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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.

Network234.32.0.0/11
Usable hosts2,097,150
Subnet mask255.224.0.0
Addresses2,097,152
Network address
234.32.0.0
Broadcast address
234.63.255.255
First usable
234.32.0.1
Last usable
234.63.255.254
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 EA200000 · Integer 3927965696 to 3930062847
Reverse DNS zones
32.234.in-addr.arpa
33.234.in-addr.arpa
34.234.in-addr.arpa
35.234.in-addr.arpa
36.234.in-addr.arpa
37.234.in-addr.arpa
38.234.in-addr.arpa
39.234.in-addr.arpa
40.234.in-addr.arpa
41.234.in-addr.arpa
42.234.in-addr.arpa
43.234.in-addr.arpa
44.234.in-addr.arpa
45.234.in-addr.arpa
46.234.in-addr.arpa
47.234.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
Address11101010.00100000.00000000.00000000234.32.0.0
Subnet mask11111111.11100000.00000000.00000000255.224.0.0
Network11101010.00100000.00000000.00000000234.32.0.0
Broadcast11101010.00111111.11111111.11111111234.63.255.255
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)

234.32.0.0/11 makes 128 subnets of /18.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1234.32.0.0/18234.32.0.1 to 234.32.63.254234.32.63.25516,382
2234.32.64.0/18234.32.64.1 to 234.32.127.254234.32.127.25516,382
3234.32.128.0/18234.32.128.1 to 234.32.191.254234.32.191.25516,382
4234.32.192.0/18234.32.192.1 to 234.32.255.254234.32.255.25516,382
5234.33.0.0/18234.33.0.1 to 234.33.63.254234.33.63.25516,382
6234.33.64.0/18234.33.64.1 to 234.33.127.254234.33.127.25516,382
7234.33.128.0/18234.33.128.1 to 234.33.191.254234.33.191.25516,382
8234.33.192.0/18234.33.192.1 to 234.33.255.254234.33.255.25516,382
9234.34.0.0/18234.34.0.1 to 234.34.63.254234.34.63.25516,382
10234.34.64.0/18234.34.64.1 to 234.34.127.254234.34.127.25516,382
11234.34.128.0/18234.34.128.1 to 234.34.191.254234.34.191.25516,382
12234.34.192.0/18234.34.192.1 to 234.34.255.254234.34.255.25516,382
13234.35.0.0/18234.35.0.1 to 234.35.63.254234.35.63.25516,382
14234.35.64.0/18234.35.64.1 to 234.35.127.254234.35.127.25516,382
15234.35.128.0/18234.35.128.1 to 234.35.191.254234.35.191.25516,382
16234.35.192.0/18234.35.192.1 to 234.35.255.254234.35.255.25516,382
17234.36.0.0/18234.36.0.1 to 234.36.63.254234.36.63.25516,382
18234.36.64.0/18234.36.64.1 to 234.36.127.254234.36.127.25516,382
19234.36.128.0/18234.36.128.1 to 234.36.191.254234.36.191.25516,382
20234.36.192.0/18234.36.192.1 to 234.36.255.254234.36.255.25516,382
21234.37.0.0/18234.37.0.1 to 234.37.63.254234.37.63.25516,382
22234.37.64.0/18234.37.64.1 to 234.37.127.254234.37.127.25516,382
23234.37.128.0/18234.37.128.1 to 234.37.191.254234.37.191.25516,382
24234.37.192.0/18234.37.192.1 to 234.37.255.254234.37.255.25516,382
25234.38.0.0/18234.38.0.1 to 234.38.63.254234.38.63.25516,382
26234.38.64.0/18234.38.64.1 to 234.38.127.254234.38.127.25516,382
27234.38.128.0/18234.38.128.1 to 234.38.191.254234.38.191.25516,382
28234.38.192.0/18234.38.192.1 to 234.38.255.254234.38.255.25516,382
29234.39.0.0/18234.39.0.1 to 234.39.63.254234.39.63.25516,382
30234.39.64.0/18234.39.64.1 to 234.39.127.254234.39.127.25516,382
31234.39.128.0/18234.39.128.1 to 234.39.191.254234.39.191.25516,382
32234.39.192.0/18234.39.192.1 to 234.39.255.254234.39.255.25516,382
