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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.

Network227.232.0.0/13
Usable hosts524,286
Subnet mask255.248.0.0
Addresses524,288
Network address
227.232.0.0
Broadcast address
227.239.255.255
First usable
227.232.0.1
Last usable
227.239.255.254
Usable hosts
524,286 (524,288 less the network and broadcast addresses)
Subnet mask
255.248.0.0
Wildcard mask
0.7.255.255 (Cisco ACLs, OSPF)
Prefix length
/13
Type
Multicast 224.0.0.0/4
One-to-many traffic, such as IPTV and routing protocols
Old class
D (multicast)
As numbers
Hex E3E80000 · Integer 3823632384 to 3824156671
Reverse DNS zones
232.227.in-addr.arpa
233.227.in-addr.arpa
234.227.in-addr.arpa
235.227.in-addr.arpa
236.227.in-addr.arpa
237.227.in-addr.arpa
238.227.in-addr.arpa
239.227.in-addr.arpa
/13 is not on a 8-bit boundary, so it takes 8 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address11100011.11101000.00000000.00000000227.232.0.0
Subnet mask11111111.11111000.00000000.00000000255.248.0.0
Network11100011.11101000.00000000.00000000227.232.0.0
Broadcast11100011.11101111.11111111.11111111227.239.255.255
Split into smaller subnets/20
/14 (2)/15 (4)/16 (8)/17 (16)/18 (32)/19 (64)/20 (128)/21 (256)/22 (512)/23 (1,024)/24 (2,048)/25 (4,096)

227.232.0.0/13 makes 128 subnets of /20.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1227.232.0.0/20227.232.0.1 to 227.232.15.254227.232.15.2554,094
2227.232.16.0/20227.232.16.1 to 227.232.31.254227.232.31.2554,094
3227.232.32.0/20227.232.32.1 to 227.232.47.254227.232.47.2554,094
4227.232.48.0/20227.232.48.1 to 227.232.63.254227.232.63.2554,094
5227.232.64.0/20227.232.64.1 to 227.232.79.254227.232.79.2554,094
6227.232.80.0/20227.232.80.1 to 227.232.95.254227.232.95.2554,094
7227.232.96.0/20227.232.96.1 to 227.232.111.254227.232.111.2554,094
8227.232.112.0/20227.232.112.1 to 227.232.127.254227.232.127.2554,094
9227.232.128.0/20227.232.128.1 to 227.232.143.254227.232.143.2554,094
10227.232.144.0/20227.232.144.1 to 227.232.159.254227.232.159.2554,094
11227.232.160.0/20227.232.160.1 to 227.232.175.254227.232.175.2554,094
12227.232.176.0/20227.232.176.1 to 227.232.191.254227.232.191.2554,094
13227.232.192.0/20227.232.192.1 to 227.232.207.254227.232.207.2554,094
14227.232.208.0/20227.232.208.1 to 227.232.223.254227.232.223.2554,094
15227.232.224.0/20227.232.224.1 to 227.232.239.254227.232.239.2554,094
16227.232.240.0/20227.232.240.1 to 227.232.255.254227.232.255.2554,094
17227.233.0.0/20227.233.0.1 to 227.233.15.254227.233.15.2554,094
18227.233.16.0/20227.233.16.1 to 227.233.31.254227.233.31.2554,094
19227.233.32.0/20227.233.32.1 to 227.233.47.254227.233.47.2554,094
20227.233.48.0/20227.233.48.1 to 227.233.63.254227.233.63.2554,094
21227.233.64.0/20227.233.64.1 to 227.233.79.254227.233.79.2554,094
22227.233.80.0/20227.233.80.1 to 227.233.95.254227.233.95.2554,094
23227.233.96.0/20227.233.96.1 to 227.233.111.254227.233.111.2554,094
24227.233.112.0/20227.233.112.1 to 227.233.127.254227.233.127.2554,094
25227.233.128.0/20227.233.128.1 to 227.233.143.254227.233.143.2554,094
26227.233.144.0/20227.233.144.1 to 227.233.159.254227.233.159.2554,094
27227.233.160.0/20227.233.160.1 to 227.233.175.254227.233.175.2554,094
28227.233.176.0/20227.233.176.1 to 227.233.191.254227.233.191.2554,094
29227.233.192.0/20227.233.192.1 to 227.233.207.254227.233.207.2554,094
30227.233.208.0/20227.233.208.1 to 227.233.223.254227.233.223.2554,094
