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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.

Network134.0.0.0/7
Usable hosts33,554,430
Subnet mask254.0.0.0
Addresses33,554,432
Network address
134.0.0.0
Broadcast address
135.255.255.255
First usable
134.0.0.1
Last usable
135.255.255.254
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
B (default /16)
As numbers
Hex 86000000 · Integer 2248146944 to 2281701375
Reverse DNS zones
134.in-addr.arpa
135.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
Address10000110.00000000.00000000.00000000134.0.0.0
Subnet mask11111110.00000000.00000000.00000000254.0.0.0
Network10000110.00000000.00000000.00000000134.0.0.0
Broadcast10000111.11111111.11111111.11111111135.255.255.255
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)

134.0.0.0/7 makes 128 subnets of /14.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1134.0.0.0/14134.0.0.1 to 134.3.255.254134.3.255.255262,142
2134.4.0.0/14134.4.0.1 to 134.7.255.254134.7.255.255262,142
3134.8.0.0/14134.8.0.1 to 134.11.255.254134.11.255.255262,142
4134.12.0.0/14134.12.0.1 to 134.15.255.254134.15.255.255262,142
5134.16.0.0/14134.16.0.1 to 134.19.255.254134.19.255.255262,142
6134.20.0.0/14134.20.0.1 to 134.23.255.254134.23.255.255262,142
7134.24.0.0/14134.24.0.1 to 134.27.255.254134.27.255.255262,142
8134.28.0.0/14134.28.0.1 to 134.31.255.254134.31.255.255262,142
9134.32.0.0/14134.32.0.1 to 134.35.255.254134.35.255.255262,142
10134.36.0.0/14134.36.0.1 to 134.39.255.254134.39.255.255262,142
11134.40.0.0/14134.40.0.1 to 134.43.255.254134.43.255.255262,142
12134.44.0.0/14134.44.0.1 to 134.47.255.254134.47.255.255262,142
13134.48.0.0/14134.48.0.1 to 134.51.255.254134.51.255.255262,142
14134.52.0.0/14134.52.0.1 to 134.55.255.254134.55.255.255262,142
15134.56.0.0/14134.56.0.1 to 134.59.255.254134.59.255.255262,142
16134.60.0.0/14134.60.0.1 to 134.63.255.254134.63.255.255262,142
17134.64.0.0/14134.64.0.1 to 134.67.255.254134.67.255.255262,142
18134.68.0.0/14134.68.0.1 to 134.71.255.254134.71.255.255262,142
19134.72.0.0/14134.72.0.1 to 134.75.255.254134.75.255.255262,142
20134.76.0.0/14134.76.0.1 to 134.79.255.254134.79.255.255262,142
21134.80.0.0/14134.80.0.1 to 134.83.255.254134.83.255.255262,142
22134.84.0.0/14134.84.0.1 to 134.87.255.254134.87.255.255262,142
23134.88.0.0/14134.88.0.1 to 134.91.255.254134.91.255.255262,142
24134.92.0.0/14134.92.0.1 to 134.95.255.254134.95.255.255262,142
25134.96.0.0/14134.96.0.1 to 134.99.255.254134.99.255.255262,142
26134.100.0.0/14134.100.0.1 to 134.103.255.254134.103.255.255262,142
27134.104.0.0/14134.104.0.1 to 134.107.255.254134.107.255.255262,142
28134.108.0.0/14134.108.0.1 to 134.111.255.254134.111.255.255262,142
29134.112.0.0/14134.112.0.1 to 134.115.255.254134.115.255.255262,142
30134.116.0.0/14134.116.0.1 to 134.119.255.254134.119.255.255262,142
31134.120.0.0/14134.120.0.1 to 134.123.255.254134.123.255.255262,142
32134.124.0.0/14134.124.0.1 to 134.127.255.254134.127.255.255262,142
33134.128.0.0/14134.128.0.1 to 134.131.255.254134.131.255.255262,142
34134.132.0.0/14134.132.0.1 to 134.135.255.254134.135.255.255262,142
35134.136.0.0/14134.136.0.1 to 134.139.255.254134.139.255.255262,142
