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IP subnet calculator

Type an address with its prefix or mask to see the network, its usable range and masks. Split it into smaller subnets, or look up any prefix in the reference tables.

Network224.76.166.0/23
Usable hosts510
Subnet mask255.255.254.0
Addresses512
Network address
224.76.166.0
Broadcast address
224.76.167.255
First usable
224.76.166.1
Last usable
224.76.167.254
Usable hosts
510 (512 less the network and broadcast addresses)
Subnet mask
255.255.254.0
Wildcard mask
0.0.1.255 (Cisco ACLs, OSPF)
Prefix length
/23
Type
Multicast 224.0.0.0/4
One-to-many traffic, such as IPTV and routing protocols
Old class
D (multicast)
As numbers
Hex E04CA600 · Integer 3763119616 to 3763120127
Reverse DNS zones
166.76.224.in-addr.arpa
167.76.224.in-addr.arpa
/23 is not on a 8-bit boundary, so it takes 2 /24 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address11100000.01001100.10100110.00000000224.76.166.0
Subnet mask11111111.11111111.11111110.00000000255.255.254.0
Network11100000.01001100.10100110.00000000224.76.166.0
Broadcast11100000.01001100.10100111.11111111224.76.167.255
Split into smaller subnets/30
/24 (2)/25 (4)/26 (8)/27 (16)/28 (32)/29 (64)/30 (128)/31 (256)/32 (512)

