@fin.cx/expenses

German travel and expense reimbursement as pure functions: the per diems, mileage and lodging flats of § 9 EStG, the BMF's foreign rates by year, the tax-free and taxable share of every claim line, whether a receipt's input tax may be deducted, and the business-meal split. A claim is computed from what the person entered: the trip's days and places, the meals the company provided, the kilometres, the nights and the receipts. Every amount is a whole number of cents.

The package is pure: it reads no clock, keeps no state, has no dependencies and fetches nothing. Each year's rates ship with it.

Issue Reporting and Security

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Install

pnpm install @fin.cx/expenses

Usage

A three-day trip to Paris. The hotel's invoice to the company includes breakfast, and on the second evening the person attended a business dinner the company paid:

import { getTravelRates, perDiemsOf, lodgingFlatOf, mileageOf, taxTreatmentOf, type ITrip } from '@fin.cx/expenses';

const rates = getTravelRates(2026); // a year without rates throws ExpensesError 'travel_year_unknown'
const paris = { country: 'FR', city: 'Paris' };

const trip: ITrip = {
  startsAt: '2026-03-09T06:30', // leaving home or the first place of work, local time
  endsAt: '2026-03-11T21:15',
  days: [
    { date: '2026-03-09', placeAtMidnight: paris, placesOfWork: [paris], overnight: true },
    {
      date: '2026-03-10',
      placeAtMidnight: paris,
      placesOfWork: [paris],
      overnight: true,
      mealsProvided: [{ meal: 'breakfast' }, { meal: 'dinner' }],
    },
    { date: '2026-03-11', placesOfWork: [paris], mealsProvided: [{ meal: 'breakfast' }] },
  ],
  beyondThreeMonths: false, // the person's answer to "had you worked at this place for more than three months?"
};

const perDiems = perDiemsOf(trip, rates);
perDiems.days.map((day) => [day.date, day.kind, day.amountCents]);
// [['2026-03-09', 'arrival', 3900], ['2026-03-10', 'intermediate', 2320], ['2026-03-11', 'departure', 2740]]
// Paris: 58 € for 24 hours, 39 € for arrival and departure; breakfast −11.60 €, dinner −23.20 € (20 % and 40 % of 58 €)
perDiems.totalCents; // 8960

lodgingFlatOf({ nights: 2, place: paris }, rates).amountCents; // 31800: 159 € a night, for nights without a receipt
mileageOf({ km: 123.4, vehicle: 'car' }, rates).amountCents; // 3702: 0.30 € per km

taxTreatmentOf({ kind: 'per_diem', trip, paidCents: 12_000 }, rates);
// { allowedCents: 8960, paidCents: 12000, taxFreeCents: 8960, taxableCents: 3040, flatTaxableCents: 3040, basis: '§ 3 Nr. 16' }

Each day of the result says which place's rates it took and why (day.rate.rule), its rate before the meals (baseCents), every meal's reduction and the amount. A day that two trips share appears once, with the higher per diem: pass the trips together, perDiemsOf([firstTrip, secondTrip], rates).

Receipts:

import { inputVatOf, businessMealOf, EXPENSE_CATEGORIES } from '@fin.cx/expenses';

inputVatOf({ document: 'invoice', grossCents: 41_650, vatCents: 2_725, vatCountry: 'DE', recipient: 'person', supplyTo: 'company' });
// { deductible: false, inputVatCents: 0, reason: 'invoice_to_person' } — above 250 €: ask the hotel for an invoice to the company

inputVatOf({ document: 'ticket', grossCents: 8_990, vatCents: 588, vatCountry: 'DE', recipient: 'person', supplyTo: 'person' });
// { deductible: false, inputVatCents: 0, reason: 'supply_to_person' } — a candidate's own journey to the interview

const vat = inputVatOf({ document: 'invoice', grossCents: 18_445, vatCents: 2_945, vatCountry: 'DE', recipient: 'company', supplyTo: 'company' });
businessMealOf({
  grossCents: 18_445,
  inputVatCents: vat.inputVatCents,
  tipCents: 1_500,
  inRestaurant: true,
  participants: ['Mara Beispiel (Acme GmbH)', 'Dr. Jan Kunde (Kunde AG)'],
  occasion: 'Rahmenvertrag 2027',
});
// { expenseCents: 17000, deductibleCents: 11900, nondeductibleCents: 5100, inputVatCents: 2945, missing: [] }

