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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.

Network232.0.0.0/11
Usable hosts2,097,150
Subnet mask255.224.0.0
Addresses2,097,152
Network address
232.0.0.0
Broadcast address
232.31.255.255
First usable
232.0.0.1
Last usable
232.31.255.254
Usable hosts
2,097,150 (2,097,152 less the network and broadcast addresses)
Subnet mask
255.224.0.0
Wildcard mask
0.31.255.255 (Cisco ACLs, OSPF)
Prefix length
/11
Type
Multicast 224.0.0.0/4
One-to-many traffic, such as IPTV and routing protocols
Old class
D (multicast)
As numbers
Hex E8000000 · Integer 3892314112 to 3894411263
Reverse DNS zones
0.232.in-addr.arpa
1.232.in-addr.arpa
2.232.in-addr.arpa
3.232.in-addr.arpa
4.232.in-addr.arpa
5.232.in-addr.arpa
6.232.in-addr.arpa
7.232.in-addr.arpa
8.232.in-addr.arpa
9.232.in-addr.arpa
10.232.in-addr.arpa
11.232.in-addr.arpa
12.232.in-addr.arpa
13.232.in-addr.arpa
14.232.in-addr.arpa
15.232.in-addr.arpa
and 16 more
/11 is not on a 8-bit boundary, so it takes 32 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address11101000.00000000.00000000.00000000232.0.0.0
Subnet mask11111111.11100000.00000000.00000000255.224.0.0
Network11101000.00000000.00000000.00000000232.0.0.0
Broadcast11101000.00011111.11111111.11111111232.31.255.255
Split into smaller subnets/18
/12 (2)/13 (4)/14 (8)/15 (16)/16 (32)/17 (64)/18 (128)/19 (256)/20 (512)/21 (1,024)/22 (2,048)/23 (4,096)

232.0.0.0/11 makes 128 subnets of /18.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1232.0.0.0/18232.0.0.1 to 232.0.63.254232.0.63.25516,382
2232.0.64.0/18232.0.64.1 to 232.0.127.254232.0.127.25516,382
3232.0.128.0/18232.0.128.1 to 232.0.191.254232.0.191.25516,382
4232.0.192.0/18232.0.192.1 to 232.0.255.254232.0.255.25516,382
5232.1.0.0/18232.1.0.1 to 232.1.63.254232.1.63.25516,382
6232.1.64.0/18232.1.64.1 to 232.1.127.254232.1.127.25516,382
7232.1.128.0/18232.1.128.1 to 232.1.191.254232.1.191.25516,382
8232.1.192.0/18232.1.192.1 to 232.1.255.254232.1.255.25516,382
9232.2.0.0/18232.2.0.1 to 232.2.63.254232.2.63.25516,382
10232.2.64.0/18232.2.64.1 to 232.2.127.254232.2.127.25516,382
11232.2.128.0/18232.2.128.1 to 232.2.191.254232.2.191.25516,382
12232.2.192.0/18232.2.192.1 to 232.2.255.254232.2.255.25516,382
13232.3.0.0/18232.3.0.1 to 232.3.63.254232.3.63.25516,382
14232.3.64.0/18232.3.64.1 to 232.3.127.254232.3.127.25516,382
15232.3.128.0/18232.3.128.1 to 232.3.191.254232.3.191.25516,382
16232.3.192.0/18232.3.192.1 to 232.3.255.254232.3.255.25516,382
17232.4.0.0/18232.4.0.1 to 232.4.63.254232.4.63.25516,382
18232.4.64.0/18232.4.64.1 to 232.4.127.254232.4.127.25516,382
19232.4.128.0/18232.4.128.1 to 232.4.191.254232.4.191.25516,382
20232.4.192.0/18232.4.192.1 to 232.4.255.254232.4.255.25516,382
21232.5.0.0/18232.5.0.1 to 232.5.63.254232.5.63.25516,382
22232.5.64.0/18232.5.64.1 to 232.5.127.254232.5.127.25516,382
23232.5.128.0/18232.5.128.1 to 232.5.191.254232.5.191.25516,382
24232.5.192.0/18232.5.192.1 to 232.5.255.254232.5.255.25516,382
25232.6.0.0/18232.6.0.1 to 232.6.63.254232.6.63.25516,382
26232.6.64.0/18232.6.64.1 to 232.6.127.254232.6.127.25516,382
27232.6.128.0/18232.6.128.1 to 232.6.191.254232.6.191.25516,382
28232.6.192.0/18232.6.192.1 to 232.6.255.254232.6.255.25516,382
29232.7.0.0/18232.7.0.1 to 232.7.63.254232.7.63.25516,382
