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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.

Network112.0.0.0/5
Usable hosts134,217,726
Subnet mask248.0.0.0
Addresses134,217,728
Network address
112.0.0.0
Broadcast address
119.255.255.255
First usable
112.0.0.1
Last usable
119.255.255.254
Usable hosts
134,217,726 (134,217,728 less the network and broadcast addresses)
Subnet mask
248.0.0.0
Wildcard mask
7.255.255.255 (Cisco ACLs, OSPF)
Prefix length
/5
Type
Public public
Old class
A (default /8)
As numbers
Hex 70000000 · Integer 1879048192 to 2013265919
Reverse DNS zones
112.in-addr.arpa
113.in-addr.arpa
114.in-addr.arpa
115.in-addr.arpa
116.in-addr.arpa
117.in-addr.arpa
118.in-addr.arpa
119.in-addr.arpa
/5 is not on a 8-bit boundary, so it takes 8 /8 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address01110000.00000000.00000000.00000000112.0.0.0
Subnet mask11111000.00000000.00000000.00000000248.0.0.0
Network01110000.00000000.00000000.00000000112.0.0.0
Broadcast01110111.11111111.11111111.11111111119.255.255.255
Split into smaller subnets/12
/6 (2)/7 (4)/8 (8)/9 (16)/10 (32)/11 (64)/12 (128)/13 (256)/14 (512)/15 (1,024)/16 (2,048)/17 (4,096)

112.0.0.0/5 makes 128 subnets of /12.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1112.0.0.0/12112.0.0.1 to 112.15.255.254112.15.255.2551,048,574
2112.16.0.0/12112.16.0.1 to 112.31.255.254112.31.255.2551,048,574
3112.32.0.0/12112.32.0.1 to 112.47.255.254112.47.255.2551,048,574
4112.48.0.0/12112.48.0.1 to 112.63.255.254112.63.255.2551,048,574
5112.64.0.0/12112.64.0.1 to 112.79.255.254112.79.255.2551,048,574
6112.80.0.0/12112.80.0.1 to 112.95.255.254112.95.255.2551,048,574
7112.96.0.0/12112.96.0.1 to 112.111.255.254112.111.255.2551,048,574
8112.112.0.0/12112.112.0.1 to 112.127.255.254112.127.255.2551,048,574
9112.128.0.0/12112.128.0.1 to 112.143.255.254112.143.255.2551,048,574
10112.144.0.0/12112.144.0.1 to 112.159.255.254112.159.255.2551,048,574
11112.160.0.0/12112.160.0.1 to 112.175.255.254112.175.255.2551,048,574
12112.176.0.0/12112.176.0.1 to 112.191.255.254112.191.255.2551,048,574
13112.192.0.0/12112.192.0.1 to 112.207.255.254112.207.255.2551,048,574
14112.208.0.0/12112.208.0.1 to 112.223.255.254112.223.255.2551,048,574
15112.224.0.0/12112.224.0.1 to 112.239.255.254112.239.255.2551,048,574
16112.240.0.0/12112.240.0.1 to 112.255.255.254112.255.255.2551,048,574
17113.0.0.0/12113.0.0.1 to 113.15.255.254113.15.255.2551,048,574
18113.16.0.0/12113.16.0.1 to 113.31.255.254113.31.255.2551,048,574
19113.32.0.0/12113.32.0.1 to 113.47.255.254113.47.255.2551,048,574
20113.48.0.0/12113.48.0.1 to 113.63.255.254113.63.255.2551,048,574
21113.64.0.0/12113.64.0.1 to 113.79.255.254113.79.255.2551,048,574
22113.80.0.0/12113.80.0.1 to 113.95.255.254113.95.255.2551,048,574
23113.96.0.0/12113.96.0.1 to 113.111.255.254113.111.255.2551,048,574
24113.112.0.0/12113.112.0.1 to 113.127.255.254113.127.255.2551,048,574
25113.128.0.0/12113.128.0.1 to 113.143.255.254113.143.255.2551,048,574
26113.144.0.0/12113.144.0.1 to 113.159.255.254113.159.255.2551,048,574
27113.160.0.0/12113.160.0.1 to 113.175.255.254113.175.255.2551,048,574
28113.176.0.0/12113.176.0.1 to 113.191.255.254113.191.255.2551,048,574
29113.192.0.0/12113.192.0.1 to 113.207.255.254113.207.255.2551,048,574
30113.208.0.0/12113.208.0.1 to 113.223.255.254113.223.255.2551,048,574
31113.224.0.0/12113.224.0.1 to 113.239.255.254113.239.255.2551,048,574
