Decimal to IP Converter

Decimal to IP Converter

Convert an integer into a dotted IPv4 address and an IPv4 address into its integer value. Paste one value per line: 3232235521 becomes 192.168.0.1, 2130706433 becomes 127.0.0.1, and 8.8.8.8 becomes 134744072.

The formula

An IPv4 address a.b.c.d is a 32-bit number, so its decimal value is:

a × 16,777,216 + b × 65,536 + c × 256 + d

(the multipliers are 256³, 256², 256¹, and 256⁰). For 192.168.0.1 that is 192 × 16,777,216 + 168 × 65,536 + 0 × 256 + 1 = 3,232,235,521.

To go back, divide by 16,777,216 for the first octet, take the remainder and divide by 65,536 for the second, and so on. Valid values range from 0 (0.0.0.0) to 4,294,967,295 (255.255.255.255).

Why store IP addresses as integers?

• Databases – an unsigned 32-bit integer column needs 4 bytes instead of up to 15 characters, and range queries such as "is this IP inside a block" become simple BETWEEN comparisons. MySQL's INET_ATON() and INET_NTOA() perform exactly this conversion.
• GeoIP and blocklists – IP-to-country databases such as MaxMind CSV exports and IP2Location list ranges as start and end integers.
• Sorting – sorting addresses as text puts 10.0.0.10 before 10.0.0.9; sorting their integer values gives the correct order.
• Logs and analytics – some systems log client addresses as integers, which you need to convert back for investigation.

Tips

• Thousands separators and spaces in the decimal input are ignored (3,232,235,521 works).
• Numbers larger than 4,294,967,295 are rejected because they do not fit into IPv4.
• A single decimal number is also a valid host in most browsers: http://3232235521/ opens http://192.168.0.1/.

For other notations, try Hex to IP, Binary to IP, or Octal to IP; to work with whole networks, use the CIDR Calculator.