The Colombia NIT validator lets you instantly compute and verify the official DIAN verification digit (DV) for any Colombian Número de Identificación Tributaria. Whether you are building an invoicing system, auditing a supplier database, or simply double-checking a NIT typed from a receipt, the tool shows you the correct DV, the full formatted NIT, and — on demand — the complete step-by-step weighted computation so you can trace every digit. It is a pure browser tool: no server, no API calls, no data retention.
How it works
Every Colombian NIT has a base (the main numeric sequence) and a verification digit (dígito de verificación, DV) after a dash. The DIAN defined the DV algorithm in Resolución 8502 of 1987 and it has remained stable since. The calculation has four steps.
Step 1 — Align right to left. Take the digits of the NIT base and number them from the rightmost digit (position 1) to the leftmost (position n).
Step 2 — Apply the weight series. Multiply each digit by the DIAN weight at its position. The official weight series is:
3 · 7 · 13 · 17 · 19 · 23 · 29 · 37 · 41 · 43 · 47 · 53 · 59 · 67 · 71
The series covers up to 15 digits (the maximum NIT base length). Position 1 (rightmost) uses weight 3, position 2 uses weight 7, and so on.
Step 3 — Sum the products. Add every digit × weight product together to get a single total S.
Step 4 — Reduce modulo 11.
remainder r = S mod 11
DV = r if r ≤ 1
DV = 11 − r if r ≥ 2
The “Show step-by-step weight breakdown” button in the tool renders a full table of every digit, weight, and product so you can audit the arithmetic directly.
Worked example
Take the fictional company NIT base 900123456 (obviously fake — do not use as a real NIT).
Aligning right to left:
| Position (R→L) | Digit | Weight | Product |
|---|---|---|---|
| 1 | 6 | 3 | 18 |
| 2 | 5 | 7 | 35 |
| 3 | 4 | 13 | 52 |
| 4 | 3 | 17 | 51 |
| 5 | 2 | 19 | 38 |
| 6 | 1 | 23 | 23 |
| 7 | 0 | 29 | 0 |
| 8 | 0 | 37 | 0 |
| 9 | 9 | 41 | 369 |
Sum = 18 + 35 + 52 + 51 + 38 + 23 + 0 + 0 + 369 = 586
586 mod 11 = 2 (since 11 × 53 = 583, 586 − 583 = 3 — wait, let us be precise: 586 ÷ 11 = 53 remainder 3, so r = 3, DV = 11 − 3 = 8)
Full NIT: 900.123.456-8
Enter 900123456 into the tool above to confirm this result. Change the last digit to
see how even a one-digit typo shifts the DV.
Formula note
The DV formula — prime-number weights applied right-to-left, summed, then reduced modulo a prime — is a standard weighted modular-arithmetic check digit scheme, similar in spirit to the ISBN-13 or IBAN check algorithms. Using prime weights rather than small consecutive numbers (like 1, 2, 3 …) makes the algorithm more sensitive to transposition and single-digit errors, because two adjacent primes are never a simple multiple of each other. The choice of modulus 11 means the DV is always a single decimal digit (0–9), since the remainder after dividing by 11 can only be 0–10, and remainders 0 and 1 map to themselves while 2–10 map to 9–1 via the subtraction rule, keeping every DV in the range 0–9.