32113.240.0.0/12113.240.0.1 to 113.255.255.254113.255.255.2551,048,574
33114.0.0.0/12114.0.0.1 to 114.15.255.254114.15.255.2551,048,574
34114.16.0.0/12114.16.0.1 to 114.31.255.254114.31.255.2551,048,574
35114.32.0.0/12114.32.0.1 to 114.47.255.254114.47.255.2551,048,574
36114.48.0.0/12114.48.0.1 to 114.63.255.254114.63.255.2551,048,574
37114.64.0.0/12114.64.0.1 to 114.79.255.254114.79.255.2551,048,574
38114.80.0.0/12114.80.0.1 to 114.95.255.254114.95.255.2551,048,574
39114.96.0.0/12114.96.0.1 to 114.111.255.254114.111.255.2551,048,574
40114.112.0.0/12114.112.0.1 to 114.127.255.254114.127.255.2551,048,574
41114.128.0.0/12114.128.0.1 to 114.143.255.254114.143.255.2551,048,574
42114.144.0.0/12114.144.0.1 to 114.159.255.254114.159.255.2551,048,574
43114.160.0.0/12114.160.0.1 to 114.175.255.254114.175.255.2551,048,574
44114.176.0.0/12114.176.0.1 to 114.191.255.254114.191.255.2551,048,574
45114.192.0.0/12114.192.0.1 to 114.207.255.254114.207.255.2551,048,574
46114.208.0.0/12114.208.0.1 to 114.223.255.254114.223.255.2551,048,574
47114.224.0.0/12114.224.0.1 to 114.239.255.254114.239.255.2551,048,574
48114.240.0.0/12114.240.0.1 to 114.255.255.254114.255.255.2551,048,574
49115.0.0.0/12115.0.0.1 to 115.15.255.254115.15.255.2551,048,574
50115.16.0.0/12115.16.0.1 to 115.31.255.254115.31.255.2551,048,574
51115.32.0.0/12115.32.0.1 to 115.47.255.254115.47.255.2551,048,574
52115.48.0.0/12115.48.0.1 to 115.63.255.254115.63.255.2551,048,574
53115.64.0.0/12115.64.0.1 to 115.79.255.254115.79.255.2551,048,574
54115.80.0.0/12115.80.0.1 to 115.95.255.254115.95.255.2551,048,574
55115.96.0.0/12115.96.0.1 to 115.111.255.254115.111.255.2551,048,574
56115.112.0.0/12115.112.0.1 to 115.127.255.254115.127.255.2551,048,574
57115.128.0.0/12115.128.0.1 to 115.143.255.254115.143.255.2551,048,574
58115.144.0.0/12115.144.0.1 to 115.159.255.254115.159.255.2551,048,574
59115.160.0.0/12115.160.0.1 to 115.175.255.254115.175.255.2551,048,574
60115.176.0.0/12115.176.0.1 to 115.191.255.254115.191.255.2551,048,574
61115.192.0.0/12115.192.0.1 to 115.207.255.254115.207.255.2551,048,574
62115.208.0.0/12115.208.0.1 to 115.223.255.254115.223.255.2551,048,574
63115.224.0.0/12115.224.0.1 to 115.239.255.254115.239.255.2551,048,574
64115.240.0.0/12115.240.0.1 to 115.255.255.254115.255.255.2551,048,574
65116.0.0.0/12116.0.0.1 to 116.15.255.254116.15.255.2551,048,574
66116.16.0.0/12116.16.0.1 to 116.31.255.254116.31.255.2551,048,574
67116.32.0.0/12116.32.0.1 to 116.47.255.254116.47.255.2551,048,574
68116.48.0.0/12116.48.0.1 to 116.63.255.254116.63.255.2551,048,574
69116.64.0.0/12116.64.0.1 to 116.79.255.254116.79.255.2551,048,574
70116.80.0.0/12116.80.0.1 to 116.95.255.254116.95.255.2551,048,574
71116.96.0.0/12116.96.0.1 to 116.111.255.254116.111.255.2551,048,574
72116.112.0.0/12116.112.0.1 to 116.127.255.254116.127.255.2551,048,574
73116.128.0.0/12116.128.0.1 to 116.143.255.254116.143.255.2551,048,574
74116.144.0.0/12116.144.0.1 to 116.159.255.254116.159.255.2551,048,574
75116.160.0.0/12116.160.0.1 to 116.175.255.254116.175.255.2551,048,574
76116.176.0.0/12116.176.0.1 to 116.191.255.254116.191.255.2551,048,574
77116.192.0.0/12116.192.0.1 to 116.207.255.254116.207.255.2551,048,574
78116.208.0.0/12116.208.0.1 to 116.223.255.254116.223.255.2551,048,574
79116.224.0.0/12116.224.0.1 to 116.239.255.254116.239.255.2551,048,574
80116.240.0.0/12116.240.0.1 to 116.255.255.254116.255.255.2551,048,574
