Free ACN lookup · no account
ACN lookup: find a company’s ABN
Got an invoice or quote that shows only an ACN? Enter the 9-digit Australian Company Number to find the company’s ABN, then see, live from the Australian Business Register, whether that ABN is active, the entity name, and its GST registration dates.
ClearABN shows Australian Business Register facts and the result of an ABN checksum. It does not provide tax, legal or financial advice. Links go to the ATO and the Australian Business Register so you can read their pages yourself.
How the ACN check digit works
The last of an ACN’s 9 digits is a check digit, so most typos can be caught before anything is looked up. Multiply the first 8 digits by 8, 7, 6, 5, 4, 3, 2 and 1, add the results, and take the remainder after dividing by 10. Ten minus that remainder (or 0 if the remainder is 0) must equal the last digit.
For our own company’s ACN, 697 458 852: 6×8 + 9×7 + 7×6 + 4×5 + 5×4 + 8×3 + 8×2 + 5×1 = 238. The remainder after dividing by 10 is 8, and 10 − 8 = 2, which matches the last digit. Its ABN on the register is 83 697 458 852.
In a spreadsheet
With the ACN in cell A2 (spaces are fine), this returns TRUE or FALSE. Format the column as text so ACNs starting with 0 keep their leading zeros. We tested it in LibreOffice Calc.
=IFERROR(IF(LEN(SUBSTITUTE(A2," ",""))<>9,FALSE,MOD(10-MOD(SUMPRODUCT(MID(SUBSTITUTE(A2," ",""),{1,2,3,4,5,6,7,8},1)*{8,7,6,5,4,3,2,1}),10),10)=VALUE(MID(SUBSTITUTE(A2," ",""),9,1))),FALSE)In code
function isValidAcn(acn) {
const digits = String(acn).replace(/\D/g, "");
if (digits.length !== 9) return false;
const weights = [8, 7, 6, 5, 4, 3, 2, 1];
const sum = weights.reduce((total, w, i) => total + Number(digits[i]) * w, 0);
return (10 - (sum % 10)) % 10 === Number(digits[8]);
}A passing check digit only means the format is right. To find the ABN and see whether it’s active and registered for GST, use the lookup above. For a whole list of ABNs, use the ABN validator or check a supplier list (the first 25 suppliers are free).
Common questions
How do I find a company's ABN from its ACN?
Enter the 9-digit ACN above. ClearABN checks the ACN's check digit, asks the Australian Business Register which ABN belongs to that company, then shows the ABN's status, entity name, GST registration and history. It's free and needs no account.
Is a company's ABN always its ACN with two digits in front?
Often, but not always. ASIC says a company's ABN is often the same as its ACN with 2 extra numbers at the beginning. Rather than guessing the two digits, this lookup reads the ABN from the register.
What's the difference between an ACN and an ABN?
ASIC issues a 9-digit ACN to every company when it's registered. The ATO issues the 11-digit ABN, which any type of business can have, including sole traders and partnerships. Most companies have both.
Why can't it find an ABN for my ACN?
The Australian Business Register only knows companies that have an ABN. A company without one, or one whose ABN record doesn't hold the ACN, won't be found. Check the number for a typo, search by company name, or use ASIC's register search, which lists every company.
Does this show directors or ASIC company details?
No. ClearABN reads the Australian Business Register (ABN status, names, GST, state and postcode). Directors, shareholders and ASIC registration status come from ASIC's registers.
Is this tax advice?
No. ClearABN shows register information and the check digit result. It does not tell you whether to withhold or claim anything.
More: ABN lookup · GST check on an invoice date · tax invoice checker · ASIC on ACNs and ABNs