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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.

Network196.0.0.0/7
Usable hosts33,554,430
Subnet mask254.0.0.0
Addresses33,554,432
Network address
196.0.0.0
Broadcast address
197.255.255.255
First usable
196.0.0.1
Last usable
197.255.255.254
Usable hosts
33,554,430 (33,554,432 less the network and broadcast addresses)
Subnet mask
254.0.0.0
Wildcard mask
1.255.255.255 (Cisco ACLs, OSPF)
Prefix length
/7
Type
Public public
Old class
C (default /24)
As numbers
Hex C4000000 · Integer 3288334336 to 3321888767
Reverse DNS zones
196.in-addr.arpa
197.in-addr.arpa
/7 is not on a 8-bit boundary, so it takes 2 /8 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address11000100.00000000.00000000.00000000196.0.0.0
Subnet mask11111110.00000000.00000000.00000000254.0.0.0
Network11000100.00000000.00000000.00000000196.0.0.0
Broadcast11000101.11111111.11111111.11111111197.255.255.255
Split into smaller subnets/14
/8 (2)/9 (4)/10 (8)/11 (16)/12 (32)/13 (64)/14 (128)/15 (256)/16 (512)/17 (1,024)/18 (2,048)/19 (4,096)

196.0.0.0/7 makes 128 subnets of /14.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1196.0.0.0/14196.0.0.1 to 196.3.255.254196.3.255.255262,142
2196.4.0.0/14196.4.0.1 to 196.7.255.254196.7.255.255262,142
3196.8.0.0/14196.8.0.1 to 196.11.255.254196.11.255.255262,142
4196.12.0.0/14196.12.0.1 to 196.15.255.254196.15.255.255262,142
5196.16.0.0/14196.16.0.1 to 196.19.255.254196.19.255.255262,142
6196.20.0.0/14196.20.0.1 to 196.23.255.254196.23.255.255262,142
7196.24.0.0/14196.24.0.1 to 196.27.255.254196.27.255.255262,142
8196.28.0.0/14196.28.0.1 to 196.31.255.254196.31.255.255262,142
9196.32.0.0/14196.32.0.1 to 196.35.255.254196.35.255.255262,142
10196.36.0.0/14196.36.0.1 to 196.39.255.254196.39.255.255262,142
11196.40.0.0/14196.40.0.1 to 196.43.255.254196.43.255.255262,142
12196.44.0.0/14196.44.0.1 to 196.47.255.254196.47.255.255262,142
13196.48.0.0/14196.48.0.1 to 196.51.255.254196.51.255.255262,142
14196.52.0.0/14196.52.0.1 to 196.55.255.254196.55.255.255262,142
15196.56.0.0/14196.56.0.1 to 196.59.255.254196.59.255.255262,142
16196.60.0.0/14196.60.0.1 to 196.63.255.254196.63.255.255262,142
17196.64.0.0/14196.64.0.1 to 196.67.255.254196.67.255.255262,142
18196.68.0.0/14196.68.0.1 to 196.71.255.254196.71.255.255262,142
19196.72.0.0/14196.72.0.1 to 196.75.255.254196.75.255.255262,142
20196.76.0.0/14196.76.0.1 to 196.79.255.254196.79.255.255262,142
21196.80.0.0/14196.80.0.1 to 196.83.255.254196.83.255.255262,142
22196.84.0.0/14196.84.0.1 to 196.87.255.254196.87.255.255262,142
23196.88.0.0/14196.88.0.1 to 196.91.255.254196.91.255.255262,142
24196.92.0.0/14196.92.0.1 to 196.95.255.254196.95.255.255262,142
25196.96.0.0/14196.96.0.1 to 196.99.255.254196.99.255.255262,142
26196.100.0.0/14196.100.0.1 to 196.103.255.254196.103.255.255262,142
27196.104.0.0/14196.104.0.1 to 196.107.255.254196.107.255.255262,142
28196.108.0.0/14196.108.0.1 to 196.111.255.254196.111.255.255262,142
29196.112.0.0/14196.112.0.1 to 196.115.255.254196.115.255.255262,142
30196.116.0.0/14196.116.0.1 to 196.119.255.254196.119.255.255262,142
31196.120.0.0/14196.120.0.1 to 196.123.255.254196.123.255.255262,142
32196.124.0.0/14196.124.0.1 to 196.127.255.254196.127.255.255262,142
