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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.

Network153.0.0.0/8
Usable hosts16,777,214
Subnet mask255.0.0.0
Addresses16,777,216
Network address
153.0.0.0
Broadcast address
153.255.255.255
First usable
153.0.0.1
Last usable
153.255.255.254
Usable hosts
16,777,214 (16,777,216 less the network and broadcast addresses)
Subnet mask
255.0.0.0
Wildcard mask
0.255.255.255 (Cisco ACLs, OSPF)
Prefix length
/8
Type
Public public
Old class
B (default /16)
As numbers
Hex 99000000 · Integer 2566914048 to 2583691263
Reverse DNS zone
153.in-addr.arpa
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address10011001..00000000.00000000.00000000153.0.0.0
Subnet mask11111111..00000000.00000000.00000000255.0.0.0
Network10011001..00000000.00000000.00000000153.0.0.0
Broadcast10011001..11111111.11111111.11111111153.255.255.255
Split into smaller subnets/15
/9 (2)/10 (4)/11 (8)/12 (16)/13 (32)/14 (64)/15 (128)/16 (256)/17 (512)/18 (1,024)/19 (2,048)/20 (4,096)

153.0.0.0/8 makes 128 subnets of /15.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1153.0.0.0/15153.0.0.1 to 153.1.255.254153.1.255.255131,070
2153.2.0.0/15153.2.0.1 to 153.3.255.254153.3.255.255131,070
3153.4.0.0/15153.4.0.1 to 153.5.255.254153.5.255.255131,070
4153.6.0.0/15153.6.0.1 to 153.7.255.254153.7.255.255131,070
5153.8.0.0/15153.8.0.1 to 153.9.255.254153.9.255.255131,070
6153.10.0.0/15153.10.0.1 to 153.11.255.254153.11.255.255131,070
7153.12.0.0/15153.12.0.1 to 153.13.255.254153.13.255.255131,070
8153.14.0.0/15153.14.0.1 to 153.15.255.254153.15.255.255131,070
9153.16.0.0/15153.16.0.1 to 153.17.255.254153.17.255.255131,070
10153.18.0.0/15153.18.0.1 to 153.19.255.254153.19.255.255131,070
11153.20.0.0/15153.20.0.1 to 153.21.255.254153.21.255.255131,070
12153.22.0.0/15153.22.0.1 to 153.23.255.254153.23.255.255131,070
13153.24.0.0/15153.24.0.1 to 153.25.255.254153.25.255.255131,070
14153.26.0.0/15153.26.0.1 to 153.27.255.254153.27.255.255131,070
15153.28.0.0/15153.28.0.1 to 153.29.255.254153.29.255.255131,070
16153.30.0.0/15153.30.0.1 to 153.31.255.254153.31.255.255131,070
17153.32.0.0/15153.32.0.1 to 153.33.255.254153.33.255.255131,070
18153.34.0.0/15153.34.0.1 to 153.35.255.254153.35.255.255131,070
19153.36.0.0/15153.36.0.1 to 153.37.255.254153.37.255.255131,070
20153.38.0.0/15153.38.0.1 to 153.39.255.254153.39.255.255131,070
21153.40.0.0/15153.40.0.1 to 153.41.255.254153.41.255.255131,070
22153.42.0.0/15153.42.0.1 to 153.43.255.254153.43.255.255131,070
23153.44.0.0/15153.44.0.1 to 153.45.255.254153.45.255.255131,070
24153.46.0.0/15153.46.0.1 to 153.47.255.254153.47.255.255131,070
25153.48.0.0/15153.48.0.1 to 153.49.255.254153.49.255.255131,070
26153.50.0.0/15153.50.0.1 to 153.51.255.254153.51.255.255131,070
27153.52.0.0/15153.52.0.1 to 153.53.255.254153.53.255.255131,070
28153.54.0.0/15153.54.0.1 to 153.55.255.254153.55.255.255131,070
29153.56.0.0/15153.56.0.1 to 153.57.255.254153.57.255.255131,070
30153.58.0.0/15153.58.0.1 to 153.59.255.254153.59.255.255131,070
31153.60.0.0/15153.60.0.1 to 153.61.255.254153.61.255.255131,070
32153.62.0.0/15153.62.0.1 to 153.63.255.254153.63.255.255131,070
33153.64.0.0/15153.64.0.1 to 153.65.255.254153.65.255.255131,070
34153.66.0.0/15153.66.0.1 to 153.67.255.254153.67.255.255131,070
