# stdnum.au.tfn

TFN (Australian Tax File Number).

The Tax File Number (TFN) is issued by the Australian Taxation Office (ATO) to taxpaying individuals and organisations. A business has both a TFN and an Australian Business Number (ABN).

The number consists of 8 (older numbers) or 9 digits and includes a check digit but otherwise without structure.

More information:

- https://en.wikipedia.org/wiki/Tax_file_number
- https://www.ato.gov.au/Individuals/Tax-file-number/

    >>> validate('123 456 782')
    '123456782'
    >>> validate('999 999 999')
    Traceback (most recent call last):
        ...
    InvalidChecksum: ...
    >>> format('123456782')
    '123 456 782'

`stdnum.au.tfn.``checksum`(number)

  Calculate the checksum.

`stdnum.au.tfn.``compact`(number)

  Convert the number to the minimal representation. This strips the number of any valid separators and removes surrounding whitespace.

`stdnum.au.tfn.``format`(number)

  Reformat the number to the standard presentation format.

`stdnum.au.tfn.``is_valid`(number)

  Check if the number is a valid TFN.

`stdnum.au.tfn.``validate`(number)

  Check if the number is a valid TFN. This checks the length, formatting and check digit.