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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.

Network169.254.176.0/20
Usable hosts4,094
Subnet mask255.255.240.0
Addresses4,096
Network address
169.254.176.0
Broadcast address
169.254.191.255
First usable
169.254.176.1
Last usable
169.254.191.254
Usable hosts
4,094 (4,096 less the network and broadcast addresses)
Subnet mask
255.255.240.0
Wildcard mask
0.0.15.255 (Cisco ACLs, OSPF)
Prefix length
/20
Type
Link-local (APIPA) 169.254.0.0/16
Self-assigned when no DHCP server answers
Old class
B (default /16)
As numbers
Hex A9FEB000 · Integer 2852040704 to 2852044799
Reverse DNS zones
176.254.169.in-addr.arpa
177.254.169.in-addr.arpa
178.254.169.in-addr.arpa
179.254.169.in-addr.arpa
180.254.169.in-addr.arpa
181.254.169.in-addr.arpa
182.254.169.in-addr.arpa
183.254.169.in-addr.arpa
184.254.169.in-addr.arpa
185.254.169.in-addr.arpa
186.254.169.in-addr.arpa
187.254.169.in-addr.arpa
188.254.169.in-addr.arpa
189.254.169.in-addr.arpa
190.254.169.in-addr.arpa
191.254.169.in-addr.arpa
/20 is not on a 8-bit boundary, so it takes 16 /24 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address10101001.11111110.10110000.00000000169.254.176.0
Subnet mask11111111.11111111.11110000.00000000255.255.240.0
Network10101001.11111110.10110000.00000000169.254.176.0
Broadcast10101001.11111110.10111111.11111111169.254.191.255
Split into smaller subnets/27
/21 (2)/22 (4)/23 (8)/24 (16)/25 (32)/26 (64)/27 (128)/28 (256)/29 (512)/30 (1,024)/31 (2,048)/32 (4,096)

169.254.176.0/20 makes 128 subnets of /27.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1169.254.176.0/27169.254.176.1 to 169.254.176.30169.254.176.3130
2169.254.176.32/27169.254.176.33 to 169.254.176.62169.254.176.6330
3169.254.176.64/27169.254.176.65 to 169.254.176.94169.254.176.9530
4169.254.176.96/27169.254.176.97 to 169.254.176.126169.254.176.12730
5169.254.176.128/27169.254.176.129 to 169.254.176.158169.254.176.15930
6169.254.176.160/27169.254.176.161 to 169.254.176.190169.254.176.19130
7169.254.176.192/27169.254.176.193 to 169.254.176.222169.254.176.22330
8169.254.176.224/27169.254.176.225 to 169.254.176.254169.254.176.25530
9169.254.177.0/27169.254.177.1 to 169.254.177.30169.254.177.3130
10169.254.177.32/27169.254.177.33 to 169.254.177.62169.254.177.6330
11169.254.177.64/27169.254.177.65 to 169.254.177.94169.254.177.9530
12169.254.177.96/27169.254.177.97 to 169.254.177.126169.254.177.12730
13169.254.177.128/27169.254.177.129 to 169.254.177.158169.254.177.15930
14169.254.177.160/27169.254.177.161 to 169.254.177.190169.254.177.19130
15169.254.177.192/27169.254.177.193 to 169.254.177.222169.254.177.22330
16169.254.177.224/27169.254.177.225 to 169.254.177.254169.254.177.25530
17169.254.178.0/27169.254.178.1 to 169.254.178.30169.254.178.3130
18169.254.178.32/27169.254.178.33 to 169.254.178.62169.254.178.6330
19169.254.178.64/27169.254.178.65 to 169.254.178.94169.254.178.9530
20169.254.178.96/27169.254.178.97 to 169.254.178.126169.254.178.12730
21169.254.178.128/27169.254.178.129 to 169.254.178.158169.254.178.15930
22169.254.178.160/27169.254.178.161 to 169.254.178.190169.254.178.19130
23169.254.178.192/27169.254.178.193 to 169.254.178.222169.254.178.22330
24169.254.178.224/27169.254.178.225 to 169.254.178.254169.254.178.25530
25169.254.179.0/27169.254.179.1 to 169.254.179.30169.254.179.3130
26169.254.179.32/27169.254.179.33 to 169.254.179.62169.254.179.6330
27169.254.179.64/27169.254.179.65 to 169.254.179.94169.254.179.9530
28169.254.179.96/27169.254.179.97 to 169.254.179.126169.254.179.12730
