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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.

Network110.166.0.0/15
Usable hosts131,070
Subnet mask255.254.0.0
Addresses131,072
Network address
110.166.0.0
Broadcast address
110.167.255.255
First usable
110.166.0.1
Last usable
110.167.255.254
Usable hosts
131,070 (131,072 less the network and broadcast addresses)
Subnet mask
255.254.0.0
Wildcard mask
0.1.255.255 (Cisco ACLs, OSPF)
Prefix length
/15
Type
Public public
Old class
A (default /8)
As numbers
Hex 6EA60000 · Integer 1856372736 to 1856503807
Reverse DNS zones
166.110.in-addr.arpa
167.110.in-addr.arpa
/15 is not on a 8-bit boundary, so it takes 2 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address01101110.10100110.00000000.00000000110.166.0.0
Subnet mask11111111.11111110.00000000.00000000255.254.0.0
Network01101110.10100110.00000000.00000000110.166.0.0
Broadcast01101110.10100111.11111111.11111111110.167.255.255
Split into smaller subnets/22
/16 (2)/17 (4)/18 (8)/19 (16)/20 (32)/21 (64)/22 (128)/23 (256)/24 (512)/25 (1,024)/26 (2,048)/27 (4,096)

110.166.0.0/15 makes 128 subnets of /22.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1110.166.0.0/22110.166.0.1 to 110.166.3.254110.166.3.2551,022
2110.166.4.0/22110.166.4.1 to 110.166.7.254110.166.7.2551,022
3110.166.8.0/22110.166.8.1 to 110.166.11.254110.166.11.2551,022
4110.166.12.0/22110.166.12.1 to 110.166.15.254110.166.15.2551,022
5110.166.16.0/22110.166.16.1 to 110.166.19.254110.166.19.2551,022
6110.166.20.0/22110.166.20.1 to 110.166.23.254110.166.23.2551,022
7110.166.24.0/22110.166.24.1 to 110.166.27.254110.166.27.2551,022
8110.166.28.0/22110.166.28.1 to 110.166.31.254110.166.31.2551,022
9110.166.32.0/22110.166.32.1 to 110.166.35.254110.166.35.2551,022
10110.166.36.0/22110.166.36.1 to 110.166.39.254110.166.39.2551,022
11110.166.40.0/22110.166.40.1 to 110.166.43.254110.166.43.2551,022
12110.166.44.0/22110.166.44.1 to 110.166.47.254110.166.47.2551,022
13110.166.48.0/22110.166.48.1 to 110.166.51.254110.166.51.2551,022
14110.166.52.0/22110.166.52.1 to 110.166.55.254110.166.55.2551,022
15110.166.56.0/22110.166.56.1 to 110.166.59.254110.166.59.2551,022
16110.166.60.0/22110.166.60.1 to 110.166.63.254110.166.63.2551,022
17110.166.64.0/22110.166.64.1 to 110.166.67.254110.166.67.2551,022
18110.166.68.0/22110.166.68.1 to 110.166.71.254110.166.71.2551,022
19110.166.72.0/22110.166.72.1 to 110.166.75.254110.166.75.2551,022
20110.166.76.0/22110.166.76.1 to 110.166.79.254110.166.79.2551,022
21110.166.80.0/22110.166.80.1 to 110.166.83.254110.166.83.2551,022
22110.166.84.0/22110.166.84.1 to 110.166.87.254110.166.87.2551,022
23110.166.88.0/22110.166.88.1 to 110.166.91.254110.166.91.2551,022
24110.166.92.0/22110.166.92.1 to 110.166.95.254110.166.95.2551,022
25110.166.96.0/22110.166.96.1 to 110.166.99.254110.166.99.2551,022
26110.166.100.0/22110.166.100.1 to 110.166.103.254110.166.103.2551,022
27110.166.104.0/22110.166.104.1 to 110.166.107.254110.166.107.2551,022
28110.166.108.0/22110.166.108.1 to 110.166.111.254110.166.111.2551,022
29110.166.112.0/22110.166.112.1 to 110.166.115.254110.166.115.2551,022
30110.166.116.0/22110.166.116.1 to 110.166.119.254110.166.119.2551,022
31110.166.120.0/22110.166.120.1 to 110.166.123.254110.166.123.2551,022
32110.166.124.0/22110.166.124.1 to 110.166.127.254110.166.127.2551,022
33110.166.128.0/22110.166.128.1 to 110.166.131.254110.166.131.2551,022
