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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.

Network124.32.0.0/11
Usable hosts2,097,150
Subnet mask255.224.0.0
Addresses2,097,152
Network address
124.32.0.0
Broadcast address
124.63.255.255
First usable
124.32.0.1
Last usable
124.63.255.254
Usable hosts
2,097,150 (2,097,152 less the network and broadcast addresses)
Subnet mask
255.224.0.0
Wildcard mask
0.31.255.255 (Cisco ACLs, OSPF)
Prefix length
/11
Type
Public public
Old class
A (default /8)
As numbers
Hex 7C200000 · Integer 2082471936 to 2084569087
Reverse DNS zones
32.124.in-addr.arpa
33.124.in-addr.arpa
34.124.in-addr.arpa
35.124.in-addr.arpa
36.124.in-addr.arpa
37.124.in-addr.arpa
38.124.in-addr.arpa
39.124.in-addr.arpa
40.124.in-addr.arpa
41.124.in-addr.arpa
42.124.in-addr.arpa
43.124.in-addr.arpa
44.124.in-addr.arpa
45.124.in-addr.arpa
46.124.in-addr.arpa
47.124.in-addr.arpa
and 16 more
/11 is not on a 8-bit boundary, so it takes 32 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address01111100.00100000.00000000.00000000124.32.0.0
Subnet mask11111111.11100000.00000000.00000000255.224.0.0
Network01111100.00100000.00000000.00000000124.32.0.0
Broadcast01111100.00111111.11111111.11111111124.63.255.255
Split into smaller subnets/18
/12 (2)/13 (4)/14 (8)/15 (16)/16 (32)/17 (64)/18 (128)/19 (256)/20 (512)/21 (1,024)/22 (2,048)/23 (4,096)

124.32.0.0/11 makes 128 subnets of /18.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1124.32.0.0/18124.32.0.1 to 124.32.63.254124.32.63.25516,382
2124.32.64.0/18124.32.64.1 to 124.32.127.254124.32.127.25516,382
3124.32.128.0/18124.32.128.1 to 124.32.191.254124.32.191.25516,382
4124.32.192.0/18124.32.192.1 to 124.32.255.254124.32.255.25516,382
5124.33.0.0/18124.33.0.1 to 124.33.63.254124.33.63.25516,382
6124.33.64.0/18124.33.64.1 to 124.33.127.254124.33.127.25516,382
7124.33.128.0/18124.33.128.1 to 124.33.191.254124.33.191.25516,382
8124.33.192.0/18124.33.192.1 to 124.33.255.254124.33.255.25516,382
9124.34.0.0/18124.34.0.1 to 124.34.63.254124.34.63.25516,382
10124.34.64.0/18124.34.64.1 to 124.34.127.254124.34.127.25516,382
11124.34.128.0/18124.34.128.1 to 124.34.191.254124.34.191.25516,382
12124.34.192.0/18124.34.192.1 to 124.34.255.254124.34.255.25516,382
13124.35.0.0/18124.35.0.1 to 124.35.63.254124.35.63.25516,382
14124.35.64.0/18124.35.64.1 to 124.35.127.254124.35.127.25516,382
15124.35.128.0/18124.35.128.1 to 124.35.191.254124.35.191.25516,382
16124.35.192.0/18124.35.192.1 to 124.35.255.254124.35.255.25516,382
17124.36.0.0/18124.36.0.1 to 124.36.63.254124.36.63.25516,382
18124.36.64.0/18124.36.64.1 to 124.36.127.254124.36.127.25516,382
19124.36.128.0/18124.36.128.1 to 124.36.191.254124.36.191.25516,382
20124.36.192.0/18124.36.192.1 to 124.36.255.254124.36.255.25516,382
21124.37.0.0/18124.37.0.1 to 124.37.63.254124.37.63.25516,382
22124.37.64.0/18124.37.64.1 to 124.37.127.254124.37.127.25516,382
23124.37.128.0/18124.37.128.1 to 124.37.191.254124.37.191.25516,382
24124.37.192.0/18124.37.192.1 to 124.37.255.254124.37.255.25516,382
25124.38.0.0/18124.38.0.1 to 124.38.63.254124.38.63.25516,382
26124.38.64.0/18124.38.64.1 to 124.38.127.254124.38.127.25516,382
27124.38.128.0/18124.38.128.1 to 124.38.191.254124.38.191.25516,382
28124.38.192.0/18124.38.192.1 to 124.38.255.254124.38.255.25516,382
