Method 2026-10-06.duplicate-invoice.1.
Candidates require original invoice and ledger review. Matching facts do not prove duplicate payment, fraud or recoverable loss. This tool does not delete invoices, approve or block payments, query a ledger, convert currency or authenticate documents.
Keep this pack private. JSON and Excel retain complete parsed sources and results. CSV uses spreadsheet-safe escaping. PDF uses explicit Unicode escapes for characters unsupported by its core serif font. DOCX and JSON preserve the original text.
PDF and DOCX summarize the first 100 rows and groups. Long summary text is abridged after 400 characters.
JSON is a parsed-source backup, not an exact original-file backup. Keep the unchanged original separately and restore it with Select file. Supply the frozen review inputs again. Candidate group membership is complete in JSON and Excel.
Find repeated supplier and invoice numbers, conflicting invoice details, and equal supplier, amount, currency and date candidates. Keep every source row for review.
Method revision 2026-10-06.duplicate-invoice.1.
Group exact supplier IDs with invoice numbers using the selected comparison. Every occurrence is retained, including the first. Original strings never change.
Separately group exact supplier IDs with equal signed decimal amounts, exact uppercase three-letter currency labels and valid YYYY-MM-DD invoice dates. This secondary comparison can flag different invoice numbers. It uses no date tolerance, currency conversion or fuzzy supplier matching.
Amounts support a minus sign, 1 through 15 integer digits and at most six decimal places. Leading zeros and trailing decimal zeros compare numerically using scaled integer arithmetic. No rounding, float arithmetic, commas, exponents or currency symbols. Negative and zero amounts remain review items, never inferred losses.
Currency labels require three uppercase ASCII letters. The tool does not infer currency or verify currency-code membership or minor units. Dates require exact YYYY-MM-DD from 1900 through 2200.
Duplicate record references and missing or unsupported values remain unresolved. Known supplier and invoice facts can still identify a candidate. Missing facts cannot establish a unique invoice.
Identifier groups report conflicting amounts, currencies or dates, including incomplete detail coverage. Group numbers follow first source occurrence. Source row numbers count the header as row 1.
Selected comparison. Exact text.
Candidates require original invoice and ledger review. Matching facts do not prove duplicate payment, fraud or recoverable loss. This tool does not delete invoices, approve or block payments, query a ledger, convert currency or authenticate documents.
