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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.

Network167.167.112.0/20
Usable hosts4,094
Subnet mask255.255.240.0
Addresses4,096
Network address
167.167.112.0
Broadcast address
167.167.127.255
First usable
167.167.112.1
Last usable
167.167.127.254
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
Public public
Old class
B (default /16)
As numbers
Hex A7A77000 · Integer 2812768256 to 2812772351
Reverse DNS zones
112.167.167.in-addr.arpa
113.167.167.in-addr.arpa
114.167.167.in-addr.arpa
115.167.167.in-addr.arpa
116.167.167.in-addr.arpa
117.167.167.in-addr.arpa
118.167.167.in-addr.arpa
119.167.167.in-addr.arpa
120.167.167.in-addr.arpa
121.167.167.in-addr.arpa
122.167.167.in-addr.arpa
123.167.167.in-addr.arpa
124.167.167.in-addr.arpa
125.167.167.in-addr.arpa
126.167.167.in-addr.arpa
127.167.167.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
Address10100111.10100111.01110000.00000000167.167.112.0
Subnet mask11111111.11111111.11110000.00000000255.255.240.0
Network10100111.10100111.01110000.00000000167.167.112.0
Broadcast10100111.10100111.01111111.11111111167.167.127.255
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)

167.167.112.0/20 makes 128 subnets of /27.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1167.167.112.0/27167.167.112.1 to 167.167.112.30167.167.112.3130
2167.167.112.32/27167.167.112.33 to 167.167.112.62167.167.112.6330
3167.167.112.64/27167.167.112.65 to 167.167.112.94167.167.112.9530
4167.167.112.96/27167.167.112.97 to 167.167.112.126167.167.112.12730
5167.167.112.128/27167.167.112.129 to 167.167.112.158167.167.112.15930
6167.167.112.160/27167.167.112.161 to 167.167.112.190167.167.112.19130
7167.167.112.192/27167.167.112.193 to 167.167.112.222167.167.112.22330
8167.167.112.224/27167.167.112.225 to 167.167.112.254167.167.112.25530
9167.167.113.0/27167.167.113.1 to 167.167.113.30167.167.113.3130
10167.167.113.32/27167.167.113.33 to 167.167.113.62167.167.113.6330
11167.167.113.64/27167.167.113.65 to 167.167.113.94167.167.113.9530
12167.167.113.96/27167.167.113.97 to 167.167.113.126167.167.113.12730
13167.167.113.128/27167.167.113.129 to 167.167.113.158167.167.113.15930
14167.167.113.160/27167.167.113.161 to 167.167.113.190167.167.113.19130
15167.167.113.192/27167.167.113.193 to 167.167.113.222167.167.113.22330
16167.167.113.224/27167.167.113.225 to 167.167.113.254167.167.113.25530
17167.167.114.0/27167.167.114.1 to 167.167.114.30167.167.114.3130
18167.167.114.32/27167.167.114.33 to 167.167.114.62167.167.114.6330
19167.167.114.64/27167.167.114.65 to 167.167.114.94167.167.114.9530
20167.167.114.96/27167.167.114.97 to 167.167.114.126167.167.114.12730
21167.167.114.128/27167.167.114.129 to 167.167.114.158167.167.114.15930
22167.167.114.160/27167.167.114.161 to 167.167.114.190167.167.114.19130
23167.167.114.192/27167.167.114.193 to 167.167.114.222167.167.114.22330
24167.167.114.224/27167.167.114.225 to 167.167.114.254167.167.114.25530
25167.167.115.0/27167.167.115.1 to 167.167.115.30167.167.115.3130
26167.167.115.32/27167.167.115.33 to 167.167.115.62167.167.115.6330
27167.167.115.64/27167.167.115.65 to 167.167.115.94167.167.115.9530
28167.167.115.96/27167.167.115.97 to 167.167.115.126167.167.115.12730
29167.167.115.128/27167.167.115.129 to 167.167.115.158167.167.115.15930
30167.167.115.160/27167.167.115.161 to 167.167.115.190167.167.115.19130
31167.167.115.192/27167.167.115.193 to 167.167.115.222167.167.115.22330
