Nigeria NUBAN Check Digit Validator

Validate legacy three-digit-bank-code NUBAN weighted check digit against ten-digit ASCII account; expanded institution-code versions require another explicit model, and checksum does not verify a live account.

Description

The legacy Nigeria Uniform Bank Account Number (NUBAN) checksum combines a three-digit bank code with nine account-body digits.

The legacy Nigeria Uniform Bank Account Number (NUBAN) checksum combines a three-digit bank code with nine account-body digits. Checksum agreement cannot establish that an account exists.^{[1, 2]}

The returned values include Expected check digit, Check digit matches. The How section below explains the calculation, input rules and interpretation.

When to use Nigeria NUBAN Check Digit Validator

Use Nigeria NUBAN Check Digit Validator when you need to evaluate the supplied records under the calculation and evidence rules below. Expanded institution-code versions and live account validation are outside this versioned model.

Prepare observed financial records and verified caller terms. Use one currency for integer minor-unit money and preserve leading zeros in identifier text. One basis point is 0.01 percentage points. Resolve dates, local clocks, counting rules and evidence flags as specified.

How to use Nigeria NUBAN Check Digit Validator and understand its results

Prepare observed financial records and verified caller terms. Use one currency for integer minor-unit money and preserve leading zeros in identifier text. One basis point is 0.01 percentage points. Resolve dates, local clocks, counting rules and evidence flags as specified.
Enter legacyThreeDigitBankCode, tenDigitAccountText using the field table and calculation rules, then run the tool.
Read expectedCheckDigit, checkDigitMatches. The explanation below defines the units, signs, ordering and any flags or placeholder values.
If the tool reports an input issue, correct the values and run it again. Apply the stated assumptions when interpreting a successfully returned result.

Input field	Meaning	Value type; see rules below	Requirement
legacyThreeDigitBankCode	Legacy three digit bank code	string	Required
tenDigitAccountText	Ten digit account text	string	Required

Enter exactly three ASCII bank-code digits and ten ASCII account digits without trimming or normalization. Concatenate bank code and first nine account digits, apply the twelve weights and compare the expected final digit. Return expected digit text and match flag; wrong lengths are input errors but checksum mismatch returns false.

digit=(10−sum(sourceDigits×[3,7,3,3,7,3,3,7,3,3,7,3]) mod 10) mod 10

Units, indexing, boundary conditions and exceptional cases are defined in the calculation rules above.

Output field	Meaning	Value type
expectedCheckDigit	Expected check digit	string
checkDigitMatches	Check digit matches	boolean

json

{
  "input": {
    "legacyThreeDigitBankCode": "044",
    "tenDigitAccountText": "0000000000"
  },
  "output": {
    "expectedCheckDigit": "0",
    "checkDigitMatches": true
  }
}

Limitations and assumptions

Expanded institution-code versions and live account validation are outside this versioned model.

Numeric inputs, where present, must be finite. Follow the calculation-specific rules for overflow, underflow and exceptional cases. Extremely large text inputs are rejected. Missing required fields, extra fields, wrong value types and violations of the calculation rules are input errors. A successfully returned false flag is an evaluated outcome; its meaning is explained above.

Alternative or Complementary methods

Use Mexico CLABE Check Digit Validator: CLABE uses eighteen digits with a final check digit. A valid checksum is a structural consistency check rather than account verification. For a complementary task, use MICR Line Routing Account Parser: Normalized MICR notation separates routing, account and check serial text. Explicit delimiters preserve leading zeros without guessing an OCR layout.

Further background: CBN Rule Book Volume 1: legacy NUBAN account-number format.

References

Nigeria NUBAN Check Digit Validator — tool.io
CBN Rule Book Volume 1: legacy NUBAN account-number format — Central Bank of Nigeria

Similar or alternative tools

Mexico CLABE Check Digit Validator
CLABE uses eighteen digits with a final check digit. A valid checksum is a structural consistency check rather than account verification.
MICR Line Routing Account Parser
Normalized MICR notation separates routing, account and check serial text. Explicit delimiters preserve leading zeros without guessing an OCR layout.