34110.166.132.0/22110.166.132.1 to 110.166.135.254110.166.135.2551,022
35110.166.136.0/22110.166.136.1 to 110.166.139.254110.166.139.2551,022
36110.166.140.0/22110.166.140.1 to 110.166.143.254110.166.143.2551,022
37110.166.144.0/22110.166.144.1 to 110.166.147.254110.166.147.2551,022
38110.166.148.0/22110.166.148.1 to 110.166.151.254110.166.151.2551,022
39110.166.152.0/22110.166.152.1 to 110.166.155.254110.166.155.2551,022
40110.166.156.0/22110.166.156.1 to 110.166.159.254110.166.159.2551,022
41110.166.160.0/22110.166.160.1 to 110.166.163.254110.166.163.2551,022
42110.166.164.0/22110.166.164.1 to 110.166.167.254110.166.167.2551,022
43110.166.168.0/22110.166.168.1 to 110.166.171.254110.166.171.2551,022
44110.166.172.0/22110.166.172.1 to 110.166.175.254110.166.175.2551,022
45110.166.176.0/22110.166.176.1 to 110.166.179.254110.166.179.2551,022
46110.166.180.0/22110.166.180.1 to 110.166.183.254110.166.183.2551,022
47110.166.184.0/22110.166.184.1 to 110.166.187.254110.166.187.2551,022
48110.166.188.0/22110.166.188.1 to 110.166.191.254110.166.191.2551,022
49110.166.192.0/22110.166.192.1 to 110.166.195.254110.166.195.2551,022
50110.166.196.0/22110.166.196.1 to 110.166.199.254110.166.199.2551,022
51110.166.200.0/22110.166.200.1 to 110.166.203.254110.166.203.2551,022
52110.166.204.0/22110.166.204.1 to 110.166.207.254110.166.207.2551,022
53110.166.208.0/22110.166.208.1 to 110.166.211.254110.166.211.2551,022
54110.166.212.0/22110.166.212.1 to 110.166.215.254110.166.215.2551,022
55110.166.216.0/22110.166.216.1 to 110.166.219.254110.166.219.2551,022
56110.166.220.0/22110.166.220.1 to 110.166.223.254110.166.223.2551,022
57110.166.224.0/22110.166.224.1 to 110.166.227.254110.166.227.2551,022
58110.166.228.0/22110.166.228.1 to 110.166.231.254110.166.231.2551,022
59110.166.232.0/22110.166.232.1 to 110.166.235.254110.166.235.2551,022
60110.166.236.0/22110.166.236.1 to 110.166.239.254110.166.239.2551,022
61110.166.240.0/22110.166.240.1 to 110.166.243.254110.166.243.2551,022
62110.166.244.0/22110.166.244.1 to 110.166.247.254110.166.247.2551,022
63110.166.248.0/22110.166.248.1 to 110.166.251.254110.166.251.2551,022
64110.166.252.0/22110.166.252.1 to 110.166.255.254110.166.255.2551,022
65110.167.0.0/22110.167.0.1 to 110.167.3.254110.167.3.2551,022
66110.167.4.0/22110.167.4.1 to 110.167.7.254110.167.7.2551,022
67110.167.8.0/22110.167.8.1 to 110.167.11.254110.167.11.2551,022
68110.167.12.0/22110.167.12.1 to 110.167.15.254110.167.15.2551,022
69110.167.16.0/22110.167.16.1 to 110.167.19.254110.167.19.2551,022
70110.167.20.0/22110.167.20.1 to 110.167.23.254110.167.23.2551,022
71110.167.24.0/22110.167.24.1 to 110.167.27.254110.167.27.2551,022
72110.167.28.0/22110.167.28.1 to 110.167.31.254110.167.31.2551,022
73110.167.32.0/22110.167.32.1 to 110.167.35.254110.167.35.2551,022
74110.167.36.0/22110.167.36.1 to 110.167.39.254110.167.39.2551,022
75110.167.40.0/22110.167.40.1 to 110.167.43.254110.167.43.2551,022
76110.167.44.0/22110.167.44.1 to 110.167.47.254110.167.47.2551,022
77110.167.48.0/22110.167.48.1 to 110.167.51.254110.167.51.2551,022
78110.167.52.0/22110.167.52.1 to 110.167.55.254110.167.55.2551,022
79110.167.56.0/22110.167.56.1 to 110.167.59.254110.167.59.2551,022
80110.167.60.0/22110.167.60.1 to 110.167.63.254110.167.63.2551,022
81110.167.64.0/22110.167.64.1 to 110.167.67.254110.167.67.2551,022