29169.254.179.128/27169.254.179.129 to 169.254.179.158169.254.179.15930
30169.254.179.160/27169.254.179.161 to 169.254.179.190169.254.179.19130
31169.254.179.192/27169.254.179.193 to 169.254.179.222169.254.179.22330
32169.254.179.224/27169.254.179.225 to 169.254.179.254169.254.179.25530
33169.254.180.0/27169.254.180.1 to 169.254.180.30169.254.180.3130
34169.254.180.32/27169.254.180.33 to 169.254.180.62169.254.180.6330
35169.254.180.64/27169.254.180.65 to 169.254.180.94169.254.180.9530
36169.254.180.96/27169.254.180.97 to 169.254.180.126169.254.180.12730
37169.254.180.128/27169.254.180.129 to 169.254.180.158169.254.180.15930
38169.254.180.160/27169.254.180.161 to 169.254.180.190169.254.180.19130
39169.254.180.192/27169.254.180.193 to 169.254.180.222169.254.180.22330
40169.254.180.224/27169.254.180.225 to 169.254.180.254169.254.180.25530
41169.254.181.0/27169.254.181.1 to 169.254.181.30169.254.181.3130
42169.254.181.32/27169.254.181.33 to 169.254.181.62169.254.181.6330
43169.254.181.64/27169.254.181.65 to 169.254.181.94169.254.181.9530
44169.254.181.96/27169.254.181.97 to 169.254.181.126169.254.181.12730
45169.254.181.128/27169.254.181.129 to 169.254.181.158169.254.181.15930
46169.254.181.160/27169.254.181.161 to 169.254.181.190169.254.181.19130
47169.254.181.192/27169.254.181.193 to 169.254.181.222169.254.181.22330
48169.254.181.224/27169.254.181.225 to 169.254.181.254169.254.181.25530
49169.254.182.0/27169.254.182.1 to 169.254.182.30169.254.182.3130
50169.254.182.32/27169.254.182.33 to 169.254.182.62169.254.182.6330
51169.254.182.64/27169.254.182.65 to 169.254.182.94169.254.182.9530
52169.254.182.96/27169.254.182.97 to 169.254.182.126169.254.182.12730
53169.254.182.128/27169.254.182.129 to 169.254.182.158169.254.182.15930
54169.254.182.160/27169.254.182.161 to 169.254.182.190169.254.182.19130
55169.254.182.192/27169.254.182.193 to 169.254.182.222169.254.182.22330
56169.254.182.224/27169.254.182.225 to 169.254.182.254169.254.182.25530
57169.254.183.0/27169.254.183.1 to 169.254.183.30169.254.183.3130
58169.254.183.32/27169.254.183.33 to 169.254.183.62169.254.183.6330
59169.254.183.64/27169.254.183.65 to 169.254.183.94169.254.183.9530
60169.254.183.96/27169.254.183.97 to 169.254.183.126169.254.183.12730
61169.254.183.128/27169.254.183.129 to 169.254.183.158169.254.183.15930
62169.254.183.160/27169.254.183.161 to 169.254.183.190169.254.183.19130
63169.254.183.192/27169.254.183.193 to 169.254.183.222169.254.183.22330
64169.254.183.224/27169.254.183.225 to 169.254.183.254169.254.183.25530
65169.254.184.0/27169.254.184.1 to 169.254.184.30169.254.184.3130
66169.254.184.32/27169.254.184.33 to 169.254.184.62169.254.184.6330
67169.254.184.64/27169.254.184.65 to 169.254.184.94169.254.184.9530
68169.254.184.96/27169.254.184.97 to 169.254.184.126169.254.184.12730
69169.254.184.128/27169.254.184.129 to 169.254.184.158169.254.184.15930
70169.254.184.160/27169.254.184.161 to 169.254.184.190169.254.184.19130
71169.254.184.192/27169.254.184.193 to 169.254.184.222169.254.184.22330
72169.254.184.224/27169.254.184.225 to 169.254.184.254169.254.184.25530
73169.254.185.0/27169.254.185.1 to 169.254.185.30169.254.185.3130
74169.254.185.32/27169.254.185.33 to 169.254.185.62169.254.185.6330
75169.254.185.64/27169.254.185.65 to 169.254.185.94169.254.185.9530
76169.254.185.96/27169.254.185.97 to 169.254.185.126169.254.185.12730
77169.254.185.128/27169.254.185.129 to 169.254.185.158169.254.185.15930
78169.254.185.160/27169.254.185.161 to 169.254.185.190169.254.185.19130
79169.254.185.192/27169.254.185.193 to 169.254.185.222169.254.185.22330
