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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.

Network193.0.0.0/8
Usable hosts16,777,214
Subnet mask255.0.0.0
Addresses16,777,216
Network address
193.0.0.0
Broadcast address
193.255.255.255
First usable
193.0.0.1
Last usable
193.255.255.254
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
C (default /24)
As numbers
Hex C1000000 · Integer 3238002688 to 3254779903
Reverse DNS zone
193.in-addr.arpa
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address11000001..00000000.00000000.00000000193.0.0.0
Subnet mask11111111..00000000.00000000.00000000255.0.0.0
Network11000001..00000000.00000000.00000000193.0.0.0
Broadcast11000001..11111111.11111111.11111111193.255.255.255
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)

193.0.0.0/8 makes 128 subnets of /15.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1193.0.0.0/15193.0.0.1 to 193.1.255.254193.1.255.255131,070
2193.2.0.0/15193.2.0.1 to 193.3.255.254193.3.255.255131,070
3193.4.0.0/15193.4.0.1 to 193.5.255.254193.5.255.255131,070
4193.6.0.0/15193.6.0.1 to 193.7.255.254193.7.255.255131,070
5193.8.0.0/15193.8.0.1 to 193.9.255.254193.9.255.255131,070
6193.10.0.0/15193.10.0.1 to 193.11.255.254193.11.255.255131,070
7193.12.0.0/15193.12.0.1 to 193.13.255.254193.13.255.255131,070
8193.14.0.0/15193.14.0.1 to 193.15.255.254193.15.255.255131,070
9193.16.0.0/15193.16.0.1 to 193.17.255.254193.17.255.255131,070
10193.18.0.0/15193.18.0.1 to 193.19.255.254193.19.255.255131,070
11193.20.0.0/15193.20.0.1 to 193.21.255.254193.21.255.255131,070
12193.22.0.0/15193.22.0.1 to 193.23.255.254193.23.255.255131,070
13193.24.0.0/15193.24.0.1 to 193.25.255.254193.25.255.255131,070
14193.26.0.0/15193.26.0.1 to 193.27.255.254193.27.255.255131,070
15193.28.0.0/15193.28.0.1 to 193.29.255.254193.29.255.255131,070
16193.30.0.0/15193.30.0.1 to 193.31.255.254193.31.255.255131,070
17193.32.0.0/15193.32.0.1 to 193.33.255.254193.33.255.255131,070
18193.34.0.0/15193.34.0.1 to 193.35.255.254193.35.255.255131,070
19193.36.0.0/15193.36.0.1 to 193.37.255.254193.37.255.255131,070
20193.38.0.0/15193.38.0.1 to 193.39.255.254193.39.255.255131,070
21193.40.0.0/15193.40.0.1 to 193.41.255.254193.41.255.255131,070
22193.42.0.0/15193.42.0.1 to 193.43.255.254193.43.255.255131,070
23193.44.0.0/15193.44.0.1 to 193.45.255.254193.45.255.255131,070
24193.46.0.0/15193.46.0.1 to 193.47.255.254193.47.255.255131,070
25193.48.0.0/15193.48.0.1 to 193.49.255.254193.49.255.255131,070
26193.50.0.0/15193.50.0.1 to 193.51.255.254193.51.255.255131,070
27193.52.0.0/15193.52.0.1 to 193.53.255.254193.53.255.255131,070
28193.54.0.0/15193.54.0.1 to 193.55.255.254193.55.255.255131,070
29193.56.0.0/15193.56.0.1 to 193.57.255.254193.57.255.255131,070
30193.58.0.0/15193.58.0.1 to 193.59.255.254193.59.255.255131,070
31193.60.0.0/15193.60.0.1 to 193.61.255.254193.61.255.255131,070
32193.62.0.0/15193.62.0.1 to 193.63.255.254193.63.255.255131,070
33193.64.0.0/15193.64.0.1 to 193.65.255.254193.65.255.255131,070
34193.66.0.0/15193.66.0.1 to 193.67.255.254193.67.255.255131,070
35193.68.0.0/15193.68.0.1 to 193.69.255.254193.69.255.255131,070
36193.70.0.0/15193.70.0.1 to 193.71.255.254193.71.255.255131,070
