CBP Directive 3550-055

MID code generator (manufacturer ID for CBP)

Give your broker the right MID before the entry goes back.

Type the factory name, street address line and city to get the manufacturer identification code built with the rules in CBP Directive 3550-055, with each of the five pieces explained.

Last updated 2026-09-28. Math runs in your browser, no data leaves your computer.

Copy the details from the commercial invoice or the factory's business licence in English, one field at a time. The code follows Attachment A of CBP Directive 3550-055, and everything runs in your browser.

Use the ISO code of the country in the factory's address, so a Guangdong factory is CN even when the invoice comes from Hong Kong.

Type the city itself, not the district or the province, because only the first three letters of the city name are used.

Use the factory that made the goods, since a trader's name gives CBP the wrong party and a different MID for every trader you buy through.

Leave out the city and the postcode, because the rule takes the largest number on the street line and a 6 digit Chinese postcode would win.

Before the booking, screen the name on the invoice. Shipment pre-check is on the paid plans, from USD 59 a month.

General guidance only. Verify against the cited primary sources before you commit to a shipment, declaration, or contract.

The five pieces CBP uses

The rules come from CBP Customs Directive 3550-055, dated 24 November 1986, which replaced the old telex number with a code "keylined" from the name and address on the invoice. The code runs to 15 characters at most, with no spaces, and is thought of as five pieces.

PieceLengthRule in Attachment A
1. Country2The ISO code for the country, such as PE for Peru.
2 and 3. Nameup to 3 eachThe first three characters of each of the first two words of the name; no third piece for a one word name.
4. Addressup to 4The largest number on the street or box line, first four digits; a suite or box number counts if it is the largest.
5. Cityup to 3The first three letters of the city name, so St. Michel gives STM.

Four general rules sit on top of the pieces. Punctuation such as commas, periods and ampersands is ignored, single character initials such as the S. in Thomas S. Delvaux Company are dropped, and the English words a, an, and, of and the are skipped. Two or more initials together count as one word, so ABC Company, A.B.C. Company and A B C Company all give ABCCOM.

Numbers split by commas or hyphens are read as one number once the punctuation is gone, so 12,34,56 Akasaka Road gives 1234. The directive also warns that some invoices print the city and its postcode before the street line, and the number to use is the one on the street line, not the city's.

Chinese invoices raise the same traps. Room and building numbers are often larger than the street number and win under the largest number rule, which is what CBP wrote, so the tool follows it rather than guessing which number the factory meant.

Worked example. The code built from the trader's letterhead

The booking. A US buyer imports a resin made by a made up factory, Guangzhou Polymer Co., Ltd., at No. 1234 Huangpu East Road in Guangzhou, but the invoice comes from the factory's Hong Kong sales company. The broker builds the code from the letterhead on the invoice and sends HK as the country with the Hong Kong office's name and street, which looks fine on paper.

The failure. That code describes an office that made nothing, so the entry points at the wrong party and the next entry through a different trader gets a different code again. The directive says entry documents with a wrong code may be returned for correction, and the choice is plain: fix the code now, or explain it later.

The fix. The buyer asks the trader for the factory's name and address, and the tool builds CN, then GUA and POL from the first two words, 1234 from the street number and GUA from Guangzhou. The code CNGUAPOL1234GUA goes to the broker, who uses it for every entry of that factory's goods.

Not sure the name on the invoice is the factory at all? The Chinese business license reader shows whether the supplier's registered business scope includes production or only sales.

Verify with CBP's own examples

Plug any line below into the form above. The output should match CBP's code exactly, because these are the nine examples printed in Attachment A of the directive.

Inputs (country, name, street line, city)Expected output
FR, La Vie de France, 243 Rue de la Payees, BremondFRLAVIE243BRE
VE, 20th Century Technologies, 5 Ricardo Munoz, Suite 5880, CaracasVE20TCEN5880CAR
GB, The E.K. Rodgers Companies, One World Trade Center, LondonGBEKRODLON
US, The Greenhouse, 45 Royal Crescent, BirminghamUSGRE45BIR
AU, Carduccio and Jones, 88 Canburra Avenue, SidneyAUCARJON88SID
JP, N. Minami & Co.,Ltd., 2-6, 8-Chome Isogami-Dori,Fukiai-Ku, KobeJPMINCO268KOB
IT, Bocchaccio S.P.A., Via Mendotti, 61, VeronaITBOCSPA61VER
GR, Murla-Praxiteles Inc., (no street line), AthensGRMURINCATH
IT, Sigma Coy E.X.T., 1640 Delgado, SmyrnaITSIGCOY1640SMY

Frequently asked

What is a MID code?

The manufacturer identification code (MID) is a code of up to 15 characters that a US entry carries for each manufacturer or shipper. CBP does not issue it; the broker builds it from the name and address on the commercial invoice using the rules in CBP Directive 3550-055. The directive says entries without the code meet significant processing delays, and entry documents with a wrong code may be returned for correction.

How is the MID code built?

Five pieces with no spaces: the 2 letter ISO country code, the first three characters of each of the first two words of the company name, up to the first four digits of the largest number on the street address line, and the first three letters of the city. Punctuation, single initials and the English words a, an, and, of and the are ignored, and initials written together count as one word, so A.B.C. Company gives ABCCOM.

Should the MID use the factory or the trading company?

CBP calls it a manufacturer/shipper code, and it is used to track who made the goods, so build it from the factory's name and address, not the Hong Kong or Shanghai trader that sends the invoice. Where several company names appear on the invoice, Attachment A says to use the name and address of the corporate headquarters rather than a division or office. Ask your broker which party CBP expects for your goods when the invoice shows only the trader.

Is a Hong Kong supplier coded HK or CN?

The first piece is the ISO code of the country in the manufacturer's address, so a factory in Guangdong is CN even when its sales office sits in Hong Kong. HK belongs only on a code for a manufacturer whose address is in Hong Kong. Getting this piece wrong gives a different MID for the same factory, which splits its entry history.

What if the address line has no number or the name is one word?

Then that piece is simply left out, which the directive allows in both cases. One World Trade Center gives no number, because the rule counts digits only, and a one word name such as Bergstrom gives just BER. The code is shorter, not invalid.

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Sourzi shows what official files say. It is not customs or legal advice. For a binding answer, ask a licensed customs broker, a CBP ruling or an Australian Border Force Tariff Advice.

File dates and links are on Data sources.