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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.

Network239.96.0.0/11
Usable hosts2,097,150
Subnet mask255.224.0.0
Addresses2,097,152
Network address
239.96.0.0
Broadcast address
239.127.255.255
First usable
239.96.0.1
Last usable
239.127.255.254
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 EF600000 · Integer 4016046080 to 4018143231
Reverse DNS zones
96.239.in-addr.arpa
97.239.in-addr.arpa
98.239.in-addr.arpa
99.239.in-addr.arpa
100.239.in-addr.arpa
101.239.in-addr.arpa
102.239.in-addr.arpa
103.239.in-addr.arpa
104.239.in-addr.arpa
105.239.in-addr.arpa
106.239.in-addr.arpa
107.239.in-addr.arpa
108.239.in-addr.arpa
109.239.in-addr.arpa
110.239.in-addr.arpa
111.239.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
Address11101111.01100000.00000000.00000000239.96.0.0
Subnet mask11111111.11100000.00000000.00000000255.224.0.0
Network11101111.01100000.00000000.00000000239.96.0.0
Broadcast11101111.01111111.11111111.11111111239.127.255.255
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)

239.96.0.0/11 makes 128 subnets of /18.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1239.96.0.0/18239.96.0.1 to 239.96.63.254239.96.63.25516,382
2239.96.64.0/18239.96.64.1 to 239.96.127.254239.96.127.25516,382
3239.96.128.0/18239.96.128.1 to 239.96.191.254239.96.191.25516,382
4239.96.192.0/18239.96.192.1 to 239.96.255.254239.96.255.25516,382
5239.97.0.0/18239.97.0.1 to 239.97.63.254239.97.63.25516,382
6239.97.64.0/18239.97.64.1 to 239.97.127.254239.97.127.25516,382
7239.97.128.0/18239.97.128.1 to 239.97.191.254239.97.191.25516,382
8239.97.192.0/18239.97.192.1 to 239.97.255.254239.97.255.25516,382
9239.98.0.0/18239.98.0.1 to 239.98.63.254239.98.63.25516,382
10239.98.64.0/18239.98.64.1 to 239.98.127.254239.98.127.25516,382
11239.98.128.0/18239.98.128.1 to 239.98.191.254239.98.191.25516,382
12239.98.192.0/18239.98.192.1 to 239.98.255.254239.98.255.25516,382
13239.99.0.0/18239.99.0.1 to 239.99.63.254239.99.63.25516,382
14239.99.64.0/18239.99.64.1 to 239.99.127.254239.99.127.25516,382
15239.99.128.0/18239.99.128.1 to 239.99.191.254239.99.191.25516,382
16239.99.192.0/18239.99.192.1 to 239.99.255.254239.99.255.25516,382
17239.100.0.0/18239.100.0.1 to 239.100.63.254239.100.63.25516,382
18239.100.64.0/18239.100.64.1 to 239.100.127.254239.100.127.25516,382
19239.100.128.0/18239.100.128.1 to 239.100.191.254239.100.191.25516,382
20239.100.192.0/18239.100.192.1 to 239.100.255.254239.100.255.25516,382
21239.101.0.0/18239.101.0.1 to 239.101.63.254239.101.63.25516,382
22239.101.64.0/18239.101.64.1 to 239.101.127.254239.101.127.25516,382
23239.101.128.0/18239.101.128.1 to 239.101.191.254239.101.191.25516,382
24239.101.192.0/18239.101.192.1 to 239.101.255.254239.101.255.25516,382
25239.102.0.0/18239.102.0.1 to 239.102.63.254239.102.63.25516,382
26239.102.64.0/18239.102.64.1 to 239.102.127.254239.102.127.25516,382
27239.102.128.0/18239.102.128.1 to 239.102.191.254239.102.191.25516,382
28239.102.192.0/18239.102.192.1 to 239.102.255.254239.102.255.25516,382
29239.103.0.0/18239.103.0.1 to 239.103.63.254239.103.63.25516,382
30239.103.64.0/18239.103.64.1 to 239.103.127.254239.103.127.25516,382
31239.103.128.0/18239.103.128.1 to 239.103.191.254239.103.191.25516,382
32239.103.192.0/18239.103.192.1 to 239.103.255.254239.103.255.25516,382
33239.104.0.0/18239.104.0.1 to 239.104.63.254239.104.63.25516,382
