Validation rules

BR-CO-17

A VAT breakdown's tax amount (BT-117) does not equal its taxable amount (BT-116) multiplied by the category rate (BT-119), allowing for rounding.

Rule: BR-CO-17 — official EN 16931 / XRechnung rule
Severity: error
Business term: BT-117 — VAT category tax amount
Field in your JSON: invoice.lines
Detected by: tier 3 — KoSIT validator (authoritative)
Reachability: Only reachable when validating your own XML — normbill-generated documents cannot trigger it

The engine computes every breakdown's tax amount exactly this way (calc/totals.ts, half-up rounding).

How to fix it

Recompute the subtotal's cbc:TaxAmount as taxable × rate / 100, rounded to 2 decimals.

BR-CO-17 auf Deutsch — was bedeutet der Fehler?

Der Steuerbetrag einer Umsatzsteueraufschlüsselung (BT-117) entspricht nicht Steuerbasisbetrag (BT-116) × Steuersatz (BT-119), unter Berücksichtigung der Rundung.

So beheben Sie den Fehler

Berechnen Sie cbc:TaxAmount des Subtotals als Basis × Satz / 100, kaufmännisch auf 2 Nachkommastellen gerundet.

Official sources

Every 422 from the API lists the rule id, the path in your request JSON, a plain-language message and a suggested fix — see the docs overview for the report format.

Or try it live: drop any XRechnung XML on the free validator — same KoSIT-backed report, no account.