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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.

Network110.0.0.0/12
Usable hosts1,048,574
Subnet mask255.240.0.0
Addresses1,048,576
Network address
110.0.0.0
Broadcast address
110.15.255.255
First usable
110.0.0.1
Last usable
110.15.255.254
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 6E000000 · Integer 1845493760 to 1846542335
Reverse DNS zones
0.110.in-addr.arpa
1.110.in-addr.arpa
2.110.in-addr.arpa
3.110.in-addr.arpa
4.110.in-addr.arpa
5.110.in-addr.arpa
6.110.in-addr.arpa
7.110.in-addr.arpa
8.110.in-addr.arpa
9.110.in-addr.arpa
10.110.in-addr.arpa
11.110.in-addr.arpa
12.110.in-addr.arpa
13.110.in-addr.arpa
14.110.in-addr.arpa
15.110.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
Address01101110.00000000.00000000.00000000110.0.0.0
Subnet mask11111111.11110000.00000000.00000000255.240.0.0
Network01101110.00000000.00000000.00000000110.0.0.0
Broadcast01101110.00001111.11111111.11111111110.15.255.255
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)

110.0.0.0/12 makes 128 subnets of /19.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1110.0.0.0/19110.0.0.1 to 110.0.31.254110.0.31.2558,190
2110.0.32.0/19110.0.32.1 to 110.0.63.254110.0.63.2558,190
3110.0.64.0/19110.0.64.1 to 110.0.95.254110.0.95.2558,190
4110.0.96.0/19110.0.96.1 to 110.0.127.254110.0.127.2558,190
5110.0.128.0/19110.0.128.1 to 110.0.159.254110.0.159.2558,190
6110.0.160.0/19110.0.160.1 to 110.0.191.254110.0.191.2558,190
7110.0.192.0/19110.0.192.1 to 110.0.223.254110.0.223.2558,190
8110.0.224.0/19110.0.224.1 to 110.0.255.254110.0.255.2558,190
9110.1.0.0/19110.1.0.1 to 110.1.31.254110.1.31.2558,190
10110.1.32.0/19110.1.32.1 to 110.1.63.254110.1.63.2558,190
11110.1.64.0/19110.1.64.1 to 110.1.95.254110.1.95.2558,190
12110.1.96.0/19110.1.96.1 to 110.1.127.254110.1.127.2558,190
13110.1.128.0/19110.1.128.1 to 110.1.159.254110.1.159.2558,190
14110.1.160.0/19110.1.160.1 to 110.1.191.254110.1.191.2558,190
15110.1.192.0/19110.1.192.1 to 110.1.223.254110.1.223.2558,190
16110.1.224.0/19110.1.224.1 to 110.1.255.254110.1.255.2558,190
17110.2.0.0/19110.2.0.1 to 110.2.31.254110.2.31.2558,190
18110.2.32.0/19110.2.32.1 to 110.2.63.254110.2.63.2558,190
19110.2.64.0/19110.2.64.1 to 110.2.95.254110.2.95.2558,190
20110.2.96.0/19110.2.96.1 to 110.2.127.254110.2.127.2558,190
21110.2.128.0/19110.2.128.1 to 110.2.159.254110.2.159.2558,190
22110.2.160.0/19110.2.160.1 to 110.2.191.254110.2.191.2558,190
23110.2.192.0/19110.2.192.1 to 110.2.223.254110.2.223.2558,190
24110.2.224.0/19110.2.224.1 to 110.2.255.254110.2.255.2558,190
25110.3.0.0/19110.3.0.1 to 110.3.31.254110.3.31.2558,190
26110.3.32.0/19110.3.32.1 to 110.3.63.254110.3.63.2558,190
27110.3.64.0/19110.3.64.1 to 110.3.95.254110.3.95.2558,190
28110.3.96.0/19110.3.96.1 to 110.3.127.254110.3.127.2558,190
29110.3.128.0/19110.3.128.1 to 110.3.159.254110.3.159.2558,190
30110.3.160.0/19110.3.160.1 to 110.3.191.254110.3.191.2558,190
31110.3.192.0/19110.3.192.1 to 110.3.223.254110.3.223.2558,190
32110.3.224.0/19110.3.224.1 to 110.3.255.254110.3.255.2558,190
