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INN Validator (Russia Tax ID)

Validate authenticity, structure, and checksum of Russian INN numbers.

About Russian INN Validation

This tool inspects the 10-digit or 12-digit INN string, verifying length and confirming check digits against official Federal Tax Service formulas.

Real-time client-side validation performed securely in browser memory.

INN Validation Algorithm

  1. Verify input contains exactly 10 digits (entity) or 12 digits (individual).
  2. For 10 digits: compute CD using weights [2, 4, 10, 3, 5, 9, 4, 6, 8] and formula (Sum % 11) % 10.
  3. For 12 digits: compute 1st CD using [7, 2, 4, 10, 3, 5, 9, 4, 6, 8] and 2nd CD using [3, 7, 2, 4, 10, 3, 5, 9, 4, 6, 8].
  4. Compare with final check digits.

Frequently Asked Questions & Technical Guidelines