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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.

Network132.0.0.0/9
Usable hosts8,388,606
Subnet mask255.128.0.0
Addresses8,388,608
Network address
132.0.0.0
Broadcast address
132.127.255.255
First usable
132.0.0.1
Last usable
132.127.255.254
Usable hosts
8,388,606 (8,388,608 less the network and broadcast addresses)
Subnet mask
255.128.0.0
Wildcard mask
0.127.255.255 (Cisco ACLs, OSPF)
Prefix length
/9
Type
Public public
Old class
B (default /16)
As numbers
Hex 84000000 · Integer 2214592512 to 2222981119
Reverse DNS zones
0.132.in-addr.arpa
1.132.in-addr.arpa
2.132.in-addr.arpa
3.132.in-addr.arpa
4.132.in-addr.arpa
5.132.in-addr.arpa
6.132.in-addr.arpa
7.132.in-addr.arpa
8.132.in-addr.arpa
9.132.in-addr.arpa
10.132.in-addr.arpa
11.132.in-addr.arpa
12.132.in-addr.arpa
13.132.in-addr.arpa
14.132.in-addr.arpa
15.132.in-addr.arpa
and 112 more
/9 is not on a 8-bit boundary, so it takes 128 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address10000100.00000000.00000000.00000000132.0.0.0
Subnet mask11111111.10000000.00000000.00000000255.128.0.0
Network10000100.00000000.00000000.00000000132.0.0.0
Broadcast10000100.01111111.11111111.11111111132.127.255.255
Split into smaller subnets/16
/10 (2)/11 (4)/12 (8)/13 (16)/14 (32)/15 (64)/16 (128)/17 (256)/18 (512)/19 (1,024)/20 (2,048)/21 (4,096)

132.0.0.0/9 makes 128 subnets of /16.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1132.0.0.0/16132.0.0.1 to 132.0.255.254132.0.255.25565,534
2132.1.0.0/16132.1.0.1 to 132.1.255.254132.1.255.25565,534
3132.2.0.0/16132.2.0.1 to 132.2.255.254132.2.255.25565,534
4132.3.0.0/16132.3.0.1 to 132.3.255.254132.3.255.25565,534
5132.4.0.0/16132.4.0.1 to 132.4.255.254132.4.255.25565,534
6132.5.0.0/16132.5.0.1 to 132.5.255.254132.5.255.25565,534
7132.6.0.0/16132.6.0.1 to 132.6.255.254132.6.255.25565,534
8132.7.0.0/16132.7.0.1 to 132.7.255.254132.7.255.25565,534
9132.8.0.0/16132.8.0.1 to 132.8.255.254132.8.255.25565,534
10132.9.0.0/16132.9.0.1 to 132.9.255.254132.9.255.25565,534
11132.10.0.0/16132.10.0.1 to 132.10.255.254132.10.255.25565,534
12132.11.0.0/16132.11.0.1 to 132.11.255.254132.11.255.25565,534
13132.12.0.0/16132.12.0.1 to 132.12.255.254132.12.255.25565,534
14132.13.0.0/16132.13.0.1 to 132.13.255.254132.13.255.25565,534
15132.14.0.0/16132.14.0.1 to 132.14.255.254132.14.255.25565,534
16132.15.0.0/16132.15.0.1 to 132.15.255.254132.15.255.25565,534
17132.16.0.0/16132.16.0.1 to 132.16.255.254132.16.255.25565,534
18132.17.0.0/16132.17.0.1 to 132.17.255.254132.17.255.25565,534
19132.18.0.0/16132.18.0.1 to 132.18.255.254132.18.255.25565,534
20132.19.0.0/16132.19.0.1 to 132.19.255.254132.19.255.25565,534
21132.20.0.0/16132.20.0.1 to 132.20.255.254132.20.255.25565,534
22132.21.0.0/16132.21.0.1 to 132.21.255.254132.21.255.25565,534
23132.22.0.0/16132.22.0.1 to 132.22.255.254132.22.255.25565,534
24132.23.0.0/16132.23.0.1 to 132.23.255.254132.23.255.25565,534
25132.24.0.0/16132.24.0.1 to 132.24.255.254132.24.255.25565,534
26132.25.0.0/16132.25.0.1 to 132.25.255.254132.25.255.25565,534
27132.26.0.0/16132.26.0.1 to 132.26.255.254132.26.255.25565,534
28132.27.0.0/16132.27.0.1 to 132.27.255.254132.27.255.25565,534
29132.28.0.0/16132.28.0.1 to 132.28.255.254132.28.255.25565,534
