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IP/Netmask: (input format example: 10.0.0.5/24 or: 10.0.0.5 255.255.255.0 )


result:

Usable addresses:
Mask:	=
Mask as hex:
Network:
First usable:
Last usable:
Broadcast:

Subnet netmask dotted decimal to CIDR notation (bits format)

result: /

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Class C subnet calculator

number of subnets to create: 2 4 8 16 32 64

result:

mask: / dotted dec. mask:
amount of usable host addresses per subnet:
addresses in each subnet:

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Number of required addresses to netmask

number of addresses needed:

result:

mask: / dotted dec. mask:
usable amount of addresses:

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Dotted decimal IP-address or mask to binary and hex

result:

Bin:
Hex:

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Hex IP-address or mask to dotted decimal

result:

dotted decimal:
Bin:

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IP-address bit-complement (inverted IP) calculator

result:

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Network Mask to amount of usable addresses

Mask: /

result:

Usable amount of addr: Total number of addr:
Netmaks in dotted decimal format:

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IP Multicast address ranges

All multicast addresses can easily be recognized because they start with the bit pattern "1110".

224.0.0.0 - 224.0.0.255 Well-known multicast addresses, control channels
224.0.1.0 - 238.255.255.255 Globally-scoped (Internet-wide) multicast addresses
239.0.0.0 - 239.255.255.255 Local multicast addresses

Special and private address ranges

Private address ranges are not routed on the Internet and can be freely allocated in any private network. NAT (network address translation) is required when connecting such a network to the Internet.

Private network addresses (RFC1597/RFC1918 addresses):
10.0.0.0 - 10.255.255.255 A 24-bit block, /8, class A network
172.16.0.0 - 172.31.255.255 A 20-bit block, /12, set of 16 contiguous class B network numbers
192.168.0.0 - 192.168.255.255 A 16-bit block, /16, set of 255 contiguous class C network numbers

Special addresses:
127.0.0.0 - 127.255.255.255 Special address range for the localhost. You can normally not use those addresses for anything else. 127.0.0.1 is generally assigned to the loopback device
0.0.0.0 Special host address commonly reserved for the default route

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Overview of common subnets and masks

Mask Hosts Usable Netmask Hex Mask
/30 4 2 255.255.255.252 fffffffc this is 1/64 of a Class C net
/29 8 6 255.255.255.248 fffffff8 this is 1/32 of a Class C net
/28 16 14 255.255.255.240 fffffff0 this is 1/16 of a Class C net
/27 32 30 255.255.255.224 ffffffe0 this is 1/8 of a Class C net
/26 64 62 255.255.255.192 ffffffc0 this is 1/4 of a Class C net
/24 256 254 255.255.255.0 ffffff00 this is a Class C net
/23 512 510 255.255.254.0 fffffe00 these are 2 Class C net
/22 1024 1022 255.255.252.0 fffffc00 these are 4 Class C net
/21 2048 2046 255.255.248.0 fffff800 these are 8 Class C net
/20 4096 4094 255.255.240.0 fffff000 these are 16 Class C net
/19 8192 8190 255.255.224.0 ffffe000 these are 32 Class C net
/18 16384 16382 255.255.192.0 ffffc000 these are 64 Class C net
/17 32768 32766 255.255.128.0 ffff8000 these are 128 Class C net
/16 65536 65534 255.255.0.0 ffff0000 these are 256 Class C net = Class B net

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© Guido Socher, version 2016年12月22日
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