How to use
Run a clean first pass
- Enter an 8-digit business number, or load a sample number.
- Click validate to see the checksum ladder and result summary.
- If the 7th digit is 7, the special-case rule is shown directly in the display.
Uniform Invoice Validator
Enter 8 digits to check the Taiwan business number checksum.
Receipt input
Enter invoice number
Only digits are kept while typing, and you can press Enter to validate.
Quick samples
Local only
Every check stays in the browser, which keeps the tool safe for embedded review flows.
Checksum board
Checksum ladder
Submit an 8-digit value to see each weighted step, split sum, and running total.
Ready
Validation results appear here.
How to use
Enter 8 digits and click Validate. The right side shows every weighted step, split-digit sum, and the final verdict.
Common use: double-check invoice forms, vendor records, or pasted spreadsheet rows before moving on.
Scope: this tool only validates format and checksum rules. It does not verify whether a company actually exists.
Quick guide
Use cases, answers, and nearby tools
Compact below-tool notes that help first-run users and repeated visitors move faster without changing the main interface.
Examples
Real jobs this page helps with
- Invoice header pre-checkQuickly check business number format and checksum before creating customer records or issuing documents.
- Educational referenceUse the result ladder to explain Taiwan business number checksum logic to colleagues.
FAQ
What people usually want to know
- Is this an official lookup?
- No. This page provides local format and checksum validation, not a government database query.
- Is my data uploaded?
- No. Validation runs locally in the browser.
- Does it support the digit-7 special case?
- Yes. The display includes the special-case rule in both the explanation and result.