36134.140.0.0/14134.140.0.1 to 134.143.255.254134.143.255.255262,142
37134.144.0.0/14134.144.0.1 to 134.147.255.254134.147.255.255262,142
38134.148.0.0/14134.148.0.1 to 134.151.255.254134.151.255.255262,142
39134.152.0.0/14134.152.0.1 to 134.155.255.254134.155.255.255262,142
40134.156.0.0/14134.156.0.1 to 134.159.255.254134.159.255.255262,142
41134.160.0.0/14134.160.0.1 to 134.163.255.254134.163.255.255262,142
42134.164.0.0/14134.164.0.1 to 134.167.255.254134.167.255.255262,142
43134.168.0.0/14134.168.0.1 to 134.171.255.254134.171.255.255262,142
44134.172.0.0/14134.172.0.1 to 134.175.255.254134.175.255.255262,142
45134.176.0.0/14134.176.0.1 to 134.179.255.254134.179.255.255262,142
46134.180.0.0/14134.180.0.1 to 134.183.255.254134.183.255.255262,142
47134.184.0.0/14134.184.0.1 to 134.187.255.254134.187.255.255262,142
48134.188.0.0/14134.188.0.1 to 134.191.255.254134.191.255.255262,142
49134.192.0.0/14134.192.0.1 to 134.195.255.254134.195.255.255262,142
50134.196.0.0/14134.196.0.1 to 134.199.255.254134.199.255.255262,142
51134.200.0.0/14134.200.0.1 to 134.203.255.254134.203.255.255262,142
52134.204.0.0/14134.204.0.1 to 134.207.255.254134.207.255.255262,142
53134.208.0.0/14134.208.0.1 to 134.211.255.254134.211.255.255262,142
54134.212.0.0/14134.212.0.1 to 134.215.255.254134.215.255.255262,142
55134.216.0.0/14134.216.0.1 to 134.219.255.254134.219.255.255262,142
56134.220.0.0/14134.220.0.1 to 134.223.255.254134.223.255.255262,142
57134.224.0.0/14134.224.0.1 to 134.227.255.254134.227.255.255262,142
58134.228.0.0/14134.228.0.1 to 134.231.255.254134.231.255.255262,142
59134.232.0.0/14134.232.0.1 to 134.235.255.254134.235.255.255262,142
60134.236.0.0/14134.236.0.1 to 134.239.255.254134.239.255.255262,142
61134.240.0.0/14134.240.0.1 to 134.243.255.254134.243.255.255262,142
62134.244.0.0/14134.244.0.1 to 134.247.255.254134.247.255.255262,142
63134.248.0.0/14134.248.0.1 to 134.251.255.254134.251.255.255262,142
64134.252.0.0/14134.252.0.1 to 134.255.255.254134.255.255.255262,142
65135.0.0.0/14135.0.0.1 to 135.3.255.254135.3.255.255262,142
66135.4.0.0/14135.4.0.1 to 135.7.255.254135.7.255.255262,142
67135.8.0.0/14135.8.0.1 to 135.11.255.254135.11.255.255262,142
68135.12.0.0/14135.12.0.1 to 135.15.255.254135.15.255.255262,142
69135.16.0.0/14135.16.0.1 to 135.19.255.254135.19.255.255262,142
70135.20.0.0/14135.20.0.1 to 135.23.255.254135.23.255.255262,142
71135.24.0.0/14135.24.0.1 to 135.27.255.254135.27.255.255262,142
72135.28.0.0/14135.28.0.1 to 135.31.255.254135.31.255.255262,142
73135.32.0.0/14135.32.0.1 to 135.35.255.254135.35.255.255262,142
74135.36.0.0/14135.36.0.1 to 135.39.255.254135.39.255.255262,142
75135.40.0.0/14135.40.0.1 to 135.43.255.254135.43.255.255262,142
76135.44.0.0/14135.44.0.1 to 135.47.255.254135.47.255.255262,142
77135.48.0.0/14135.48.0.1 to 135.51.255.254135.51.255.255262,142
78135.52.0.0/14135.52.0.1 to 135.55.255.254135.55.255.255262,142
79135.56.0.0/14135.56.0.1 to 135.59.255.254135.59.255.255262,142
80135.60.0.0/14135.60.0.1 to 135.63.255.254135.63.255.255262,142
81135.64.0.0/14135.64.0.1 to 135.67.255.254135.67.255.255262,142
82135.68.0.0/14135.68.0.1 to 135.71.255.254135.71.255.255262,142
83135.72.0.0/14135.72.0.1 to 135.75.255.254135.75.255.255262,142