32167.167.115.224/27167.167.115.225 to 167.167.115.254167.167.115.25530
33167.167.116.0/27167.167.116.1 to 167.167.116.30167.167.116.3130
34167.167.116.32/27167.167.116.33 to 167.167.116.62167.167.116.6330
35167.167.116.64/27167.167.116.65 to 167.167.116.94167.167.116.9530
36167.167.116.96/27167.167.116.97 to 167.167.116.126167.167.116.12730
37167.167.116.128/27167.167.116.129 to 167.167.116.158167.167.116.15930
38167.167.116.160/27167.167.116.161 to 167.167.116.190167.167.116.19130
39167.167.116.192/27167.167.116.193 to 167.167.116.222167.167.116.22330
40167.167.116.224/27167.167.116.225 to 167.167.116.254167.167.116.25530
41167.167.117.0/27167.167.117.1 to 167.167.117.30167.167.117.3130
42167.167.117.32/27167.167.117.33 to 167.167.117.62167.167.117.6330
43167.167.117.64/27167.167.117.65 to 167.167.117.94167.167.117.9530
44167.167.117.96/27167.167.117.97 to 167.167.117.126167.167.117.12730
45167.167.117.128/27167.167.117.129 to 167.167.117.158167.167.117.15930
46167.167.117.160/27167.167.117.161 to 167.167.117.190167.167.117.19130
47167.167.117.192/27167.167.117.193 to 167.167.117.222167.167.117.22330
48167.167.117.224/27167.167.117.225 to 167.167.117.254167.167.117.25530
49167.167.118.0/27167.167.118.1 to 167.167.118.30167.167.118.3130
50167.167.118.32/27167.167.118.33 to 167.167.118.62167.167.118.6330
51167.167.118.64/27167.167.118.65 to 167.167.118.94167.167.118.9530
52167.167.118.96/27167.167.118.97 to 167.167.118.126167.167.118.12730
53167.167.118.128/27167.167.118.129 to 167.167.118.158167.167.118.15930
54167.167.118.160/27167.167.118.161 to 167.167.118.190167.167.118.19130
55167.167.118.192/27167.167.118.193 to 167.167.118.222167.167.118.22330
56167.167.118.224/27167.167.118.225 to 167.167.118.254167.167.118.25530
57167.167.119.0/27167.167.119.1 to 167.167.119.30167.167.119.3130
58167.167.119.32/27167.167.119.33 to 167.167.119.62167.167.119.6330
59167.167.119.64/27167.167.119.65 to 167.167.119.94167.167.119.9530
60167.167.119.96/27167.167.119.97 to 167.167.119.126167.167.119.12730
61167.167.119.128/27167.167.119.129 to 167.167.119.158167.167.119.15930
62167.167.119.160/27167.167.119.161 to 167.167.119.190167.167.119.19130
63167.167.119.192/27167.167.119.193 to 167.167.119.222167.167.119.22330
64167.167.119.224/27167.167.119.225 to 167.167.119.254167.167.119.25530
65167.167.120.0/27167.167.120.1 to 167.167.120.30167.167.120.3130
66167.167.120.32/27167.167.120.33 to 167.167.120.62167.167.120.6330
67167.167.120.64/27167.167.120.65 to 167.167.120.94167.167.120.9530
68167.167.120.96/27167.167.120.97 to 167.167.120.126167.167.120.12730
69167.167.120.128/27167.167.120.129 to 167.167.120.158167.167.120.15930
70167.167.120.160/27167.167.120.161 to 167.167.120.190167.167.120.19130
71167.167.120.192/27167.167.120.193 to 167.167.120.222167.167.120.22330
72167.167.120.224/27167.167.120.225 to 167.167.120.254167.167.120.25530
73167.167.121.0/27167.167.121.1 to 167.167.121.30167.167.121.3130
74167.167.121.32/27167.167.121.33 to 167.167.121.62167.167.121.6330
75167.167.121.64/27167.167.121.65 to 167.167.121.94167.167.121.9530
76167.167.121.96/27167.167.121.97 to 167.167.121.126167.167.121.12730
77167.167.121.128/27167.167.121.129 to 167.167.121.158167.167.121.15930
78167.167.121.160/27167.167.121.161 to 167.167.121.190167.167.121.19130
79167.167.121.192/27167.167.121.193 to 167.167.121.222167.167.121.22330
80167.167.121.224/27167.167.121.225 to 167.167.121.254167.167.121.25530