30232.7.64.0/18232.7.64.1 to 232.7.127.254232.7.127.25516,382
31232.7.128.0/18232.7.128.1 to 232.7.191.254232.7.191.25516,382
32232.7.192.0/18232.7.192.1 to 232.7.255.254232.7.255.25516,382
33232.8.0.0/18232.8.0.1 to 232.8.63.254232.8.63.25516,382
34232.8.64.0/18232.8.64.1 to 232.8.127.254232.8.127.25516,382
35232.8.128.0/18232.8.128.1 to 232.8.191.254232.8.191.25516,382
36232.8.192.0/18232.8.192.1 to 232.8.255.254232.8.255.25516,382
37232.9.0.0/18232.9.0.1 to 232.9.63.254232.9.63.25516,382
38232.9.64.0/18232.9.64.1 to 232.9.127.254232.9.127.25516,382
39232.9.128.0/18232.9.128.1 to 232.9.191.254232.9.191.25516,382
40232.9.192.0/18232.9.192.1 to 232.9.255.254232.9.255.25516,382
41232.10.0.0/18232.10.0.1 to 232.10.63.254232.10.63.25516,382
42232.10.64.0/18232.10.64.1 to 232.10.127.254232.10.127.25516,382
43232.10.128.0/18232.10.128.1 to 232.10.191.254232.10.191.25516,382
44232.10.192.0/18232.10.192.1 to 232.10.255.254232.10.255.25516,382
45232.11.0.0/18232.11.0.1 to 232.11.63.254232.11.63.25516,382
46232.11.64.0/18232.11.64.1 to 232.11.127.254232.11.127.25516,382
47232.11.128.0/18232.11.128.1 to 232.11.191.254232.11.191.25516,382
48232.11.192.0/18232.11.192.1 to 232.11.255.254232.11.255.25516,382
49232.12.0.0/18232.12.0.1 to 232.12.63.254232.12.63.25516,382
50232.12.64.0/18232.12.64.1 to 232.12.127.254232.12.127.25516,382
51232.12.128.0/18232.12.128.1 to 232.12.191.254232.12.191.25516,382
52232.12.192.0/18232.12.192.1 to 232.12.255.254232.12.255.25516,382
53232.13.0.0/18232.13.0.1 to 232.13.63.254232.13.63.25516,382
54232.13.64.0/18232.13.64.1 to 232.13.127.254232.13.127.25516,382
55232.13.128.0/18232.13.128.1 to 232.13.191.254232.13.191.25516,382
56232.13.192.0/18232.13.192.1 to 232.13.255.254232.13.255.25516,382
57232.14.0.0/18232.14.0.1 to 232.14.63.254232.14.63.25516,382
58232.14.64.0/18232.14.64.1 to 232.14.127.254232.14.127.25516,382
59232.14.128.0/18232.14.128.1 to 232.14.191.254232.14.191.25516,382
60232.14.192.0/18232.14.192.1 to 232.14.255.254232.14.255.25516,382
61232.15.0.0/18232.15.0.1 to 232.15.63.254232.15.63.25516,382
62232.15.64.0/18232.15.64.1 to 232.15.127.254232.15.127.25516,382
63232.15.128.0/18232.15.128.1 to 232.15.191.254232.15.191.25516,382
64232.15.192.0/18232.15.192.1 to 232.15.255.254232.15.255.25516,382
65232.16.0.0/18232.16.0.1 to 232.16.63.254232.16.63.25516,382
66232.16.64.0/18232.16.64.1 to 232.16.127.254232.16.127.25516,382
67232.16.128.0/18232.16.128.1 to 232.16.191.254232.16.191.25516,382
68232.16.192.0/18232.16.192.1 to 232.16.255.254232.16.255.25516,382
69232.17.0.0/18232.17.0.1 to 232.17.63.254232.17.63.25516,382
70232.17.64.0/18232.17.64.1 to 232.17.127.254232.17.127.25516,382
71232.17.128.0/18232.17.128.1 to 232.17.191.254232.17.191.25516,382
72232.17.192.0/18232.17.192.1 to 232.17.255.254232.17.255.25516,382
73232.18.0.0/18232.18.0.1 to 232.18.63.254232.18.63.25516,382
74232.18.64.0/18232.18.64.1 to 232.18.127.254232.18.127.25516,382
75232.18.128.0/18232.18.128.1 to 232.18.191.254232.18.191.25516,382
76232.18.192.0/18232.18.192.1 to 232.18.255.254232.18.255.25516,382
77232.19.0.0/18232.19.0.1 to 232.19.63.254232.19.63.25516,382
78232.19.64.0/18232.19.64.1 to 232.19.127.254232.19.127.25516,382
79232.19.128.0/18232.19.128.1 to 232.19.191.254232.19.191.25516,382
