Calculate subnet information from IP address and CIDR notation.
Input
Enter IPv4 address with CIDR notation (e.g., 192.168.1.0/24)
Results
Network Address: -
Broadcast Address: -
First Host: -
Last Host: -
Subnet Mask: -
Wildcard Mask: -
Prefix Length: -
Total Addresses: -
Usable Hosts: -
IP Class: -
Type: -
IPv4 CIDR Reference
| CIDR | Subnet Mask | Usable Hosts | CIDR | Subnet Mask | Usable Hosts |
|---|---|---|---|---|---|
| /8 | 255.0.0.0 | 16,777,214 | /24 | 255.255.255.0 | 254 |
| /16 | 255.255.0.0 | 65,534 | /25 | 255.255.255.128 | 126 |
| /17 | 255.255.128.0 | 32,766 | /26 | 255.255.255.192 | 62 |
| /18 | 255.255.192.0 | 16,382 | /27 | 255.255.255.224 | 30 |
| /19 | 255.255.224.0 | 8,190 | /28 | 255.255.255.240 | 14 |
| /20 | 255.255.240.0 | 4,094 | /29 | 255.255.255.248 | 6 |
| /21 | 255.255.248.0 | 2,046 | /30 | 255.255.255.252 | 2 |
| /22 | 255.255.252.0 | 1,022 | /31 | 255.255.255.254 | 2 (P2P) |
| /23 | 255.255.254.0 | 510 | /32 | 255.255.255.255 | 1 (Host) |
RFC 1918 Private Address Ranges
| Address Range | CIDR Notation | Default Subnet Mask | Number of Addresses | Typical Use |
|---|---|---|---|---|
| 10.0.0.0 – 10.255.255.255 | 10.0.0.0/8 | 255.0.0.0 | 16,777,216 | Large networks |
| 172.16.0.0 – 172.31.255.255 | 172.16.0.0/12 | 255.240.0.0 | 1,048,576 | Medium networks |
| 192.168.0.0 – 192.168.255.255 | 192.168.0.0/16 | 255.255.0.0 | 65,536 | Home/small networks |
Other Reserved Ranges
- 127.0.0.0/8 - Loopback addresses (127.0.0.1)
- 169.254.0.0/16 - Link-local (APIPA)
- 224.0.0.0/4 - Multicast (Class D)
- 240.0.0.0/4 - Reserved (Class E)
- 255.255.255.255 - Broadcast address
- 0.0.0.0 - Default route / unknown
IPv6 Common Prefix Lengths
| Prefix | Total Addresses | Typical Use |
|---|---|---|
| /48 | 2^80 (1.2 × 10^24) | Site allocation (65,536 /64 subnets) |
| /56 | 2^72 (4.7 × 10^21) | Home/small business (256 /64 subnets) |
| /64 | 2^64 (18.4 quintillion) | Single subnet (standard) |
| /128 | 1 | Single host |
IPv6 Special Address Ranges
| Address Range | Prefix | Purpose | RFC |
|---|---|---|---|
| ::1/128 | ::1 | Loopback address | RFC 4291 |
| ::/128 | :: | Unspecified address | RFC 4291 |
| fe80::/10 | fe80-febf | Link-Local Unicast (LLA) | RFC 4291 |
| fc00::/7 | fc00-fdff | Unique Local Address (ULA) | RFC 4193 |
| fd00::/8 | fd00-fdff | ULA (locally assigned) | RFC 4193 |
| ff00::/8 | ff00-ffff | Multicast | RFC 4291 |
| 2000::/3 | 2000-3fff | Global Unicast (GUA) | RFC 4291 |
| 2001:db8::/32 | 2001:db8 | Documentation | RFC 3849 |
| 2002::/16 | 2002 | 6to4 (deprecated) | RFC 3056 |
Common IPv6 Multicast Addresses
- ff02::1 - All nodes (link-local)
- ff02::2 - All routers (link-local)
- ff02::1:2 - All DHCP servers/relays
- ff05::2 - All routers (site-local)
- ff02::fb - mDNSv6
- ff02::101 - NTP