29124.39.0.0/18124.39.0.1 to 124.39.63.254124.39.63.25516,382
30124.39.64.0/18124.39.64.1 to 124.39.127.254124.39.127.25516,382
31124.39.128.0/18124.39.128.1 to 124.39.191.254124.39.191.25516,382
32124.39.192.0/18124.39.192.1 to 124.39.255.254124.39.255.25516,382
33124.40.0.0/18124.40.0.1 to 124.40.63.254124.40.63.25516,382
34124.40.64.0/18124.40.64.1 to 124.40.127.254124.40.127.25516,382
35124.40.128.0/18124.40.128.1 to 124.40.191.254124.40.191.25516,382
36124.40.192.0/18124.40.192.1 to 124.40.255.254124.40.255.25516,382
37124.41.0.0/18124.41.0.1 to 124.41.63.254124.41.63.25516,382
38124.41.64.0/18124.41.64.1 to 124.41.127.254124.41.127.25516,382
39124.41.128.0/18124.41.128.1 to 124.41.191.254124.41.191.25516,382
40124.41.192.0/18124.41.192.1 to 124.41.255.254124.41.255.25516,382
41124.42.0.0/18124.42.0.1 to 124.42.63.254124.42.63.25516,382
42124.42.64.0/18124.42.64.1 to 124.42.127.254124.42.127.25516,382
43124.42.128.0/18124.42.128.1 to 124.42.191.254124.42.191.25516,382
44124.42.192.0/18124.42.192.1 to 124.42.255.254124.42.255.25516,382
45124.43.0.0/18124.43.0.1 to 124.43.63.254124.43.63.25516,382
46124.43.64.0/18124.43.64.1 to 124.43.127.254124.43.127.25516,382
47124.43.128.0/18124.43.128.1 to 124.43.191.254124.43.191.25516,382
48124.43.192.0/18124.43.192.1 to 124.43.255.254124.43.255.25516,382
49124.44.0.0/18124.44.0.1 to 124.44.63.254124.44.63.25516,382
50124.44.64.0/18124.44.64.1 to 124.44.127.254124.44.127.25516,382
51124.44.128.0/18124.44.128.1 to 124.44.191.254124.44.191.25516,382
52124.44.192.0/18124.44.192.1 to 124.44.255.254124.44.255.25516,382
53124.45.0.0/18124.45.0.1 to 124.45.63.254124.45.63.25516,382
54124.45.64.0/18124.45.64.1 to 124.45.127.254124.45.127.25516,382
55124.45.128.0/18124.45.128.1 to 124.45.191.254124.45.191.25516,382
56124.45.192.0/18124.45.192.1 to 124.45.255.254124.45.255.25516,382
57124.46.0.0/18124.46.0.1 to 124.46.63.254124.46.63.25516,382
58124.46.64.0/18124.46.64.1 to 124.46.127.254124.46.127.25516,382
59124.46.128.0/18124.46.128.1 to 124.46.191.254124.46.191.25516,382
60124.46.192.0/18124.46.192.1 to 124.46.255.254124.46.255.25516,382
61124.47.0.0/18124.47.0.1 to 124.47.63.254124.47.63.25516,382
62124.47.64.0/18124.47.64.1 to 124.47.127.254124.47.127.25516,382
63124.47.128.0/18124.47.128.1 to 124.47.191.254124.47.191.25516,382
64124.47.192.0/18124.47.192.1 to 124.47.255.254124.47.255.25516,382
65124.48.0.0/18124.48.0.1 to 124.48.63.254124.48.63.25516,382
66124.48.64.0/18124.48.64.1 to 124.48.127.254124.48.127.25516,382
67124.48.128.0/18124.48.128.1 to 124.48.191.254124.48.191.25516,382
68124.48.192.0/18124.48.192.1 to 124.48.255.254124.48.255.25516,382
69124.49.0.0/18124.49.0.1 to 124.49.63.254124.49.63.25516,382
70124.49.64.0/18124.49.64.1 to 124.49.127.254124.49.127.25516,382
71124.49.128.0/18124.49.128.1 to 124.49.191.254124.49.191.25516,382
72124.49.192.0/18124.49.192.1 to 124.49.255.254124.49.255.25516,382
73124.50.0.0/18124.50.0.1 to 124.50.63.254124.50.63.25516,382
74124.50.64.0/18124.50.64.1 to 124.50.127.254124.50.127.25516,382
75124.50.128.0/18124.50.128.1 to 124.50.191.254124.50.191.25516,382
76124.50.192.0/18124.50.192.1 to 124.50.255.254124.50.255.25516,382
77124.51.0.0/18124.51.0.1 to 124.51.63.254124.51.63.25516,382
78124.51.64.0/18124.51.64.1 to 124.51.127.254124.51.127.25516,382
79124.51.128.0/18124.51.128.1 to 124.51.191.254124.51.191.25516,382
