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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.

Network229.136.0.0/15
Usable hosts131,070
Subnet mask255.254.0.0
Addresses131,072
Network address
229.136.0.0
Broadcast address
229.137.255.255
First usable
229.136.0.1
Last usable
229.137.255.254
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
Multicast 224.0.0.0/4
One-to-many traffic, such as IPTV and routing protocols
Old class
D (multicast)
As numbers
Hex E5880000 · Integer 3850895360 to 3851026431
Reverse DNS zones
136.229.in-addr.arpa
137.229.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
Address11100101.10001000.00000000.00000000229.136.0.0
Subnet mask11111111.11111110.00000000.00000000255.254.0.0
Network11100101.10001000.00000000.00000000229.136.0.0
Broadcast11100101.10001001.11111111.11111111229.137.255.255
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)

229.136.0.0/15 makes 128 subnets of /22.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1229.136.0.0/22229.136.0.1 to 229.136.3.254229.136.3.2551,022
2229.136.4.0/22229.136.4.1 to 229.136.7.254229.136.7.2551,022
3229.136.8.0/22229.136.8.1 to 229.136.11.254229.136.11.2551,022
4229.136.12.0/22229.136.12.1 to 229.136.15.254229.136.15.2551,022
5229.136.16.0/22229.136.16.1 to 229.136.19.254229.136.19.2551,022
6229.136.20.0/22229.136.20.1 to 229.136.23.254229.136.23.2551,022
7229.136.24.0/22229.136.24.1 to 229.136.27.254229.136.27.2551,022
8229.136.28.0/22229.136.28.1 to 229.136.31.254229.136.31.2551,022
9229.136.32.0/22229.136.32.1 to 229.136.35.254229.136.35.2551,022
10229.136.36.0/22229.136.36.1 to 229.136.39.254229.136.39.2551,022
11229.136.40.0/22229.136.40.1 to 229.136.43.254229.136.43.2551,022
12229.136.44.0/22229.136.44.1 to 229.136.47.254229.136.47.2551,022
13229.136.48.0/22229.136.48.1 to 229.136.51.254229.136.51.2551,022
14229.136.52.0/22229.136.52.1 to 229.136.55.254229.136.55.2551,022
15229.136.56.0/22229.136.56.1 to 229.136.59.254229.136.59.2551,022
16229.136.60.0/22229.136.60.1 to 229.136.63.254229.136.63.2551,022
17229.136.64.0/22229.136.64.1 to 229.136.67.254229.136.67.2551,022
18229.136.68.0/22229.136.68.1 to 229.136.71.254229.136.71.2551,022
19229.136.72.0/22229.136.72.1 to 229.136.75.254229.136.75.2551,022
20229.136.76.0/22229.136.76.1 to 229.136.79.254229.136.79.2551,022
21229.136.80.0/22229.136.80.1 to 229.136.83.254229.136.83.2551,022
22229.136.84.0/22229.136.84.1 to 229.136.87.254229.136.87.2551,022
23229.136.88.0/22229.136.88.1 to 229.136.91.254229.136.91.2551,022
24229.136.92.0/22229.136.92.1 to 229.136.95.254229.136.95.2551,022
25229.136.96.0/22229.136.96.1 to 229.136.99.254229.136.99.2551,022
26229.136.100.0/22229.136.100.1 to 229.136.103.254229.136.103.2551,022
27229.136.104.0/22229.136.104.1 to 229.136.107.254229.136.107.2551,022
28229.136.108.0/22229.136.108.1 to 229.136.111.254229.136.111.2551,022
29229.136.112.0/22229.136.112.1 to 229.136.115.254229.136.115.2551,022
30229.136.116.0/22229.136.116.1 to 229.136.119.254229.136.119.2551,022
31229.136.120.0/22229.136.120.1 to 229.136.123.254229.136.123.2551,022
32229.136.124.0/22229.136.124.1 to 229.136.127.254229.136.127.2551,022
33229.136.128.0/22229.136.128.1 to 229.136.131.254229.136.131.2551,022
34229.136.132.0/22229.136.132.1 to 229.136.135.254229.136.135.2551,022