37193.72.0.0/15193.72.0.1 to 193.73.255.254193.73.255.255131,070
38193.74.0.0/15193.74.0.1 to 193.75.255.254193.75.255.255131,070
39193.76.0.0/15193.76.0.1 to 193.77.255.254193.77.255.255131,070
40193.78.0.0/15193.78.0.1 to 193.79.255.254193.79.255.255131,070
41193.80.0.0/15193.80.0.1 to 193.81.255.254193.81.255.255131,070
42193.82.0.0/15193.82.0.1 to 193.83.255.254193.83.255.255131,070
43193.84.0.0/15193.84.0.1 to 193.85.255.254193.85.255.255131,070
44193.86.0.0/15193.86.0.1 to 193.87.255.254193.87.255.255131,070
45193.88.0.0/15193.88.0.1 to 193.89.255.254193.89.255.255131,070
46193.90.0.0/15193.90.0.1 to 193.91.255.254193.91.255.255131,070
47193.92.0.0/15193.92.0.1 to 193.93.255.254193.93.255.255131,070
48193.94.0.0/15193.94.0.1 to 193.95.255.254193.95.255.255131,070
49193.96.0.0/15193.96.0.1 to 193.97.255.254193.97.255.255131,070
50193.98.0.0/15193.98.0.1 to 193.99.255.254193.99.255.255131,070
51193.100.0.0/15193.100.0.1 to 193.101.255.254193.101.255.255131,070
52193.102.0.0/15193.102.0.1 to 193.103.255.254193.103.255.255131,070
53193.104.0.0/15193.104.0.1 to 193.105.255.254193.105.255.255131,070
54193.106.0.0/15193.106.0.1 to 193.107.255.254193.107.255.255131,070
55193.108.0.0/15193.108.0.1 to 193.109.255.254193.109.255.255131,070
56193.110.0.0/15193.110.0.1 to 193.111.255.254193.111.255.255131,070
57193.112.0.0/15193.112.0.1 to 193.113.255.254193.113.255.255131,070
58193.114.0.0/15193.114.0.1 to 193.115.255.254193.115.255.255131,070
59193.116.0.0/15193.116.0.1 to 193.117.255.254193.117.255.255131,070
60193.118.0.0/15193.118.0.1 to 193.119.255.254193.119.255.255131,070
61193.120.0.0/15193.120.0.1 to 193.121.255.254193.121.255.255131,070
62193.122.0.0/15193.122.0.1 to 193.123.255.254193.123.255.255131,070
63193.124.0.0/15193.124.0.1 to 193.125.255.254193.125.255.255131,070
64193.126.0.0/15193.126.0.1 to 193.127.255.254193.127.255.255131,070
65193.128.0.0/15193.128.0.1 to 193.129.255.254193.129.255.255131,070
66193.130.0.0/15193.130.0.1 to 193.131.255.254193.131.255.255131,070
67193.132.0.0/15193.132.0.1 to 193.133.255.254193.133.255.255131,070
68193.134.0.0/15193.134.0.1 to 193.135.255.254193.135.255.255131,070
69193.136.0.0/15193.136.0.1 to 193.137.255.254193.137.255.255131,070
70193.138.0.0/15193.138.0.1 to 193.139.255.254193.139.255.255131,070
71193.140.0.0/15193.140.0.1 to 193.141.255.254193.141.255.255131,070
72193.142.0.0/15193.142.0.1 to 193.143.255.254193.143.255.255131,070
73193.144.0.0/15193.144.0.1 to 193.145.255.254193.145.255.255131,070
74193.146.0.0/15193.146.0.1 to 193.147.255.254193.147.255.255131,070
75193.148.0.0/15193.148.0.1 to 193.149.255.254193.149.255.255131,070
76193.150.0.0/15193.150.0.1 to 193.151.255.254193.151.255.255131,070
77193.152.0.0/15193.152.0.1 to 193.153.255.254193.153.255.255131,070
78193.154.0.0/15193.154.0.1 to 193.155.255.254193.155.255.255131,070
79193.156.0.0/15193.156.0.1 to 193.157.255.254193.157.255.255131,070
80193.158.0.0/15193.158.0.1 to 193.159.255.254193.159.255.255131,070
81193.160.0.0/15193.160.0.1 to 193.161.255.254193.161.255.255131,070
82193.162.0.0/15193.162.0.1 to 193.163.255.254193.163.255.255131,070
83193.164.0.0/15193.164.0.1 to 193.165.255.254193.165.255.255131,070