30132.29.0.0/16132.29.0.1 to 132.29.255.254132.29.255.25565,534
31132.30.0.0/16132.30.0.1 to 132.30.255.254132.30.255.25565,534
32132.31.0.0/16132.31.0.1 to 132.31.255.254132.31.255.25565,534
33132.32.0.0/16132.32.0.1 to 132.32.255.254132.32.255.25565,534
34132.33.0.0/16132.33.0.1 to 132.33.255.254132.33.255.25565,534
35132.34.0.0/16132.34.0.1 to 132.34.255.254132.34.255.25565,534
36132.35.0.0/16132.35.0.1 to 132.35.255.254132.35.255.25565,534
37132.36.0.0/16132.36.0.1 to 132.36.255.254132.36.255.25565,534
38132.37.0.0/16132.37.0.1 to 132.37.255.254132.37.255.25565,534
39132.38.0.0/16132.38.0.1 to 132.38.255.254132.38.255.25565,534
40132.39.0.0/16132.39.0.1 to 132.39.255.254132.39.255.25565,534
41132.40.0.0/16132.40.0.1 to 132.40.255.254132.40.255.25565,534
42132.41.0.0/16132.41.0.1 to 132.41.255.254132.41.255.25565,534
43132.42.0.0/16132.42.0.1 to 132.42.255.254132.42.255.25565,534
44132.43.0.0/16132.43.0.1 to 132.43.255.254132.43.255.25565,534
45132.44.0.0/16132.44.0.1 to 132.44.255.254132.44.255.25565,534
46132.45.0.0/16132.45.0.1 to 132.45.255.254132.45.255.25565,534
47132.46.0.0/16132.46.0.1 to 132.46.255.254132.46.255.25565,534
48132.47.0.0/16132.47.0.1 to 132.47.255.254132.47.255.25565,534
49132.48.0.0/16132.48.0.1 to 132.48.255.254132.48.255.25565,534
50132.49.0.0/16132.49.0.1 to 132.49.255.254132.49.255.25565,534
51132.50.0.0/16132.50.0.1 to 132.50.255.254132.50.255.25565,534
52132.51.0.0/16132.51.0.1 to 132.51.255.254132.51.255.25565,534
53132.52.0.0/16132.52.0.1 to 132.52.255.254132.52.255.25565,534
54132.53.0.0/16132.53.0.1 to 132.53.255.254132.53.255.25565,534
55132.54.0.0/16132.54.0.1 to 132.54.255.254132.54.255.25565,534
56132.55.0.0/16132.55.0.1 to 132.55.255.254132.55.255.25565,534
57132.56.0.0/16132.56.0.1 to 132.56.255.254132.56.255.25565,534
58132.57.0.0/16132.57.0.1 to 132.57.255.254132.57.255.25565,534
59132.58.0.0/16132.58.0.1 to 132.58.255.254132.58.255.25565,534
60132.59.0.0/16132.59.0.1 to 132.59.255.254132.59.255.25565,534
61132.60.0.0/16132.60.0.1 to 132.60.255.254132.60.255.25565,534
62132.61.0.0/16132.61.0.1 to 132.61.255.254132.61.255.25565,534
63132.62.0.0/16132.62.0.1 to 132.62.255.254132.62.255.25565,534
64132.63.0.0/16132.63.0.1 to 132.63.255.254132.63.255.25565,534
65132.64.0.0/16132.64.0.1 to 132.64.255.254132.64.255.25565,534
66132.65.0.0/16132.65.0.1 to 132.65.255.254132.65.255.25565,534
67132.66.0.0/16132.66.0.1 to 132.66.255.254132.66.255.25565,534
68132.67.0.0/16132.67.0.1 to 132.67.255.254132.67.255.25565,534
69132.68.0.0/16132.68.0.1 to 132.68.255.254132.68.255.25565,534
70132.69.0.0/16132.69.0.1 to 132.69.255.254132.69.255.25565,534
71132.70.0.0/16132.70.0.1 to 132.70.255.254132.70.255.25565,534
72132.71.0.0/16132.71.0.1 to 132.71.255.254132.71.255.25565,534
73132.72.0.0/16132.72.0.1 to 132.72.255.254132.72.255.25565,534
74132.73.0.0/16132.73.0.1 to 132.73.255.254132.73.255.25565,534
75132.74.0.0/16132.74.0.1 to 132.74.255.254132.74.255.25565,534
76132.75.0.0/16132.75.0.1 to 132.75.255.254132.75.255.25565,534
77132.76.0.0/16132.76.0.1 to 132.76.255.254132.76.255.25565,534
78132.77.0.0/16132.77.0.1 to 132.77.255.254132.77.255.25565,534
79132.78.0.0/16132.78.0.1 to 132.78.255.254132.78.255.25565,534
80132.79.0.0/16132.79.0.1 to 132.79.255.254132.79.255.25565,534
