Turkey IBAN Validator

The Turkey IBAN Validator confirms that a Turkish bank account number in IBAN format is structurally correct. It verifies the TR country code, the 26-character length, the 5-digit bank code, the reserved national digit, and the full ISO 7064 MOD-97-10 checksum — all without sending a single character to a server.

Turkish domestic transfers settle through the EFT (Electronic Funds Transfer) system, and a correctly formed IBAN is required for both domestic and SWIFT cross-border payments. A fast offline validator catches typos before they cause failed transfers in invoicing, payroll, and checkout flows.

How it works

A Turkish IBAN follows a fixed structure from the SWIFT IBAN Registry:

• TR — the country code for Turkey
• kk — 2 IBAN check digits (ISO 7064 MOD-97-10)
• bbbbb — 5-digit bank code
• r — 1 reserved digit, currently always 0
• 16 characters — the account number (letters and/or digits)

Total: 26 characters.

Validation runs two checks:

1. IBAN MOD-97-10 — move TR plus the check digits to the end, expand letters to numbers, and confirm the result modulo 97 equals 1.
2. Reserve digit — the single digit immediately after the bank code must be 0.

Worked example

Take TR33 0006 1005 1978 6457 8413 26:

• Country code: TR — Turkey
• Check digits: 33
• Bank code: 00061 (Türkiye İş Bankası)
• Reserve digit: 0
• Account: 0519786457841326

Moving TR33 to the end and expanding the letters produces a long numeric string that reduces to a MOD-97 remainder of 1, and the reserve digit is 0, so the IBAN is valid.

Changing any single character in a valid IBAN almost always produces a remainder other than 1, which is why the checksum catches the vast majority of typos. Every character is processed locally — nothing is uploaded, logged, or transmitted.