84193.166.0.0/15193.166.0.1 to 193.167.255.254193.167.255.255131,070
85193.168.0.0/15193.168.0.1 to 193.169.255.254193.169.255.255131,070
86193.170.0.0/15193.170.0.1 to 193.171.255.254193.171.255.255131,070
87193.172.0.0/15193.172.0.1 to 193.173.255.254193.173.255.255131,070
88193.174.0.0/15193.174.0.1 to 193.175.255.254193.175.255.255131,070
89193.176.0.0/15193.176.0.1 to 193.177.255.254193.177.255.255131,070
90193.178.0.0/15193.178.0.1 to 193.179.255.254193.179.255.255131,070
91193.180.0.0/15193.180.0.1 to 193.181.255.254193.181.255.255131,070
92193.182.0.0/15193.182.0.1 to 193.183.255.254193.183.255.255131,070
93193.184.0.0/15193.184.0.1 to 193.185.255.254193.185.255.255131,070
94193.186.0.0/15193.186.0.1 to 193.187.255.254193.187.255.255131,070
95193.188.0.0/15193.188.0.1 to 193.189.255.254193.189.255.255131,070
96193.190.0.0/15193.190.0.1 to 193.191.255.254193.191.255.255131,070
97193.192.0.0/15193.192.0.1 to 193.193.255.254193.193.255.255131,070
98193.194.0.0/15193.194.0.1 to 193.195.255.254193.195.255.255131,070
99193.196.0.0/15193.196.0.1 to 193.197.255.254193.197.255.255131,070
100193.198.0.0/15193.198.0.1 to 193.199.255.254193.199.255.255131,070
101193.200.0.0/15193.200.0.1 to 193.201.255.254193.201.255.255131,070
102193.202.0.0/15193.202.0.1 to 193.203.255.254193.203.255.255131,070
103193.204.0.0/15193.204.0.1 to 193.205.255.254193.205.255.255131,070
104193.206.0.0/15193.206.0.1 to 193.207.255.254193.207.255.255131,070
105193.208.0.0/15193.208.0.1 to 193.209.255.254193.209.255.255131,070
106193.210.0.0/15193.210.0.1 to 193.211.255.254193.211.255.255131,070
107193.212.0.0/15193.212.0.1 to 193.213.255.254193.213.255.255131,070
108193.214.0.0/15193.214.0.1 to 193.215.255.254193.215.255.255131,070
109193.216.0.0/15193.216.0.1 to 193.217.255.254193.217.255.255131,070
110193.218.0.0/15193.218.0.1 to 193.219.255.254193.219.255.255131,070
111193.220.0.0/15193.220.0.1 to 193.221.255.254193.221.255.255131,070
112193.222.0.0/15193.222.0.1 to 193.223.255.254193.223.255.255131,070
113193.224.0.0/15193.224.0.1 to 193.225.255.254193.225.255.255131,070
114193.226.0.0/15193.226.0.1 to 193.227.255.254193.227.255.255131,070
115193.228.0.0/15193.228.0.1 to 193.229.255.254193.229.255.255131,070
116193.230.0.0/15193.230.0.1 to 193.231.255.254193.231.255.255131,070
117193.232.0.0/15193.232.0.1 to 193.233.255.254193.233.255.255131,070
118193.234.0.0/15193.234.0.1 to 193.235.255.254193.235.255.255131,070
119193.236.0.0/15193.236.0.1 to 193.237.255.254193.237.255.255131,070
120193.238.0.0/15193.238.0.1 to 193.239.255.254193.239.255.255131,070
121193.240.0.0/15193.240.0.1 to 193.241.255.254193.241.255.255131,070
122193.242.0.0/15193.242.0.1 to 193.243.255.254193.243.255.255131,070
123193.244.0.0/15193.244.0.1 to 193.245.255.254193.245.255.255131,070
124193.246.0.0/15193.246.0.1 to 193.247.255.254193.247.255.255131,070
125193.248.0.0/15193.248.0.1 to 193.249.255.254193.249.255.255131,070
126193.250.0.0/15193.250.0.1 to 193.251.255.254193.251.255.255131,070
127193.252.0.0/15193.252.0.1 to 193.253.255.254193.253.255.255131,070
128193.254.0.0/15193.254.0.1 to 193.255.255.254193.255.255.255131,070

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.