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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.

Network112.96.0.0/12
Usable hosts1,048,574
Subnet mask255.240.0.0
Addresses1,048,576
Network address
112.96.0.0
Broadcast address
112.111.255.255
First usable
112.96.0.1
Last usable
112.111.255.254
Usable hosts
1,048,574 (1,048,576 less the network and broadcast addresses)
Subnet mask
255.240.0.0
Wildcard mask
0.15.255.255 (Cisco ACLs, OSPF)
Prefix length
/12
Type
Public public
Old class
A (default /8)
As numbers
Hex 70600000 · Integer 1885339648 to 1886388223
Reverse DNS zones
96.112.in-addr.arpa
97.112.in-addr.arpa
98.112.in-addr.arpa
99.112.in-addr.arpa
100.112.in-addr.arpa
101.112.in-addr.arpa
102.112.in-addr.arpa
103.112.in-addr.arpa
104.112.in-addr.arpa
105.112.in-addr.arpa
106.112.in-addr.arpa
107.112.in-addr.arpa
108.112.in-addr.arpa
109.112.in-addr.arpa
110.112.in-addr.arpa
111.112.in-addr.arpa
/12 is not on a 8-bit boundary, so it takes 16 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address01110000.01100000.00000000.00000000112.96.0.0
Subnet mask11111111.11110000.00000000.00000000255.240.0.0
Network01110000.01100000.00000000.00000000112.96.0.0
Broadcast01110000.01101111.11111111.11111111112.111.255.255
Split into smaller subnets/19
/13 (2)/14 (4)/15 (8)/16 (16)/17 (32)/18 (64)/19 (128)/20 (256)/21 (512)/22 (1,024)/23 (2,048)/24 (4,096)

112.96.0.0/12 makes 128 subnets of /19.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1112.96.0.0/19112.96.0.1 to 112.96.31.254112.96.31.2558,190
2112.96.32.0/19112.96.32.1 to 112.96.63.254112.96.63.2558,190
3112.96.64.0/19112.96.64.1 to 112.96.95.254112.96.95.2558,190
4112.96.96.0/19112.96.96.1 to 112.96.127.254112.96.127.2558,190
5112.96.128.0/19112.96.128.1 to 112.96.159.254112.96.159.2558,190
6112.96.160.0/19112.96.160.1 to 112.96.191.254112.96.191.2558,190
7112.96.192.0/19112.96.192.1 to 112.96.223.254112.96.223.2558,190
8112.96.224.0/19112.96.224.1 to 112.96.255.254112.96.255.2558,190
9112.97.0.0/19112.97.0.1 to 112.97.31.254112.97.31.2558,190
10112.97.32.0/19112.97.32.1 to 112.97.63.254112.97.63.2558,190
11112.97.64.0/19112.97.64.1 to 112.97.95.254112.97.95.2558,190
12112.97.96.0/19112.97.96.1 to 112.97.127.254112.97.127.2558,190
13112.97.128.0/19112.97.128.1 to 112.97.159.254112.97.159.2558,190
14112.97.160.0/19112.97.160.1 to 112.97.191.254112.97.191.2558,190
15112.97.192.0/19112.97.192.1 to 112.97.223.254112.97.223.2558,190
16112.97.224.0/19112.97.224.1 to 112.97.255.254112.97.255.2558,190
17112.98.0.0/19112.98.0.1 to 112.98.31.254112.98.31.2558,190
18112.98.32.0/19112.98.32.1 to 112.98.63.254112.98.63.2558,190
19112.98.64.0/19112.98.64.1 to 112.98.95.254112.98.95.2558,190
20112.98.96.0/19112.98.96.1 to 112.98.127.254112.98.127.2558,190
21112.98.128.0/19112.98.128.1 to 112.98.159.254112.98.159.2558,190
22112.98.160.0/19112.98.160.1 to 112.98.191.254112.98.191.2558,190
23112.98.192.0/19112.98.192.1 to 112.98.223.254112.98.223.2558,190
24112.98.224.0/19112.98.224.1 to 112.98.255.254112.98.255.2558,190
25112.99.0.0/19112.99.0.1 to 112.99.31.254112.99.31.2558,190
26112.99.32.0/19112.99.32.1 to 112.99.63.254112.99.63.2558,190
27112.99.64.0/19112.99.64.1 to 112.99.95.254112.99.95.2558,190
28112.99.96.0/19112.99.96.1 to 112.99.127.254112.99.127.2558,190
29112.99.128.0/19112.99.128.1 to 112.99.159.254112.99.159.2558,190
30112.99.160.0/19112.99.160.1 to 112.99.191.254112.99.191.2558,190