35153.68.0.0/15153.68.0.1 to 153.69.255.254153.69.255.255131,070
36153.70.0.0/15153.70.0.1 to 153.71.255.254153.71.255.255131,070
37153.72.0.0/15153.72.0.1 to 153.73.255.254153.73.255.255131,070
38153.74.0.0/15153.74.0.1 to 153.75.255.254153.75.255.255131,070
39153.76.0.0/15153.76.0.1 to 153.77.255.254153.77.255.255131,070
40153.78.0.0/15153.78.0.1 to 153.79.255.254153.79.255.255131,070
41153.80.0.0/15153.80.0.1 to 153.81.255.254153.81.255.255131,070
42153.82.0.0/15153.82.0.1 to 153.83.255.254153.83.255.255131,070
43153.84.0.0/15153.84.0.1 to 153.85.255.254153.85.255.255131,070
44153.86.0.0/15153.86.0.1 to 153.87.255.254153.87.255.255131,070
45153.88.0.0/15153.88.0.1 to 153.89.255.254153.89.255.255131,070
46153.90.0.0/15153.90.0.1 to 153.91.255.254153.91.255.255131,070
47153.92.0.0/15153.92.0.1 to 153.93.255.254153.93.255.255131,070
48153.94.0.0/15153.94.0.1 to 153.95.255.254153.95.255.255131,070
49153.96.0.0/15153.96.0.1 to 153.97.255.254153.97.255.255131,070
50153.98.0.0/15153.98.0.1 to 153.99.255.254153.99.255.255131,070
51153.100.0.0/15153.100.0.1 to 153.101.255.254153.101.255.255131,070
52153.102.0.0/15153.102.0.1 to 153.103.255.254153.103.255.255131,070
53153.104.0.0/15153.104.0.1 to 153.105.255.254153.105.255.255131,070
54153.106.0.0/15153.106.0.1 to 153.107.255.254153.107.255.255131,070
55153.108.0.0/15153.108.0.1 to 153.109.255.254153.109.255.255131,070
56153.110.0.0/15153.110.0.1 to 153.111.255.254153.111.255.255131,070
57153.112.0.0/15153.112.0.1 to 153.113.255.254153.113.255.255131,070
58153.114.0.0/15153.114.0.1 to 153.115.255.254153.115.255.255131,070
59153.116.0.0/15153.116.0.1 to 153.117.255.254153.117.255.255131,070
60153.118.0.0/15153.118.0.1 to 153.119.255.254153.119.255.255131,070
61153.120.0.0/15153.120.0.1 to 153.121.255.254153.121.255.255131,070
62153.122.0.0/15153.122.0.1 to 153.123.255.254153.123.255.255131,070
63153.124.0.0/15153.124.0.1 to 153.125.255.254153.125.255.255131,070
64153.126.0.0/15153.126.0.1 to 153.127.255.254153.127.255.255131,070
65153.128.0.0/15153.128.0.1 to 153.129.255.254153.129.255.255131,070
66153.130.0.0/15153.130.0.1 to 153.131.255.254153.131.255.255131,070
67153.132.0.0/15153.132.0.1 to 153.133.255.254153.133.255.255131,070
68153.134.0.0/15153.134.0.1 to 153.135.255.254153.135.255.255131,070
69153.136.0.0/15153.136.0.1 to 153.137.255.254153.137.255.255131,070
70153.138.0.0/15153.138.0.1 to 153.139.255.254153.139.255.255131,070
71153.140.0.0/15153.140.0.1 to 153.141.255.254153.141.255.255131,070
72153.142.0.0/15153.142.0.1 to 153.143.255.254153.143.255.255131,070
73153.144.0.0/15153.144.0.1 to 153.145.255.254153.145.255.255131,070
74153.146.0.0/15153.146.0.1 to 153.147.255.254153.147.255.255131,070
75153.148.0.0/15153.148.0.1 to 153.149.255.254153.149.255.255131,070
76153.150.0.0/15153.150.0.1 to 153.151.255.254153.151.255.255131,070
77153.152.0.0/15153.152.0.1 to 153.153.255.254153.153.255.255131,070
78153.154.0.0/15153.154.0.1 to 153.155.255.254153.155.255.255131,070
79153.156.0.0/15153.156.0.1 to 153.157.255.254153.157.255.255131,070
80153.158.0.0/15153.158.0.1 to 153.159.255.254153.159.255.255131,070
81153.160.0.0/15153.160.0.1 to 153.161.255.254153.161.255.255131,070
82153.162.0.0/15153.162.0.1 to 153.163.255.254153.163.255.255131,070
