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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.

Network112.0.0.0/4
Usable hosts268,435,454
Subnet mask240.0.0.0
Addresses268,435,456
Network address
112.0.0.0
Broadcast address
127.255.255.255
First usable
112.0.0.1
Last usable
127.255.255.254
Usable hosts
268,435,454 (268,435,456 less the network and broadcast addresses)
Subnet mask
240.0.0.0
Wildcard mask
15.255.255.255 (Cisco ACLs, OSPF)
Prefix length
/4
Type
Public public
Old class
A (default /8)
As numbers
Hex 70000000 · Integer 1879048192 to 2147483647
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
120.in-addr.arpa
121.in-addr.arpa
122.in-addr.arpa
123.in-addr.arpa
124.in-addr.arpa
125.in-addr.arpa
126.in-addr.arpa
127.in-addr.arpa
/4 is not on a 8-bit boundary, so it takes 16 /8 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address01110000.00000000.00000000.00000000112.0.0.0
Subnet mask11110000.00000000.00000000.00000000240.0.0.0
Network01110000.00000000.00000000.00000000112.0.0.0
Broadcast01111111.11111111.11111111.11111111127.255.255.255
Split into smaller subnets/11
/5 (2)/6 (4)/7 (8)/8 (16)/9 (32)/10 (64)/11 (128)/12 (256)/13 (512)/14 (1,024)/15 (2,048)/16 (4,096)

112.0.0.0/4 makes 128 subnets of /11.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1112.0.0.0/11112.0.0.1 to 112.31.255.254112.31.255.2552,097,150
2112.32.0.0/11112.32.0.1 to 112.63.255.254112.63.255.2552,097,150
3112.64.0.0/11112.64.0.1 to 112.95.255.254112.95.255.2552,097,150
4112.96.0.0/11112.96.0.1 to 112.127.255.254112.127.255.2552,097,150
5112.128.0.0/11112.128.0.1 to 112.159.255.254112.159.255.2552,097,150
6112.160.0.0/11112.160.0.1 to 112.191.255.254112.191.255.2552,097,150
7112.192.0.0/11112.192.0.1 to 112.223.255.254112.223.255.2552,097,150
8112.224.0.0/11112.224.0.1 to 112.255.255.254112.255.255.2552,097,150
9113.0.0.0/11113.0.0.1 to 113.31.255.254113.31.255.2552,097,150
10113.32.0.0/11113.32.0.1 to 113.63.255.254113.63.255.2552,097,150
11113.64.0.0/11113.64.0.1 to 113.95.255.254113.95.255.2552,097,150
12113.96.0.0/11113.96.0.1 to 113.127.255.254113.127.255.2552,097,150
13113.128.0.0/11113.128.0.1 to 113.159.255.254113.159.255.2552,097,150
14113.160.0.0/11113.160.0.1 to 113.191.255.254113.191.255.2552,097,150
15113.192.0.0/11113.192.0.1 to 113.223.255.254113.223.255.2552,097,150
16113.224.0.0/11113.224.0.1 to 113.255.255.254113.255.255.2552,097,150
17114.0.0.0/11114.0.0.1 to 114.31.255.254114.31.255.2552,097,150
18114.32.0.0/11114.32.0.1 to 114.63.255.254114.63.255.2552,097,150
19114.64.0.0/11114.64.0.1 to 114.95.255.254114.95.255.2552,097,150
20114.96.0.0/11114.96.0.1 to 114.127.255.254114.127.255.2552,097,150
21114.128.0.0/11114.128.0.1 to 114.159.255.254114.159.255.2552,097,150
22114.160.0.0/11114.160.0.1 to 114.191.255.254114.191.255.2552,097,150
23114.192.0.0/11114.192.0.1 to 114.223.255.254114.223.255.2552,097,150
24114.224.0.0/11114.224.0.1 to 114.255.255.254114.255.255.2552,097,150
25115.0.0.0/11115.0.0.1 to 115.31.255.254115.31.255.2552,097,150
26115.32.0.0/11115.32.0.1 to 115.63.255.254115.63.255.2552,097,150
27115.64.0.0/11115.64.0.1 to 115.95.255.254115.95.255.2552,097,150
28115.96.0.0/11115.96.0.1 to 115.127.255.254115.127.255.2552,097,150
29115.128.0.0/11115.128.0.1 to 115.159.255.254115.159.255.2552,097,150
30115.160.0.0/11115.160.0.1 to 115.191.255.254115.191.255.2552,097,150
31115.192.0.0/11115.192.0.1 to 115.223.255.254115.223.255.2552,097,150
