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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.

Network182.0.192.0/19
Usable hosts8,190
Subnet mask255.255.224.0
Addresses8,192
Network address
182.0.192.0
Broadcast address
182.0.223.255
First usable
182.0.192.1
Last usable
182.0.223.254
Usable hosts
8,190 (8,192 less the network and broadcast addresses)
Subnet mask
255.255.224.0
Wildcard mask
0.0.31.255 (Cisco ACLs, OSPF)
Prefix length
/19
Type
Public public
Old class
B (default /16)
As numbers
Hex B600C000 · Integer 3053502464 to 3053510655
Reverse DNS zones
192.0.182.in-addr.arpa
193.0.182.in-addr.arpa
194.0.182.in-addr.arpa
195.0.182.in-addr.arpa
196.0.182.in-addr.arpa
197.0.182.in-addr.arpa
198.0.182.in-addr.arpa
199.0.182.in-addr.arpa
200.0.182.in-addr.arpa
201.0.182.in-addr.arpa
202.0.182.in-addr.arpa
203.0.182.in-addr.arpa
204.0.182.in-addr.arpa
205.0.182.in-addr.arpa
206.0.182.in-addr.arpa
207.0.182.in-addr.arpa
and 16 more
/19 is not on a 8-bit boundary, so it takes 32 /24 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address10110110.00000000.11000000.00000000182.0.192.0
Subnet mask11111111.11111111.11100000.00000000255.255.224.0
Network10110110.00000000.11000000.00000000182.0.192.0
Broadcast10110110.00000000.11011111.11111111182.0.223.255
Split into smaller subnets/26
/20 (2)/21 (4)/22 (8)/23 (16)/24 (32)/25 (64)/26 (128)/27 (256)/28 (512)/29 (1,024)/30 (2,048)/31 (4,096)

182.0.192.0/19 makes 128 subnets of /26.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1182.0.192.0/26182.0.192.1 to 182.0.192.62182.0.192.6362
2182.0.192.64/26182.0.192.65 to 182.0.192.126182.0.192.12762
3182.0.192.128/26182.0.192.129 to 182.0.192.190182.0.192.19162
4182.0.192.192/26182.0.192.193 to 182.0.192.254182.0.192.25562
5182.0.193.0/26182.0.193.1 to 182.0.193.62182.0.193.6362
6182.0.193.64/26182.0.193.65 to 182.0.193.126182.0.193.12762
7182.0.193.128/26182.0.193.129 to 182.0.193.190182.0.193.19162
8182.0.193.192/26182.0.193.193 to 182.0.193.254182.0.193.25562
9182.0.194.0/26182.0.194.1 to 182.0.194.62182.0.194.6362
10182.0.194.64/26182.0.194.65 to 182.0.194.126182.0.194.12762
11182.0.194.128/26182.0.194.129 to 182.0.194.190182.0.194.19162
12182.0.194.192/26182.0.194.193 to 182.0.194.254182.0.194.25562
13182.0.195.0/26182.0.195.1 to 182.0.195.62182.0.195.6362
14182.0.195.64/26182.0.195.65 to 182.0.195.126182.0.195.12762
15182.0.195.128/26182.0.195.129 to 182.0.195.190182.0.195.19162
16182.0.195.192/26182.0.195.193 to 182.0.195.254182.0.195.25562
17182.0.196.0/26182.0.196.1 to 182.0.196.62182.0.196.6362
18182.0.196.64/26182.0.196.65 to 182.0.196.126182.0.196.12762
19182.0.196.128/26182.0.196.129 to 182.0.196.190182.0.196.19162
20182.0.196.192/26182.0.196.193 to 182.0.196.254182.0.196.25562
21182.0.197.0/26182.0.197.1 to 182.0.197.62182.0.197.6362
22182.0.197.64/26182.0.197.65 to 182.0.197.126182.0.197.12762
23182.0.197.128/26182.0.197.129 to 182.0.197.190182.0.197.19162
24182.0.197.192/26182.0.197.193 to 182.0.197.254182.0.197.25562
25182.0.198.0/26182.0.198.1 to 182.0.198.62182.0.198.6362
26182.0.198.64/26182.0.198.65 to 182.0.198.126182.0.198.12762
27182.0.198.128/26182.0.198.129 to 182.0.198.190182.0.198.19162