33196.128.0.0/14196.128.0.1 to 196.131.255.254196.131.255.255262,142
34196.132.0.0/14196.132.0.1 to 196.135.255.254196.135.255.255262,142
35196.136.0.0/14196.136.0.1 to 196.139.255.254196.139.255.255262,142
36196.140.0.0/14196.140.0.1 to 196.143.255.254196.143.255.255262,142
37196.144.0.0/14196.144.0.1 to 196.147.255.254196.147.255.255262,142
38196.148.0.0/14196.148.0.1 to 196.151.255.254196.151.255.255262,142
39196.152.0.0/14196.152.0.1 to 196.155.255.254196.155.255.255262,142
40196.156.0.0/14196.156.0.1 to 196.159.255.254196.159.255.255262,142
41196.160.0.0/14196.160.0.1 to 196.163.255.254196.163.255.255262,142
42196.164.0.0/14196.164.0.1 to 196.167.255.254196.167.255.255262,142
43196.168.0.0/14196.168.0.1 to 196.171.255.254196.171.255.255262,142
44196.172.0.0/14196.172.0.1 to 196.175.255.254196.175.255.255262,142
45196.176.0.0/14196.176.0.1 to 196.179.255.254196.179.255.255262,142
46196.180.0.0/14196.180.0.1 to 196.183.255.254196.183.255.255262,142
47196.184.0.0/14196.184.0.1 to 196.187.255.254196.187.255.255262,142
48196.188.0.0/14196.188.0.1 to 196.191.255.254196.191.255.255262,142
49196.192.0.0/14196.192.0.1 to 196.195.255.254196.195.255.255262,142
50196.196.0.0/14196.196.0.1 to 196.199.255.254196.199.255.255262,142
51196.200.0.0/14196.200.0.1 to 196.203.255.254196.203.255.255262,142
52196.204.0.0/14196.204.0.1 to 196.207.255.254196.207.255.255262,142
53196.208.0.0/14196.208.0.1 to 196.211.255.254196.211.255.255262,142
54196.212.0.0/14196.212.0.1 to 196.215.255.254196.215.255.255262,142
55196.216.0.0/14196.216.0.1 to 196.219.255.254196.219.255.255262,142
56196.220.0.0/14196.220.0.1 to 196.223.255.254196.223.255.255262,142
57196.224.0.0/14196.224.0.1 to 196.227.255.254196.227.255.255262,142
58196.228.0.0/14196.228.0.1 to 196.231.255.254196.231.255.255262,142
59196.232.0.0/14196.232.0.1 to 196.235.255.254196.235.255.255262,142
60196.236.0.0/14196.236.0.1 to 196.239.255.254196.239.255.255262,142
61196.240.0.0/14196.240.0.1 to 196.243.255.254196.243.255.255262,142
62196.244.0.0/14196.244.0.1 to 196.247.255.254196.247.255.255262,142
63196.248.0.0/14196.248.0.1 to 196.251.255.254196.251.255.255262,142
64196.252.0.0/14196.252.0.1 to 196.255.255.254196.255.255.255262,142
65197.0.0.0/14197.0.0.1 to 197.3.255.254197.3.255.255262,142
66197.4.0.0/14197.4.0.1 to 197.7.255.254197.7.255.255262,142
67197.8.0.0/14197.8.0.1 to 197.11.255.254197.11.255.255262,142
68197.12.0.0/14197.12.0.1 to 197.15.255.254197.15.255.255262,142
69197.16.0.0/14197.16.0.1 to 197.19.255.254197.19.255.255262,142
70197.20.0.0/14197.20.0.1 to 197.23.255.254197.23.255.255262,142
71197.24.0.0/14197.24.0.1 to 197.27.255.254197.27.255.255262,142
72197.28.0.0/14197.28.0.1 to 197.31.255.254197.31.255.255262,142
73197.32.0.0/14197.32.0.1 to 197.35.255.254197.35.255.255262,142
74197.36.0.0/14197.36.0.1 to 197.39.255.254197.39.255.255262,142
75197.40.0.0/14197.40.0.1 to 197.43.255.254197.43.255.255262,142
76197.44.0.0/14197.44.0.1 to 197.47.255.254197.47.255.255262,142
77197.48.0.0/14197.48.0.1 to 197.51.255.254197.51.255.255262,142
78197.52.0.0/14197.52.0.1 to 197.55.255.254197.55.255.255262,142
79197.56.0.0/14197.56.0.1 to 197.59.255.254197.59.255.255262,142
80197.60.0.0/14197.60.0.1 to 197.63.255.254197.63.255.255262,142
81197.64.0.0/14197.64.0.1 to 197.67.255.254197.67.255.255262,142