81117.0.0.0/12117.0.0.1 to 117.15.255.254117.15.255.2551,048,574
82117.16.0.0/12117.16.0.1 to 117.31.255.254117.31.255.2551,048,574
83117.32.0.0/12117.32.0.1 to 117.47.255.254117.47.255.2551,048,574
84117.48.0.0/12117.48.0.1 to 117.63.255.254117.63.255.2551,048,574
85117.64.0.0/12117.64.0.1 to 117.79.255.254117.79.255.2551,048,574
86117.80.0.0/12117.80.0.1 to 117.95.255.254117.95.255.2551,048,574
87117.96.0.0/12117.96.0.1 to 117.111.255.254117.111.255.2551,048,574
88117.112.0.0/12117.112.0.1 to 117.127.255.254117.127.255.2551,048,574
89117.128.0.0/12117.128.0.1 to 117.143.255.254117.143.255.2551,048,574
90117.144.0.0/12117.144.0.1 to 117.159.255.254117.159.255.2551,048,574
91117.160.0.0/12117.160.0.1 to 117.175.255.254117.175.255.2551,048,574
92117.176.0.0/12117.176.0.1 to 117.191.255.254117.191.255.2551,048,574
93117.192.0.0/12117.192.0.1 to 117.207.255.254117.207.255.2551,048,574
94117.208.0.0/12117.208.0.1 to 117.223.255.254117.223.255.2551,048,574
95117.224.0.0/12117.224.0.1 to 117.239.255.254117.239.255.2551,048,574
96117.240.0.0/12117.240.0.1 to 117.255.255.254117.255.255.2551,048,574
97118.0.0.0/12118.0.0.1 to 118.15.255.254118.15.255.2551,048,574
98118.16.0.0/12118.16.0.1 to 118.31.255.254118.31.255.2551,048,574
99118.32.0.0/12118.32.0.1 to 118.47.255.254118.47.255.2551,048,574
100118.48.0.0/12118.48.0.1 to 118.63.255.254118.63.255.2551,048,574
101118.64.0.0/12118.64.0.1 to 118.79.255.254118.79.255.2551,048,574
102118.80.0.0/12118.80.0.1 to 118.95.255.254118.95.255.2551,048,574
103118.96.0.0/12118.96.0.1 to 118.111.255.254118.111.255.2551,048,574
104118.112.0.0/12118.112.0.1 to 118.127.255.254118.127.255.2551,048,574
105118.128.0.0/12118.128.0.1 to 118.143.255.254118.143.255.2551,048,574
106118.144.0.0/12118.144.0.1 to 118.159.255.254118.159.255.2551,048,574
107118.160.0.0/12118.160.0.1 to 118.175.255.254118.175.255.2551,048,574
108118.176.0.0/12118.176.0.1 to 118.191.255.254118.191.255.2551,048,574
109118.192.0.0/12118.192.0.1 to 118.207.255.254118.207.255.2551,048,574
110118.208.0.0/12118.208.0.1 to 118.223.255.254118.223.255.2551,048,574
111118.224.0.0/12118.224.0.1 to 118.239.255.254118.239.255.2551,048,574
112118.240.0.0/12118.240.0.1 to 118.255.255.254118.255.255.2551,048,574
113119.0.0.0/12119.0.0.1 to 119.15.255.254119.15.255.2551,048,574
114119.16.0.0/12119.16.0.1 to 119.31.255.254119.31.255.2551,048,574
115119.32.0.0/12119.32.0.1 to 119.47.255.254119.47.255.2551,048,574
116119.48.0.0/12119.48.0.1 to 119.63.255.254119.63.255.2551,048,574
117119.64.0.0/12119.64.0.1 to 119.79.255.254119.79.255.2551,048,574
118119.80.0.0/12119.80.0.1 to 119.95.255.254119.95.255.2551,048,574
119119.96.0.0/12119.96.0.1 to 119.111.255.254119.111.255.2551,048,574
120119.112.0.0/12119.112.0.1 to 119.127.255.254119.127.255.2551,048,574
121119.128.0.0/12119.128.0.1 to 119.143.255.254119.143.255.2551,048,574
122119.144.0.0/12119.144.0.1 to 119.159.255.254119.159.255.2551,048,574
123119.160.0.0/12119.160.0.1 to 119.175.255.254119.175.255.2551,048,574
124119.176.0.0/12119.176.0.1 to 119.191.255.254119.191.255.2551,048,574
125119.192.0.0/12119.192.0.1 to 119.207.255.254119.207.255.2551,048,574
126119.208.0.0/12119.208.0.1 to 119.223.255.254119.223.255.2551,048,574
127119.224.0.0/12119.224.0.1 to 119.239.255.254119.239.255.2551,048,574
128119.240.0.0/12119.240.0.1 to 119.255.255.254119.255.255.2551,048,574

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.