CT AP57
    90032 Rome


Preparing Global Express Guaranteed, Express Mail Internationa​​l, Priority Mail International, and First Class International:

Global Express Gu​​​​aranteed Service, Express Mail International

Appropriate USPS labels should be used for these services. The labels may be obtained from any DMMS mail center or from the Mail Customer Service Branch. After the label has been prepared (including foreign ZIP Code, if available), attach it to the front of the Global Express Mail or Express Mail International envelope in the area designated, seal the document and place into the NIH mail stream. Please do not remove any copies of these labels.

Although USPS service specific envelopes are preferred, plain white envelopes may be used if they are larger than the label and the label may be placed on the front of the envelope. AIR MAIL envelopes should not be used for Global Express Mail-Guaranteed or Express Mail International.

Parcels mailed using these services must also include a completed PS Form 2976-A, Customs Declaration and Dispatch Note that is placed within PS Form Envelope 2976-E. This form should be centered and placed next to the label on the top of the box, if possible. In addition, Global Express Guaranteed Service requires use of PS Form 6182, Commercial Invoice.

Priority Mail Internationa​​l a​​​nd First Class Mail International

Packaging should be sufficient to withstand the wear and tear of international handling. Do not leave room in the parcel for contents to shift around and don’t over pack the parcel. If the parcel is damaged in transit, the contents of your parcel could be returned, lost or destroyed.

Letters of five pages or less should be folded and placed in a letter-sized envelope. Letters and documents with more than five pages and too large to place in letter envelopes but too small for boxes, should use the larger envelopes (9 x 12 flats) for mailings.

Customs forms are required for Priority Mail International and First Class International parcels.

Cust​​​o​​ms Forms

Customs forms are necessary for parcels dispatched to all countries. For the correct form contact the Mail Customer Service Branch for assistance.

Forwarding and​​ ​​Returning International Mail

International mail for persons no longer assigned or employed by NIH should follow the same procedures for forwarding and returning domestic mail, as explained on page 14.