31112.99.192.0/19112.99.192.1 to 112.99.223.254112.99.223.2558,190
32112.99.224.0/19112.99.224.1 to 112.99.255.254112.99.255.2558,190
33112.100.0.0/19112.100.0.1 to 112.100.31.254112.100.31.2558,190
34112.100.32.0/19112.100.32.1 to 112.100.63.254112.100.63.2558,190
35112.100.64.0/19112.100.64.1 to 112.100.95.254112.100.95.2558,190
36112.100.96.0/19112.100.96.1 to 112.100.127.254112.100.127.2558,190
37112.100.128.0/19112.100.128.1 to 112.100.159.254112.100.159.2558,190
38112.100.160.0/19112.100.160.1 to 112.100.191.254112.100.191.2558,190
39112.100.192.0/19112.100.192.1 to 112.100.223.254112.100.223.2558,190
40112.100.224.0/19112.100.224.1 to 112.100.255.254112.100.255.2558,190
41112.101.0.0/19112.101.0.1 to 112.101.31.254112.101.31.2558,190
42112.101.32.0/19112.101.32.1 to 112.101.63.254112.101.63.2558,190
43112.101.64.0/19112.101.64.1 to 112.101.95.254112.101.95.2558,190
44112.101.96.0/19112.101.96.1 to 112.101.127.254112.101.127.2558,190
45112.101.128.0/19112.101.128.1 to 112.101.159.254112.101.159.2558,190
46112.101.160.0/19112.101.160.1 to 112.101.191.254112.101.191.2558,190
47112.101.192.0/19112.101.192.1 to 112.101.223.254112.101.223.2558,190
48112.101.224.0/19112.101.224.1 to 112.101.255.254112.101.255.2558,190
49112.102.0.0/19112.102.0.1 to 112.102.31.254112.102.31.2558,190
50112.102.32.0/19112.102.32.1 to 112.102.63.254112.102.63.2558,190
51112.102.64.0/19112.102.64.1 to 112.102.95.254112.102.95.2558,190
52112.102.96.0/19112.102.96.1 to 112.102.127.254112.102.127.2558,190
53112.102.128.0/19112.102.128.1 to 112.102.159.254112.102.159.2558,190
54112.102.160.0/19112.102.160.1 to 112.102.191.254112.102.191.2558,190
55112.102.192.0/19112.102.192.1 to 112.102.223.254112.102.223.2558,190
56112.102.224.0/19112.102.224.1 to 112.102.255.254112.102.255.2558,190
57112.103.0.0/19112.103.0.1 to 112.103.31.254112.103.31.2558,190
58112.103.32.0/19112.103.32.1 to 112.103.63.254112.103.63.2558,190
59112.103.64.0/19112.103.64.1 to 112.103.95.254112.103.95.2558,190
60112.103.96.0/19112.103.96.1 to 112.103.127.254112.103.127.2558,190
61112.103.128.0/19112.103.128.1 to 112.103.159.254112.103.159.2558,190
62112.103.160.0/19112.103.160.1 to 112.103.191.254112.103.191.2558,190
63112.103.192.0/19112.103.192.1 to 112.103.223.254112.103.223.2558,190
64112.103.224.0/19112.103.224.1 to 112.103.255.254112.103.255.2558,190
65112.104.0.0/19112.104.0.1 to 112.104.31.254112.104.31.2558,190
66112.104.32.0/19112.104.32.1 to 112.104.63.254112.104.63.2558,190
67112.104.64.0/19112.104.64.1 to 112.104.95.254112.104.95.2558,190
68112.104.96.0/19112.104.96.1 to 112.104.127.254112.104.127.2558,190
69112.104.128.0/19112.104.128.1 to 112.104.159.254112.104.159.2558,190
70112.104.160.0/19112.104.160.1 to 112.104.191.254112.104.191.2558,190
71112.104.192.0/19112.104.192.1 to 112.104.223.254112.104.223.2558,190
72112.104.224.0/19112.104.224.1 to 112.104.255.254112.104.255.2558,190
73112.105.0.0/19112.105.0.1 to 112.105.31.254112.105.31.2558,190
74112.105.32.0/19112.105.32.1 to 112.105.63.254112.105.63.2558,190
75112.105.64.0/19112.105.64.1 to 112.105.95.254112.105.95.2558,190
76112.105.96.0/19112.105.96.1 to 112.105.127.254112.105.127.2558,190
77112.105.128.0/19112.105.128.1 to 112.105.159.254112.105.159.2558,190
78112.105.160.0/19112.105.160.1 to 112.105.191.254112.105.191.2558,190
79112.105.192.0/19112.105.192.1 to 112.105.223.254112.105.223.2558,190
80112.105.224.0/19112.105.224.1 to 112.105.255.254112.105.255.2558,190