224.76.166.0/23 makes 128 subnets of /30.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1224.76.166.0/30224.76.166.1 to 224.76.166.2224.76.166.32
2224.76.166.4/30224.76.166.5 to 224.76.166.6224.76.166.72
3224.76.166.8/30224.76.166.9 to 224.76.166.10224.76.166.112
4224.76.166.12/30224.76.166.13 to 224.76.166.14224.76.166.152
5224.76.166.16/30224.76.166.17 to 224.76.166.18224.76.166.192
6224.76.166.20/30224.76.166.21 to 224.76.166.22224.76.166.232
7224.76.166.24/30224.76.166.25 to 224.76.166.26224.76.166.272
8224.76.166.28/30224.76.166.29 to 224.76.166.30224.76.166.312
9224.76.166.32/30224.76.166.33 to 224.76.166.34224.76.166.352
10224.76.166.36/30224.76.166.37 to 224.76.166.38224.76.166.392
11224.76.166.40/30224.76.166.41 to 224.76.166.42224.76.166.432
12224.76.166.44/30224.76.166.45 to 224.76.166.46224.76.166.472
13224.76.166.48/30224.76.166.49 to 224.76.166.50224.76.166.512
14224.76.166.52/30224.76.166.53 to 224.76.166.54224.76.166.552
15224.76.166.56/30224.76.166.57 to 224.76.166.58224.76.166.592
16224.76.166.60/30224.76.166.61 to 224.76.166.62224.76.166.632
17224.76.166.64/30224.76.166.65 to 224.76.166.66224.76.166.672
18224.76.166.68/30224.76.166.69 to 224.76.166.70224.76.166.712
19224.76.166.72/30224.76.166.73 to 224.76.166.74224.76.166.752
20224.76.166.76/30224.76.166.77 to 224.76.166.78224.76.166.792
21224.76.166.80/30224.76.166.81 to 224.76.166.82224.76.166.832
22224.76.166.84/30224.76.166.85 to 224.76.166.86224.76.166.872
23224.76.166.88/30224.76.166.89 to 224.76.166.90224.76.166.912
24224.76.166.92/30224.76.166.93 to 224.76.166.94224.76.166.952
25224.76.166.96/30224.76.166.97 to 224.76.166.98224.76.166.992
26224.76.166.100/30224.76.166.101 to 224.76.166.102224.76.166.1032
27224.76.166.104/30224.76.166.105 to 224.76.166.106224.76.166.1072
28224.76.166.108/30224.76.166.109 to 224.76.166.110224.76.166.1112
29224.76.166.112/30224.76.166.113 to 224.76.166.114224.76.166.1152
30224.76.166.116/30224.76.166.117 to 224.76.166.118224.76.166.1192
31224.76.166.120/30224.76.166.121 to 224.76.166.122224.76.166.1232
32224.76.166.124/30224.76.166.125 to 224.76.166.126224.76.166.1272
33224.76.166.128/30224.76.166.129 to 224.76.166.130224.76.166.1312
34224.76.166.132/30224.76.166.133 to 224.76.166.134224.76.166.1352
35224.76.166.136/30224.76.166.137 to 224.76.166.138224.76.166.1392
36224.76.166.140/30224.76.166.141 to 224.76.166.142224.76.166.1432
37224.76.166.144/30224.76.166.145 to 224.76.166.146224.76.166.1472
38224.76.166.148/30224.76.166.149 to 224.76.166.150224.76.166.1512
39224.76.166.152/30224.76.166.153 to 224.76.166.154224.76.166.1552
40224.76.166.156/30224.76.166.157 to 224.76.166.158224.76.166.1592
41224.76.166.160/30224.76.166.161 to 224.76.166.162224.76.166.1632
42224.76.166.164/30224.76.166.165 to 224.76.166.166224.76.166.1672
43224.76.166.168/30224.76.166.169 to 224.76.166.170224.76.166.1712
44224.76.166.172/30224.76.166.173 to 224.76.166.174224.76.166.1752
45224.76.166.176/30224.76.166.177 to 224.76.166.178224.76.166.1792
46224.76.166.180/30224.76.166.181 to 224.76.166.182224.76.166.1832
47224.76.166.184/30224.76.166.185 to 224.76.166.186224.76.166.1872
48224.76.166.188/30224.76.166.189 to 224.76.166.190224.76.166.1912
49224.76.166.192/30224.76.166.193 to 224.76.166.194224.76.166.1952
50224.76.166.196/30224.76.166.197 to 224.76.166.198224.76.166.1992
51224.76.166.200/30224.76.166.201 to 224.76.166.202224.76.166.2032
52224.76.166.204/30224.76.166.205 to 224.76.166.206224.76.166.2072
53224.76.166.208/30224.76.166.209 to 224.76.166.210224.76.166.2112
54224.76.166.212/30224.76.166.213 to 224.76.166.214224.76.166.2152
55224.76.166.216/30224.76.166.217 to 224.76.166.218224.76.166.2192
56224.76.166.220/30224.76.166.221 to 224.76.166.222224.76.166.2232
57224.76.166.224/30224.76.166.225 to 224.76.166.226224.76.166.2272
58224.76.166.228/30224.76.166.229 to 224.76.166.230224.76.166.2312
59224.76.166.232/30224.76.166.233 to 224.76.166.234224.76.166.2352
60224.76.166.236/30224.76.166.237 to 224.76.166.238224.76.166.2392
61224.76.166.240/30224.76.166.241 to 224.76.166.242224.76.166.2432
62224.76.166.244/30224.76.166.245 to 224.76.166.246224.76.166.2472
63224.76.166.248/30224.76.166.249 to 224.76.166.250224.76.166.2512
64224.76.166.252/30224.76.166.253 to 224.76.166.254224.76.166.2552