EXPENSE_CATEGORIES.find((category) => category.category === 'lodging');
// { category: 'lodging', accountRole: 'travel_employee_lodging', travel: true, taxFreeBasis: '§ 3 Nr. 16', requirements: ['receipt', 'trip', 'breakfast_stated'], … }

What it computes

Per diems (perDiemsOf)

Day	Rule	Source
A day of 24 hours away	28 € in Germany; abroad the place's full-day rate	§ 9 Abs. 4a Satz 3 Nr. 1, Satz 5 EStG
The arrival and departure day of a trip with a night away	14 €, or the place's partial rate, without a minimum of hours	§ 9 Abs. 4a Satz 3 Nr. 2 EStG; BMF 25.11.2020, Rz. 49, 51
A day of more than 8 hours without a night away	14 €, or the partial rate; 8 hours or less give nothing	§ 9 Abs. 4a Satz 3 Nr. 3 EStG
An absence over midnight without a night away	Its hours added, the 14 € on the day of the greater part (on equal parts, the first day)	§ 9 Abs. 4a Satz 3 Nr. 3 second half-sentence; Rz. 47
Meals provided	−20 % for breakfast, −40 % each for lunch and dinner of the day's full-day rate, less what the person paid for that meal, the day never below 0	§ 9 Abs. 4a Satz 8 to 10 EStG; Rz. 73 to 78
Two trips meeting on a day	Only the higher per diem; the day's meals reduce it by its own full-day rate	BMF 5.12.2025, p. 2; Rz. 49
More than three months at the place	Nothing, with the warning three_month_rule	§ 9 Abs. 4a Satz 6 and 7 EStG

The place whose rate a day takes abroad:

• the arrival day and each day between: the place reached last before 24:00 local time; where that place is in Germany, the last place of work abroad that day (§ 9 Abs. 4a Satz 5 EStG; R 9.6 Abs. 3 Satz 3 LStR);
• the departure day: the trip's last place of work (BMF 5.12.2025, p. 1; BMF 25.11.2020, Rz. 52);
• a one-day trip: its last place of work abroad (BMF 5.12.2025, p. 1).

The person gives, per day, the place at 24:00 (placeAtMidnight), where they worked (placesOfWork, in order), whether they spent the night away (overnight) and the meals provided. A meal counts as provided where the employer, or a third at its instigation, gave it: a breakfast on a hotel invoice to the company, a lunch at a seminar the company booked, a business meal, a meal the company reimbursed (Rz. 64, 75, 82). It reduces the day whether it was eaten or not.

The rate of a place (rateOfPlace)

A place is a country by its ISO 3166-1 alpha-2 code and, where it matters, a city. DE is Germany.

• A city the letter lists for its country takes the city's rate; any other city the country's rate "im Übrigen". Paris includes the départements 77, 78 and 91 to 95: give Paris for a place there. Cities are compared without regard to case, as the letter writes them (New York City, Washington, D. C., Kanarische Inseln, Hongkong).
• Micronesia takes the Philippines' rates, and Antigua and Barbuda, Dominica, Grenada, Guyana, St. Kitts and Nevis, St. Lucia, St. Vincent and the Grenadines and Suriname take Trinidad and Tobago's (BMF 5.12.2025, p. 2).
• An overseas or outlying territory the letter does not list takes its mother country's rate: Réunion France's, Puerto Rico that of the United States, Hong Kong (HK) China's city rate for Hongkong (p. 2; R 9.6 Abs. 3 Satz 2 LStR).
• Any other country the letter does not list takes Luxembourg's rate.