33110.4.0.0/19110.4.0.1 to 110.4.31.254110.4.31.2558,190
34110.4.32.0/19110.4.32.1 to 110.4.63.254110.4.63.2558,190
35110.4.64.0/19110.4.64.1 to 110.4.95.254110.4.95.2558,190
36110.4.96.0/19110.4.96.1 to 110.4.127.254110.4.127.2558,190
37110.4.128.0/19110.4.128.1 to 110.4.159.254110.4.159.2558,190
38110.4.160.0/19110.4.160.1 to 110.4.191.254110.4.191.2558,190
39110.4.192.0/19110.4.192.1 to 110.4.223.254110.4.223.2558,190
40110.4.224.0/19110.4.224.1 to 110.4.255.254110.4.255.2558,190
41110.5.0.0/19110.5.0.1 to 110.5.31.254110.5.31.2558,190
42110.5.32.0/19110.5.32.1 to 110.5.63.254110.5.63.2558,190
43110.5.64.0/19110.5.64.1 to 110.5.95.254110.5.95.2558,190
44110.5.96.0/19110.5.96.1 to 110.5.127.254110.5.127.2558,190
45110.5.128.0/19110.5.128.1 to 110.5.159.254110.5.159.2558,190
46110.5.160.0/19110.5.160.1 to 110.5.191.254110.5.191.2558,190
47110.5.192.0/19110.5.192.1 to 110.5.223.254110.5.223.2558,190
48110.5.224.0/19110.5.224.1 to 110.5.255.254110.5.255.2558,190
49110.6.0.0/19110.6.0.1 to 110.6.31.254110.6.31.2558,190
50110.6.32.0/19110.6.32.1 to 110.6.63.254110.6.63.2558,190
51110.6.64.0/19110.6.64.1 to 110.6.95.254110.6.95.2558,190
52110.6.96.0/19110.6.96.1 to 110.6.127.254110.6.127.2558,190
53110.6.128.0/19110.6.128.1 to 110.6.159.254110.6.159.2558,190
54110.6.160.0/19110.6.160.1 to 110.6.191.254110.6.191.2558,190
55110.6.192.0/19110.6.192.1 to 110.6.223.254110.6.223.2558,190
56110.6.224.0/19110.6.224.1 to 110.6.255.254110.6.255.2558,190
57110.7.0.0/19110.7.0.1 to 110.7.31.254110.7.31.2558,190
58110.7.32.0/19110.7.32.1 to 110.7.63.254110.7.63.2558,190
59110.7.64.0/19110.7.64.1 to 110.7.95.254110.7.95.2558,190
60110.7.96.0/19110.7.96.1 to 110.7.127.254110.7.127.2558,190
61110.7.128.0/19110.7.128.1 to 110.7.159.254110.7.159.2558,190
62110.7.160.0/19110.7.160.1 to 110.7.191.254110.7.191.2558,190
63110.7.192.0/19110.7.192.1 to 110.7.223.254110.7.223.2558,190
64110.7.224.0/19110.7.224.1 to 110.7.255.254110.7.255.2558,190
65110.8.0.0/19110.8.0.1 to 110.8.31.254110.8.31.2558,190
66110.8.32.0/19110.8.32.1 to 110.8.63.254110.8.63.2558,190
67110.8.64.0/19110.8.64.1 to 110.8.95.254110.8.95.2558,190
68110.8.96.0/19110.8.96.1 to 110.8.127.254110.8.127.2558,190
69110.8.128.0/19110.8.128.1 to 110.8.159.254110.8.159.2558,190
70110.8.160.0/19110.8.160.1 to 110.8.191.254110.8.191.2558,190
71110.8.192.0/19110.8.192.1 to 110.8.223.254110.8.223.2558,190
72110.8.224.0/19110.8.224.1 to 110.8.255.254110.8.255.2558,190
73110.9.0.0/19110.9.0.1 to 110.9.31.254110.9.31.2558,190
74110.9.32.0/19110.9.32.1 to 110.9.63.254110.9.63.2558,190
75110.9.64.0/19110.9.64.1 to 110.9.95.254110.9.95.2558,190
76110.9.96.0/19110.9.96.1 to 110.9.127.254110.9.127.2558,190
77110.9.128.0/19110.9.128.1 to 110.9.159.254110.9.159.2558,190
78110.9.160.0/19110.9.160.1 to 110.9.191.254110.9.191.2558,190
79110.9.192.0/19110.9.192.1 to 110.9.223.254110.9.223.2558,190
80110.9.224.0/19110.9.224.1 to 110.9.255.254110.9.255.2558,190
81110.10.0.0/19110.10.0.1 to 110.10.31.254110.10.31.2558,190
82110.10.32.0/19110.10.32.1 to 110.10.63.254110.10.63.2558,190