65224.76.167.0/30224.76.167.1 to 224.76.167.2224.76.167.32
66224.76.167.4/30224.76.167.5 to 224.76.167.6224.76.167.72
67224.76.167.8/30224.76.167.9 to 224.76.167.10224.76.167.112
68224.76.167.12/30224.76.167.13 to 224.76.167.14224.76.167.152
69224.76.167.16/30224.76.167.17 to 224.76.167.18224.76.167.192
70224.76.167.20/30224.76.167.21 to 224.76.167.22224.76.167.232
71224.76.167.24/30224.76.167.25 to 224.76.167.26224.76.167.272
72224.76.167.28/30224.76.167.29 to 224.76.167.30224.76.167.312
73224.76.167.32/30224.76.167.33 to 224.76.167.34224.76.167.352
74224.76.167.36/30224.76.167.37 to 224.76.167.38224.76.167.392
75224.76.167.40/30224.76.167.41 to 224.76.167.42224.76.167.432
76224.76.167.44/30224.76.167.45 to 224.76.167.46224.76.167.472
77224.76.167.48/30224.76.167.49 to 224.76.167.50224.76.167.512
78224.76.167.52/30224.76.167.53 to 224.76.167.54224.76.167.552
79224.76.167.56/30224.76.167.57 to 224.76.167.58224.76.167.592
80224.76.167.60/30224.76.167.61 to 224.76.167.62224.76.167.632
81224.76.167.64/30224.76.167.65 to 224.76.167.66224.76.167.672
82224.76.167.68/30224.76.167.69 to 224.76.167.70224.76.167.712
83224.76.167.72/30224.76.167.73 to 224.76.167.74224.76.167.752
84224.76.167.76/30224.76.167.77 to 224.76.167.78224.76.167.792
85224.76.167.80/30224.76.167.81 to 224.76.167.82224.76.167.832
86224.76.167.84/30224.76.167.85 to 224.76.167.86224.76.167.872
87224.76.167.88/30224.76.167.89 to 224.76.167.90224.76.167.912
88224.76.167.92/30224.76.167.93 to 224.76.167.94224.76.167.952
89224.76.167.96/30224.76.167.97 to 224.76.167.98224.76.167.992
90224.76.167.100/30224.76.167.101 to 224.76.167.102224.76.167.1032
91224.76.167.104/30224.76.167.105 to 224.76.167.106224.76.167.1072
92224.76.167.108/30224.76.167.109 to 224.76.167.110224.76.167.1112
93224.76.167.112/30224.76.167.113 to 224.76.167.114224.76.167.1152
94224.76.167.116/30224.76.167.117 to 224.76.167.118224.76.167.1192
95224.76.167.120/30224.76.167.121 to 224.76.167.122224.76.167.1232
96224.76.167.124/30224.76.167.125 to 224.76.167.126224.76.167.1272
97224.76.167.128/30224.76.167.129 to 224.76.167.130224.76.167.1312
98224.76.167.132/30224.76.167.133 to 224.76.167.134224.76.167.1352
99224.76.167.136/30224.76.167.137 to 224.76.167.138224.76.167.1392
100224.76.167.140/30224.76.167.141 to 224.76.167.142224.76.167.1432
101224.76.167.144/30224.76.167.145 to 224.76.167.146224.76.167.1472
102224.76.167.148/30224.76.167.149 to 224.76.167.150224.76.167.1512
103224.76.167.152/30224.76.167.153 to 224.76.167.154224.76.167.1552
104224.76.167.156/30224.76.167.157 to 224.76.167.158224.76.167.1592
105224.76.167.160/30224.76.167.161 to 224.76.167.162224.76.167.1632
106224.76.167.164/30224.76.167.165 to 224.76.167.166224.76.167.1672
107224.76.167.168/30224.76.167.169 to 224.76.167.170224.76.167.1712
108224.76.167.172/30224.76.167.173 to 224.76.167.174224.76.167.1752
109224.76.167.176/30224.76.167.177 to 224.76.167.178224.76.167.1792
110224.76.167.180/30224.76.167.181 to 224.76.167.182224.76.167.1832
111224.76.167.184/30224.76.167.185 to 224.76.167.186224.76.167.1872
112224.76.167.188/30224.76.167.189 to 224.76.167.190224.76.167.1912
113224.76.167.192/30224.76.167.193 to 224.76.167.194224.76.167.1952
114224.76.167.196/30224.76.167.197 to 224.76.167.198224.76.167.1992
115224.76.167.200/30224.76.167.201 to 224.76.167.202224.76.167.2032
116224.76.167.204/30224.76.167.205 to 224.76.167.206224.76.167.2072
117224.76.167.208/30224.76.167.209 to 224.76.167.210224.76.167.2112
118224.76.167.212/30224.76.167.213 to 224.76.167.214224.76.167.2152
119224.76.167.216/30224.76.167.217 to 224.76.167.218224.76.167.2192
120224.76.167.220/30224.76.167.221 to 224.76.167.222224.76.167.2232
121224.76.167.224/30224.76.167.225 to 224.76.167.226224.76.167.2272
122224.76.167.228/30224.76.167.229 to 224.76.167.230224.76.167.2312
123224.76.167.232/30224.76.167.233 to 224.76.167.234224.76.167.2352
124224.76.167.236/30224.76.167.237 to 224.76.167.238224.76.167.2392
125224.76.167.240/30224.76.167.241 to 224.76.167.242224.76.167.2432
126224.76.167.244/30224.76.167.245 to 224.76.167.246224.76.167.2472
127224.76.167.248/30224.76.167.249 to 224.76.167.250224.76.167.2512
128224.76.167.252/30224.76.167.253 to 224.76.167.254224.76.167.2552