28182.0.198.192/26182.0.198.193 to 182.0.198.254182.0.198.25562
29182.0.199.0/26182.0.199.1 to 182.0.199.62182.0.199.6362
30182.0.199.64/26182.0.199.65 to 182.0.199.126182.0.199.12762
31182.0.199.128/26182.0.199.129 to 182.0.199.190182.0.199.19162
32182.0.199.192/26182.0.199.193 to 182.0.199.254182.0.199.25562
33182.0.200.0/26182.0.200.1 to 182.0.200.62182.0.200.6362
34182.0.200.64/26182.0.200.65 to 182.0.200.126182.0.200.12762
35182.0.200.128/26182.0.200.129 to 182.0.200.190182.0.200.19162
36182.0.200.192/26182.0.200.193 to 182.0.200.254182.0.200.25562
37182.0.201.0/26182.0.201.1 to 182.0.201.62182.0.201.6362
38182.0.201.64/26182.0.201.65 to 182.0.201.126182.0.201.12762
39182.0.201.128/26182.0.201.129 to 182.0.201.190182.0.201.19162
40182.0.201.192/26182.0.201.193 to 182.0.201.254182.0.201.25562
41182.0.202.0/26182.0.202.1 to 182.0.202.62182.0.202.6362
42182.0.202.64/26182.0.202.65 to 182.0.202.126182.0.202.12762
43182.0.202.128/26182.0.202.129 to 182.0.202.190182.0.202.19162
44182.0.202.192/26182.0.202.193 to 182.0.202.254182.0.202.25562
45182.0.203.0/26182.0.203.1 to 182.0.203.62182.0.203.6362
46182.0.203.64/26182.0.203.65 to 182.0.203.126182.0.203.12762
47182.0.203.128/26182.0.203.129 to 182.0.203.190182.0.203.19162
48182.0.203.192/26182.0.203.193 to 182.0.203.254182.0.203.25562
49182.0.204.0/26182.0.204.1 to 182.0.204.62182.0.204.6362
50182.0.204.64/26182.0.204.65 to 182.0.204.126182.0.204.12762
51182.0.204.128/26182.0.204.129 to 182.0.204.190182.0.204.19162
52182.0.204.192/26182.0.204.193 to 182.0.204.254182.0.204.25562
53182.0.205.0/26182.0.205.1 to 182.0.205.62182.0.205.6362
54182.0.205.64/26182.0.205.65 to 182.0.205.126182.0.205.12762
55182.0.205.128/26182.0.205.129 to 182.0.205.190182.0.205.19162
56182.0.205.192/26182.0.205.193 to 182.0.205.254182.0.205.25562
57182.0.206.0/26182.0.206.1 to 182.0.206.62182.0.206.6362
58182.0.206.64/26182.0.206.65 to 182.0.206.126182.0.206.12762
59182.0.206.128/26182.0.206.129 to 182.0.206.190182.0.206.19162
60182.0.206.192/26182.0.206.193 to 182.0.206.254182.0.206.25562
61182.0.207.0/26182.0.207.1 to 182.0.207.62182.0.207.6362
62182.0.207.64/26182.0.207.65 to 182.0.207.126182.0.207.12762
63182.0.207.128/26182.0.207.129 to 182.0.207.190182.0.207.19162
64182.0.207.192/26182.0.207.193 to 182.0.207.254182.0.207.25562
65182.0.208.0/26182.0.208.1 to 182.0.208.62182.0.208.6362
66182.0.208.64/26182.0.208.65 to 182.0.208.126182.0.208.12762
67182.0.208.128/26182.0.208.129 to 182.0.208.190182.0.208.19162
68182.0.208.192/26182.0.208.193 to 182.0.208.254182.0.208.25562
69182.0.209.0/26182.0.209.1 to 182.0.209.62182.0.209.6362
70182.0.209.64/26182.0.209.65 to 182.0.209.126182.0.209.12762
71182.0.209.128/26182.0.209.129 to 182.0.209.190182.0.209.19162
72182.0.209.192/26182.0.209.193 to 182.0.209.254182.0.209.25562
73182.0.210.0/26182.0.210.1 to 182.0.210.62182.0.210.6362
74182.0.210.64/26182.0.210.65 to 182.0.210.126182.0.210.12762
75182.0.210.128/26182.0.210.129 to 182.0.210.190182.0.210.19162
76182.0.210.192/26182.0.210.193 to 182.0.210.254182.0.210.25562
77182.0.211.0/26182.0.211.1 to 182.0.211.62182.0.211.6362
78182.0.211.64/26182.0.211.65 to 182.0.211.126182.0.211.12762