33234.40.0.0/18234.40.0.1 to 234.40.63.254234.40.63.25516,382
34234.40.64.0/18234.40.64.1 to 234.40.127.254234.40.127.25516,382
35234.40.128.0/18234.40.128.1 to 234.40.191.254234.40.191.25516,382
36234.40.192.0/18234.40.192.1 to 234.40.255.254234.40.255.25516,382
37234.41.0.0/18234.41.0.1 to 234.41.63.254234.41.63.25516,382
38234.41.64.0/18234.41.64.1 to 234.41.127.254234.41.127.25516,382
39234.41.128.0/18234.41.128.1 to 234.41.191.254234.41.191.25516,382
40234.41.192.0/18234.41.192.1 to 234.41.255.254234.41.255.25516,382
41234.42.0.0/18234.42.0.1 to 234.42.63.254234.42.63.25516,382
42234.42.64.0/18234.42.64.1 to 234.42.127.254234.42.127.25516,382
43234.42.128.0/18234.42.128.1 to 234.42.191.254234.42.191.25516,382
44234.42.192.0/18234.42.192.1 to 234.42.255.254234.42.255.25516,382
45234.43.0.0/18234.43.0.1 to 234.43.63.254234.43.63.25516,382
46234.43.64.0/18234.43.64.1 to 234.43.127.254234.43.127.25516,382
47234.43.128.0/18234.43.128.1 to 234.43.191.254234.43.191.25516,382
48234.43.192.0/18234.43.192.1 to 234.43.255.254234.43.255.25516,382
49234.44.0.0/18234.44.0.1 to 234.44.63.254234.44.63.25516,382
50234.44.64.0/18234.44.64.1 to 234.44.127.254234.44.127.25516,382
51234.44.128.0/18234.44.128.1 to 234.44.191.254234.44.191.25516,382
52234.44.192.0/18234.44.192.1 to 234.44.255.254234.44.255.25516,382
53234.45.0.0/18234.45.0.1 to 234.45.63.254234.45.63.25516,382
54234.45.64.0/18234.45.64.1 to 234.45.127.254234.45.127.25516,382
55234.45.128.0/18234.45.128.1 to 234.45.191.254234.45.191.25516,382
56234.45.192.0/18234.45.192.1 to 234.45.255.254234.45.255.25516,382
57234.46.0.0/18234.46.0.1 to 234.46.63.254234.46.63.25516,382
58234.46.64.0/18234.46.64.1 to 234.46.127.254234.46.127.25516,382
59234.46.128.0/18234.46.128.1 to 234.46.191.254234.46.191.25516,382
60234.46.192.0/18234.46.192.1 to 234.46.255.254234.46.255.25516,382
61234.47.0.0/18234.47.0.1 to 234.47.63.254234.47.63.25516,382
62234.47.64.0/18234.47.64.1 to 234.47.127.254234.47.127.25516,382
63234.47.128.0/18234.47.128.1 to 234.47.191.254234.47.191.25516,382
64234.47.192.0/18234.47.192.1 to 234.47.255.254234.47.255.25516,382
65234.48.0.0/18234.48.0.1 to 234.48.63.254234.48.63.25516,382
66234.48.64.0/18234.48.64.1 to 234.48.127.254234.48.127.25516,382
67234.48.128.0/18234.48.128.1 to 234.48.191.254234.48.191.25516,382
68234.48.192.0/18234.48.192.1 to 234.48.255.254234.48.255.25516,382
69234.49.0.0/18234.49.0.1 to 234.49.63.254234.49.63.25516,382
70234.49.64.0/18234.49.64.1 to 234.49.127.254234.49.127.25516,382
71234.49.128.0/18234.49.128.1 to 234.49.191.254234.49.191.25516,382
72234.49.192.0/18234.49.192.1 to 234.49.255.254234.49.255.25516,382
73234.50.0.0/18234.50.0.1 to 234.50.63.254234.50.63.25516,382
74234.50.64.0/18234.50.64.1 to 234.50.127.254234.50.127.25516,382
75234.50.128.0/18234.50.128.1 to 234.50.191.254234.50.191.25516,382
76234.50.192.0/18234.50.192.1 to 234.50.255.254234.50.255.25516,382
77234.51.0.0/18234.51.0.1 to 234.51.63.254234.51.63.25516,382
78234.51.64.0/18234.51.64.1 to 234.51.127.254234.51.127.25516,382
79234.51.128.0/18234.51.128.1 to 234.51.191.254234.51.191.25516,382
80234.51.192.0/18234.51.192.1 to 234.51.255.254234.51.255.25516,382
