Turkish VKN Tax ID Validator
Validate Turkish Vergi Kimlik Numarası (VKN) tax numbers in real time.
Turkish VKN Validation
Validates the 10-digit structure using the official GİB cascading modulo algorithm.
Essential for Turkish e-invoicing (e-Fatura / e-Arşiv) and enterprise ERP testing.
Anatomy & Structure of the VKN (Vergi Kimlik Numarası)
The Turkish Tax Identification Number consists of 10 digits in 2 parts:
| Position | Field | Length | Meaning & Rule | Example |
|---|---|---|---|---|
| 1 to 9 | Base Tax Identifier | 9 digits | Sequential tax number issued by Turkish Revenue Administration (GİB) | 123456789 |
| 10 | Check Digit | 1 digit | Calculated via power-modular base-10 and Modulo-9 algorithm | 0 |
Official Algorithm (Base-10 Modular Power / Modulo 9 — GİB)
Official check digit calculation for Turkish VKN:
c1 = (d[i] + (9 - i)) % 10; c2 = (c1 * 2^(9-i)) % 9; sum += (c1 !== 0 && c2 === 0 ? 9 : c2); DV = (10 - (sum % 10)) % 10
- 1. For each of the first 9 digits (i=0 to 8), calculate c1 = (d[i] + (9 - i)) mod 10.
- 2. Calculate c2 = (c1 × 2^(9-i)) mod 9.
- 3. If c1 is not 0 and c2 is 0, add 9; otherwise add c2.
- 4. Sum all partial results into total.
- 5. Check digit = (10 - (total mod 10)) mod 10.