83110.10.64.0/19110.10.64.1 to 110.10.95.254110.10.95.2558,190
84110.10.96.0/19110.10.96.1 to 110.10.127.254110.10.127.2558,190
85110.10.128.0/19110.10.128.1 to 110.10.159.254110.10.159.2558,190
86110.10.160.0/19110.10.160.1 to 110.10.191.254110.10.191.2558,190
87110.10.192.0/19110.10.192.1 to 110.10.223.254110.10.223.2558,190
88110.10.224.0/19110.10.224.1 to 110.10.255.254110.10.255.2558,190
89110.11.0.0/19110.11.0.1 to 110.11.31.254110.11.31.2558,190
90110.11.32.0/19110.11.32.1 to 110.11.63.254110.11.63.2558,190
91110.11.64.0/19110.11.64.1 to 110.11.95.254110.11.95.2558,190
92110.11.96.0/19110.11.96.1 to 110.11.127.254110.11.127.2558,190
93110.11.128.0/19110.11.128.1 to 110.11.159.254110.11.159.2558,190
94110.11.160.0/19110.11.160.1 to 110.11.191.254110.11.191.2558,190
95110.11.192.0/19110.11.192.1 to 110.11.223.254110.11.223.2558,190
96110.11.224.0/19110.11.224.1 to 110.11.255.254110.11.255.2558,190
97110.12.0.0/19110.12.0.1 to 110.12.31.254110.12.31.2558,190
98110.12.32.0/19110.12.32.1 to 110.12.63.254110.12.63.2558,190
99110.12.64.0/19110.12.64.1 to 110.12.95.254110.12.95.2558,190
100110.12.96.0/19110.12.96.1 to 110.12.127.254110.12.127.2558,190
101110.12.128.0/19110.12.128.1 to 110.12.159.254110.12.159.2558,190
102110.12.160.0/19110.12.160.1 to 110.12.191.254110.12.191.2558,190
103110.12.192.0/19110.12.192.1 to 110.12.223.254110.12.223.2558,190
104110.12.224.0/19110.12.224.1 to 110.12.255.254110.12.255.2558,190
105110.13.0.0/19110.13.0.1 to 110.13.31.254110.13.31.2558,190
106110.13.32.0/19110.13.32.1 to 110.13.63.254110.13.63.2558,190
107110.13.64.0/19110.13.64.1 to 110.13.95.254110.13.95.2558,190
108110.13.96.0/19110.13.96.1 to 110.13.127.254110.13.127.2558,190
109110.13.128.0/19110.13.128.1 to 110.13.159.254110.13.159.2558,190
110110.13.160.0/19110.13.160.1 to 110.13.191.254110.13.191.2558,190
111110.13.192.0/19110.13.192.1 to 110.13.223.254110.13.223.2558,190
112110.13.224.0/19110.13.224.1 to 110.13.255.254110.13.255.2558,190
113110.14.0.0/19110.14.0.1 to 110.14.31.254110.14.31.2558,190
114110.14.32.0/19110.14.32.1 to 110.14.63.254110.14.63.2558,190
115110.14.64.0/19110.14.64.1 to 110.14.95.254110.14.95.2558,190
116110.14.96.0/19110.14.96.1 to 110.14.127.254110.14.127.2558,190
117110.14.128.0/19110.14.128.1 to 110.14.159.254110.14.159.2558,190
118110.14.160.0/19110.14.160.1 to 110.14.191.254110.14.191.2558,190
119110.14.192.0/19110.14.192.1 to 110.14.223.254110.14.223.2558,190
120110.14.224.0/19110.14.224.1 to 110.14.255.254110.14.255.2558,190
121110.15.0.0/19110.15.0.1 to 110.15.31.254110.15.31.2558,190
122110.15.32.0/19110.15.32.1 to 110.15.63.254110.15.63.2558,190
123110.15.64.0/19110.15.64.1 to 110.15.95.254110.15.95.2558,190
124110.15.96.0/19110.15.96.1 to 110.15.127.254110.15.127.2558,190
125110.15.128.0/19110.15.128.1 to 110.15.159.254110.15.159.2558,190
126110.15.160.0/19110.15.160.1 to 110.15.191.254110.15.191.2558,190
127110.15.192.0/19110.15.192.1 to 110.15.223.254110.15.223.2558,190
128110.15.224.0/19110.15.224.1 to 110.15.255.254110.15.255.2558,190

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.