Chile RUT Check Digit Calculator (Rol Único Tributario Validator)
Free calculator to validate and calculate the check digit of Chile's RUT (Rol Único Tributario), the national tax ID for individuals and companies. Enter just the body to calculate the check digit (a digit or 'K'), or enter it with a hyphen to validate. Everything runs right in your browser.
What is the Chile RUT Check Digit Calculator?
This is a free online calculator for validating and calculating the check digit of Chile's RUT (Rol Único Tributario), the national tax ID. It multiplies each digit of the body by a cycling weight of 2, 3, 4, 5, 6, 7 (starting from the rightmost digit), sums the results, and derives the check digit as "11 minus the remainder after dividing by 11" (with 11 becoming '0' and 10 becoming 'K').
The tool automatically figures out what kind of input you've given based on the hyphen, a trailing 'K', and the digit count, so there's no need to switch modes manually. If you enter a number that already includes a check digit, it validates it; if you enter just the body, it calculates and fills in the check digit for you. Keep in mind this tool only confirms that the format is correct — it can't determine whether the number belongs to an actual person or company (for that, you'd need to check with a Chilean government agency).
How to Use
- Enter the RUT You can paste it in with periods already included.
- Check the type The detected type (body only, or including a check digit) is shown.
- Check the result The validation result, or the calculated check digit, is displayed.
- Try another number Use the clear button to reset the input and check a different number.
Tips for getting more out of it
- You can paste the number in with periods (.) still in place — they're stripped automatically before the calculation runs.
- If you enter just the body without a check digit, the tool calculates the correct check digit for you automatically.
- Digits entered with no hyphen are treated as the body only. To validate a full RUT with its check digit, be sure to include the hyphen (e.g. 12345678-5).
- A trailing 'K' (either case) is automatically recognized as a check digit even without a hyphen.
- This tool only checks whether the format (check digit) is correct — it can't confirm whether the number was actually issued to a real person or company. For that, you'd need to check with Chile's Servicio de Registro Civil e Identificación or Servicio de Impuestos Internos.
Use Cases
Catching input errors on e-commerce and payment forms
Confirm that a RUT entered on a Chile-facing checkout or payment form matches its check digit before it's submitted, catching transcription mistakes early.
Catching input errors in HR and payroll
Verify the check digit of a RUT received from a new hire or an employee posted to Chile before entering it into an internal system.
Reference for designing validation logic
Use it as a reference to confirm the expected behavior of RUT validation logic (the cycling-weight mod 11 calculation) you're implementing in a Chile-facing form or sign-up system.
Digitizing older paperwork
When entering RUTs from paper documents into a database, use the check digit to catch any OCR misreads.
Glossary
- RUT (Rol Único Tributario)
- Chile's unified tax identification number, assigned to both individuals and companies. Used far beyond tax filing — for banking, sign-ups, and everyday identity verification.
- Dígito Verificador (check digit)
- The single verification character (a digit or 'K') at the end of a RUT, calculated from a formula to help catch input mistakes and typos.
- Mod 11 (cycling weights)
- A calculation method that multiplies each digit of the body by a cycling weight of 2, 3, 4, 5, 6, 7 (from the rightmost digit), sums the results, and derives the check digit from the remainder after dividing by 11.
- Servicio de Impuestos Internos (SII)
- Chile's tax authority, responsible for issuing RUTs to companies and overseeing tax administration generally.
- Servicio de Registro Civil e Identificación
- Chile's civil registry agency, responsible for issuing RUTs to individuals along with other identity and civil status records.
Frequently Asked Questions
Side Note — the "divide by 11" formula used across all of Chile
The RUT (Rol Único Tributario) is Chile's unified tax identification number, assigned to individuals and companies alike. It started out as a tax ID, but today it's become the go-to way to verify identity in Chile — from opening a bank account and signing up for a phone plan, to checking out online or looking yourself up on the electoral roll. Individuals get one automatically at birth (or when registering as an immigrant), while companies receive theirs when registering with the Servicio de Impuestos Internos (SII), Chile's tax authority.
The RUT's check digit (Dígito Verificador) is worked out by multiplying each digit of the body by a cycling weight of 2, 3, 4, 5, 6, 7 starting from the rightmost digit, summing the results, and subtracting the remainder after dividing by 11 from 11 itself. If that comes out to 11, the check digit is '0'; if it comes out to 10, Chile's rule is to use the letter 'K' rather than the number ten. Unlike most countries' purely numeric check digits, a RUT can end in a single letter — a quirk that's uniquely Chilean.
As it happens, the RUT of the SII itself — 60.803.000-K — runs through this exact formula and lands on 'K'. The fact that the tax authority's own number happens to end in a letter is a small piece of trivia that Chilean accountants and developers alike tend to know.