81132.80.0.0/16132.80.0.1 to 132.80.255.254132.80.255.25565,534
82132.81.0.0/16132.81.0.1 to 132.81.255.254132.81.255.25565,534
83132.82.0.0/16132.82.0.1 to 132.82.255.254132.82.255.25565,534
84132.83.0.0/16132.83.0.1 to 132.83.255.254132.83.255.25565,534
85132.84.0.0/16132.84.0.1 to 132.84.255.254132.84.255.25565,534
86132.85.0.0/16132.85.0.1 to 132.85.255.254132.85.255.25565,534
87132.86.0.0/16132.86.0.1 to 132.86.255.254132.86.255.25565,534
88132.87.0.0/16132.87.0.1 to 132.87.255.254132.87.255.25565,534
89132.88.0.0/16132.88.0.1 to 132.88.255.254132.88.255.25565,534
90132.89.0.0/16132.89.0.1 to 132.89.255.254132.89.255.25565,534
91132.90.0.0/16132.90.0.1 to 132.90.255.254132.90.255.25565,534
92132.91.0.0/16132.91.0.1 to 132.91.255.254132.91.255.25565,534
93132.92.0.0/16132.92.0.1 to 132.92.255.254132.92.255.25565,534
94132.93.0.0/16132.93.0.1 to 132.93.255.254132.93.255.25565,534
95132.94.0.0/16132.94.0.1 to 132.94.255.254132.94.255.25565,534
96132.95.0.0/16132.95.0.1 to 132.95.255.254132.95.255.25565,534
97132.96.0.0/16132.96.0.1 to 132.96.255.254132.96.255.25565,534
98132.97.0.0/16132.97.0.1 to 132.97.255.254132.97.255.25565,534
99132.98.0.0/16132.98.0.1 to 132.98.255.254132.98.255.25565,534
100132.99.0.0/16132.99.0.1 to 132.99.255.254132.99.255.25565,534
101132.100.0.0/16132.100.0.1 to 132.100.255.254132.100.255.25565,534
102132.101.0.0/16132.101.0.1 to 132.101.255.254132.101.255.25565,534
103132.102.0.0/16132.102.0.1 to 132.102.255.254132.102.255.25565,534
104132.103.0.0/16132.103.0.1 to 132.103.255.254132.103.255.25565,534
105132.104.0.0/16132.104.0.1 to 132.104.255.254132.104.255.25565,534
106132.105.0.0/16132.105.0.1 to 132.105.255.254132.105.255.25565,534
107132.106.0.0/16132.106.0.1 to 132.106.255.254132.106.255.25565,534
108132.107.0.0/16132.107.0.1 to 132.107.255.254132.107.255.25565,534
109132.108.0.0/16132.108.0.1 to 132.108.255.254132.108.255.25565,534
110132.109.0.0/16132.109.0.1 to 132.109.255.254132.109.255.25565,534
111132.110.0.0/16132.110.0.1 to 132.110.255.254132.110.255.25565,534
112132.111.0.0/16132.111.0.1 to 132.111.255.254132.111.255.25565,534
113132.112.0.0/16132.112.0.1 to 132.112.255.254132.112.255.25565,534
114132.113.0.0/16132.113.0.1 to 132.113.255.254132.113.255.25565,534
115132.114.0.0/16132.114.0.1 to 132.114.255.254132.114.255.25565,534
116132.115.0.0/16132.115.0.1 to 132.115.255.254132.115.255.25565,534
117132.116.0.0/16132.116.0.1 to 132.116.255.254132.116.255.25565,534
118132.117.0.0/16132.117.0.1 to 132.117.255.254132.117.255.25565,534
119132.118.0.0/16132.118.0.1 to 132.118.255.254132.118.255.25565,534
120132.119.0.0/16132.119.0.1 to 132.119.255.254132.119.255.25565,534
121132.120.0.0/16132.120.0.1 to 132.120.255.254132.120.255.25565,534
122132.121.0.0/16132.121.0.1 to 132.121.255.254132.121.255.25565,534
123132.122.0.0/16132.122.0.1 to 132.122.255.254132.122.255.25565,534
124132.123.0.0/16132.123.0.1 to 132.123.255.254132.123.255.25565,534
125132.124.0.0/16132.124.0.1 to 132.124.255.254132.124.255.25565,534
126132.125.0.0/16132.125.0.1 to 132.125.255.254132.125.255.25565,534
127132.126.0.0/16132.126.0.1 to 132.126.255.254132.126.255.25565,534
128132.127.0.0/16132.127.0.1 to 132.127.255.254132.127.255.25565,534

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.