31227.233.224.0/20227.233.224.1 to 227.233.239.254227.233.239.2554,094
32227.233.240.0/20227.233.240.1 to 227.233.255.254227.233.255.2554,094
33227.234.0.0/20227.234.0.1 to 227.234.15.254227.234.15.2554,094
34227.234.16.0/20227.234.16.1 to 227.234.31.254227.234.31.2554,094
35227.234.32.0/20227.234.32.1 to 227.234.47.254227.234.47.2554,094
36227.234.48.0/20227.234.48.1 to 227.234.63.254227.234.63.2554,094
37227.234.64.0/20227.234.64.1 to 227.234.79.254227.234.79.2554,094
38227.234.80.0/20227.234.80.1 to 227.234.95.254227.234.95.2554,094
39227.234.96.0/20227.234.96.1 to 227.234.111.254227.234.111.2554,094
40227.234.112.0/20227.234.112.1 to 227.234.127.254227.234.127.2554,094
41227.234.128.0/20227.234.128.1 to 227.234.143.254227.234.143.2554,094
42227.234.144.0/20227.234.144.1 to 227.234.159.254227.234.159.2554,094
43227.234.160.0/20227.234.160.1 to 227.234.175.254227.234.175.2554,094
44227.234.176.0/20227.234.176.1 to 227.234.191.254227.234.191.2554,094
45227.234.192.0/20227.234.192.1 to 227.234.207.254227.234.207.2554,094
46227.234.208.0/20227.234.208.1 to 227.234.223.254227.234.223.2554,094
47227.234.224.0/20227.234.224.1 to 227.234.239.254227.234.239.2554,094
48227.234.240.0/20227.234.240.1 to 227.234.255.254227.234.255.2554,094
49227.235.0.0/20227.235.0.1 to 227.235.15.254227.235.15.2554,094
50227.235.16.0/20227.235.16.1 to 227.235.31.254227.235.31.2554,094
51227.235.32.0/20227.235.32.1 to 227.235.47.254227.235.47.2554,094
52227.235.48.0/20227.235.48.1 to 227.235.63.254227.235.63.2554,094
53227.235.64.0/20227.235.64.1 to 227.235.79.254227.235.79.2554,094
54227.235.80.0/20227.235.80.1 to 227.235.95.254227.235.95.2554,094
55227.235.96.0/20227.235.96.1 to 227.235.111.254227.235.111.2554,094
56227.235.112.0/20227.235.112.1 to 227.235.127.254227.235.127.2554,094
57227.235.128.0/20227.235.128.1 to 227.235.143.254227.235.143.2554,094
58227.235.144.0/20227.235.144.1 to 227.235.159.254227.235.159.2554,094
59227.235.160.0/20227.235.160.1 to 227.235.175.254227.235.175.2554,094
60227.235.176.0/20227.235.176.1 to 227.235.191.254227.235.191.2554,094
61227.235.192.0/20227.235.192.1 to 227.235.207.254227.235.207.2554,094
62227.235.208.0/20227.235.208.1 to 227.235.223.254227.235.223.2554,094
63227.235.224.0/20227.235.224.1 to 227.235.239.254227.235.239.2554,094
64227.235.240.0/20227.235.240.1 to 227.235.255.254227.235.255.2554,094
65227.236.0.0/20227.236.0.1 to 227.236.15.254227.236.15.2554,094
66227.236.16.0/20227.236.16.1 to 227.236.31.254227.236.31.2554,094
67227.236.32.0/20227.236.32.1 to 227.236.47.254227.236.47.2554,094
68227.236.48.0/20227.236.48.1 to 227.236.63.254227.236.63.2554,094
69227.236.64.0/20227.236.64.1 to 227.236.79.254227.236.79.2554,094
70227.236.80.0/20227.236.80.1 to 227.236.95.254227.236.95.2554,094
71227.236.96.0/20227.236.96.1 to 227.236.111.254227.236.111.2554,094
72227.236.112.0/20227.236.112.1 to 227.236.127.254227.236.127.2554,094
73227.236.128.0/20227.236.128.1 to 227.236.143.254227.236.143.2554,094
74227.236.144.0/20227.236.144.1 to 227.236.159.254227.236.159.2554,094
75227.236.160.0/20227.236.160.1 to 227.236.175.254227.236.175.2554,094
76227.236.176.0/20227.236.176.1 to 227.236.191.254227.236.191.2554,094
77227.236.192.0/20227.236.192.1 to 227.236.207.254227.236.207.2554,094
78227.236.208.0/20227.236.208.1 to 227.236.223.254227.236.223.2554,094
79227.236.224.0/20227.236.224.1 to 227.236.239.254227.236.239.2554,094
80227.236.240.0/20227.236.240.1 to 227.236.255.254227.236.255.2554,094