82110.167.68.0/22110.167.68.1 to 110.167.71.254110.167.71.2551,022
83110.167.72.0/22110.167.72.1 to 110.167.75.254110.167.75.2551,022
84110.167.76.0/22110.167.76.1 to 110.167.79.254110.167.79.2551,022
85110.167.80.0/22110.167.80.1 to 110.167.83.254110.167.83.2551,022
86110.167.84.0/22110.167.84.1 to 110.167.87.254110.167.87.2551,022
87110.167.88.0/22110.167.88.1 to 110.167.91.254110.167.91.2551,022
88110.167.92.0/22110.167.92.1 to 110.167.95.254110.167.95.2551,022
89110.167.96.0/22110.167.96.1 to 110.167.99.254110.167.99.2551,022
90110.167.100.0/22110.167.100.1 to 110.167.103.254110.167.103.2551,022
91110.167.104.0/22110.167.104.1 to 110.167.107.254110.167.107.2551,022
92110.167.108.0/22110.167.108.1 to 110.167.111.254110.167.111.2551,022
93110.167.112.0/22110.167.112.1 to 110.167.115.254110.167.115.2551,022
94110.167.116.0/22110.167.116.1 to 110.167.119.254110.167.119.2551,022
95110.167.120.0/22110.167.120.1 to 110.167.123.254110.167.123.2551,022
96110.167.124.0/22110.167.124.1 to 110.167.127.254110.167.127.2551,022
97110.167.128.0/22110.167.128.1 to 110.167.131.254110.167.131.2551,022
98110.167.132.0/22110.167.132.1 to 110.167.135.254110.167.135.2551,022
99110.167.136.0/22110.167.136.1 to 110.167.139.254110.167.139.2551,022
100110.167.140.0/22110.167.140.1 to 110.167.143.254110.167.143.2551,022
101110.167.144.0/22110.167.144.1 to 110.167.147.254110.167.147.2551,022
102110.167.148.0/22110.167.148.1 to 110.167.151.254110.167.151.2551,022
103110.167.152.0/22110.167.152.1 to 110.167.155.254110.167.155.2551,022
104110.167.156.0/22110.167.156.1 to 110.167.159.254110.167.159.2551,022
105110.167.160.0/22110.167.160.1 to 110.167.163.254110.167.163.2551,022
106110.167.164.0/22110.167.164.1 to 110.167.167.254110.167.167.2551,022
107110.167.168.0/22110.167.168.1 to 110.167.171.254110.167.171.2551,022
108110.167.172.0/22110.167.172.1 to 110.167.175.254110.167.175.2551,022
109110.167.176.0/22110.167.176.1 to 110.167.179.254110.167.179.2551,022
110110.167.180.0/22110.167.180.1 to 110.167.183.254110.167.183.2551,022
111110.167.184.0/22110.167.184.1 to 110.167.187.254110.167.187.2551,022
112110.167.188.0/22110.167.188.1 to 110.167.191.254110.167.191.2551,022
113110.167.192.0/22110.167.192.1 to 110.167.195.254110.167.195.2551,022
114110.167.196.0/22110.167.196.1 to 110.167.199.254110.167.199.2551,022
115110.167.200.0/22110.167.200.1 to 110.167.203.254110.167.203.2551,022
116110.167.204.0/22110.167.204.1 to 110.167.207.254110.167.207.2551,022
117110.167.208.0/22110.167.208.1 to 110.167.211.254110.167.211.2551,022
118110.167.212.0/22110.167.212.1 to 110.167.215.254110.167.215.2551,022
119110.167.216.0/22110.167.216.1 to 110.167.219.254110.167.219.2551,022
120110.167.220.0/22110.167.220.1 to 110.167.223.254110.167.223.2551,022
121110.167.224.0/22110.167.224.1 to 110.167.227.254110.167.227.2551,022
122110.167.228.0/22110.167.228.1 to 110.167.231.254110.167.231.2551,022
123110.167.232.0/22110.167.232.1 to 110.167.235.254110.167.235.2551,022
124110.167.236.0/22110.167.236.1 to 110.167.239.254110.167.239.2551,022
125110.167.240.0/22110.167.240.1 to 110.167.243.254110.167.243.2551,022
126110.167.244.0/22110.167.244.1 to 110.167.247.254110.167.247.2551,022
127110.167.248.0/22110.167.248.1 to 110.167.251.254110.167.251.2551,022
128110.167.252.0/22110.167.252.1 to 110.167.255.254110.167.255.2551,022

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.