Mileage and lodging (mileageOf, lodgingFlatOf)

• Mileage in the person's own vehicle: 0.30 € per km by car, 0.20 € per km by another motor vehicle, the highest Wegstreckenentschädigung of the BRKG (§ 9 Abs. 1 Satz 3 Nr. 4a Satz 2 EStG; § 5 Abs. 1 and 2 BRKG; Rz. 37). Kilometres take one decimal; the amount is rounded to the cent. A bicycle gives no flat: § 5 BRKG sets none for it. A company car gives none either (R 9.5 Abs. 2 Satz 3 LStR).
• Lodging without a receipt: 20 € a night in Germany, the BMF's flat of the place abroad. Only the employer may pay these flats, and only for a night the person paid for. They do not apply to lodging provided free, a night in a vehicle, or a sleeping car or ship's cabin unless the night began or ended elsewhere (R 9.7 Abs. 3 LStR; Rz. 128).

Tax-free and taxable (taxTreatmentOf)

Line	Tax-free up to	Basis
per_diem	the per diems computed	§ 3 Nr. 16 EStG
mileage, lodging_flat	the flat	§ 3 Nr. 16 EStG
receipt, replacement of a travel category (tickets, taxi, rental car, parking, lodging)	the receipt's gross	§ 3 Nr. 16 EStG
receipt, replacement of any other category	the receipt's gross (Auslagenersatz)	§ 3 Nr. 50 EStG

Whatever the company pays above that is wages (taxableCents). Per diems paid above the tax-free amount may be taxed at a flat 25 % up to 100 % of the per diems before meal reductions (flatTaxableCents), but not after the three months (§ 40 Abs. 2 Satz 1 Nr. 4 EStG; Rz. 58, 59, Beispiele 42, 50, 51).

Input tax (inputVatOf)

recipient is whom the document names; supplyTo is whom the supply was made to. An employee's business travel and an outlay for the company are supplies to the company (company). A guest's own travel, such as a candidate's journey to the interview, is a supply to the guest (person), which the company only reimburses: its input tax is deducted only where the invoice names the company.

Receipt	Input tax	Reason
An invoice naming the company	deductible	invoice_to_company (§ 15 Abs. 1 Satz 1 Nr. 1, § 14 Abs. 4 UStG)
Up to 250 € gross, naming anyone or no one	deductible	small_amount_invoice (§ 33 UStDV)
A ticket	deductible	ticket (§ 34 Abs. 1 UStDV)
A cross-border ticket without the carrier's statement of the domestic share	not deductible	cross_border_ticket (§ 34 Abs. 2 UStDV)
Above 250 € naming the person	not deductible	invoice_to_person
Above 250 € naming no one	not deductible	recipient_missing
A supply to the person, the invoice not naming the company, even a ticket or up to 250 €	not deductible	supply_to_person (§ 15 Abs. 1 Satz 1 Nr. 1 UStG)
Another country's VAT	not deductible here	foreign_vat
No VAT shown	none	no_vat_shown
An Ersatzbeleg; a per diem, mileage or lodging flat	none	replacement, flat_amount

Whether an invoice carries every detail of § 14 Abs. 4 UStG is not checked.

Business meals (businessMealOf)

70 % of the expense is deductible and 30 % is not; the tip is part of the expense, and so are the host's and the employees' shares (§ 4 Abs. 5 Satz 1 Nr. 2 EStG; R 4.10 Abs. 5 Satz 4, Abs. 6 Satz 7 EStR). The expense is the gross less the deductible input tax, plus the tip. The input tax is deducted in full (§ 15 Abs. 1a Satz 2 UStG). The deductible part is rounded down to the cent, so it never exceeds 70 %; the rest is the non-deductible part. missing names the details the Bewirtungsbeleg still lacks:

• always the participants and the occasion;
• outside a restaurant also the place and the day;
• for a restaurant invoice above 250 €, the host named on the invoice (§ 4 Abs. 5 Satz 1 Nr. 2 Satz 2 and 3 EStG; R 4.10 Abs. 8 and 9 EStR).