34239.104.64.0/18239.104.64.1 to 239.104.127.254239.104.127.25516,382
35239.104.128.0/18239.104.128.1 to 239.104.191.254239.104.191.25516,382
36239.104.192.0/18239.104.192.1 to 239.104.255.254239.104.255.25516,382
37239.105.0.0/18239.105.0.1 to 239.105.63.254239.105.63.25516,382
38239.105.64.0/18239.105.64.1 to 239.105.127.254239.105.127.25516,382
39239.105.128.0/18239.105.128.1 to 239.105.191.254239.105.191.25516,382
40239.105.192.0/18239.105.192.1 to 239.105.255.254239.105.255.25516,382
41239.106.0.0/18239.106.0.1 to 239.106.63.254239.106.63.25516,382
42239.106.64.0/18239.106.64.1 to 239.106.127.254239.106.127.25516,382
43239.106.128.0/18239.106.128.1 to 239.106.191.254239.106.191.25516,382
44239.106.192.0/18239.106.192.1 to 239.106.255.254239.106.255.25516,382
45239.107.0.0/18239.107.0.1 to 239.107.63.254239.107.63.25516,382
46239.107.64.0/18239.107.64.1 to 239.107.127.254239.107.127.25516,382
47239.107.128.0/18239.107.128.1 to 239.107.191.254239.107.191.25516,382
48239.107.192.0/18239.107.192.1 to 239.107.255.254239.107.255.25516,382
49239.108.0.0/18239.108.0.1 to 239.108.63.254239.108.63.25516,382
50239.108.64.0/18239.108.64.1 to 239.108.127.254239.108.127.25516,382
51239.108.128.0/18239.108.128.1 to 239.108.191.254239.108.191.25516,382
52239.108.192.0/18239.108.192.1 to 239.108.255.254239.108.255.25516,382
53239.109.0.0/18239.109.0.1 to 239.109.63.254239.109.63.25516,382
54239.109.64.0/18239.109.64.1 to 239.109.127.254239.109.127.25516,382
55239.109.128.0/18239.109.128.1 to 239.109.191.254239.109.191.25516,382
56239.109.192.0/18239.109.192.1 to 239.109.255.254239.109.255.25516,382
57239.110.0.0/18239.110.0.1 to 239.110.63.254239.110.63.25516,382
58239.110.64.0/18239.110.64.1 to 239.110.127.254239.110.127.25516,382
59239.110.128.0/18239.110.128.1 to 239.110.191.254239.110.191.25516,382
60239.110.192.0/18239.110.192.1 to 239.110.255.254239.110.255.25516,382
61239.111.0.0/18239.111.0.1 to 239.111.63.254239.111.63.25516,382
62239.111.64.0/18239.111.64.1 to 239.111.127.254239.111.127.25516,382
63239.111.128.0/18239.111.128.1 to 239.111.191.254239.111.191.25516,382
64239.111.192.0/18239.111.192.1 to 239.111.255.254239.111.255.25516,382
65239.112.0.0/18239.112.0.1 to 239.112.63.254239.112.63.25516,382
66239.112.64.0/18239.112.64.1 to 239.112.127.254239.112.127.25516,382
67239.112.128.0/18239.112.128.1 to 239.112.191.254239.112.191.25516,382
68239.112.192.0/18239.112.192.1 to 239.112.255.254239.112.255.25516,382
69239.113.0.0/18239.113.0.1 to 239.113.63.254239.113.63.25516,382
70239.113.64.0/18239.113.64.1 to 239.113.127.254239.113.127.25516,382
71239.113.128.0/18239.113.128.1 to 239.113.191.254239.113.191.25516,382
72239.113.192.0/18239.113.192.1 to 239.113.255.254239.113.255.25516,382
73239.114.0.0/18239.114.0.1 to 239.114.63.254239.114.63.25516,382
74239.114.64.0/18239.114.64.1 to 239.114.127.254239.114.127.25516,382
75239.114.128.0/18239.114.128.1 to 239.114.191.254239.114.191.25516,382
76239.114.192.0/18239.114.192.1 to 239.114.255.254239.114.255.25516,382
77239.115.0.0/18239.115.0.1 to 239.115.63.254239.115.63.25516,382
78239.115.64.0/18239.115.64.1 to 239.115.127.254239.115.127.25516,382
79239.115.128.0/18239.115.128.1 to 239.115.191.254239.115.191.25516,382
80239.115.192.0/18239.115.192.1 to 239.115.255.254239.115.255.25516,382
81239.116.0.0/18239.116.0.1 to 239.116.63.254239.116.63.25516,382