35229.136.136.0/22229.136.136.1 to 229.136.139.254229.136.139.2551,022
36229.136.140.0/22229.136.140.1 to 229.136.143.254229.136.143.2551,022
37229.136.144.0/22229.136.144.1 to 229.136.147.254229.136.147.2551,022
38229.136.148.0/22229.136.148.1 to 229.136.151.254229.136.151.2551,022
39229.136.152.0/22229.136.152.1 to 229.136.155.254229.136.155.2551,022
40229.136.156.0/22229.136.156.1 to 229.136.159.254229.136.159.2551,022
41229.136.160.0/22229.136.160.1 to 229.136.163.254229.136.163.2551,022
42229.136.164.0/22229.136.164.1 to 229.136.167.254229.136.167.2551,022
43229.136.168.0/22229.136.168.1 to 229.136.171.254229.136.171.2551,022
44229.136.172.0/22229.136.172.1 to 229.136.175.254229.136.175.2551,022
45229.136.176.0/22229.136.176.1 to 229.136.179.254229.136.179.2551,022
46229.136.180.0/22229.136.180.1 to 229.136.183.254229.136.183.2551,022
47229.136.184.0/22229.136.184.1 to 229.136.187.254229.136.187.2551,022
48229.136.188.0/22229.136.188.1 to 229.136.191.254229.136.191.2551,022
49229.136.192.0/22229.136.192.1 to 229.136.195.254229.136.195.2551,022
50229.136.196.0/22229.136.196.1 to 229.136.199.254229.136.199.2551,022
51229.136.200.0/22229.136.200.1 to 229.136.203.254229.136.203.2551,022
52229.136.204.0/22229.136.204.1 to 229.136.207.254229.136.207.2551,022
53229.136.208.0/22229.136.208.1 to 229.136.211.254229.136.211.2551,022
54229.136.212.0/22229.136.212.1 to 229.136.215.254229.136.215.2551,022
55229.136.216.0/22229.136.216.1 to 229.136.219.254229.136.219.2551,022
56229.136.220.0/22229.136.220.1 to 229.136.223.254229.136.223.2551,022
57229.136.224.0/22229.136.224.1 to 229.136.227.254229.136.227.2551,022
58229.136.228.0/22229.136.228.1 to 229.136.231.254229.136.231.2551,022
59229.136.232.0/22229.136.232.1 to 229.136.235.254229.136.235.2551,022
60229.136.236.0/22229.136.236.1 to 229.136.239.254229.136.239.2551,022
61229.136.240.0/22229.136.240.1 to 229.136.243.254229.136.243.2551,022
62229.136.244.0/22229.136.244.1 to 229.136.247.254229.136.247.2551,022
63229.136.248.0/22229.136.248.1 to 229.136.251.254229.136.251.2551,022
64229.136.252.0/22229.136.252.1 to 229.136.255.254229.136.255.2551,022
65229.137.0.0/22229.137.0.1 to 229.137.3.254229.137.3.2551,022
66229.137.4.0/22229.137.4.1 to 229.137.7.254229.137.7.2551,022
67229.137.8.0/22229.137.8.1 to 229.137.11.254229.137.11.2551,022
68229.137.12.0/22229.137.12.1 to 229.137.15.254229.137.15.2551,022
69229.137.16.0/22229.137.16.1 to 229.137.19.254229.137.19.2551,022
70229.137.20.0/22229.137.20.1 to 229.137.23.254229.137.23.2551,022
71229.137.24.0/22229.137.24.1 to 229.137.27.254229.137.27.2551,022
72229.137.28.0/22229.137.28.1 to 229.137.31.254229.137.31.2551,022
73229.137.32.0/22229.137.32.1 to 229.137.35.254229.137.35.2551,022
74229.137.36.0/22229.137.36.1 to 229.137.39.254229.137.39.2551,022
75229.137.40.0/22229.137.40.1 to 229.137.43.254229.137.43.2551,022
76229.137.44.0/22229.137.44.1 to 229.137.47.254229.137.47.2551,022
77229.137.48.0/22229.137.48.1 to 229.137.51.254229.137.51.2551,022
78229.137.52.0/22229.137.52.1 to 229.137.55.254229.137.55.2551,022
79229.137.56.0/22229.137.56.1 to 229.137.59.254229.137.59.2551,022
80229.137.60.0/22229.137.60.1 to 229.137.63.254229.137.63.2551,022
81229.137.64.0/22229.137.64.1 to 229.137.67.254229.137.67.2551,022
82229.137.68.0/22229.137.68.1 to 229.137.71.254229.137.71.2551,022
