Line Items and Units

Each item and each bundle of the line items is an invoice line (BG-25) of the e-invoice, in the profiles with invoice lines ("basic", "en16931" and "xrechnung"); a bundle whose items have several VAT groups is one line per group. "minimum" and "basic-wl" state the totals only.

Unit Codes

ZUGFeRD requires line-item units to comply with the UN/ECE Recommendation 20 unit code standard. To ensure a fully compliant configuration, the following approaches are supported (in order of preference):

• Predefined Units (Recommended): Use the predefined unit builder functions from the unit module (e.g., unit.hour, unit.day, unit.piece, etc.). These are automatically resolved using the document's global locale and map to compliant UN/ECE codes. See the Unit API Reference for details.

  unit: unit.hour

• Custom / Dictionary Units: If you have special or custom unit requirements, pass a dictionary containing both the display text and the official UN/ECE code:

  unit: (display: "Piece", code: "C62")

• Automatic Mapping: A string that is exactly a unit code (e.g. "H87") is used as is. Other strings are mapped by the unit names of every language of invoice-pro, the symbols of the unit module and common abbreviations, e.g. "Std." or "hrs" for hours, "Tage" for days, "m²" or "qm" for square metres, "km", "t", "kWh", "Stk." for pieces, "Seiten" for pages or "pauschal" for a lump sum. A string invoice-pro does not know is an error (IP-UNIT-02) rather than a guess: with the code C62 (one), the XML would be valid, but it would state another unit than the invoice prints. Pass the unit as a dictionary with its code, e.g. (display: "Nacht", code: "C62") for a number of nights. A code that is also a common German abbreviation of another unit ("STK" is the code of sticks, "PAL" of pascal; also "FL", "GL" and "KT") is taken as a code, with a warning (IP-UNIT-01).

Unit codes are checked against the UN/ECE Recommendation 20 code list.

Prices and Quantities

Unit prices are rounded to the fine precision of the locale (normalize.money-fine, 4 decimals by default) before the line totals are calculated, and the printed invoice and the XML use this rounded price. For prices with more decimals (e.g. energy tariffs), round them more finely, up to 6 decimals:

#show: invoice.with(
  locale: locale.de-de.with(
    locale.custom.normalize(money-fine: x => calc.round(x, digits: 6)),
  ),
  // ...
)

A base-quantity (e.g. a price per 100 pieces) is written as the price base quantity (BT-149); it must be greater than 0.

Quantities and base quantities are rounded to 4 decimals, the precision the built-in number formats print, before anything is calculated with them. A quantity of 1/3 is therefore printed and written as 0.3333, and with a price of 1000.00 the line total is 333.30, as a reader of the invoice would calculate it. If you print numbers with a custom format.number, keep at least 4 decimals so the printed quantity is the one the total is based on.

Item Identifiers

Line items can carry article identifiers through the item-id parameter:

• Seller's Item Identifier (BT-155): A plain string such as item-id: "ART-4711", or (seller: "ART-4711"), is your own article number.
• Buyer's Item Identifier (BT-156): (buyer: "B-778") is the buyer's article number.
• Standard Identifier (BT-157): (standard: "4006381333931") is always declared as a GS1 GTIN (scheme 0160). Use it only for real EAN/UPC barcode numbers.

The "basic" profile only supports the standard identifier. See The item-id Parameter for details.

Item Notes, Periods and Country of Origin

Besides its name and description, an item can state a note, its date and the country its goods come from. They are printed with the item and written into its invoice line:

item parameter	Printed	XML	Profiles
note, a text	below the description	invoice line note (BT-127), with its line breaks	"basic", "en16931", "xrechnung"
date, a datetime or a period (start, end)	as the date of the item	invoice line period (BG-26, BT-134 and BT-135); a single date is a period of one day	"basic", "en16931", "xrechnung"
origin, a country (country.it) or an ISO 3166-1 code ("IT")	below the note, e.g. "Ursprungsland: IT" or "Country of origin: IT"	item country of origin (BT-159)	"en16931", "xrechnung"

"minimum" and "basic-wl" have no invoice lines. "basic" has no country of origin: origin is only printed there, which is reported as a warning (IP-PROFILE-01). A bundle is one line, printed with the names of its items, so an item inside it cannot have a note or an origin (an error); mention them in the description of the bundle. A country that is not in the ISO 3166-1 code list of EN 16931 (BR-CL-15) and a period that ends before it starts (BR-30) stop the e-invoice.

The dates of the items are the service period of the invoice, unless you set service-period (see Service Period). Then the date of every item must lie within it: XRechnung requires this for an invoicing period (PEPPOL-EN16931-R110 and R111, which the KoSIT validator reports as warnings and Mustang as errors, so invoice-pro reports an error); in the other profiles, and for a service period of a single day, a date outside it is a warning (IP-PERIOD-02).

#import "@preview/invoice-pro:0.5.0": *

#show: invoice.with(
  zugferd: "en16931",
  sender: (
    name: "Consulting Group GmbH",
    address: "Tech Avenue 42",
    city: "80331 München",
    country: country.de,
    vat-id: "DE123456789",
    contact: (
      name: "Max Mustermann",
      phone: "+49 89 1234567",
      email: "max@consultinggroup.de",
    ),
  ),
  recipient: (
    name: "Acme Corp",
    address: "Industrial Road 1",
    city: "70173 Stuttgart",
    country: country.de,
    vat-id: "DE987654321",
  ),
  invoice-nr: "INV-2026-118",
  date: datetime(year: 2026, month: 9, day: 1),
)

#line-items[
  #item(
    [Espresso machine],
    price: 1290.00,
    tax: tax.vat(19%),
    date: datetime(year: 2026, month: 8, day: 3),
    note: "Serial number 4711-0815",
    origin: country.it,
  )
  #item(
    [Barista training],
    quantity: 2,
    unit: unit.day,
    price: 450.00,
    tax: tax.vat(19%),
    date: (
      datetime(year: 2026, month: 8, day: 10),
      datetime(year: 2026, month: 8, day: 11),
    ),
  )
]

#payment-goal(days: 14)

#bank-details(
  bank: "Acme Bank",
  iban: "DE89370400440532013000",
)