81234.52.0.0/18234.52.0.1 to 234.52.63.254234.52.63.25516,382
82234.52.64.0/18234.52.64.1 to 234.52.127.254234.52.127.25516,382
83234.52.128.0/18234.52.128.1 to 234.52.191.254234.52.191.25516,382
84234.52.192.0/18234.52.192.1 to 234.52.255.254234.52.255.25516,382
85234.53.0.0/18234.53.0.1 to 234.53.63.254234.53.63.25516,382
86234.53.64.0/18234.53.64.1 to 234.53.127.254234.53.127.25516,382
87234.53.128.0/18234.53.128.1 to 234.53.191.254234.53.191.25516,382
88234.53.192.0/18234.53.192.1 to 234.53.255.254234.53.255.25516,382
89234.54.0.0/18234.54.0.1 to 234.54.63.254234.54.63.25516,382
90234.54.64.0/18234.54.64.1 to 234.54.127.254234.54.127.25516,382
91234.54.128.0/18234.54.128.1 to 234.54.191.254234.54.191.25516,382
92234.54.192.0/18234.54.192.1 to 234.54.255.254234.54.255.25516,382
93234.55.0.0/18234.55.0.1 to 234.55.63.254234.55.63.25516,382
94234.55.64.0/18234.55.64.1 to 234.55.127.254234.55.127.25516,382
95234.55.128.0/18234.55.128.1 to 234.55.191.254234.55.191.25516,382
96234.55.192.0/18234.55.192.1 to 234.55.255.254234.55.255.25516,382
97234.56.0.0/18234.56.0.1 to 234.56.63.254234.56.63.25516,382
98234.56.64.0/18234.56.64.1 to 234.56.127.254234.56.127.25516,382
99234.56.128.0/18234.56.128.1 to 234.56.191.254234.56.191.25516,382
100234.56.192.0/18234.56.192.1 to 234.56.255.254234.56.255.25516,382
101234.57.0.0/18234.57.0.1 to 234.57.63.254234.57.63.25516,382
102234.57.64.0/18234.57.64.1 to 234.57.127.254234.57.127.25516,382
103234.57.128.0/18234.57.128.1 to 234.57.191.254234.57.191.25516,382
104234.57.192.0/18234.57.192.1 to 234.57.255.254234.57.255.25516,382
105234.58.0.0/18234.58.0.1 to 234.58.63.254234.58.63.25516,382
106234.58.64.0/18234.58.64.1 to 234.58.127.254234.58.127.25516,382
107234.58.128.0/18234.58.128.1 to 234.58.191.254234.58.191.25516,382
108234.58.192.0/18234.58.192.1 to 234.58.255.254234.58.255.25516,382
109234.59.0.0/18234.59.0.1 to 234.59.63.254234.59.63.25516,382
110234.59.64.0/18234.59.64.1 to 234.59.127.254234.59.127.25516,382
111234.59.128.0/18234.59.128.1 to 234.59.191.254234.59.191.25516,382
112234.59.192.0/18234.59.192.1 to 234.59.255.254234.59.255.25516,382
113234.60.0.0/18234.60.0.1 to 234.60.63.254234.60.63.25516,382
114234.60.64.0/18234.60.64.1 to 234.60.127.254234.60.127.25516,382
115234.60.128.0/18234.60.128.1 to 234.60.191.254234.60.191.25516,382
116234.60.192.0/18234.60.192.1 to 234.60.255.254234.60.255.25516,382
117234.61.0.0/18234.61.0.1 to 234.61.63.254234.61.63.25516,382
118234.61.64.0/18234.61.64.1 to 234.61.127.254234.61.127.25516,382
119234.61.128.0/18234.61.128.1 to 234.61.191.254234.61.191.25516,382
120234.61.192.0/18234.61.192.1 to 234.61.255.254234.61.255.25516,382
121234.62.0.0/18234.62.0.1 to 234.62.63.254234.62.63.25516,382
122234.62.64.0/18234.62.64.1 to 234.62.127.254234.62.127.25516,382
123234.62.128.0/18234.62.128.1 to 234.62.191.254234.62.191.25516,382
124234.62.192.0/18234.62.192.1 to 234.62.255.254234.62.255.25516,382
125234.63.0.0/18234.63.0.1 to 234.63.63.254234.63.63.25516,382
126234.63.64.0/18234.63.64.1 to 234.63.127.254234.63.127.25516,382
127234.63.128.0/18234.63.128.1 to 234.63.191.254234.63.191.25516,382
128234.63.192.0/18234.63.192.1 to 234.63.255.254234.63.255.25516,382

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.