81112.106.0.0/19112.106.0.1 to 112.106.31.254112.106.31.2558,190
82112.106.32.0/19112.106.32.1 to 112.106.63.254112.106.63.2558,190
83112.106.64.0/19112.106.64.1 to 112.106.95.254112.106.95.2558,190
84112.106.96.0/19112.106.96.1 to 112.106.127.254112.106.127.2558,190
85112.106.128.0/19112.106.128.1 to 112.106.159.254112.106.159.2558,190
86112.106.160.0/19112.106.160.1 to 112.106.191.254112.106.191.2558,190
87112.106.192.0/19112.106.192.1 to 112.106.223.254112.106.223.2558,190
88112.106.224.0/19112.106.224.1 to 112.106.255.254112.106.255.2558,190
89112.107.0.0/19112.107.0.1 to 112.107.31.254112.107.31.2558,190
90112.107.32.0/19112.107.32.1 to 112.107.63.254112.107.63.2558,190
91112.107.64.0/19112.107.64.1 to 112.107.95.254112.107.95.2558,190
92112.107.96.0/19112.107.96.1 to 112.107.127.254112.107.127.2558,190
93112.107.128.0/19112.107.128.1 to 112.107.159.254112.107.159.2558,190
94112.107.160.0/19112.107.160.1 to 112.107.191.254112.107.191.2558,190
95112.107.192.0/19112.107.192.1 to 112.107.223.254112.107.223.2558,190
96112.107.224.0/19112.107.224.1 to 112.107.255.254112.107.255.2558,190
97112.108.0.0/19112.108.0.1 to 112.108.31.254112.108.31.2558,190
98112.108.32.0/19112.108.32.1 to 112.108.63.254112.108.63.2558,190
99112.108.64.0/19112.108.64.1 to 112.108.95.254112.108.95.2558,190
100112.108.96.0/19112.108.96.1 to 112.108.127.254112.108.127.2558,190
101112.108.128.0/19112.108.128.1 to 112.108.159.254112.108.159.2558,190
102112.108.160.0/19112.108.160.1 to 112.108.191.254112.108.191.2558,190
103112.108.192.0/19112.108.192.1 to 112.108.223.254112.108.223.2558,190
104112.108.224.0/19112.108.224.1 to 112.108.255.254112.108.255.2558,190
105112.109.0.0/19112.109.0.1 to 112.109.31.254112.109.31.2558,190
106112.109.32.0/19112.109.32.1 to 112.109.63.254112.109.63.2558,190
107112.109.64.0/19112.109.64.1 to 112.109.95.254112.109.95.2558,190
108112.109.96.0/19112.109.96.1 to 112.109.127.254112.109.127.2558,190
109112.109.128.0/19112.109.128.1 to 112.109.159.254112.109.159.2558,190
110112.109.160.0/19112.109.160.1 to 112.109.191.254112.109.191.2558,190
111112.109.192.0/19112.109.192.1 to 112.109.223.254112.109.223.2558,190
112112.109.224.0/19112.109.224.1 to 112.109.255.254112.109.255.2558,190
113112.110.0.0/19112.110.0.1 to 112.110.31.254112.110.31.2558,190
114112.110.32.0/19112.110.32.1 to 112.110.63.254112.110.63.2558,190
115112.110.64.0/19112.110.64.1 to 112.110.95.254112.110.95.2558,190
116112.110.96.0/19112.110.96.1 to 112.110.127.254112.110.127.2558,190
117112.110.128.0/19112.110.128.1 to 112.110.159.254112.110.159.2558,190
118112.110.160.0/19112.110.160.1 to 112.110.191.254112.110.191.2558,190
119112.110.192.0/19112.110.192.1 to 112.110.223.254112.110.223.2558,190
120112.110.224.0/19112.110.224.1 to 112.110.255.254112.110.255.2558,190
121112.111.0.0/19112.111.0.1 to 112.111.31.254112.111.31.2558,190
122112.111.32.0/19112.111.32.1 to 112.111.63.254112.111.63.2558,190
123112.111.64.0/19112.111.64.1 to 112.111.95.254112.111.95.2558,190
124112.111.96.0/19112.111.96.1 to 112.111.127.254112.111.127.2558,190
125112.111.128.0/19112.111.128.1 to 112.111.159.254112.111.159.2558,190
126112.111.160.0/19112.111.160.1 to 112.111.191.254112.111.191.2558,190
127112.111.192.0/19112.111.192.1 to 112.111.223.254112.111.223.2558,190
128112.111.224.0/19112.111.224.1 to 112.111.255.254112.111.255.2558,190

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.