Not really a calculator, but more so a table containing all the subnets and how many usable addresses (Subnet Size - 2 for the network and broadcast address)
| Subnets | Usable Addresses | |||||||||
| Subnet Mask | Class A | Class B | Class C | Class A | Class B | Class C | ||||
| Class A | /8 | 255.0.0.0 | 1 | 16777214 | ||||||
| /9 | 255.128.0.0 | 2 | 8388606 | |||||||
| /10 | 255.192.0.0 | 4 | 4194302 | |||||||
| /11 | 255.224.0.0 | 8 | 2097150 | |||||||
| /12 | 255.240.0.0 | 16 | 1048574 | |||||||
| /13 | 255.248.0.0 | 32 | 524286 | |||||||
| /14 | 255.252.0.0 | 64 | 262142 | |||||||
| /15 | 255.254.0.0 | 128 | 131070 | |||||||
| Class B | /16 | 255.255.0.0 | 256 | 1 | 65534 | 65534 | ||||
| /17 | 255.255.128.0 | 512 | 2 | 32766 | 32766 | |||||
| /18 | 255.255.192.0 | 1024 | 4 | 16382 | 16382 | |||||
| /19 | 255.255.224.0 | 2048 | 8 | 8190 | 8190 | |||||
| /20 | 255.255.240.0 | 4096 | 16 | 4094 | 4094 | |||||
| /21 | 255.255.248.0 | 8192 | 32 | 2046 | 2046 | |||||
| /22 | 255.255.252.0 | 16384 | 64 | 1022 | 1022 | |||||
| /23 | 255.255.254.0 | 32768 | 128 | 510 | 510 | |||||
| Class C | /24 | 255.255.255.0 | 65536 | 256 | 1 | 254 | 254 | 254 | ||
| /25 | 255.255.255.128 | 131072 | 512 | 2 | 126 | 126 | 126 | |||
| /26 | 255.255.255.192 | 262144 | 1024 | 4 | 62 | 62 | 62 | |||
| /27 | 255.255.255.224 | 524288 | 2048 | 8 | 30 | 30 | 30 | |||
| /28 | 255.255.255.240 | 1048576 | 4096 | 16 | 14 | 14 | 14 | |||
| /29 | 255.255.255.248 | 2097152 | 8192 | 32 | 6 | 6 | 6 | |||
| /30 | 255.255.255.252 | 4194304 | 16384 | 64 | 2 | 2 | 2 | |||
Special Use IPv4 Addresses
| Address block | Address range | Number of addresses | Scope | Description |
|---|---|---|---|---|
| 0.0.0.0/8 | 0.0.0.0–0.255.255.255 | 16777216 | Software | Current network[3] (only valid as source address). |
| 10.0.0.0/8 | 10.0.0.0–10.255.255.255 | 16777216 | Private network | Used for local communications within a private network.[4] |
| 100.64.0.0/10 | 100.64.0.0–100.127.255.255 | 4194304 | Private network | Shared address space[5] for communications between a service provider and its subscribers when using a carrier-grade NAT. |
| 127.0.0.0/8 | 127.0.0.0–127.255.255.255 | 16777216 | Host | Used for loopback addresses to the local host.[3] |
| 169.254.0.0/16 | 169.254.0.0–169.254.255.255 | 65536 | Subnet | Used for link-local addresses[6] between two hosts on a single link when no IP address is otherwise specified, such as would have normally been retrieved from a DHCP server. |
| 172.16.0.0/12 | 172.16.0.0–172.31.255.255 | 1048576 | Private network | Used for local communications within a private network.[4] |
| 192.0.0.0/24 | 192.0.0.0–192.0.0.255 | 256 | Private network | IETF Protocol Assignments.[3] |
| 192.0.2.0/24 | 192.0.2.0–192.0.2.255 | 256 | Documentation | Assigned as TEST-NET-1, documentation and examples.[7] |
| 192.88.99.0/24 | 192.88.99.0–192.88.99.255 | 256 | Internet | Reserved.[8] Formerly used for IPv6 to IPv4 relay[9] (included IPv6 address block 2002::/16). |
| 192.168.0.0/16 | 192.168.0.0–192.168.255.255 | 65536 | Private network | Used for local communications within a private network.[4] |
| 198.18.0.0/15 | 198.18.0.0–198.19.255.255 | 131072 | Private network | Used for benchmark testing of inter-network communications between two separate subnets.[10] |
| 198.51.100.0/24 | 198.51.100.0–198.51.100.255 | 256 | Documentation | Assigned as TEST-NET-2, documentation and examples.[7] |
| 203.0.113.0/24 | 203.0.113.0–203.0.113.255 | 256 | Documentation | Assigned as TEST-NET-3, documentation and examples.[7] |
| 224.0.0.0/4 | 224.0.0.0–239.255.255.255 | 268435456 | Internet | In use for IP multicast.[11] (Former Class D network). |
| 240.0.0.0/4 | 240.0.0.0–255.255.255.254 | 268435456 | Internet | Reserved for future use.[12] (Former Class E network). |
| 255.255.255.255/32 | 255.255.255.255 | 1 | Subnet | Reserved for the "limited broadcast" destination address.[3][13] |
https://en.wikipedia.org/wiki/IPv4#Special-use_addresses
Special Use IPv6 Addresses
| Address block (CIDR) | First address | Last address | Number of addresses | Usage | Purpose |
|---|---|---|---|---|---|
| ::/0 | :: | ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff | 2128 | Routing | Default route. |
| ::/128 | :: | 1 | Software | Unspecified address. | |
| ::1/128 | ::1 | 1 | Host | Loopback address to the local host. | |
| ::ffff:0:0/96 | ::ffff:0.0.0.0 | ::ffff:255.255.255.255 | 2128−96 = 232= 4294967296 | Software | IPv4 mapped addresses. |
| ::ffff:0:0:0/96 | ::ffff:0:0.0.0.0 | ::ffff:0:255.255.255.255 | 232 | Software | IPv4 translated addresses. |
| 64:ff9b::/96 | 64:ff9b::0.0.0.0 | 64:ff9b::255.255.255.255 | 232 | Global Internet | IPv4/IPv6 translation.[26] |
| 100::/64 | 100:: | 100::ffff:ffff:ffff:ffff | 264 | Routing | Discard prefix.[27] |
| 2001::/32 | 2001:: | 2001::ffff:ffff:ffff:ffff:ffff:ffff | 296 | Global Internet | Teredo tunneling. |
| 2001:20::/28 | 2001:20:: | 2001:2f:ffff:ffff:ffff:ffff:ffff:ffff | 2100 | Software | ORCHIDv2.[28] |
| 2001:db8::/32 | 2001:db8:: | 2001:db8:ffff:ffff:ffff:ffff:ffff:ffff | 296 | Documentation | Addresses used in documentation and example source code.[29] |
| 2002::/16 | 2002:: | 2002:ffff:ffff:ffff:ffff:ffff:ffff:ffff | 2112 | Global Internet | The 6to4 addressing scheme (now deprecated).[30] |
| fc00::/7 | fc00:: | fdff:ffff:ffff:ffff:ffff:ffff:ffff:ffff | 2121 | Private network | Unique local address.[31] |
| fe80::/10 | fe80:: | febf:ffff:ffff:ffff:ffff:ffff:ffff:ffff | 2118 | Link | Link-local address. |
| ff00::/8 | ff00:: | ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff | 2120 | Global Internet | Multicast address. |
https://en.wikipedia.org/wiki/IPv6_address#Special_addresses
Great, thank you!