81167.167.122.0/27167.167.122.1 to 167.167.122.30167.167.122.3130
82167.167.122.32/27167.167.122.33 to 167.167.122.62167.167.122.6330
83167.167.122.64/27167.167.122.65 to 167.167.122.94167.167.122.9530
84167.167.122.96/27167.167.122.97 to 167.167.122.126167.167.122.12730
85167.167.122.128/27167.167.122.129 to 167.167.122.158167.167.122.15930
86167.167.122.160/27167.167.122.161 to 167.167.122.190167.167.122.19130
87167.167.122.192/27167.167.122.193 to 167.167.122.222167.167.122.22330
88167.167.122.224/27167.167.122.225 to 167.167.122.254167.167.122.25530
89167.167.123.0/27167.167.123.1 to 167.167.123.30167.167.123.3130
90167.167.123.32/27167.167.123.33 to 167.167.123.62167.167.123.6330
91167.167.123.64/27167.167.123.65 to 167.167.123.94167.167.123.9530
92167.167.123.96/27167.167.123.97 to 167.167.123.126167.167.123.12730
93167.167.123.128/27167.167.123.129 to 167.167.123.158167.167.123.15930
94167.167.123.160/27167.167.123.161 to 167.167.123.190167.167.123.19130
95167.167.123.192/27167.167.123.193 to 167.167.123.222167.167.123.22330
96167.167.123.224/27167.167.123.225 to 167.167.123.254167.167.123.25530
97167.167.124.0/27167.167.124.1 to 167.167.124.30167.167.124.3130
98167.167.124.32/27167.167.124.33 to 167.167.124.62167.167.124.6330
99167.167.124.64/27167.167.124.65 to 167.167.124.94167.167.124.9530
100167.167.124.96/27167.167.124.97 to 167.167.124.126167.167.124.12730
101167.167.124.128/27167.167.124.129 to 167.167.124.158167.167.124.15930
102167.167.124.160/27167.167.124.161 to 167.167.124.190167.167.124.19130
103167.167.124.192/27167.167.124.193 to 167.167.124.222167.167.124.22330
104167.167.124.224/27167.167.124.225 to 167.167.124.254167.167.124.25530
105167.167.125.0/27167.167.125.1 to 167.167.125.30167.167.125.3130
106167.167.125.32/27167.167.125.33 to 167.167.125.62167.167.125.6330
107167.167.125.64/27167.167.125.65 to 167.167.125.94167.167.125.9530
108167.167.125.96/27167.167.125.97 to 167.167.125.126167.167.125.12730
109167.167.125.128/27167.167.125.129 to 167.167.125.158167.167.125.15930
110167.167.125.160/27167.167.125.161 to 167.167.125.190167.167.125.19130
111167.167.125.192/27167.167.125.193 to 167.167.125.222167.167.125.22330
112167.167.125.224/27167.167.125.225 to 167.167.125.254167.167.125.25530
113167.167.126.0/27167.167.126.1 to 167.167.126.30167.167.126.3130
114167.167.126.32/27167.167.126.33 to 167.167.126.62167.167.126.6330
115167.167.126.64/27167.167.126.65 to 167.167.126.94167.167.126.9530
116167.167.126.96/27167.167.126.97 to 167.167.126.126167.167.126.12730
117167.167.126.128/27167.167.126.129 to 167.167.126.158167.167.126.15930
118167.167.126.160/27167.167.126.161 to 167.167.126.190167.167.126.19130
119167.167.126.192/27167.167.126.193 to 167.167.126.222167.167.126.22330
120167.167.126.224/27167.167.126.225 to 167.167.126.254167.167.126.25530
121167.167.127.0/27167.167.127.1 to 167.167.127.30167.167.127.3130
122167.167.127.32/27167.167.127.33 to 167.167.127.62167.167.127.6330
123167.167.127.64/27167.167.127.65 to 167.167.127.94167.167.127.9530
124167.167.127.96/27167.167.127.97 to 167.167.127.126167.167.127.12730
125167.167.127.128/27167.167.127.129 to 167.167.127.158167.167.127.15930
126167.167.127.160/27167.167.127.161 to 167.167.127.190167.167.127.19130
127167.167.127.192/27167.167.127.193 to 167.167.127.222167.167.127.22330
128167.167.127.224/27167.167.127.225 to 167.167.127.254167.167.127.25530

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.