What Is a Peru RUC? Format, Prefixes and Check Digit
Last reviewed 2026-11-14 · HALPII S.A.C.
A RUC (Registro Único de Contribuyentes, "single taxpayer registry") is the 11-digit number that SUNAT, Peru's tax authority, assigns to every company and individual registered for tax. It is the number a Peruvian supplier prints on its invoices, and it is the number you look up to see whether the supplier is still active.
What a RUC looks like
A RUC has exactly 11 digits and nothing else. People often paste it with spaces, dots or dashes (for example 20-10004721-8); remove them before checking. The number has three parts:
| Digits | What they are |
|---|---|
| 1–2 | Prefix: the type of taxpayer (see below) |
| 3–10 | Body of the number |
| 11 | Check digit, calculated from the first ten digits |
RUC prefixes: 10, 15, 16, 17 and 20
The first two digits tell you who holds the number:
| Prefix | Taxpayer type | What our lookup returns |
|---|---|---|
20 | Legal entity: a company, association or government body | Legal name, status, address condition, fiscal address and a verdict |
10 | Natural person identified with a DNI (Peruvian national ID), often a sole proprietor | Format and check digit only |
15, 16, 17 | Natural persons identified with another document | Format and check digit only |
If a supplier tells you it is a company but gives you a RUC that starts with 10, you are dealing with an individual, not a company. That can be perfectly legitimate, but your contract, invoice and bank details should then be in that person's name. We do not return names or addresses for individuals, in line with Peru's Personal Data Protection Law (Ley 29733); check those directly on SUNAT's RUC lookup.
How the RUC check digit works
The 11th digit catches typos. It is a modulo-11 check over the first ten digits:
- Multiply each of the first ten digits by these weights, in order:
5 4 3 2 7 6 5 4 3 2. - Add the ten products.
- Take the remainder of that sum divided by 11, and subtract it from 11.
- If the result is 10, the check digit is 0. If it is 11, the check digit is 1. Otherwise the result is the check digit.
Worked example with 20100047218:
digits 2 0 1 0 0 0 4 7 2 1
weights 5 4 3 2 7 6 5 4 3 2
product 10 0 3 0 0 0 20 28 6 2 sum = 69
69 mod 11 = 3 11 - 3 = 8 check digit = 8 ✓Change the last digit to 9 and the number fails the check. A failed check digit almost always means a typo, so ask the supplier to confirm the number in writing. Our lookup runs this check before it touches the registry and returns a fail verdict when it does not match.
Where the registry data comes from
SUNAT publishes a downloadable file called the Padrón Reducido del RUC. It lists each RUC with its name, taxpayer status, fiscal-address condition and address. Our lookup and API read from a copy of that file, and every answer shows the date of the copy it used. Read next: what each status code means and HABIDO vs NO HABIDO.
This guide is general information, not legal, tax or accounting advice. Peru RUC Check is an independent service run by HALPII S.A.C. and is not affiliated with or endorsed by SUNAT. Rules change; for a decision that matters, check SUNAT's own pages and ask a qualified adviser.