Convert your FIRE (Pub 1220) file to IRIS

A FIRE file is a stack of 750-character records: one T record for the transmitter, an A record for each issuer and form type with the amount codes it uses, a B record per payee with 18 payment amount fields and a form-specific tail in positions 544 to 750, then C, K and F records with totals. IRIS takes the same data as XML (A2A) or as a CSV template per form (the Taxpayer Portal), with each box named rather than numbered. The converter maps every amount code and every position of the 544 to 750 tail to its IRIS element, form by form, from the four Pub 1220 editions.

Some things do not translate. IRIS wants an individual's first and last name separately; FIRE has one name line, so the converter splits it using the name control and tells you when it was unsure. IRIS wants a two-letter country code; FIRE packs a foreign city, province, postal code and country into one field. IRIS has no field for a few FIRE amount codes (prior-year nonemployee compensation; the 1099-PATR box 12 lump sum, which IRIS splits into six named credits) and FIRE has no field for a few IRIS boxes (1099-NEC excess golden parachute payments). Each case is listed by record, with the FIRE position it came from.

The T record

Positions 2 to 5 give the payment year and position 6 the prior-year flag. Without the flag, the file follows that year's edition. With it, the file was produced later than the payment year, and the converter works out which later edition from the records themselves.

The A records

Every edition reads the same positions, so the edition mostly decides which codes are valid: amount codes that only some editions define (1099-MISC code B, excess golden parachute payments, through 2024) are evidence. One trap: the 2022 edition misprints its A record table two positions to the right (issuer name from 55) while its own text says 53. A file built from the misprinted table is recognised and read accordingly. The converter shows every piece of evidence and the edition it points to.

Never applied silently

The guess is shown with its evidence, and you choose the edition before anything is converted. When the evidence conflicts, for example an amount code that no longer exists in the edition the payment year implies, the converter says so and stops, because reading a file against the wrong edition would produce a tidy file with the wrong money in it. A 2026 file has no edition of its own (the IRS printed none); it follows the 2025 edition and converts to IRIS tax year 2026.

The output goes through the IRIS schema check and the IRIS business rules for the file's tax year, the same check the IRIS 1099 File Checker runs. On top of that, the conversion report lists what needed a judgment call (names split, foreign addresses parsed, TIN types assumed), what IRIS requires that FIRE did not carry (an IRIS TCC and Software ID for A2A, a country code, a first name), and what FIRE carried that IRIS has no place for. Work through that list, then file through the portal or your A2A software.

Corrections are kept apart: B records coded G or C become a separate corrected transmission, with the recipient marked as previously filed through FIRE. The portal CSV is split at 250 rows, the portal's upload limit, and each file is checked as a portal upload. Tax years before 2022 cannot go to IRIS at all, and the converter says so instead of producing a file the IRS would turn away.