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About this tool
Validate the 4 letters, 5 digits, 1 letter structure of a TAN offline, decode its location code and catch typos.
A TAN is the ten-character Tax Deduction and Collection Account Number that section 203A of the Income-tax Act requires every deductor to quote, built as four letters, five digits and one closing letter. This validator checks that structure offline, splits the number into its location code, deductor initial, serial and final letter, and names the exact position that is wrong when it fails. It is built for payroll and accounts teams reconciling TDS challans, and for developers adding a client-side format check before an API call.
Open TAN Format Validator on AltFTool — it loads instantly in your browser.
Paste your code or data sample into the workspace.
Pick the format, conversion, or analysis you need.
Copy the polished result straight back into your project.
Names the failing position instead of just saying invalid, and suggests the likely fix.
Paste a whole list and get a valid or invalid verdict for every line at once.
The check is pure pattern matching in JavaScript, so no TAN is transmitted or stored.
A TAN is exactly ten characters in the pattern AAAA99999A: three letters for the city of the allotting income-tax office, a fourth letter that is the initial of the deductor's name, five digits, and one final letter. Anything longer, shorter or out of that order is not a TAN.
Only its structure. A TAN has no published check digit, so an offline tool can prove the shape is right but never that the number was actually allotted. Use the Know your TAN service on the Income Tax e-filing portal to confirm the deductor's name against a TAN.
A PAN is five letters, four digits and one letter and identifies a taxpayer; a TAN is four letters, five digits and one letter and identifies a person who deducts or collects tax at source. A business normally holds both, and quoting a PAN where a TAN is required makes the TDS statement invalid.
Section 272BB provides a penalty of Rs 10,000 for failing to apply for a TAN or for quoting a wrong TAN in challans, statements or certificates. Banks also refuse TDS challans that do not carry a valid TAN, so the deposit itself can fail.