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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.

Network226.2.192.0/18
Usable hosts16,382
Subnet mask255.255.192.0
Addresses16,384
Network address
226.2.192.0
Broadcast address
226.2.255.255
First usable
226.2.192.1
Last usable
226.2.255.254
Usable hosts
16,382 (16,384 less the network and broadcast addresses)
Subnet mask
255.255.192.0
Wildcard mask
0.0.63.255 (Cisco ACLs, OSPF)
Prefix length
/18
Type
Multicast 224.0.0.0/4
One-to-many traffic, such as IPTV and routing protocols
Old class
D (multicast)
As numbers
Hex E202C000 · Integer 3791831040 to 3791847423
Reverse DNS zones
192.2.226.in-addr.arpa
193.2.226.in-addr.arpa
194.2.226.in-addr.arpa
195.2.226.in-addr.arpa
196.2.226.in-addr.arpa
197.2.226.in-addr.arpa
198.2.226.in-addr.arpa
199.2.226.in-addr.arpa
200.2.226.in-addr.arpa
201.2.226.in-addr.arpa
202.2.226.in-addr.arpa
203.2.226.in-addr.arpa
204.2.226.in-addr.arpa
205.2.226.in-addr.arpa
206.2.226.in-addr.arpa
207.2.226.in-addr.arpa
and 48 more
/18 is not on a 8-bit boundary, so it takes 64 /24 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address11100010.00000010.11000000.00000000226.2.192.0
Subnet mask11111111.11111111.11000000.00000000255.255.192.0
Network11100010.00000010.11000000.00000000226.2.192.0
Broadcast11100010.00000010.11111111.11111111226.2.255.255
Split into smaller subnets/25
/19 (2)/20 (4)/21 (8)/22 (16)/23 (32)/24 (64)/25 (128)/26 (256)/27 (512)/28 (1,024)/29 (2,048)/30 (4,096)

226.2.192.0/18 makes 128 subnets of /25.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1226.2.192.0/25226.2.192.1 to 226.2.192.126226.2.192.127126
2226.2.192.128/25226.2.192.129 to 226.2.192.254226.2.192.255126
3226.2.193.0/25226.2.193.1 to 226.2.193.126226.2.193.127126
4226.2.193.128/25226.2.193.129 to 226.2.193.254226.2.193.255126
5226.2.194.0/25226.2.194.1 to 226.2.194.126226.2.194.127126
6226.2.194.128/25226.2.194.129 to 226.2.194.254226.2.194.255126
7226.2.195.0/25226.2.195.1 to 226.2.195.126226.2.195.127126
8226.2.195.128/25226.2.195.129 to 226.2.195.254226.2.195.255126
9226.2.196.0/25226.2.196.1 to 226.2.196.126226.2.196.127126
10226.2.196.128/25226.2.196.129 to 226.2.196.254226.2.196.255126
11226.2.197.0/25226.2.197.1 to 226.2.197.126226.2.197.127126
12226.2.197.128/25226.2.197.129 to 226.2.197.254226.2.197.255126
13226.2.198.0/25226.2.198.1 to 226.2.198.126226.2.198.127126
14226.2.198.128/25226.2.198.129 to 226.2.198.254226.2.198.255126
15226.2.199.0/25226.2.199.1 to 226.2.199.126226.2.199.127126
16226.2.199.128/25226.2.199.129 to 226.2.199.254226.2.199.255126
17226.2.200.0/25226.2.200.1 to 226.2.200.126226.2.200.127126
18226.2.200.128/25226.2.200.129 to 226.2.200.254226.2.200.255126
19226.2.201.0/25226.2.201.1 to 226.2.201.126226.2.201.127126
20226.2.201.128/25226.2.201.129 to 226.2.201.254226.2.201.255126
21226.2.202.0/25226.2.202.1 to 226.2.202.126226.2.202.127126
22226.2.202.128/25226.2.202.129 to 226.2.202.254226.2.202.255126
23226.2.203.0/25226.2.203.1 to 226.2.203.126226.2.203.127126
24226.2.203.128/25226.2.203.129 to 226.2.203.254226.2.203.255126
25226.2.204.0/25226.2.204.1 to 226.2.204.126226.2.204.127126
26226.2.204.128/25226.2.204.129 to 226.2.204.254226.2.204.255126
