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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.

Network131.167.232.0/24
Usable hosts254
Subnet mask255.255.255.0
Addresses256
Network address
131.167.232.0
Broadcast address
131.167.232.255
First usable
131.167.232.1
Last usable
131.167.232.254
Usable hosts
254 (256 less the network and broadcast addresses)
Subnet mask
255.255.255.0
Wildcard mask
0.0.0.255 (Cisco ACLs, OSPF)
Prefix length
/24
Type
Public public
Old class
B (default /16)
As numbers
Hex 83A7E800 · Integer 2208819200 to 2208819455
Reverse DNS zone
232.167.131.in-addr.arpa
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address10000011.10100111.11101000..00000000131.167.232.0
Subnet mask11111111.11111111.11111111..00000000255.255.255.0
Network10000011.10100111.11101000..00000000131.167.232.0
Broadcast10000011.10100111.11101000..11111111131.167.232.255
Split into smaller subnets/30
/25 (2)/26 (4)/27 (8)/28 (16)/29 (32)/30 (64)/31 (128)/32 (256)

131.167.232.0/24 makes 64 subnets of /30.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1131.167.232.0/30131.167.232.1 to 131.167.232.2131.167.232.32
2131.167.232.4/30131.167.232.5 to 131.167.232.6131.167.232.72
3131.167.232.8/30131.167.232.9 to 131.167.232.10131.167.232.112
4131.167.232.12/30131.167.232.13 to 131.167.232.14131.167.232.152
5131.167.232.16/30131.167.232.17 to 131.167.232.18131.167.232.192
6131.167.232.20/30131.167.232.21 to 131.167.232.22131.167.232.232
7131.167.232.24/30131.167.232.25 to 131.167.232.26131.167.232.272
8131.167.232.28/30131.167.232.29 to 131.167.232.30131.167.232.312
9131.167.232.32/30131.167.232.33 to 131.167.232.34131.167.232.352
10131.167.232.36/30131.167.232.37 to 131.167.232.38131.167.232.392
11131.167.232.40/30131.167.232.41 to 131.167.232.42131.167.232.432
12131.167.232.44/30131.167.232.45 to 131.167.232.46131.167.232.472
13131.167.232.48/30131.167.232.49 to 131.167.232.50131.167.232.512
14131.167.232.52/30131.167.232.53 to 131.167.232.54131.167.232.552
15131.167.232.56/30131.167.232.57 to 131.167.232.58131.167.232.592
16131.167.232.60/30131.167.232.61 to 131.167.232.62131.167.232.632
17131.167.232.64/30131.167.232.65 to 131.167.232.66131.167.232.672
18131.167.232.68/30131.167.232.69 to 131.167.232.70131.167.232.712
19131.167.232.72/30131.167.232.73 to 131.167.232.74131.167.232.752
20131.167.232.76/30131.167.232.77 to 131.167.232.78131.167.232.792
21131.167.232.80/30131.167.232.81 to 131.167.232.82131.167.232.832
22131.167.232.84/30131.167.232.85 to 131.167.232.86131.167.232.872
23131.167.232.88/30131.167.232.89 to 131.167.232.90131.167.232.912
24131.167.232.92/30131.167.232.93 to 131.167.232.94131.167.232.952
25131.167.232.96/30131.167.232.97 to 131.167.232.98131.167.232.992
26131.167.232.100/30131.167.232.101 to 131.167.232.102131.167.232.1032
27131.167.232.104/30131.167.232.105 to 131.167.232.106131.167.232.1072
28131.167.232.108/30131.167.232.109 to 131.167.232.110131.167.232.1112
29131.167.232.112/30131.167.232.113 to 131.167.232.114131.167.232.1152
30131.167.232.116/30131.167.232.117 to 131.167.232.118131.167.232.1192
31131.167.232.120/30131.167.232.121 to 131.167.232.122131.167.232.1232
32131.167.232.124/30131.167.232.125 to 131.167.232.126131.167.232.1272
33131.167.232.128/30131.167.232.129 to 131.167.232.130131.167.232.1312
34131.167.232.132/30131.167.232.133 to 131.167.232.134131.167.232.1352
35131.167.232.136/30131.167.232.137 to 131.167.232.138131.167.232.1392
36131.167.232.140/30131.167.232.141 to 131.167.232.142131.167.232.1432
37131.167.232.144/30131.167.232.145 to 131.167.232.146131.167.232.1472
38131.167.232.148/30131.167.232.149 to 131.167.232.150131.167.232.1512
39131.167.232.152/30131.167.232.153 to 131.167.232.154131.167.232.1552
40131.167.232.156/30131.167.232.157 to 131.167.232.158131.167.232.1592
41131.167.232.160/30131.167.232.161 to 131.167.232.162131.167.232.1632
42131.167.232.164/30131.167.232.165 to 131.167.232.166131.167.232.1672
43131.167.232.168/30131.167.232.169 to 131.167.232.170131.167.232.1712
44131.167.232.172/30131.167.232.173 to 131.167.232.174131.167.232.1752
45131.167.232.176/30131.167.232.177 to 131.167.232.178131.167.232.1792
46131.167.232.180/30131.167.232.181 to 131.167.232.182131.167.232.1832
47131.167.232.184/30131.167.232.185 to 131.167.232.186131.167.232.1872
48131.167.232.188/30131.167.232.189 to 131.167.232.190131.167.232.1912
49131.167.232.192/30131.167.232.193 to 131.167.232.194131.167.232.1952
50131.167.232.196/30131.167.232.197 to 131.167.232.198131.167.232.1992
51131.167.232.200/30131.167.232.201 to 131.167.232.202131.167.232.2032
52131.167.232.204/30131.167.232.205 to 131.167.232.206131.167.232.2072
53131.167.232.208/30131.167.232.209 to 131.167.232.210131.167.232.2112
54131.167.232.212/30131.167.232.213 to 131.167.232.214131.167.232.2152
55131.167.232.216/30131.167.232.217 to 131.167.232.218131.167.232.2192
56131.167.232.220/30131.167.232.221 to 131.167.232.222131.167.232.2232
57131.167.232.224/30131.167.232.225 to 131.167.232.226131.167.232.2272
58131.167.232.228/30131.167.232.229 to 131.167.232.230131.167.232.2312
59131.167.232.232/30131.167.232.233 to 131.167.232.234131.167.232.2352
60131.167.232.236/30131.167.232.237 to 131.167.232.238131.167.232.2392
61131.167.232.240/30131.167.232.241 to 131.167.232.242131.167.232.2432
62131.167.232.244/30131.167.232.245 to 131.167.232.246131.167.232.2472
63131.167.232.248/30131.167.232.249 to 131.167.232.250131.167.232.2512
64131.167.232.252/30131.167.232.253 to 131.167.232.254131.167.232.2552

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.