IPv4 CIDR reference (/0 to /32)

IPv4 prefix lengths
PrefixSubnet maskWildcardAddressesUsable hostsSizeTypical use
/00.0.0.0255.255.255.2554,294,967,2964,294,967,29416,777,216 × /24
/1128.0.0.0127.255.255.2552,147,483,6482,147,483,6468,388,608 × /24
/2192.0.0.063.255.255.2551,073,741,8241,073,741,8224,194,304 × /24
/3224.0.0.031.255.255.255536,870,912536,870,9102,097,152 × /24
/4240.0.0.015.255.255.255268,435,456268,435,4541,048,576 × /24
/5248.0.0.07.255.255.255134,217,728134,217,726524,288 × /24
/6252.0.0.03.255.255.25567,108,86467,108,862262,144 × /24
/7254.0.0.01.255.255.25533,554,43233,554,430131,072 × /24
/8255.0.0.00.255.255.25516,777,21616,777,21465,536 × /24Old class A; 10.0.0.0/8
/9255.128.0.00.127.255.2558,388,6088,388,60632,768 × /24
/10255.192.0.00.63.255.2554,194,3044,194,30216,384 × /24
/11255.224.0.00.31.255.2552,097,1522,097,1508,192 × /24
/12255.240.0.00.15.255.2551,048,5761,048,5744,096 × /24172.16.0.0/12
/13255.248.0.00.7.255.255524,288524,2862,048 × /24
/14255.252.0.00.3.255.255262,144262,1421,024 × /24
/15255.254.0.00.1.255.255131,072131,070512 × /24
/16255.255.0.00.0.255.25565,53665,534256 × /24Old class B; 192.168.0.0/16
/17255.255.128.00.0.127.25532,76832,766128 × /24
/18255.255.192.00.0.63.25516,38416,38264 × /24
/19255.255.224.00.0.31.2558,1928,19032 × /24
/20255.255.240.00.0.15.2554,0964,09416 × /24
/21255.255.248.00.0.7.2552,0482,0468 × /24
/22255.255.252.00.0.3.2551,0241,0224 × /24Large office or guest Wi-Fi (1,022 hosts)
/23255.255.254.00.0.1.2555125102 × /24Larger office LAN (510 hosts)
/24255.255.255.00.0.0.2552562541 × /24Typical office LAN (old class C)
/25255.255.255.1280.0.0.1271281261/2 of a /24Smaller LAN or VLAN
/26255.255.255.1920.0.0.6364621/4 of a /24Smaller LAN or VLAN
/27255.255.255.2240.0.0.3132301/8 of a /24Small VLAN, phones, cameras
/28255.255.255.2400.0.0.1516141/16 of a /24Small VLAN, phones, cameras
/29255.255.255.2480.0.0.7861/32 of a /24Small fixed public block (5 usable)
/30255.255.255.2520.0.0.3421/64 of a /24Point-to-point (old style)
/31255.255.255.2540.0.0.1221/128 of a /24Point-to-point link (RFC 3021)
/32255.255.255.2550.0.0.0111/256 of a /24One host

IPv6 prefix reference

IPv6 prefix lengths
PrefixAddresses/64 LANs/48 sitesNibbleTypical use
/342,535,295,865,117,307,932,921,825,928,971,026,432 (2^125)2,305,843,009,213,693,95235,184,372,088,832NoAll global unicast (2000::/3)
/165,192,296,858,534,827,628,530,496,329,220,096 (2^112)281,474,976,710,6564,294,967,296Yes
/20324,518,553,658,426,726,783,156,020,576,256 (2^108)17,592,186,044,416268,435,456YesLarge provider allocation (RIPE minimum for some)
/29633,825,300,114,114,700,748,351,602,688 (2^99)34,359,738,368524,288NoRIPE allocation to a provider (often)
/3279,228,162,514,264,337,593,543,950,336 (2^96)4,294,967,29665,536YesProvider allocation (RIPE default)
/364,951,760,157,141,521,099,596,496,896 (2^92)268,435,4564,096Yes
/40309,485,009,821,345,068,724,781,056 (2^88)16,777,216256Yes
/4419,342,813,113,834,066,795,298,816 (2^84)1,048,57616Yes
/481,208,925,819,614,629,174,706,176 (2^80)65,5361YesOne site or organisation (RIPE PI / assignment)
/5275,557,863,725,914,323,419,136 (2^76)4,096Yes
/564,722,366,482,869,645,213,696 (2^72)256YesSmall site or home (common provider assignment)
/60295,147,905,179,352,825,856 (2^68)16YesSome home broadband (16 LANs)
/6418,446,744,073,709,551,616 (2^64)1YesOne LAN or VLAN (needed for SLAAC)
/7272,057,594,037,927,936 (2^56)1/256 of a /64Yes
/80281,474,976,710,656 (2^48)1/65,536 of a /64Yes
/964,294,967,2961/4,294,967,296 of a /64YesEmbeds an IPv4 address (NAT64)
/11265,5361/281,474,976,710,656 of a /64Yes
/1202561/72,057,594,037,927,936 of a /64Yes
/124161/1,152,921,504,606,846,976 of a /64Yes
/12641/4,611,686,018,427,387,904 of a /64No
/12721/9,223,372,036,854,775,808 of a /64NoPoint-to-point link (RFC 6164)
/12811/18,446,744,073,709,551,616 of a /64YesOne host or loopback

