Regex for IFSC Code Validation — Indian Bank Codes Explained

The Indian Financial System Code (IFSC) uniquely identifies every bank branch that participates in RBI electronic transfer systems like NEFT, RTGS, and IMPS. If you're building a payments form, payroll tool, or banking integration for Indian users, validating IFSC format before hitting a bank verification API saves both API calls and user frustration. This guide covers the exact format, a battle-tested regex, and implementation examples in JavaScript and Python.

Understanding the IFSC format

An IFSC code is always exactly 11 characters, structured as follows:

• First 4 characters — uppercase letters identifying the bank (e.g. HDFC, SBIN, ICIC).
• 5th character — always the digit 0, reserved by RBI for future use.
• Last 6 characters — alphanumeric, identifying the specific branch.

An example valid code is HDFC0001234, where HDFC is the bank code and 001234 identifies the branch.

The IFSC regex pattern

^[A-Z]{4}0[A-Z0-9]{6}$

This pattern requires exactly four uppercase letters, a literal 0, and six trailing alphanumeric characters — no more, no less, thanks to the anchors.

JavaScript example

function isValidIFSC(code) {
  const ifscRegex = /^[A-Z]{4}0[A-Z0-9]{6}$/;
  const normalized = code.trim().toUpperCase();
  return ifscRegex.test(normalized);
}

console.log(isValidIFSC("hdfc0001234")); // true
console.log(isValidIFSC("HDFC1001234")); // false - 5th char must be 0
console.log(isValidIFSC("HDF0001234")); // false - only 3 letters at start

Python example

import re

IFSC_REGEX = re.compile(r"^[A-Z]{4}0[A-Z0-9]{6}$")

def is_valid_ifsc(code: str) -> bool:
    normalized = code.strip().upper()
    return bool(IFSC_REGEX.match(normalized))

print(is_valid_ifsc("sbin0000123"))  # True
print(is_valid_ifsc("SBIN000012"))   # False - only 5 trailing characters

SQL example for bulk validation

If you're cleaning a branch master table in PostgreSQL, you can flag invalid IFSC codes using a regex match directly in SQL:

SELECT branch_name, ifsc_code
FROM bank_branches
WHERE ifsc_code !~ '^[A-Z]{4}0[A-Z0-9]{6}$';

Common pitfalls

• Allowing lowercase input without normalizing — IFSC codes in bank records are always uppercase.
• Forgetting the fixed 0 in position five, which loosens the pattern and accepts invalid codes.
• Treating a regex pass as branch existence confirmation. Always cross-check against the RBI IFSC list or a banking API before processing an actual transfer.

Frequently Asked Questions