27226.2.205.0/25226.2.205.1 to 226.2.205.126226.2.205.127126
28226.2.205.128/25226.2.205.129 to 226.2.205.254226.2.205.255126
29226.2.206.0/25226.2.206.1 to 226.2.206.126226.2.206.127126
30226.2.206.128/25226.2.206.129 to 226.2.206.254226.2.206.255126
31226.2.207.0/25226.2.207.1 to 226.2.207.126226.2.207.127126
32226.2.207.128/25226.2.207.129 to 226.2.207.254226.2.207.255126
33226.2.208.0/25226.2.208.1 to 226.2.208.126226.2.208.127126
34226.2.208.128/25226.2.208.129 to 226.2.208.254226.2.208.255126
35226.2.209.0/25226.2.209.1 to 226.2.209.126226.2.209.127126
36226.2.209.128/25226.2.209.129 to 226.2.209.254226.2.209.255126
37226.2.210.0/25226.2.210.1 to 226.2.210.126226.2.210.127126
38226.2.210.128/25226.2.210.129 to 226.2.210.254226.2.210.255126
39226.2.211.0/25226.2.211.1 to 226.2.211.126226.2.211.127126
40226.2.211.128/25226.2.211.129 to 226.2.211.254226.2.211.255126
41226.2.212.0/25226.2.212.1 to 226.2.212.126226.2.212.127126
42226.2.212.128/25226.2.212.129 to 226.2.212.254226.2.212.255126
43226.2.213.0/25226.2.213.1 to 226.2.213.126226.2.213.127126
44226.2.213.128/25226.2.213.129 to 226.2.213.254226.2.213.255126
45226.2.214.0/25226.2.214.1 to 226.2.214.126226.2.214.127126
46226.2.214.128/25226.2.214.129 to 226.2.214.254226.2.214.255126
47226.2.215.0/25226.2.215.1 to 226.2.215.126226.2.215.127126
48226.2.215.128/25226.2.215.129 to 226.2.215.254226.2.215.255126
49226.2.216.0/25226.2.216.1 to 226.2.216.126226.2.216.127126
50226.2.216.128/25226.2.216.129 to 226.2.216.254226.2.216.255126
51226.2.217.0/25226.2.217.1 to 226.2.217.126226.2.217.127126
52226.2.217.128/25226.2.217.129 to 226.2.217.254226.2.217.255126
53226.2.218.0/25226.2.218.1 to 226.2.218.126226.2.218.127126
54226.2.218.128/25226.2.218.129 to 226.2.218.254226.2.218.255126
55226.2.219.0/25226.2.219.1 to 226.2.219.126226.2.219.127126
56226.2.219.128/25226.2.219.129 to 226.2.219.254226.2.219.255126
57226.2.220.0/25226.2.220.1 to 226.2.220.126226.2.220.127126
58226.2.220.128/25226.2.220.129 to 226.2.220.254226.2.220.255126
59226.2.221.0/25226.2.221.1 to 226.2.221.126226.2.221.127126
60226.2.221.128/25226.2.221.129 to 226.2.221.254226.2.221.255126
61226.2.222.0/25226.2.222.1 to 226.2.222.126226.2.222.127126
62226.2.222.128/25226.2.222.129 to 226.2.222.254226.2.222.255126
63226.2.223.0/25226.2.223.1 to 226.2.223.126226.2.223.127126
64226.2.223.128/25226.2.223.129 to 226.2.223.254226.2.223.255126
65226.2.224.0/25226.2.224.1 to 226.2.224.126226.2.224.127126
66226.2.224.128/25226.2.224.129 to 226.2.224.254226.2.224.255126
67226.2.225.0/25226.2.225.1 to 226.2.225.126226.2.225.127126
68226.2.225.128/25226.2.225.129 to 226.2.225.254226.2.225.255126
69226.2.226.0/25226.2.226.1 to 226.2.226.126226.2.226.127126
70226.2.226.128/25226.2.226.129 to 226.2.226.254226.2.226.255126
71226.2.227.0/25226.2.227.1 to 226.2.227.126226.2.227.127126
72226.2.227.128/25226.2.227.129 to 226.2.227.254226.2.227.255126
73226.2.228.0/25226.2.228.1 to 226.2.228.126226.2.228.127126
74226.2.228.128/25226.2.228.129 to 226.2.228.254226.2.228.255126
75226.2.229.0/25226.2.229.1 to 226.2.229.126226.2.229.127126
76226.2.229.128/25226.2.229.129 to 226.2.229.254226.2.229.255126
77226.2.230.0/25226.2.230.1 to 226.2.230.126226.2.230.127126
78226.2.230.128/25226.2.230.129 to 226.2.230.254226.2.230.255126