82239.116.64.0/18239.116.64.1 to 239.116.127.254239.116.127.25516,382
83239.116.128.0/18239.116.128.1 to 239.116.191.254239.116.191.25516,382
84239.116.192.0/18239.116.192.1 to 239.116.255.254239.116.255.25516,382
85239.117.0.0/18239.117.0.1 to 239.117.63.254239.117.63.25516,382
86239.117.64.0/18239.117.64.1 to 239.117.127.254239.117.127.25516,382
87239.117.128.0/18239.117.128.1 to 239.117.191.254239.117.191.25516,382
88239.117.192.0/18239.117.192.1 to 239.117.255.254239.117.255.25516,382
89239.118.0.0/18239.118.0.1 to 239.118.63.254239.118.63.25516,382
90239.118.64.0/18239.118.64.1 to 239.118.127.254239.118.127.25516,382
91239.118.128.0/18239.118.128.1 to 239.118.191.254239.118.191.25516,382
92239.118.192.0/18239.118.192.1 to 239.118.255.254239.118.255.25516,382
93239.119.0.0/18239.119.0.1 to 239.119.63.254239.119.63.25516,382
94239.119.64.0/18239.119.64.1 to 239.119.127.254239.119.127.25516,382
95239.119.128.0/18239.119.128.1 to 239.119.191.254239.119.191.25516,382
96239.119.192.0/18239.119.192.1 to 239.119.255.254239.119.255.25516,382
97239.120.0.0/18239.120.0.1 to 239.120.63.254239.120.63.25516,382
98239.120.64.0/18239.120.64.1 to 239.120.127.254239.120.127.25516,382
99239.120.128.0/18239.120.128.1 to 239.120.191.254239.120.191.25516,382
100239.120.192.0/18239.120.192.1 to 239.120.255.254239.120.255.25516,382
101239.121.0.0/18239.121.0.1 to 239.121.63.254239.121.63.25516,382
102239.121.64.0/18239.121.64.1 to 239.121.127.254239.121.127.25516,382
103239.121.128.0/18239.121.128.1 to 239.121.191.254239.121.191.25516,382
104239.121.192.0/18239.121.192.1 to 239.121.255.254239.121.255.25516,382
105239.122.0.0/18239.122.0.1 to 239.122.63.254239.122.63.25516,382
106239.122.64.0/18239.122.64.1 to 239.122.127.254239.122.127.25516,382
107239.122.128.0/18239.122.128.1 to 239.122.191.254239.122.191.25516,382
108239.122.192.0/18239.122.192.1 to 239.122.255.254239.122.255.25516,382
109239.123.0.0/18239.123.0.1 to 239.123.63.254239.123.63.25516,382
110239.123.64.0/18239.123.64.1 to 239.123.127.254239.123.127.25516,382
111239.123.128.0/18239.123.128.1 to 239.123.191.254239.123.191.25516,382
112239.123.192.0/18239.123.192.1 to 239.123.255.254239.123.255.25516,382
113239.124.0.0/18239.124.0.1 to 239.124.63.254239.124.63.25516,382
114239.124.64.0/18239.124.64.1 to 239.124.127.254239.124.127.25516,382
115239.124.128.0/18239.124.128.1 to 239.124.191.254239.124.191.25516,382
116239.124.192.0/18239.124.192.1 to 239.124.255.254239.124.255.25516,382
117239.125.0.0/18239.125.0.1 to 239.125.63.254239.125.63.25516,382
118239.125.64.0/18239.125.64.1 to 239.125.127.254239.125.127.25516,382
119239.125.128.0/18239.125.128.1 to 239.125.191.254239.125.191.25516,382
120239.125.192.0/18239.125.192.1 to 239.125.255.254239.125.255.25516,382
121239.126.0.0/18239.126.0.1 to 239.126.63.254239.126.63.25516,382
122239.126.64.0/18239.126.64.1 to 239.126.127.254239.126.127.25516,382
123239.126.128.0/18239.126.128.1 to 239.126.191.254239.126.191.25516,382
124239.126.192.0/18239.126.192.1 to 239.126.255.254239.126.255.25516,382
125239.127.0.0/18239.127.0.1 to 239.127.63.254239.127.63.25516,382
126239.127.64.0/18239.127.64.1 to 239.127.127.254239.127.127.25516,382
127239.127.128.0/18239.127.128.1 to 239.127.191.254239.127.191.25516,382
128239.127.192.0/18239.127.192.1 to 239.127.255.254239.127.255.25516,382

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.