79182.0.211.128/26182.0.211.129 to 182.0.211.190182.0.211.19162
80182.0.211.192/26182.0.211.193 to 182.0.211.254182.0.211.25562
81182.0.212.0/26182.0.212.1 to 182.0.212.62182.0.212.6362
82182.0.212.64/26182.0.212.65 to 182.0.212.126182.0.212.12762
83182.0.212.128/26182.0.212.129 to 182.0.212.190182.0.212.19162
84182.0.212.192/26182.0.212.193 to 182.0.212.254182.0.212.25562
85182.0.213.0/26182.0.213.1 to 182.0.213.62182.0.213.6362
86182.0.213.64/26182.0.213.65 to 182.0.213.126182.0.213.12762
87182.0.213.128/26182.0.213.129 to 182.0.213.190182.0.213.19162
88182.0.213.192/26182.0.213.193 to 182.0.213.254182.0.213.25562
89182.0.214.0/26182.0.214.1 to 182.0.214.62182.0.214.6362
90182.0.214.64/26182.0.214.65 to 182.0.214.126182.0.214.12762
91182.0.214.128/26182.0.214.129 to 182.0.214.190182.0.214.19162
92182.0.214.192/26182.0.214.193 to 182.0.214.254182.0.214.25562
93182.0.215.0/26182.0.215.1 to 182.0.215.62182.0.215.6362
94182.0.215.64/26182.0.215.65 to 182.0.215.126182.0.215.12762
95182.0.215.128/26182.0.215.129 to 182.0.215.190182.0.215.19162
96182.0.215.192/26182.0.215.193 to 182.0.215.254182.0.215.25562
97182.0.216.0/26182.0.216.1 to 182.0.216.62182.0.216.6362
98182.0.216.64/26182.0.216.65 to 182.0.216.126182.0.216.12762
99182.0.216.128/26182.0.216.129 to 182.0.216.190182.0.216.19162
100182.0.216.192/26182.0.216.193 to 182.0.216.254182.0.216.25562
101182.0.217.0/26182.0.217.1 to 182.0.217.62182.0.217.6362
102182.0.217.64/26182.0.217.65 to 182.0.217.126182.0.217.12762
103182.0.217.128/26182.0.217.129 to 182.0.217.190182.0.217.19162
104182.0.217.192/26182.0.217.193 to 182.0.217.254182.0.217.25562
105182.0.218.0/26182.0.218.1 to 182.0.218.62182.0.218.6362
106182.0.218.64/26182.0.218.65 to 182.0.218.126182.0.218.12762
107182.0.218.128/26182.0.218.129 to 182.0.218.190182.0.218.19162
108182.0.218.192/26182.0.218.193 to 182.0.218.254182.0.218.25562
109182.0.219.0/26182.0.219.1 to 182.0.219.62182.0.219.6362
110182.0.219.64/26182.0.219.65 to 182.0.219.126182.0.219.12762
111182.0.219.128/26182.0.219.129 to 182.0.219.190182.0.219.19162
112182.0.219.192/26182.0.219.193 to 182.0.219.254182.0.219.25562
113182.0.220.0/26182.0.220.1 to 182.0.220.62182.0.220.6362
114182.0.220.64/26182.0.220.65 to 182.0.220.126182.0.220.12762
115182.0.220.128/26182.0.220.129 to 182.0.220.190182.0.220.19162
116182.0.220.192/26182.0.220.193 to 182.0.220.254182.0.220.25562
117182.0.221.0/26182.0.221.1 to 182.0.221.62182.0.221.6362
118182.0.221.64/26182.0.221.65 to 182.0.221.126182.0.221.12762
119182.0.221.128/26182.0.221.129 to 182.0.221.190182.0.221.19162
120182.0.221.192/26182.0.221.193 to 182.0.221.254182.0.221.25562
121182.0.222.0/26182.0.222.1 to 182.0.222.62182.0.222.6362
122182.0.222.64/26182.0.222.65 to 182.0.222.126182.0.222.12762
123182.0.222.128/26182.0.222.129 to 182.0.222.190182.0.222.19162
124182.0.222.192/26182.0.222.193 to 182.0.222.254182.0.222.25562
125182.0.223.0/26182.0.223.1 to 182.0.223.62182.0.223.6362
126182.0.223.64/26182.0.223.65 to 182.0.223.126182.0.223.12762
127182.0.223.128/26182.0.223.129 to 182.0.223.190182.0.223.19162
128182.0.223.192/26182.0.223.193 to 182.0.223.254182.0.223.25562

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.