79226.2.231.0/25226.2.231.1 to 226.2.231.126226.2.231.127126
80226.2.231.128/25226.2.231.129 to 226.2.231.254226.2.231.255126
81226.2.232.0/25226.2.232.1 to 226.2.232.126226.2.232.127126
82226.2.232.128/25226.2.232.129 to 226.2.232.254226.2.232.255126
83226.2.233.0/25226.2.233.1 to 226.2.233.126226.2.233.127126
84226.2.233.128/25226.2.233.129 to 226.2.233.254226.2.233.255126
85226.2.234.0/25226.2.234.1 to 226.2.234.126226.2.234.127126
86226.2.234.128/25226.2.234.129 to 226.2.234.254226.2.234.255126
87226.2.235.0/25226.2.235.1 to 226.2.235.126226.2.235.127126
88226.2.235.128/25226.2.235.129 to 226.2.235.254226.2.235.255126
89226.2.236.0/25226.2.236.1 to 226.2.236.126226.2.236.127126
90226.2.236.128/25226.2.236.129 to 226.2.236.254226.2.236.255126
91226.2.237.0/25226.2.237.1 to 226.2.237.126226.2.237.127126
92226.2.237.128/25226.2.237.129 to 226.2.237.254226.2.237.255126
93226.2.238.0/25226.2.238.1 to 226.2.238.126226.2.238.127126
94226.2.238.128/25226.2.238.129 to 226.2.238.254226.2.238.255126
95226.2.239.0/25226.2.239.1 to 226.2.239.126226.2.239.127126
96226.2.239.128/25226.2.239.129 to 226.2.239.254226.2.239.255126
97226.2.240.0/25226.2.240.1 to 226.2.240.126226.2.240.127126
98226.2.240.128/25226.2.240.129 to 226.2.240.254226.2.240.255126
99226.2.241.0/25226.2.241.1 to 226.2.241.126226.2.241.127126
100226.2.241.128/25226.2.241.129 to 226.2.241.254226.2.241.255126
101226.2.242.0/25226.2.242.1 to 226.2.242.126226.2.242.127126
102226.2.242.128/25226.2.242.129 to 226.2.242.254226.2.242.255126
103226.2.243.0/25226.2.243.1 to 226.2.243.126226.2.243.127126
104226.2.243.128/25226.2.243.129 to 226.2.243.254226.2.243.255126
105226.2.244.0/25226.2.244.1 to 226.2.244.126226.2.244.127126
106226.2.244.128/25226.2.244.129 to 226.2.244.254226.2.244.255126
107226.2.245.0/25226.2.245.1 to 226.2.245.126226.2.245.127126
108226.2.245.128/25226.2.245.129 to 226.2.245.254226.2.245.255126
109226.2.246.0/25226.2.246.1 to 226.2.246.126226.2.246.127126
110226.2.246.128/25226.2.246.129 to 226.2.246.254226.2.246.255126
111226.2.247.0/25226.2.247.1 to 226.2.247.126226.2.247.127126
112226.2.247.128/25226.2.247.129 to 226.2.247.254226.2.247.255126
113226.2.248.0/25226.2.248.1 to 226.2.248.126226.2.248.127126
114226.2.248.128/25226.2.248.129 to 226.2.248.254226.2.248.255126
115226.2.249.0/25226.2.249.1 to 226.2.249.126226.2.249.127126
116226.2.249.128/25226.2.249.129 to 226.2.249.254226.2.249.255126
117226.2.250.0/25226.2.250.1 to 226.2.250.126226.2.250.127126
118226.2.250.128/25226.2.250.129 to 226.2.250.254226.2.250.255126
119226.2.251.0/25226.2.251.1 to 226.2.251.126226.2.251.127126
120226.2.251.128/25226.2.251.129 to 226.2.251.254226.2.251.255126
121226.2.252.0/25226.2.252.1 to 226.2.252.126226.2.252.127126
122226.2.252.128/25226.2.252.129 to 226.2.252.254226.2.252.255126
123226.2.253.0/25226.2.253.1 to 226.2.253.126226.2.253.127126
124226.2.253.128/25226.2.253.129 to 226.2.253.254226.2.253.255126
125226.2.254.0/25226.2.254.1 to 226.2.254.126226.2.254.127126
126226.2.254.128/25226.2.254.129 to 226.2.254.254226.2.254.255126
127226.2.255.0/25226.2.255.1 to 226.2.255.126226.2.255.127126
128226.2.255.128/25226.2.255.129 to 226.2.255.254226.2.255.255126

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.