The restaurant's invoice must be machine-made, registered and itemised (R 4.10 Abs. 8 Satz 8 and 9 EStR). This is not checked.

A business meal on a trip day is a meal provided, which reduces that day's per diem (Rz. 82).

Categories (EXPENSE_CATEGORIES)

Tickets, taxi, rental car, fuel (of a company car), parking and tolls, lodging, business meal, office supplies, postage, literature, training, software, other. Each comes with:

• the @fin.cx/chartdata account role it books on (TExpenseAccountRole), and the role of a business meal's non-deductible part;
• whether it is a travel cost;
• its tax-free basis;
• what a line must carry (receipt, trip, breakfast stated, vehicle, participants, occasion, place and day).

The allowances book on travel_employee_meals, mileage_employee and travel_employee_lodging (ALLOWANCE_ACCOUNT_ROLES).

The roles are those of @fin.cx/chartdata from 3.2.0 (TExpenseRole), which gives a role's account in a chart:

import { getExpenseAccount } from '@fin.cx/chartdata';

getExpenseAccount('SKR03', 2026, 'travel_employee_meals')?.accountNumber; // '4664'
getExpenseAccount('SKR04', 2026, 'travel_employee_meals')?.accountNumber; // '6664'

This package does not depend on chartdata at runtime; a test holds every role against both standard charts.

What is refused

Every input is checked. A refusal throws an ExpensesError with a code and the field it is about (days[2].placeAtMidnight, [1].days[0].date for the second of several trips):

Code	Refused
travel_year_unknown	A year without rates; a trip day in a year whose rates were not passed
invalid_place	A country that is no ISO 3166-1 alpha-2 code in capitals (or XK); an empty city
invalid_trip	Times that are not YYYY-MM-DDTHH:MM; days that are not the trip's calendar days in order; no place at 24:00 on an arrival or intermediate day; no place of work for the departure day; a night away after the last day; three or more days without a night away; a meal listed twice on a day
trip_end_not_after_start	A trip's end at or before its start (endsAt)
invalid_amount	Cents that are not whole numbers from 0; kilometres with more than one decimal; nights that are not whole; a tax amount above its gross
invalid_line	A line kind, category or vehicle this package does not know
invalid_receipt	A document kind, recipient, supply or VAT country this package does not know

The years

Year	Rates	Foreign table
2026	28 € / 14 €, 20 € lodging in Germany, 0.30 € / 0.20 € per km	BMF letter of 5 December 2025, GZ IV C 5 - S 2353/00094/007/012, DOK COO.7005.100.3.13672232: 166 countries, 48 cities

TRAVEL_RATE_YEARS lists them. A trip over the turn of a year takes both years' rates: perDiemsOf(trip, [getTravelRates(2026), getTravelRates(2027)]), once 2027 exists. Each year's letter comes as a minor release.

How the foreign table is made

ts/data/travelrates.<year>.ts is generated from the letter's PDF, as published on bundesfinanzministerium.de:

1. tools/extract-pdf-rows.mjs lays out the PDF's text with pdf.js (not a dependency: pass the path of any pdfjs-dist).
2. tools/generate-travelrates.ts reads the table's rows. The text layer splits some cells, such as Chile's "29" into "2" and "9", and some names run over two lines ("Paris sowie die / Departments 77, 78, 91 bis 95", "Vereinigte Staaten von Amerika / (USA)"). The generator joins them and reports each one.
3. tools/check-travelrates.ts reads the same PDF a second time through Ghostscript and compares every row's name and amounts.

For 2026, both readings agree on all 214 rows. Every row was also compared by hand with the rendered pages 1 to 7 of the letter's Anlage. The changes against the previous year, printed bold in the letter, are not recorded.

ts/data/countries.ts (the ISO codes and the mother country of each territory) is generated by tools/generate-countries.ts from Wikipedia's "List of ISO 3166 country codes".