82197.68.0.0/14197.68.0.1 to 197.71.255.254197.71.255.255262,142
83197.72.0.0/14197.72.0.1 to 197.75.255.254197.75.255.255262,142
84197.76.0.0/14197.76.0.1 to 197.79.255.254197.79.255.255262,142
85197.80.0.0/14197.80.0.1 to 197.83.255.254197.83.255.255262,142
86197.84.0.0/14197.84.0.1 to 197.87.255.254197.87.255.255262,142
87197.88.0.0/14197.88.0.1 to 197.91.255.254197.91.255.255262,142
88197.92.0.0/14197.92.0.1 to 197.95.255.254197.95.255.255262,142
89197.96.0.0/14197.96.0.1 to 197.99.255.254197.99.255.255262,142
90197.100.0.0/14197.100.0.1 to 197.103.255.254197.103.255.255262,142
91197.104.0.0/14197.104.0.1 to 197.107.255.254197.107.255.255262,142
92197.108.0.0/14197.108.0.1 to 197.111.255.254197.111.255.255262,142
93197.112.0.0/14197.112.0.1 to 197.115.255.254197.115.255.255262,142
94197.116.0.0/14197.116.0.1 to 197.119.255.254197.119.255.255262,142
95197.120.0.0/14197.120.0.1 to 197.123.255.254197.123.255.255262,142
96197.124.0.0/14197.124.0.1 to 197.127.255.254197.127.255.255262,142
97197.128.0.0/14197.128.0.1 to 197.131.255.254197.131.255.255262,142
98197.132.0.0/14197.132.0.1 to 197.135.255.254197.135.255.255262,142
99197.136.0.0/14197.136.0.1 to 197.139.255.254197.139.255.255262,142
100197.140.0.0/14197.140.0.1 to 197.143.255.254197.143.255.255262,142
101197.144.0.0/14197.144.0.1 to 197.147.255.254197.147.255.255262,142
102197.148.0.0/14197.148.0.1 to 197.151.255.254197.151.255.255262,142
103197.152.0.0/14197.152.0.1 to 197.155.255.254197.155.255.255262,142
104197.156.0.0/14197.156.0.1 to 197.159.255.254197.159.255.255262,142
105197.160.0.0/14197.160.0.1 to 197.163.255.254197.163.255.255262,142
106197.164.0.0/14197.164.0.1 to 197.167.255.254197.167.255.255262,142
107197.168.0.0/14197.168.0.1 to 197.171.255.254197.171.255.255262,142
108197.172.0.0/14197.172.0.1 to 197.175.255.254197.175.255.255262,142
109197.176.0.0/14197.176.0.1 to 197.179.255.254197.179.255.255262,142
110197.180.0.0/14197.180.0.1 to 197.183.255.254197.183.255.255262,142
111197.184.0.0/14197.184.0.1 to 197.187.255.254197.187.255.255262,142
112197.188.0.0/14197.188.0.1 to 197.191.255.254197.191.255.255262,142
113197.192.0.0/14197.192.0.1 to 197.195.255.254197.195.255.255262,142
114197.196.0.0/14197.196.0.1 to 197.199.255.254197.199.255.255262,142
115197.200.0.0/14197.200.0.1 to 197.203.255.254197.203.255.255262,142
116197.204.0.0/14197.204.0.1 to 197.207.255.254197.207.255.255262,142
117197.208.0.0/14197.208.0.1 to 197.211.255.254197.211.255.255262,142
118197.212.0.0/14197.212.0.1 to 197.215.255.254197.215.255.255262,142
119197.216.0.0/14197.216.0.1 to 197.219.255.254197.219.255.255262,142
120197.220.0.0/14197.220.0.1 to 197.223.255.254197.223.255.255262,142
121197.224.0.0/14197.224.0.1 to 197.227.255.254197.227.255.255262,142
122197.228.0.0/14197.228.0.1 to 197.231.255.254197.231.255.255262,142
123197.232.0.0/14197.232.0.1 to 197.235.255.254197.235.255.255262,142
124197.236.0.0/14197.236.0.1 to 197.239.255.254197.239.255.255262,142
125197.240.0.0/14197.240.0.1 to 197.243.255.254197.243.255.255262,142
126197.244.0.0/14197.244.0.1 to 197.247.255.254197.247.255.255262,142
127197.248.0.0/14197.248.0.1 to 197.251.255.254197.251.255.255262,142
128197.252.0.0/14197.252.0.1 to 197.255.255.254197.255.255.255262,142

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.