80124.51.192.0/18124.51.192.1 to 124.51.255.254124.51.255.25516,382
81124.52.0.0/18124.52.0.1 to 124.52.63.254124.52.63.25516,382
82124.52.64.0/18124.52.64.1 to 124.52.127.254124.52.127.25516,382
83124.52.128.0/18124.52.128.1 to 124.52.191.254124.52.191.25516,382
84124.52.192.0/18124.52.192.1 to 124.52.255.254124.52.255.25516,382
85124.53.0.0/18124.53.0.1 to 124.53.63.254124.53.63.25516,382
86124.53.64.0/18124.53.64.1 to 124.53.127.254124.53.127.25516,382
87124.53.128.0/18124.53.128.1 to 124.53.191.254124.53.191.25516,382
88124.53.192.0/18124.53.192.1 to 124.53.255.254124.53.255.25516,382
89124.54.0.0/18124.54.0.1 to 124.54.63.254124.54.63.25516,382
90124.54.64.0/18124.54.64.1 to 124.54.127.254124.54.127.25516,382
91124.54.128.0/18124.54.128.1 to 124.54.191.254124.54.191.25516,382
92124.54.192.0/18124.54.192.1 to 124.54.255.254124.54.255.25516,382
93124.55.0.0/18124.55.0.1 to 124.55.63.254124.55.63.25516,382
94124.55.64.0/18124.55.64.1 to 124.55.127.254124.55.127.25516,382
95124.55.128.0/18124.55.128.1 to 124.55.191.254124.55.191.25516,382
96124.55.192.0/18124.55.192.1 to 124.55.255.254124.55.255.25516,382
97124.56.0.0/18124.56.0.1 to 124.56.63.254124.56.63.25516,382
98124.56.64.0/18124.56.64.1 to 124.56.127.254124.56.127.25516,382
99124.56.128.0/18124.56.128.1 to 124.56.191.254124.56.191.25516,382
100124.56.192.0/18124.56.192.1 to 124.56.255.254124.56.255.25516,382
101124.57.0.0/18124.57.0.1 to 124.57.63.254124.57.63.25516,382
102124.57.64.0/18124.57.64.1 to 124.57.127.254124.57.127.25516,382
103124.57.128.0/18124.57.128.1 to 124.57.191.254124.57.191.25516,382
104124.57.192.0/18124.57.192.1 to 124.57.255.254124.57.255.25516,382
105124.58.0.0/18124.58.0.1 to 124.58.63.254124.58.63.25516,382
106124.58.64.0/18124.58.64.1 to 124.58.127.254124.58.127.25516,382
107124.58.128.0/18124.58.128.1 to 124.58.191.254124.58.191.25516,382
108124.58.192.0/18124.58.192.1 to 124.58.255.254124.58.255.25516,382
109124.59.0.0/18124.59.0.1 to 124.59.63.254124.59.63.25516,382
110124.59.64.0/18124.59.64.1 to 124.59.127.254124.59.127.25516,382
111124.59.128.0/18124.59.128.1 to 124.59.191.254124.59.191.25516,382
112124.59.192.0/18124.59.192.1 to 124.59.255.254124.59.255.25516,382
113124.60.0.0/18124.60.0.1 to 124.60.63.254124.60.63.25516,382
114124.60.64.0/18124.60.64.1 to 124.60.127.254124.60.127.25516,382
115124.60.128.0/18124.60.128.1 to 124.60.191.254124.60.191.25516,382
116124.60.192.0/18124.60.192.1 to 124.60.255.254124.60.255.25516,382
117124.61.0.0/18124.61.0.1 to 124.61.63.254124.61.63.25516,382
118124.61.64.0/18124.61.64.1 to 124.61.127.254124.61.127.25516,382
119124.61.128.0/18124.61.128.1 to 124.61.191.254124.61.191.25516,382
120124.61.192.0/18124.61.192.1 to 124.61.255.254124.61.255.25516,382
121124.62.0.0/18124.62.0.1 to 124.62.63.254124.62.63.25516,382
122124.62.64.0/18124.62.64.1 to 124.62.127.254124.62.127.25516,382
123124.62.128.0/18124.62.128.1 to 124.62.191.254124.62.191.25516,382
124124.62.192.0/18124.62.192.1 to 124.62.255.254124.62.255.25516,382
125124.63.0.0/18124.63.0.1 to 124.63.63.254124.63.63.25516,382
126124.63.64.0/18124.63.64.1 to 124.63.127.254124.63.127.25516,382
127124.63.128.0/18124.63.128.1 to 124.63.191.254124.63.191.25516,382
128124.63.192.0/18124.63.192.1 to 124.63.255.254124.63.255.25516,382

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.