Not covered

• Double household (doppelte Haushaltsführung), the professional drivers' allowance for nights in a vehicle (§ 9 Abs. 1 Satz 3 Nr. 5b EStG), meal benefits outside trips, and the flat 25 % tax itself (flatTaxableCents says how much it may cover). These belong to payroll.
• The three-month period itself: it is the person's answer, not computed from earlier trips.
• Several separate absences on one day (BMF 25.11.2020, Rz. 47, Beispiel 29): give the day's longest trip, or add the times yourself.
• Days in the air over more than two calendar days (Austria's rate) and sea voyages (Luxembourg's rate), R 9.6 Abs. 3 Satz 4 LStR: give the place yourself.
• Meals above 60 € taxed as wages, which reduce nothing (Rz. 86): leave them out of mealsProvided.
• The limit on actual lodging costs after 48 months at one place of work (§ 9 Abs. 1 Satz 3 Nr. 5a Satz 4 EStG).
• Whether an expense is reasonable, whether a meal of the company's own employees is a business meal (it is not, R 4.10 Abs. 7 EStR), and whether an invoice meets § 14 Abs. 4 UStG.
• Changes of daylight saving time: hours away are wall-clock hours.

Sources

• § 3 EStG Nr. 16 and Nr. 50; § 4 EStG Abs. 5 Satz 1 Nr. 2; § 9 EStG Abs. 1 Satz 3 Nr. 4a, Abs. 4a; § 40 EStG Abs. 2 Satz 1 Nr. 4; § 5 BRKG; § 15 UStG Abs. 1 and 1a; § 33 and § 34 UStDV (read 2026-10-08).
• BMF, "Steuerliche Behandlung von Reisekosten und Reisekostenvergütungen bei betrieblich und beruflich veranlassten Auslandsreisen ab 1. Januar 2026", 5 December 2025, GZ IV C 5 - S 2353/00094/007/012, DOK COO.7005.100.3.13672232, with its Anlage "Übersicht": bundesfinanzministerium.de, PDF SHA-256 0eacf14b6eedcc17d9147d374bd1bb76036d9c4b424b3f966040109984f9d760.
• BMF, "Steuerliche Behandlung der Reisekosten von Arbeitnehmern", 25 November 2020, BStBl I S. 1228 ("Rz." above), as printed in the BMF's Lohnsteuer-Handbuch 2026, Anhang 25 III: lsth.bundesfinanzministerium.de.
• R 9.5, R 9.6 and R 9.7 LStR, as printed in the Lohnsteuer-Handbuch 2026: lsth.bundesfinanzministerium.de.
• R 4.10 Abs. 5 to 9 EStR, as printed in the Einkommensteuer-Handbuch 2024: esth.bundesfinanzministerium.de.
• Wikipedia, "List of ISO 3166 country codes", columns "Sovereignty" and "A-2" (read 2026-10-08).

Unconfirmed:

• That a crown dependency (Guernsey, Jersey, Isle of Man) or another non-sovereign ISO territory is an "Übersee- oder Außengebiet" in the letter's sense, taking its mother country's rate, is this package's reading. The letter does not list them.
• The worked example of BMF 25.11.2020, Beispiel 50 Abwandlung 1, states a payment of 5 € for breakfast but computes with 6 €; it is not used.
• The Einkommensteuer-Handbuch was read in its 2024 edition, the newest found; R 4.10 EStR's text there gives the host's name above 150 €, with a note raising the limit to 250 € from 2017.
• That a guest's own travel, such as a candidate's journey to the interview, is a supply to the guest and not to the company is this package's reading of § 15 Abs. 1 Satz 1 Nr. 1 UStG (a supply "für sein Unternehmen"); confirm it with a tax advisor.
• The UStAE's section on input tax from employees' travel receipts was not read. Not deducting the input tax of an invoice above 250 € that names the person follows § 14 Abs. 4 Satz 1 Nr. 1 UStG (the recipient's name and address).

License and Legal Information

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