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Standards/fim

FIM

TypePostal Mark
PrimaryUS
Completeness70%high

Overview

The Facing Identification Mark (FIM) is a pattern of vertical bars printed in the upper-right portion of a letter-size mailpiece, to the left of the postage area, defined by the United States Postal Service 1, 10. It allows automatic facing (orientation) of letter mail for cancellation and identifies reply mail that carries a preprinted barcode so that equipment can route it directly to high-speed barcode sorters 10. A FIM is "essentially a nine-bit code consisting of bars and no-bar placeholders"; five patterns, FIM A through FIM E, are defined 3, 1.

History

  • The FIM was designed by the USPS to assist automated processing of mail, letting letters be faced correctly for cancellation 1, 6.
  • Patterns A–D were originally assigned to courtesy/meter reply mail (A), Business Reply Mail without a preprinted ZIP+4 barcode (B), Business Reply Mail with a preprinted ZIP+4 barcode (C), and information-based indicia (IBI) postage (D) 4, 5. Early references describe the barcode on reply mail as a POSTNET ZIP+4 barcode 6.
  • Effective June 7, 2010, the USPS revised Domestic Mail Manual (DMM) section 708.9.2 to add a fifth pattern, FIM E (101000101), for postcard- and letter-size First-Class Mail with customized services, limited to pre-approved customers in specific USPS programs 4. The test pieces combined FIM E with an Intelligent Mail Barcode and a "No Postage Necessary If Mailed in the United States" legend in place of postage 4.

No fetched source gives the year the FIM was first introduced; it is omitted here.

Technical specification

The FIM is a fixed-pattern, non-data-bearing 1D bar mark: it carries no variable payload, only one of five predefined patterns 6, 3. Each of the nine positions is either a bar (1) or an empty placeholder (0) 3.

Pattern Binary code Bars Assigned use (Publication 25)
FIM A 110010011 5 Courtesy Reply Mail and metered reply mail with a preprinted barcode
FIM B 101101101 6 Business Reply Mail, no preprinted barcode
FIM C 110101011 6 Business Reply Mail / Permit Reply Mail with a preprinted barcode
FIM D 111010111 7 PC Postage / IBI postage (printed in nonfluorescent ink directly on the envelope)
FIM E 101000101 4 First-Class postcards and letters with customized services and an Intelligent Mail barcode

Codes and uses per 3; bar counts are the number of 1 positions in each code. Seagull Scientific confirms five bars for FIM A and six for FIM C 6.

Structural rules — every pattern starts and ends with a bar, is palindromic (reads the same in either direction), and never has more than three consecutive bars or spaces 1.

Physical dimensions and placement 5, 6:

Parameter Value
Bar height 5/8 in ± 1/8 in (0.625 in)
Bar width 1/32 in ± 0.008 in (0.03125 in)
Overall width 0.53125 in
Horizontal position rightmost bar 2 in ± 1/8 in from the right edge of the mailpiece
Vertical position top of bars no lower than 1/8 in from the top edge (may extend over the flap)
Clear zone no other printing; spans 3 in to 1.75 in from the right edge, 0.625 in down from the top; bar bottoms touch the clear-zone boundary within 1/8 in

There is no check digit or error correction: the mark identifies a mail category, it does not encode data 6.

Use cases

Publication 25 makes the FIM mandatory on specific letter-size mail and forbids it elsewhere 2:

  • Business Reply Mail (BRM) — FIM B or FIM C 2.
  • Permit Reply Mail (PRM) — FIM C 2.
  • Courtesy Reply Mail (CRM) and metered reply mail — FIM A 2.
  • IBI meter mail / PC Postage — FIM D 2, 3.
  • Absentee balloting materials — FIM C 2.
  • Customized-service First-Class postcards — FIM E, for pre-approved mailers ("Share Mail" in Wikipedia's description) 4, 1.

Mailers may not use a FIM on other mail, except a letter-size permit-imprint envelope designed as a reusable mailpiece 2. On the processing side, FIM E is described as orienting, separating, and capturing mailpiece images on the USPS Advanced Facer Canceler System (AFCS) 4, and Publication 25 states that the FIM serves "to orient and separate certain types of First-Class Mail pieces during the facing-canceling process" 2.

Implementations

  • JavaScript — metafloor/bwip-js — ~2.4k★, release 4.11.4 (2026-08-19). Port of Barcode Writer in Pure PostScript (BWIPP); FIMs are rendered with the symbol encoder and data values fima, fimb, fimc, fimd 7, 8. (bwip-js in the Barcoder environment also accepted fime during verification, but BWIPP's wiki documents only A–D.)
  • C — zint/zint — 810★, BSD-3 library with GPL CLI/GUI; exposes FIM as symbology BARCODE_FIM, surfaced in the ruby-zint bindings as Zint::Fim 9.
  • Commercial — Neodynamic's barcode SDKs (.NET, WPF, ThermalLabel) include a FIM symbology enum covering A–D 5.
  • Decoders — no open-source FIM decoder was found. As a fixed pattern-matching mark, reading is done inside USPS facer-canceler equipment 2, 4.

Comparison

vs. POSTNET and Intelligent Mail Barcode — POSTNET and the IMb are height-modulated symbologies that carry variable routing (and, for the IMb, tracking) data with check digits or a CRC; the FIM carries no data and uses full-height bars at fixed positions to signal mail category and orientation 6, 3. The two are complementary: FIM A and FIM C announce that a preprinted barcode (historically POSTNET, today the IMb) is present, so the piece can bypass optical character reading and go straight to barcode sorting 10, 6, 3.

vs. PLANET — PLANET encoded tracking numbers for USPS Confirm; the FIM never identifies an individual piece 6.

When to use — print a FIM only when the DMM requires it for the reply/IBI mail categories above; pick the pattern by mail type and whether a barcode is preprinted 2, 3.

Fun facts

  • All five FIM patterns are palindromes, so they read identically whichever way a letter travels through the facer 1.
  • FIM D for PC Postage is printed in nonfluorescent ink directly on the envelope, unlike conventionally tagged stamps that facer-cancelers detect by phosphorescence 3, 1.

Status

Active. The FIM remains defined in USPS Publication 25 (Chapter 10) and DMM 708.9, with five patterns in use; Wikipedia's article (updated January 2026) lists FIM A–E as current, with FIM A and FIM C now referencing the Intelligent Mail barcode 1, 2, 3. No successor has been announced.

Sources

  1. Facing Identification Mark — Wikipedia — Wikipedia, accessed 2026-10-03
  2. Publication 25, 10-1.2 Using FIMs — USPS — USPS, accessed 2026-10-03
  3. Publication 25, 10-1.3 Patterns — USPS — USPS, accessed 2026-10-03
  4. DMM Revision: New Facing Identification Mark E Pattern — Postal Bulletin 22285 — USPS, 2010, accessed 2026-10-03
  5. USPS Facing Identification Marks Barcode — Neodynamic — Neodynamic, accessed 2026-10-03
  6. FIM — Seagull Scientific Barcode Guide — Seagull Scientific, accessed 2026-10-03
  7. metafloor/bwip-js — GitHub — GitHub, accessed 2026-10-03
  8. USPS FIM symbols — BWIPP wiki — GitHub, accessed 2026-10-03
  9. Zint::Fim — ruby-zint documentation — RubyDoc, accessed 2026-10-03
  10. Publication 25, 10-1.1 Overview — USPS — USPS, accessed 2026-10-03

Deployments

No country reports mention this standard by name.

source · content/standards/fim/index.md