Medicare Number Validator
Check whether an Australian Medicare number is well formed
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How the check digit works
Multiply the first eight digits by 1, 3, 7, 9, 1, 3, 7 and 9, add the results, and take the remainder modulo 10. That remainder is the ninth digit. Note that it is the plain remainder, not ten minus it: implementations that reach for the complement, as most check digit schemes use, end up rejecting nine numbers in ten.
The tenth digit is the issue number and takes no part in the calculation, and neither does the IRN if you include it as an eleventh digit. This tool accepts either length and splits the parts out for you.
Why the first digit is a warning, not an error
Numbers in circulation begin with a digit from 2 to 6. That is a pattern in how numbers have been allocated rather than a rule in a published specification, so a number that satisfies the check digit but starts with something else is flagged here rather than rejected. Services Australia does not publish the algorithm at all, which is worth stating plainly: the weights above are the ones every independent implementation uses and every card in circulation matches, but they are not quoted from an official document.
What this cannot do
It cannot tell you whether a card exists, whether it is current, or who it belongs to. Only Services Australia can, through its own verification channels. A passing check digit means the number was typed correctly, which is exactly the right thing to check at the point of data entry and nothing more. Treat a valid result as permission to accept the field, not as identity verification.
Handling Medicare numbers responsibly
Everything here runs in your browser: there is no request as you type, nothing is logged and nothing is stored between visits. Even so, the habit worth keeping is not pasting real health identifiers into websites at all. For anything other than checking a number you are already responsible for, use the Medicare number generator and work with numbers issued to nobody.
Frequently Asked Questions
How is the Medicare check digit calculated?
Multiply the first eight digits by 1, 3, 7, 9, 1, 3, 7 and 9, add the results, and take the remainder after dividing by 10. That remainder is the ninth digit. It is the plain remainder, not ten minus it, which is the opposite of most check digit schemes and the single most common implementation mistake.
What is the difference between the issue number and the IRN?
The issue number is the tenth digit of the card number and increases each time a replacement card is sent, so an old card and its replacement share the first nine digits. The individual reference number is the small digit printed beside each person on the card, identifying which family member is which. Neither takes part in the checksum.
Can this tool tell me if a Medicare card is current?
No. Only Services Australia can confirm that a number is issued, current and matched to a person, through its own verification channels. A passing check digit means the digits are internally consistent, which is the right thing to test at data entry and nothing more.
Is it safe to enter a Medicare number here?
The check runs entirely in your browser, with no network request as you type and nothing stored. Even so, the better habit is not to paste real health identifiers into any website. If you are testing software, use a generated number instead.