32115.224.0.0/11115.224.0.1 to 115.255.255.254115.255.255.2552,097,150
33116.0.0.0/11116.0.0.1 to 116.31.255.254116.31.255.2552,097,150
34116.32.0.0/11116.32.0.1 to 116.63.255.254116.63.255.2552,097,150
35116.64.0.0/11116.64.0.1 to 116.95.255.254116.95.255.2552,097,150
36116.96.0.0/11116.96.0.1 to 116.127.255.254116.127.255.2552,097,150
37116.128.0.0/11116.128.0.1 to 116.159.255.254116.159.255.2552,097,150
38116.160.0.0/11116.160.0.1 to 116.191.255.254116.191.255.2552,097,150
39116.192.0.0/11116.192.0.1 to 116.223.255.254116.223.255.2552,097,150
40116.224.0.0/11116.224.0.1 to 116.255.255.254116.255.255.2552,097,150
41117.0.0.0/11117.0.0.1 to 117.31.255.254117.31.255.2552,097,150
42117.32.0.0/11117.32.0.1 to 117.63.255.254117.63.255.2552,097,150
43117.64.0.0/11117.64.0.1 to 117.95.255.254117.95.255.2552,097,150
44117.96.0.0/11117.96.0.1 to 117.127.255.254117.127.255.2552,097,150
45117.128.0.0/11117.128.0.1 to 117.159.255.254117.159.255.2552,097,150
46117.160.0.0/11117.160.0.1 to 117.191.255.254117.191.255.2552,097,150
47117.192.0.0/11117.192.0.1 to 117.223.255.254117.223.255.2552,097,150
48117.224.0.0/11117.224.0.1 to 117.255.255.254117.255.255.2552,097,150
49118.0.0.0/11118.0.0.1 to 118.31.255.254118.31.255.2552,097,150
50118.32.0.0/11118.32.0.1 to 118.63.255.254118.63.255.2552,097,150
51118.64.0.0/11118.64.0.1 to 118.95.255.254118.95.255.2552,097,150
52118.96.0.0/11118.96.0.1 to 118.127.255.254118.127.255.2552,097,150
53118.128.0.0/11118.128.0.1 to 118.159.255.254118.159.255.2552,097,150
54118.160.0.0/11118.160.0.1 to 118.191.255.254118.191.255.2552,097,150
55118.192.0.0/11118.192.0.1 to 118.223.255.254118.223.255.2552,097,150
56118.224.0.0/11118.224.0.1 to 118.255.255.254118.255.255.2552,097,150
57119.0.0.0/11119.0.0.1 to 119.31.255.254119.31.255.2552,097,150
58119.32.0.0/11119.32.0.1 to 119.63.255.254119.63.255.2552,097,150
59119.64.0.0/11119.64.0.1 to 119.95.255.254119.95.255.2552,097,150
60119.96.0.0/11119.96.0.1 to 119.127.255.254119.127.255.2552,097,150
61119.128.0.0/11119.128.0.1 to 119.159.255.254119.159.255.2552,097,150
62119.160.0.0/11119.160.0.1 to 119.191.255.254119.191.255.2552,097,150
63119.192.0.0/11119.192.0.1 to 119.223.255.254119.223.255.2552,097,150
64119.224.0.0/11119.224.0.1 to 119.255.255.254119.255.255.2552,097,150
65120.0.0.0/11120.0.0.1 to 120.31.255.254120.31.255.2552,097,150
66120.32.0.0/11120.32.0.1 to 120.63.255.254120.63.255.2552,097,150
67120.64.0.0/11120.64.0.1 to 120.95.255.254120.95.255.2552,097,150
68120.96.0.0/11120.96.0.1 to 120.127.255.254120.127.255.2552,097,150
69120.128.0.0/11120.128.0.1 to 120.159.255.254120.159.255.2552,097,150
70120.160.0.0/11120.160.0.1 to 120.191.255.254120.191.255.2552,097,150
71120.192.0.0/11120.192.0.1 to 120.223.255.254120.223.255.2552,097,150
72120.224.0.0/11120.224.0.1 to 120.255.255.254120.255.255.2552,097,150
73121.0.0.0/11121.0.0.1 to 121.31.255.254121.31.255.2552,097,150
74121.32.0.0/11121.32.0.1 to 121.63.255.254121.63.255.2552,097,150
75121.64.0.0/11121.64.0.1 to 121.95.255.254121.95.255.2552,097,150
76121.96.0.0/11121.96.0.1 to 121.127.255.254121.127.255.2552,097,150
77121.128.0.0/11121.128.0.1 to 121.159.255.254121.159.255.2552,097,150
78121.160.0.0/11121.160.0.1 to 121.191.255.254121.191.255.2552,097,150
79121.192.0.0/11121.192.0.1 to 121.223.255.254121.223.255.2552,097,150
80121.224.0.0/11121.224.0.1 to 121.255.255.254121.255.255.2552,097,150