83153.164.0.0/15153.164.0.1 to 153.165.255.254153.165.255.255131,070
84153.166.0.0/15153.166.0.1 to 153.167.255.254153.167.255.255131,070
85153.168.0.0/15153.168.0.1 to 153.169.255.254153.169.255.255131,070
86153.170.0.0/15153.170.0.1 to 153.171.255.254153.171.255.255131,070
87153.172.0.0/15153.172.0.1 to 153.173.255.254153.173.255.255131,070
88153.174.0.0/15153.174.0.1 to 153.175.255.254153.175.255.255131,070
89153.176.0.0/15153.176.0.1 to 153.177.255.254153.177.255.255131,070
90153.178.0.0/15153.178.0.1 to 153.179.255.254153.179.255.255131,070
91153.180.0.0/15153.180.0.1 to 153.181.255.254153.181.255.255131,070
92153.182.0.0/15153.182.0.1 to 153.183.255.254153.183.255.255131,070
93153.184.0.0/15153.184.0.1 to 153.185.255.254153.185.255.255131,070
94153.186.0.0/15153.186.0.1 to 153.187.255.254153.187.255.255131,070
95153.188.0.0/15153.188.0.1 to 153.189.255.254153.189.255.255131,070
96153.190.0.0/15153.190.0.1 to 153.191.255.254153.191.255.255131,070
97153.192.0.0/15153.192.0.1 to 153.193.255.254153.193.255.255131,070
98153.194.0.0/15153.194.0.1 to 153.195.255.254153.195.255.255131,070
99153.196.0.0/15153.196.0.1 to 153.197.255.254153.197.255.255131,070
100153.198.0.0/15153.198.0.1 to 153.199.255.254153.199.255.255131,070
101153.200.0.0/15153.200.0.1 to 153.201.255.254153.201.255.255131,070
102153.202.0.0/15153.202.0.1 to 153.203.255.254153.203.255.255131,070
103153.204.0.0/15153.204.0.1 to 153.205.255.254153.205.255.255131,070
104153.206.0.0/15153.206.0.1 to 153.207.255.254153.207.255.255131,070
105153.208.0.0/15153.208.0.1 to 153.209.255.254153.209.255.255131,070
106153.210.0.0/15153.210.0.1 to 153.211.255.254153.211.255.255131,070
107153.212.0.0/15153.212.0.1 to 153.213.255.254153.213.255.255131,070
108153.214.0.0/15153.214.0.1 to 153.215.255.254153.215.255.255131,070
109153.216.0.0/15153.216.0.1 to 153.217.255.254153.217.255.255131,070
110153.218.0.0/15153.218.0.1 to 153.219.255.254153.219.255.255131,070
111153.220.0.0/15153.220.0.1 to 153.221.255.254153.221.255.255131,070
112153.222.0.0/15153.222.0.1 to 153.223.255.254153.223.255.255131,070
113153.224.0.0/15153.224.0.1 to 153.225.255.254153.225.255.255131,070
114153.226.0.0/15153.226.0.1 to 153.227.255.254153.227.255.255131,070
115153.228.0.0/15153.228.0.1 to 153.229.255.254153.229.255.255131,070
116153.230.0.0/15153.230.0.1 to 153.231.255.254153.231.255.255131,070
117153.232.0.0/15153.232.0.1 to 153.233.255.254153.233.255.255131,070
118153.234.0.0/15153.234.0.1 to 153.235.255.254153.235.255.255131,070
119153.236.0.0/15153.236.0.1 to 153.237.255.254153.237.255.255131,070
120153.238.0.0/15153.238.0.1 to 153.239.255.254153.239.255.255131,070
121153.240.0.0/15153.240.0.1 to 153.241.255.254153.241.255.255131,070
122153.242.0.0/15153.242.0.1 to 153.243.255.254153.243.255.255131,070
123153.244.0.0/15153.244.0.1 to 153.245.255.254153.245.255.255131,070
124153.246.0.0/15153.246.0.1 to 153.247.255.254153.247.255.255131,070
125153.248.0.0/15153.248.0.1 to 153.249.255.254153.249.255.255131,070
126153.250.0.0/15153.250.0.1 to 153.251.255.254153.251.255.255131,070
127153.252.0.0/15153.252.0.1 to 153.253.255.254153.253.255.255131,070
128153.254.0.0/15153.254.0.1 to 153.255.255.254153.255.255.255131,070

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.