84135.76.0.0/14135.76.0.1 to 135.79.255.254135.79.255.255262,142
85135.80.0.0/14135.80.0.1 to 135.83.255.254135.83.255.255262,142
86135.84.0.0/14135.84.0.1 to 135.87.255.254135.87.255.255262,142
87135.88.0.0/14135.88.0.1 to 135.91.255.254135.91.255.255262,142
88135.92.0.0/14135.92.0.1 to 135.95.255.254135.95.255.255262,142
89135.96.0.0/14135.96.0.1 to 135.99.255.254135.99.255.255262,142
90135.100.0.0/14135.100.0.1 to 135.103.255.254135.103.255.255262,142
91135.104.0.0/14135.104.0.1 to 135.107.255.254135.107.255.255262,142
92135.108.0.0/14135.108.0.1 to 135.111.255.254135.111.255.255262,142
93135.112.0.0/14135.112.0.1 to 135.115.255.254135.115.255.255262,142
94135.116.0.0/14135.116.0.1 to 135.119.255.254135.119.255.255262,142
95135.120.0.0/14135.120.0.1 to 135.123.255.254135.123.255.255262,142
96135.124.0.0/14135.124.0.1 to 135.127.255.254135.127.255.255262,142
97135.128.0.0/14135.128.0.1 to 135.131.255.254135.131.255.255262,142
98135.132.0.0/14135.132.0.1 to 135.135.255.254135.135.255.255262,142
99135.136.0.0/14135.136.0.1 to 135.139.255.254135.139.255.255262,142
100135.140.0.0/14135.140.0.1 to 135.143.255.254135.143.255.255262,142
101135.144.0.0/14135.144.0.1 to 135.147.255.254135.147.255.255262,142
102135.148.0.0/14135.148.0.1 to 135.151.255.254135.151.255.255262,142
103135.152.0.0/14135.152.0.1 to 135.155.255.254135.155.255.255262,142
104135.156.0.0/14135.156.0.1 to 135.159.255.254135.159.255.255262,142
105135.160.0.0/14135.160.0.1 to 135.163.255.254135.163.255.255262,142
106135.164.0.0/14135.164.0.1 to 135.167.255.254135.167.255.255262,142
107135.168.0.0/14135.168.0.1 to 135.171.255.254135.171.255.255262,142
108135.172.0.0/14135.172.0.1 to 135.175.255.254135.175.255.255262,142
109135.176.0.0/14135.176.0.1 to 135.179.255.254135.179.255.255262,142
110135.180.0.0/14135.180.0.1 to 135.183.255.254135.183.255.255262,142
111135.184.0.0/14135.184.0.1 to 135.187.255.254135.187.255.255262,142
112135.188.0.0/14135.188.0.1 to 135.191.255.254135.191.255.255262,142
113135.192.0.0/14135.192.0.1 to 135.195.255.254135.195.255.255262,142
114135.196.0.0/14135.196.0.1 to 135.199.255.254135.199.255.255262,142
115135.200.0.0/14135.200.0.1 to 135.203.255.254135.203.255.255262,142
116135.204.0.0/14135.204.0.1 to 135.207.255.254135.207.255.255262,142
117135.208.0.0/14135.208.0.1 to 135.211.255.254135.211.255.255262,142
118135.212.0.0/14135.212.0.1 to 135.215.255.254135.215.255.255262,142
119135.216.0.0/14135.216.0.1 to 135.219.255.254135.219.255.255262,142
120135.220.0.0/14135.220.0.1 to 135.223.255.254135.223.255.255262,142
121135.224.0.0/14135.224.0.1 to 135.227.255.254135.227.255.255262,142
122135.228.0.0/14135.228.0.1 to 135.231.255.254135.231.255.255262,142
123135.232.0.0/14135.232.0.1 to 135.235.255.254135.235.255.255262,142
124135.236.0.0/14135.236.0.1 to 135.239.255.254135.239.255.255262,142
125135.240.0.0/14135.240.0.1 to 135.243.255.254135.243.255.255262,142
126135.244.0.0/14135.244.0.1 to 135.247.255.254135.247.255.255262,142
127135.248.0.0/14135.248.0.1 to 135.251.255.254135.251.255.255262,142
128135.252.0.0/14135.252.0.1 to 135.255.255.254135.255.255.255262,142

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.