Private and special ranges

IPv4

Special-purpose ranges
RangeNameWhat it is
255.255.255.255/32Limited broadcastEvery host on the local network
0.0.0.0/8This networkNot routed; 0.0.0.0 means "any address" in settings
10.0.0.0/8Private (RFC 1918)Office and home networks; not routed on the internet
100.64.0.0/10Shared address space (CGNAT)Used by providers behind carrier-grade NAT (RFC 6598)
127.0.0.0/8LoopbackThis computer
169.254.0.0/16Link-local (APIPA)Self-assigned when no DHCP server answers
172.16.0.0/12Private (RFC 1918)Office and home networks; not routed on the internet
192.0.0.0/24IETF protocol assignmentsSpecial uses such as DS-Lite
192.0.2.0/24Documentation (TEST-NET-1)For examples; never used on a network
192.88.99.0/246to4 relay (deprecated)Formerly anycast for 6to4
192.168.0.0/16Private (RFC 1918)Office and home networks; not routed on the internet
198.18.0.0/15BenchmarkingNetwork equipment testing (RFC 2544)
198.51.100.0/24Documentation (TEST-NET-2)For examples; never used on a network
203.0.113.0/24Documentation (TEST-NET-3)For examples; never used on a network
224.0.0.0/4MulticastOne-to-many traffic, such as IPTV and routing protocols
240.0.0.0/4ReservedFuture use; not usable on most systems

IPv6

Special-purpose ranges
RangeNameWhat it is
::/128UnspecifiedNo address; :: means "any address" in settings
::1/128LoopbackThis computer
::ffff:0:0/96IPv4-mappedAn IPv4 address written as IPv6
64:ff9b::/96NAT64IPv4 addresses reached through a NAT64 gateway
100::/64Discard onlyTraffic sent here is dropped (RFC 6666)
2001:db8::/32DocumentationFor examples; never used on a network
2001::/32TeredoIPv6 tunnelled over IPv4 UDP
2002::/166to4IPv6 tunnelled over IPv4 (largely retired)
3fff::/20DocumentationFor examples (RFC 9637)
fc00::/7Unique local (ULA)Private IPv6, like RFC 1918; usually fd00::/8
fe80::/10Link-localEvery IPv6 interface has one; not routed
ff00::/8MulticastOne-to-many traffic; replaces broadcast
2000::/3Global unicastPublic internet addresses

About this tool

A network is written as an address and a prefix length, such as 192.168.1.0/24: the first 24 bits name the network and the rest number the devices on it. The calculator works out where the network starts and ends, how many devices it holds, its subnet and wildcard masks, and the reverse DNS zone to ask your provider for.

It also splits a network into equal smaller ones (one per VLAN or site), turns a range of addresses into the fewest CIDR blocks for a firewall rule, and lists every IPv4 prefix length and the common IPv6 ones in reference tables.

Common questions

Why are two addresses lost in every IPv4 subnet?

The first address names the network and the last is the broadcast address, so a /24 has 256 addresses but 254 for devices. A /31 (a link between two routers) and a /32 (one host) are the exceptions.

What size of IPv6 network should a LAN use?

Always /64. Devices pick their own address within it (SLAAC), which needs the full 64 bits. A site usually gets a /48 or /56 from its provider, which holds 65,536 or 256 LANs.

What is a wildcard mask?

The subnet mask turned inside out: 255.255.255.0 becomes 0.0.0.255. Cisco access lists and OSPF use it to say which bits must match.

Which ranges can I use inside an office?

IPv4: 10.0.0.0/8, 172.16.0.0/12 and 192.168.0.0/16. IPv6: unique local addresses from fd00::/8, though most networks use the public prefix from their provider.