80232.19.192.0/18232.19.192.1 to 232.19.255.254232.19.255.25516,382
81232.20.0.0/18232.20.0.1 to 232.20.63.254232.20.63.25516,382
82232.20.64.0/18232.20.64.1 to 232.20.127.254232.20.127.25516,382
83232.20.128.0/18232.20.128.1 to 232.20.191.254232.20.191.25516,382
84232.20.192.0/18232.20.192.1 to 232.20.255.254232.20.255.25516,382
85232.21.0.0/18232.21.0.1 to 232.21.63.254232.21.63.25516,382
86232.21.64.0/18232.21.64.1 to 232.21.127.254232.21.127.25516,382
87232.21.128.0/18232.21.128.1 to 232.21.191.254232.21.191.25516,382
88232.21.192.0/18232.21.192.1 to 232.21.255.254232.21.255.25516,382
89232.22.0.0/18232.22.0.1 to 232.22.63.254232.22.63.25516,382
90232.22.64.0/18232.22.64.1 to 232.22.127.254232.22.127.25516,382
91232.22.128.0/18232.22.128.1 to 232.22.191.254232.22.191.25516,382
92232.22.192.0/18232.22.192.1 to 232.22.255.254232.22.255.25516,382
93232.23.0.0/18232.23.0.1 to 232.23.63.254232.23.63.25516,382
94232.23.64.0/18232.23.64.1 to 232.23.127.254232.23.127.25516,382
95232.23.128.0/18232.23.128.1 to 232.23.191.254232.23.191.25516,382
96232.23.192.0/18232.23.192.1 to 232.23.255.254232.23.255.25516,382
97232.24.0.0/18232.24.0.1 to 232.24.63.254232.24.63.25516,382
98232.24.64.0/18232.24.64.1 to 232.24.127.254232.24.127.25516,382
99232.24.128.0/18232.24.128.1 to 232.24.191.254232.24.191.25516,382
100232.24.192.0/18232.24.192.1 to 232.24.255.254232.24.255.25516,382
101232.25.0.0/18232.25.0.1 to 232.25.63.254232.25.63.25516,382
102232.25.64.0/18232.25.64.1 to 232.25.127.254232.25.127.25516,382
103232.25.128.0/18232.25.128.1 to 232.25.191.254232.25.191.25516,382
104232.25.192.0/18232.25.192.1 to 232.25.255.254232.25.255.25516,382
105232.26.0.0/18232.26.0.1 to 232.26.63.254232.26.63.25516,382
106232.26.64.0/18232.26.64.1 to 232.26.127.254232.26.127.25516,382
107232.26.128.0/18232.26.128.1 to 232.26.191.254232.26.191.25516,382
108232.26.192.0/18232.26.192.1 to 232.26.255.254232.26.255.25516,382
109232.27.0.0/18232.27.0.1 to 232.27.63.254232.27.63.25516,382
110232.27.64.0/18232.27.64.1 to 232.27.127.254232.27.127.25516,382
111232.27.128.0/18232.27.128.1 to 232.27.191.254232.27.191.25516,382
112232.27.192.0/18232.27.192.1 to 232.27.255.254232.27.255.25516,382
113232.28.0.0/18232.28.0.1 to 232.28.63.254232.28.63.25516,382
114232.28.64.0/18232.28.64.1 to 232.28.127.254232.28.127.25516,382
115232.28.128.0/18232.28.128.1 to 232.28.191.254232.28.191.25516,382
116232.28.192.0/18232.28.192.1 to 232.28.255.254232.28.255.25516,382
117232.29.0.0/18232.29.0.1 to 232.29.63.254232.29.63.25516,382
118232.29.64.0/18232.29.64.1 to 232.29.127.254232.29.127.25516,382
119232.29.128.0/18232.29.128.1 to 232.29.191.254232.29.191.25516,382
120232.29.192.0/18232.29.192.1 to 232.29.255.254232.29.255.25516,382
121232.30.0.0/18232.30.0.1 to 232.30.63.254232.30.63.25516,382
122232.30.64.0/18232.30.64.1 to 232.30.127.254232.30.127.25516,382
123232.30.128.0/18232.30.128.1 to 232.30.191.254232.30.191.25516,382
124232.30.192.0/18232.30.192.1 to 232.30.255.254232.30.255.25516,382
125232.31.0.0/18232.31.0.1 to 232.31.63.254232.31.63.25516,382
126232.31.64.0/18232.31.64.1 to 232.31.127.254232.31.127.25516,382
127232.31.128.0/18232.31.128.1 to 232.31.191.254232.31.191.25516,382
128232.31.192.0/18232.31.192.1 to 232.31.255.254232.31.255.25516,382

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.