81227.237.0.0/20227.237.0.1 to 227.237.15.254227.237.15.2554,094
82227.237.16.0/20227.237.16.1 to 227.237.31.254227.237.31.2554,094
83227.237.32.0/20227.237.32.1 to 227.237.47.254227.237.47.2554,094
84227.237.48.0/20227.237.48.1 to 227.237.63.254227.237.63.2554,094
85227.237.64.0/20227.237.64.1 to 227.237.79.254227.237.79.2554,094
86227.237.80.0/20227.237.80.1 to 227.237.95.254227.237.95.2554,094
87227.237.96.0/20227.237.96.1 to 227.237.111.254227.237.111.2554,094
88227.237.112.0/20227.237.112.1 to 227.237.127.254227.237.127.2554,094
89227.237.128.0/20227.237.128.1 to 227.237.143.254227.237.143.2554,094
90227.237.144.0/20227.237.144.1 to 227.237.159.254227.237.159.2554,094
91227.237.160.0/20227.237.160.1 to 227.237.175.254227.237.175.2554,094
92227.237.176.0/20227.237.176.1 to 227.237.191.254227.237.191.2554,094
93227.237.192.0/20227.237.192.1 to 227.237.207.254227.237.207.2554,094
94227.237.208.0/20227.237.208.1 to 227.237.223.254227.237.223.2554,094
95227.237.224.0/20227.237.224.1 to 227.237.239.254227.237.239.2554,094
96227.237.240.0/20227.237.240.1 to 227.237.255.254227.237.255.2554,094
97227.238.0.0/20227.238.0.1 to 227.238.15.254227.238.15.2554,094
98227.238.16.0/20227.238.16.1 to 227.238.31.254227.238.31.2554,094
99227.238.32.0/20227.238.32.1 to 227.238.47.254227.238.47.2554,094
100227.238.48.0/20227.238.48.1 to 227.238.63.254227.238.63.2554,094
101227.238.64.0/20227.238.64.1 to 227.238.79.254227.238.79.2554,094
102227.238.80.0/20227.238.80.1 to 227.238.95.254227.238.95.2554,094
103227.238.96.0/20227.238.96.1 to 227.238.111.254227.238.111.2554,094
104227.238.112.0/20227.238.112.1 to 227.238.127.254227.238.127.2554,094
105227.238.128.0/20227.238.128.1 to 227.238.143.254227.238.143.2554,094
106227.238.144.0/20227.238.144.1 to 227.238.159.254227.238.159.2554,094
107227.238.160.0/20227.238.160.1 to 227.238.175.254227.238.175.2554,094
108227.238.176.0/20227.238.176.1 to 227.238.191.254227.238.191.2554,094
109227.238.192.0/20227.238.192.1 to 227.238.207.254227.238.207.2554,094
110227.238.208.0/20227.238.208.1 to 227.238.223.254227.238.223.2554,094
111227.238.224.0/20227.238.224.1 to 227.238.239.254227.238.239.2554,094
112227.238.240.0/20227.238.240.1 to 227.238.255.254227.238.255.2554,094
113227.239.0.0/20227.239.0.1 to 227.239.15.254227.239.15.2554,094
114227.239.16.0/20227.239.16.1 to 227.239.31.254227.239.31.2554,094
115227.239.32.0/20227.239.32.1 to 227.239.47.254227.239.47.2554,094
116227.239.48.0/20227.239.48.1 to 227.239.63.254227.239.63.2554,094
117227.239.64.0/20227.239.64.1 to 227.239.79.254227.239.79.2554,094
118227.239.80.0/20227.239.80.1 to 227.239.95.254227.239.95.2554,094
119227.239.96.0/20227.239.96.1 to 227.239.111.254227.239.111.2554,094
120227.239.112.0/20227.239.112.1 to 227.239.127.254227.239.127.2554,094
121227.239.128.0/20227.239.128.1 to 227.239.143.254227.239.143.2554,094
122227.239.144.0/20227.239.144.1 to 227.239.159.254227.239.159.2554,094
123227.239.160.0/20227.239.160.1 to 227.239.175.254227.239.175.2554,094
124227.239.176.0/20227.239.176.1 to 227.239.191.254227.239.191.2554,094
125227.239.192.0/20227.239.192.1 to 227.239.207.254227.239.207.2554,094
126227.239.208.0/20227.239.208.1 to 227.239.223.254227.239.223.2554,094
127227.239.224.0/20227.239.224.1 to 227.239.239.254227.239.239.2554,094
128227.239.240.0/20227.239.240.1 to 227.239.255.254227.239.255.2554,094

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.