Danish VAT Number Validation
Format, pattern, and MOD 11 checksum algorithm for DK VAT numbers
Danish VAT numbers consist of 8 digits and use a weighted MOD 11 checksum algorithm. For most Danish businesses, the number is the company's CVR number. Older or special tax registrations may use an 8-digit SE number instead.
Format vs. Active Validation
This checks format and checksum only, not if a VAT number is really registered. Use VatDB's API to verify if a number is really registered and active. VatDB checks official EU and national datasources.
Format Overview
| Property | Value |
|---|---|
| Country Code | DK |
| Format | 8 digits |
| Length | 8 digits (10 characters with DK country prefix) |
| Examples | DK62565314 DK25508386 DK61126228 |
Regex Pattern
^DK[0-9]{8}$
Checksum Algorithm (MOD 11)
def validate_dk_vat(number):
if number.startswith('DK'):
number = number[2:]
if len(number) != 8 or not number.isdigit():
return False
weights = [2, 7, 6, 5, 4, 3, 2, 1]
total = sum(int(d) * w for d, w in zip(number, weights))
return total % 11 == 0
The weighted sum must be divisible by 11 for the number to be valid.
Important Notes
- The 8-digit identifier is usually a CVR number (Det Centrale Virksomhedsregister).
- Older or special tax registrations may use an SE number (Stamregister over Erhvervsdrivende). These are not to be confused with Swedish VAT numbers.
- For EU VAT validation, both use the same canonical format:
DKfollowed by 8 digits. Both use MOD11 as the checksum algorithm.
Frequently Asked Questions
How do I verify a Danish VAT number?
Danish VAT numbers use MOD 11 validation with weights [2,7,6,5,4,3,2,1]. The weighted sum must be divisible by 11. This only verifies the checksum. It does not prove the number is really registered or active. Use VatDB's API for official verification against EU and Danish data sources.
What does a Danish VAT number look like?
A Danish VAT number has the format DK12345678 - DK followed by exactly 8 digits. For most Danish businesses, those digits are the company's CVR number. Older or special tax registrations may use an SE number.
How many digits are in a Danish VAT number?
A Danish VAT number contains exactly 8 digits after the DK country code. The complete number is 10 characters: DK + 8 digits.
What is a Danish CVR number?
CVR (Det Centrale Virksomhedsregister) is the Danish Central Business Register number. For most Danish businesses, the CVR number is also used as the VAT number. Older or special tax registrations may use a separate 8-digit SE number.
Can I look up a Danish company by CVR number?
Yes, you can look up Danish company details on cvr.dk, the official Central Business Register. Enter the 8-digit CVR/VAT number to see company name, address, status, and more.
Where can I check if a Danish VAT number is valid?
Check VAT numbers using VatDB's API for real-time validation against official EU and national databases, with company details included.
What's the difference between format validation and checking if a VAT number is active?
Format validation is offline - it doesn't query any database. A valid-looking number might not exist or could be inactive. VatDB performs real-time lookups to confirm genuine registration.
What real Danish VAT numbers can I validate as a test?
These are three actual, in-use Danish VAT numbers: DK62565314, DK25508386, DK61126228.