83229.137.72.0/22229.137.72.1 to 229.137.75.254229.137.75.2551,022
84229.137.76.0/22229.137.76.1 to 229.137.79.254229.137.79.2551,022
85229.137.80.0/22229.137.80.1 to 229.137.83.254229.137.83.2551,022
86229.137.84.0/22229.137.84.1 to 229.137.87.254229.137.87.2551,022
87229.137.88.0/22229.137.88.1 to 229.137.91.254229.137.91.2551,022
88229.137.92.0/22229.137.92.1 to 229.137.95.254229.137.95.2551,022
89229.137.96.0/22229.137.96.1 to 229.137.99.254229.137.99.2551,022
90229.137.100.0/22229.137.100.1 to 229.137.103.254229.137.103.2551,022
91229.137.104.0/22229.137.104.1 to 229.137.107.254229.137.107.2551,022
92229.137.108.0/22229.137.108.1 to 229.137.111.254229.137.111.2551,022
93229.137.112.0/22229.137.112.1 to 229.137.115.254229.137.115.2551,022
94229.137.116.0/22229.137.116.1 to 229.137.119.254229.137.119.2551,022
95229.137.120.0/22229.137.120.1 to 229.137.123.254229.137.123.2551,022
96229.137.124.0/22229.137.124.1 to 229.137.127.254229.137.127.2551,022
97229.137.128.0/22229.137.128.1 to 229.137.131.254229.137.131.2551,022
98229.137.132.0/22229.137.132.1 to 229.137.135.254229.137.135.2551,022
99229.137.136.0/22229.137.136.1 to 229.137.139.254229.137.139.2551,022
100229.137.140.0/22229.137.140.1 to 229.137.143.254229.137.143.2551,022
101229.137.144.0/22229.137.144.1 to 229.137.147.254229.137.147.2551,022
102229.137.148.0/22229.137.148.1 to 229.137.151.254229.137.151.2551,022
103229.137.152.0/22229.137.152.1 to 229.137.155.254229.137.155.2551,022
104229.137.156.0/22229.137.156.1 to 229.137.159.254229.137.159.2551,022
105229.137.160.0/22229.137.160.1 to 229.137.163.254229.137.163.2551,022
106229.137.164.0/22229.137.164.1 to 229.137.167.254229.137.167.2551,022
107229.137.168.0/22229.137.168.1 to 229.137.171.254229.137.171.2551,022
108229.137.172.0/22229.137.172.1 to 229.137.175.254229.137.175.2551,022
109229.137.176.0/22229.137.176.1 to 229.137.179.254229.137.179.2551,022
110229.137.180.0/22229.137.180.1 to 229.137.183.254229.137.183.2551,022
111229.137.184.0/22229.137.184.1 to 229.137.187.254229.137.187.2551,022
112229.137.188.0/22229.137.188.1 to 229.137.191.254229.137.191.2551,022
113229.137.192.0/22229.137.192.1 to 229.137.195.254229.137.195.2551,022
114229.137.196.0/22229.137.196.1 to 229.137.199.254229.137.199.2551,022
115229.137.200.0/22229.137.200.1 to 229.137.203.254229.137.203.2551,022
116229.137.204.0/22229.137.204.1 to 229.137.207.254229.137.207.2551,022
117229.137.208.0/22229.137.208.1 to 229.137.211.254229.137.211.2551,022
118229.137.212.0/22229.137.212.1 to 229.137.215.254229.137.215.2551,022
119229.137.216.0/22229.137.216.1 to 229.137.219.254229.137.219.2551,022
120229.137.220.0/22229.137.220.1 to 229.137.223.254229.137.223.2551,022
121229.137.224.0/22229.137.224.1 to 229.137.227.254229.137.227.2551,022
122229.137.228.0/22229.137.228.1 to 229.137.231.254229.137.231.2551,022
123229.137.232.0/22229.137.232.1 to 229.137.235.254229.137.235.2551,022
124229.137.236.0/22229.137.236.1 to 229.137.239.254229.137.239.2551,022
125229.137.240.0/22229.137.240.1 to 229.137.243.254229.137.243.2551,022
126229.137.244.0/22229.137.244.1 to 229.137.247.254229.137.247.2551,022
127229.137.248.0/22229.137.248.1 to 229.137.251.254229.137.251.2551,022
128229.137.252.0/22229.137.252.1 to 229.137.255.254229.137.255.2551,022

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.