80169.254.185.224/27169.254.185.225 to 169.254.185.254169.254.185.25530
81169.254.186.0/27169.254.186.1 to 169.254.186.30169.254.186.3130
82169.254.186.32/27169.254.186.33 to 169.254.186.62169.254.186.6330
83169.254.186.64/27169.254.186.65 to 169.254.186.94169.254.186.9530
84169.254.186.96/27169.254.186.97 to 169.254.186.126169.254.186.12730
85169.254.186.128/27169.254.186.129 to 169.254.186.158169.254.186.15930
86169.254.186.160/27169.254.186.161 to 169.254.186.190169.254.186.19130
87169.254.186.192/27169.254.186.193 to 169.254.186.222169.254.186.22330
88169.254.186.224/27169.254.186.225 to 169.254.186.254169.254.186.25530
89169.254.187.0/27169.254.187.1 to 169.254.187.30169.254.187.3130
90169.254.187.32/27169.254.187.33 to 169.254.187.62169.254.187.6330
91169.254.187.64/27169.254.187.65 to 169.254.187.94169.254.187.9530
92169.254.187.96/27169.254.187.97 to 169.254.187.126169.254.187.12730
93169.254.187.128/27169.254.187.129 to 169.254.187.158169.254.187.15930
94169.254.187.160/27169.254.187.161 to 169.254.187.190169.254.187.19130
95169.254.187.192/27169.254.187.193 to 169.254.187.222169.254.187.22330
96169.254.187.224/27169.254.187.225 to 169.254.187.254169.254.187.25530
97169.254.188.0/27169.254.188.1 to 169.254.188.30169.254.188.3130
98169.254.188.32/27169.254.188.33 to 169.254.188.62169.254.188.6330
99169.254.188.64/27169.254.188.65 to 169.254.188.94169.254.188.9530
100169.254.188.96/27169.254.188.97 to 169.254.188.126169.254.188.12730
101169.254.188.128/27169.254.188.129 to 169.254.188.158169.254.188.15930
102169.254.188.160/27169.254.188.161 to 169.254.188.190169.254.188.19130
103169.254.188.192/27169.254.188.193 to 169.254.188.222169.254.188.22330
104169.254.188.224/27169.254.188.225 to 169.254.188.254169.254.188.25530
105169.254.189.0/27169.254.189.1 to 169.254.189.30169.254.189.3130
106169.254.189.32/27169.254.189.33 to 169.254.189.62169.254.189.6330
107169.254.189.64/27169.254.189.65 to 169.254.189.94169.254.189.9530
108169.254.189.96/27169.254.189.97 to 169.254.189.126169.254.189.12730
109169.254.189.128/27169.254.189.129 to 169.254.189.158169.254.189.15930
110169.254.189.160/27169.254.189.161 to 169.254.189.190169.254.189.19130
111169.254.189.192/27169.254.189.193 to 169.254.189.222169.254.189.22330
112169.254.189.224/27169.254.189.225 to 169.254.189.254169.254.189.25530
113169.254.190.0/27169.254.190.1 to 169.254.190.30169.254.190.3130
114169.254.190.32/27169.254.190.33 to 169.254.190.62169.254.190.6330
115169.254.190.64/27169.254.190.65 to 169.254.190.94169.254.190.9530
116169.254.190.96/27169.254.190.97 to 169.254.190.126169.254.190.12730
117169.254.190.128/27169.254.190.129 to 169.254.190.158169.254.190.15930
118169.254.190.160/27169.254.190.161 to 169.254.190.190169.254.190.19130
119169.254.190.192/27169.254.190.193 to 169.254.190.222169.254.190.22330
120169.254.190.224/27169.254.190.225 to 169.254.190.254169.254.190.25530
121169.254.191.0/27169.254.191.1 to 169.254.191.30169.254.191.3130
122169.254.191.32/27169.254.191.33 to 169.254.191.62169.254.191.6330
123169.254.191.64/27169.254.191.65 to 169.254.191.94169.254.191.9530
124169.254.191.96/27169.254.191.97 to 169.254.191.126169.254.191.12730
125169.254.191.128/27169.254.191.129 to 169.254.191.158169.254.191.15930
126169.254.191.160/27169.254.191.161 to 169.254.191.190169.254.191.19130
127169.254.191.192/27169.254.191.193 to 169.254.191.222169.254.191.22330
128169.254.191.224/27169.254.191.225 to 169.254.191.254169.254.191.25530

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.