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IP subnet calculator, CIDR converter, and network toolkit. Free — no signup required.

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IPv4 CIDR Cheat Sheet

Prefix Subnet Mask Wildcard Total IPs Usable
/0 0.0.0.0 255.255.255.255 4,294,967,296 4,294,967,294
/1 128.0.0.0 127.255.255.255 2,147,483,648 2,147,483,646
/2 192.0.0.0 63.255.255.255 1,073,741,824 1,073,741,822
/3 224.0.0.0 31.255.255.255 536,870,912 536,870,910
/4 240.0.0.0 15.255.255.255 268,435,456 268,435,454
/5 248.0.0.0 7.255.255.255 134,217,728 134,217,726
/6 252.0.0.0 3.255.255.255 67,108,864 67,108,862
/7 254.0.0.0 1.255.255.255 33,554,432 33,554,430
/8 255.0.0.0 0.255.255.255 16,777,216 16,777,214
/9 255.128.0.0 0.127.255.255 8,388,608 8,388,606
/10 255.192.0.0 0.63.255.255 4,194,304 4,194,302
/11 255.224.0.0 0.31.255.255 2,097,152 2,097,150
/12 255.240.0.0 0.15.255.255 1,048,576 1,048,574
/13 255.248.0.0 0.7.255.255 524,288 524,286
/14 255.252.0.0 0.3.255.255 262,144 262,142
/15 255.254.0.0 0.1.255.255 131,072 131,070
/16 255.255.0.0 0.0.255.255 65,536 65,534
/17 255.255.128.0 0.0.127.255 32,768 32,766
/18 255.255.192.0 0.0.63.255 16,384 16,382
/19 255.255.224.0 0.0.31.255 8,192 8,190
/20 255.255.240.0 0.0.15.255 4,096 4,094
/21 255.255.248.0 0.0.7.255 2,048 2,046
/22 255.255.252.0 0.0.3.255 1,024 1,022
/23 255.255.254.0 0.0.1.255 512 510
/24 255.255.255.0 0.0.0.255 256 254
/25 255.255.255.128 0.0.0.127 128 126
/26 255.255.255.192 0.0.0.63 64 62
/27 255.255.255.224 0.0.0.31 32 30
/28 255.255.255.240 0.0.0.15 16 14
/29 255.255.255.248 0.0.0.7 8 6
/30 255.255.255.252 0.0.0.3 4 2
/31 255.255.255.254 0.0.0.1 2 2
/32 255.255.255.255 0.0.0.0 1 1

IPv4 Private Ranges (RFC 1918)

10.0.0.0/8

10.0.0.0 - 10.255.255.255

16,777,216 IPs (Class A)

172.16.0.0/12

172.16.0.0 - 172.31.255.255

1,048,576 IPs (Class B)

192.168.0.0/16

192.168.0.0 - 192.168.255.255

65,536 IPs (Class C)

IPv6 Special Ranges

::1/128 Loopback
fe80::/10 Link-Local
fc00::/7 Unique Local (ULA)
ff00::/8 Multicast
2000::/3 Global Unicast
::ffff:0:0/96 IPv4-Mapped

Common Ports

20 FTP Data
21 FTP Control
22 SSH
23 Telnet
25 SMTP
53 DNS
67 DHCP Server
68 DHCP Client
80 HTTP
110 POP3
123 NTP
143 IMAP
443 HTTPS
465 SMTPS
587 SMTP Submission
993 IMAPS
995 POP3S
1433 MSSQL
3306 MySQL
3389 RDP
5432 PostgreSQL
5900 VNC
6379 Redis
8080 HTTP Alt

Smart Detection

Paste any IP format and get instant results. Supports CIDR, ranges, subnet masks, hex, decimal, and IPv6.

Subnet Splitter

Split any network into smaller equal subnets. Perfect for VLSM planning and network segmentation.

Route Aggregation

Combine multiple CIDRs into the smallest possible supernets. Reduce routing table size and simplify ACLs.

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