IPv4 Address Regex

Four numbers from 0 to 255 separated by dots, without leading zeros.

/^(?:(?:25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)\.){3}(?:25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)$/

Piece by piece

1. ^the start of the text
2. (?:a group (not captured)
3. (?:a group (not captured)
4. 25the text “25”
5. [0-5]one of 0–5
6. |or
7. 2the character “2”
8. [0-4]one of 0–4
9. \da digit (0–9)
10. |or
11. 1the character “1”
12. \da digit (0–9)
13. \da digit (0–9)
14. |or
15. [1-9]?one of 1–9, repeated optionally (0 or 1 time), as many as possible
16. \da digit (0–9)
17. )end of the group
18. \.the character “.”
19. ){3}end of the group, repeated exactly 3 times, as many as possible
20. (?:a group (not captured)
21. 25the text “25”
22. [0-5]one of 0–5
23. |or
24. 2the character “2”
25. [0-4]one of 0–4
26. \da digit (0–9)
27. |or
28. 1the character “1”
29. \da digit (0–9)
30. \da digit (0–9)
31. |or
32. [1-9]?one of 1–9, repeated optionally (0 or 1 time), as many as possible
33. \da digit (0–9)
34. )end of the group
35. $the end of the text

Examples

• It doesn't accept CIDR suffixes such as /24 or IPv6 addresses.

Other common patterns

• Email Address Regex
• URL Regex
• Date (YYYY-MM-DD) Regex
• UUID Regex
• Hex Colour Regex
• International Phone Number Regex
• 24-Hour Time Regex
• URL Slug Regex
• Strong Password Regex
• US ZIP Code Regex

Test any regular expression →