Slovenian VAT Number Validation
Format, pattern, and MOD 11 checksum algorithm for SI VAT numbers
Slovenian VAT numbers (Identifikacijska številka za DDV) consist of 8 digits with a weighted MOD 11 checksum.
Format vs. Active Validation
This checks format only, not if a VAT number is really registered. Use VatDB's API to verify is a number is really registered and active. VatDB checks official EU and national datasources.
Format Overview
| Property | Value |
|---|---|
| Country Code | SI |
| Format | 8 digits |
| Length | 8 digits |
| Examples | SI68911564 SI95023828 SI81280483 |
Regex Pattern
^SI[0-9]{8}$
Checksum Algorithm (MOD 11)
def validate_si_vat(number):
if number.startswith('SI'):
number = number[2:]
if len(number) != 8 or not number.isdigit():
return False
weights = [8, 7, 6, 5, 4, 3, 2]
total = sum(int(d) * w for d, w in zip(number[:7], weights))
check = 11 - (total % 11)
if check == 10:
check = 0
elif check == 11:
return False # Invalid number
return check == int(number[7])
Note: If the check calculation results in 10, the check digit is 0. If it results in 11, the VAT number is invalid.
Frequently Asked Questions
How do I verify a Slovenian VAT number?
Slovenian VAT numbers use weighted MOD 11 with weights [8,7,6,5,4,3,2]. If check=10, the check digit is 0. If check=11, the number is invalid. Use VatDB's API for official verification against EU and national databases.
What does a Slovenian VAT number look like?
A Slovenian VAT number has the format SI12345678 - 'SI' followed by exactly 8 digits. The last digit is the check digit.
How many digits are in a Slovenian VAT number?
A Slovenian VAT number contains exactly 8 digits after the SI country code. The complete number is 10 characters: SI + 8 digits.
What happens if the Slovenian VAT checksum equals 10?
If the MOD 11 check calculation results in 10, the check digit is 0. If it results in 11, the VAT number is invalid.
Where can I check a Slovenian company's VAT number?
Use VatDB's API to validate VAT numbers against official EU and national databases. Get instant verification with company information.
What's the difference between format validation and checking if a VAT number is active?
Format validation proves the number is properly structured, not that it's registered. Businesses close, VAT registrations get revoked. VatDB verifies the number is genuinely active.
Are there any real Slovenian (SI) VAT numbers to try?
You can validate these genuine Slovenian (SI) VAT numbers: SI68911564, SI95023828, SI81280483.
Validate Slovenian VAT Numbers Instantly
Use our API for real-time SI VAT number validation
Try Free