Official rule text
[DECIMAL_PRECISION] Amount field exceeds maximum decimal precision defined in §2.6 of FA(3) specification
Why this error occurs
KSeF checks the FA(3) XML in two stages: XSD schema (structure, element order, data types, patterns such as NIP or dates) and semantic rules from the Ministry of Finance information sheet (consistency of amounts, annotations P_16 to P_23, roles of Podmiot2/Podmiot3, bank account formats, currency rates).
How to fix it
Fix the element named in the message. For XSD errors compare the element order and value pattern with the FA(3) schema; for semantic errors apply the cause and fix hints listed on this page. Re-validate before submitting to KSeF: a rejected invoice has no KSeF number and is not issued.
What the validator checks
Typical causes
- Unit price has more than 8 decimal places
- General amount has more than 2 decimal places
- Quantity or exchange rate has more than 6 decimal places
- System generating excessive decimal precision
Check your invoice
Drop your XML or PDF on the validator and every failed rule is linked to its page here. Free, no account, the file is not stored.
Same check via API:
curl -F file=@invoice.xml https://einvoicechecker.com/v1/validateRelated rules
AMOUNT_NO_SEPARATORSAmount fields must not contain spaces, commas, or any non-numeric characters except…GTU_FORMATGTU value must match pattern GTU_XX (GTU_01 through GTU_13)INVALID_BANK_ACCOUNT_FORMATPolish bank account (NrRB) must be 28 characters for IBAN format (PL + 26 digits) or…IPKSEF_FORMATIPKSeF must be exactly 13 alphanumeric characters [0-9a-zA-Z] (§12.1)NRRB_LENGTHNrRB must be 10–34 characters (§12.1)
Frequently asked questions
What does DECIMAL_PRECISION mean?
DECIMAL_PRECISION is a ksef fa(3) rule: Amount field exceeds maximum decimal precision defined in §2.6 of FA(3) specification
Will my invoice be rejected because of DECIMAL_PRECISION?
Yes. DECIMAL_PRECISION is flagged "fatal"; validators (KoSIT, Peppol access points, the German ZRE/OZG-RE portals, KSeF) reject the invoice until it is fixed.
Which formats does DECIMAL_PRECISION apply to?
Structured invoices (FA(3) schema) submitted to the Polish KSeF. XSD codes come from the schema, semantic codes from the Ministry of Finance information sheet; KSeF rejects invoices that fail an error-level rule. Syntax: FA3.
Source: KSeF FA(3) schema 1-0E + semantic rules (@ksefuj/validator 0.4). Catalogue generated from the official rule sets on 2026-10-15.