ABN Validator

abn_validator validates the format and checksum of Australian Business Numbers (ABNs).

It accepts both compact ABNs and the conventionally grouped form:

use abn_validator::{AbnError, validate};

assert_eq!(validate("51 824 753 556"), Ok(()));
assert_eq!(validate("51824753556"), Ok(()));
assert_eq!(
    validate("51824753557"),
    Err(AbnError::ChecksumMismatch),
);

This crate only verifies that an ABN is well-formed. It does not query the Australian Business Register or confirm that the ABN has been issued or is currently active.

Installation

Add the crate to your project:

[dependencies]
abn_validator = "0.1"

Then call validate with an ABN supplied as a string:

fn process_abn(abn: &str) -> Result<(), abn_validator::AbnError> {
    abn_validator::validate(abn)?;

    // The ABN has the correct format and checksum. Registration status
    // requires a separate lookup with the Australian Business Register.
    Ok(())
}

Accepted input

An input is valid when, after removing whitespace, it contains exactly 11 ASCII digits and passes the ABN checksum.

Whitespace is ignored, including spaces, tabs, line breaks, and Unicode whitespace.
Other separators are rejected. For example, 51-824-753-556 contains an invalid - character.
Non-ASCII numerals are rejected.

Validation failures identify the reason:

Error	Meaning
`AbnError::InvalidCharacter(character)`	A character was neither an ASCII digit nor whitespace.
`AbnError::InvalidLength(length)`	The input did not contain exactly 11 digits after whitespace was removed.
`AbnError::ChecksumMismatch`	The input had 11 digits but failed the checksum.

Validation algorithm

ABNs contain a nine-digit identifier and two leading check digits. Validation subtracts one from the first digit, applies the weighting factors defined by the Australian Business Register, and checks that the weighted sum is evenly divisible by 89.

See the Australian Business Register's ABN format documentation for the authoritative algorithm and worked example.

Minimum supported Rust version

The minimum supported Rust version (MSRV) is Rust 1.85. The crate uses the Rust 2024 edition and tests this toolchain in CI.

License