Lab tool
CAS Number Checker
A mistyped CAS number is one of the most common reasons for a wrong quotation. Check the number here before you add it to an enquiry.
Results update as you type. Nothing is sent or stored.
Check result—
How the result is worked out
Every CAS number ends in a check digit. Take the other digits from right to left, multiply each by its position (1, 2, 3 …), add the products and divide by 10. The remainder must equal the check digit.
Good to know
- A valid check digit proves the number is well formed, not that it belongs to the substance you expect.
- Compare the name and formula on the product page as well.
- Paste a whole list into Bulk CAS lookup to check availability in one go.
Have a list of compounds to price?
Paste up to 200 CAS numbers into Bulk CAS lookup, or send one enquiry for everything in your quote list. We reply with price, lead time and documents.