81122.0.0.0/11122.0.0.1 to 122.31.255.254122.31.255.2552,097,150
82122.32.0.0/11122.32.0.1 to 122.63.255.254122.63.255.2552,097,150
83122.64.0.0/11122.64.0.1 to 122.95.255.254122.95.255.2552,097,150
84122.96.0.0/11122.96.0.1 to 122.127.255.254122.127.255.2552,097,150
85122.128.0.0/11122.128.0.1 to 122.159.255.254122.159.255.2552,097,150
86122.160.0.0/11122.160.0.1 to 122.191.255.254122.191.255.2552,097,150
87122.192.0.0/11122.192.0.1 to 122.223.255.254122.223.255.2552,097,150
88122.224.0.0/11122.224.0.1 to 122.255.255.254122.255.255.2552,097,150
89123.0.0.0/11123.0.0.1 to 123.31.255.254123.31.255.2552,097,150
90123.32.0.0/11123.32.0.1 to 123.63.255.254123.63.255.2552,097,150
91123.64.0.0/11123.64.0.1 to 123.95.255.254123.95.255.2552,097,150
92123.96.0.0/11123.96.0.1 to 123.127.255.254123.127.255.2552,097,150
93123.128.0.0/11123.128.0.1 to 123.159.255.254123.159.255.2552,097,150
94123.160.0.0/11123.160.0.1 to 123.191.255.254123.191.255.2552,097,150
95123.192.0.0/11123.192.0.1 to 123.223.255.254123.223.255.2552,097,150
96123.224.0.0/11123.224.0.1 to 123.255.255.254123.255.255.2552,097,150
97124.0.0.0/11124.0.0.1 to 124.31.255.254124.31.255.2552,097,150
98124.32.0.0/11124.32.0.1 to 124.63.255.254124.63.255.2552,097,150
99124.64.0.0/11124.64.0.1 to 124.95.255.254124.95.255.2552,097,150
100124.96.0.0/11124.96.0.1 to 124.127.255.254124.127.255.2552,097,150
101124.128.0.0/11124.128.0.1 to 124.159.255.254124.159.255.2552,097,150
102124.160.0.0/11124.160.0.1 to 124.191.255.254124.191.255.2552,097,150
103124.192.0.0/11124.192.0.1 to 124.223.255.254124.223.255.2552,097,150
104124.224.0.0/11124.224.0.1 to 124.255.255.254124.255.255.2552,097,150
105125.0.0.0/11125.0.0.1 to 125.31.255.254125.31.255.2552,097,150
106125.32.0.0/11125.32.0.1 to 125.63.255.254125.63.255.2552,097,150
107125.64.0.0/11125.64.0.1 to 125.95.255.254125.95.255.2552,097,150
108125.96.0.0/11125.96.0.1 to 125.127.255.254125.127.255.2552,097,150
109125.128.0.0/11125.128.0.1 to 125.159.255.254125.159.255.2552,097,150
110125.160.0.0/11125.160.0.1 to 125.191.255.254125.191.255.2552,097,150
111125.192.0.0/11125.192.0.1 to 125.223.255.254125.223.255.2552,097,150
112125.224.0.0/11125.224.0.1 to 125.255.255.254125.255.255.2552,097,150
113126.0.0.0/11126.0.0.1 to 126.31.255.254126.31.255.2552,097,150
114126.32.0.0/11126.32.0.1 to 126.63.255.254126.63.255.2552,097,150
115126.64.0.0/11126.64.0.1 to 126.95.255.254126.95.255.2552,097,150
116126.96.0.0/11126.96.0.1 to 126.127.255.254126.127.255.2552,097,150
117126.128.0.0/11126.128.0.1 to 126.159.255.254126.159.255.2552,097,150
118126.160.0.0/11126.160.0.1 to 126.191.255.254126.191.255.2552,097,150
119126.192.0.0/11126.192.0.1 to 126.223.255.254126.223.255.2552,097,150
120126.224.0.0/11126.224.0.1 to 126.255.255.254126.255.255.2552,097,150
121127.0.0.0/11127.0.0.1 to 127.31.255.254127.31.255.2552,097,150
122127.32.0.0/11127.32.0.1 to 127.63.255.254127.63.255.2552,097,150
123127.64.0.0/11127.64.0.1 to 127.95.255.254127.95.255.2552,097,150
124127.96.0.0/11127.96.0.1 to 127.127.255.254127.127.255.2552,097,150
125127.128.0.0/11127.128.0.1 to 127.159.255.254127.159.255.2552,097,150
126127.160.0.0/11127.160.0.1 to 127.191.255.254127.191.255.2552,097,150
127127.192.0.0/11127.192.0.1 to 127.223.255.254127.223.255.2552,097,150
128127.224.0.0/11127.224.0.1 to 127.255.255.254127.255.255.2552,097,150

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.