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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.

Network213.2.32.0/19
Usable hosts8,190
Subnet mask255.255.224.0
Addresses8,192
Network address
213.2.32.0
Broadcast address
213.2.63.255
First usable
213.2.32.1
Last usable
213.2.63.254
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
C (default /24)
As numbers
Hex D5022000 · Integer 3573686272 to 3573694463
Reverse DNS zones
32.2.213.in-addr.arpa
33.2.213.in-addr.arpa
34.2.213.in-addr.arpa
35.2.213.in-addr.arpa
36.2.213.in-addr.arpa
37.2.213.in-addr.arpa
38.2.213.in-addr.arpa
39.2.213.in-addr.arpa
40.2.213.in-addr.arpa
41.2.213.in-addr.arpa
42.2.213.in-addr.arpa
43.2.213.in-addr.arpa
44.2.213.in-addr.arpa
45.2.213.in-addr.arpa
46.2.213.in-addr.arpa
47.2.213.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
Address11010101.00000010.00100000.00000000213.2.32.0
Subnet mask11111111.11111111.11100000.00000000255.255.224.0
Network11010101.00000010.00100000.00000000213.2.32.0
Broadcast11010101.00000010.00111111.11111111213.2.63.255
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)

213.2.32.0/19 makes 128 subnets of /26.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1213.2.32.0/26213.2.32.1 to 213.2.32.62213.2.32.6362
2213.2.32.64/26213.2.32.65 to 213.2.32.126213.2.32.12762
3213.2.32.128/26213.2.32.129 to 213.2.32.190213.2.32.19162
4213.2.32.192/26213.2.32.193 to 213.2.32.254213.2.32.25562
5213.2.33.0/26213.2.33.1 to 213.2.33.62213.2.33.6362
6213.2.33.64/26213.2.33.65 to 213.2.33.126213.2.33.12762
7213.2.33.128/26213.2.33.129 to 213.2.33.190213.2.33.19162
8213.2.33.192/26213.2.33.193 to 213.2.33.254213.2.33.25562
9213.2.34.0/26213.2.34.1 to 213.2.34.62213.2.34.6362
10213.2.34.64/26213.2.34.65 to 213.2.34.126213.2.34.12762
11213.2.34.128/26213.2.34.129 to 213.2.34.190213.2.34.19162
12213.2.34.192/26213.2.34.193 to 213.2.34.254213.2.34.25562
13213.2.35.0/26213.2.35.1 to 213.2.35.62213.2.35.6362
14213.2.35.64/26213.2.35.65 to 213.2.35.126213.2.35.12762
15213.2.35.128/26213.2.35.129 to 213.2.35.190213.2.35.19162
16213.2.35.192/26213.2.35.193 to 213.2.35.254213.2.35.25562
17213.2.36.0/26213.2.36.1 to 213.2.36.62213.2.36.6362
18213.2.36.64/26213.2.36.65 to 213.2.36.126213.2.36.12762
19213.2.36.128/26213.2.36.129 to 213.2.36.190213.2.36.19162
20213.2.36.192/26213.2.36.193 to 213.2.36.254213.2.36.25562
21213.2.37.0/26213.2.37.1 to 213.2.37.62213.2.37.6362
22213.2.37.64/26213.2.37.65 to 213.2.37.126213.2.37.12762
23213.2.37.128/26213.2.37.129 to 213.2.37.190213.2.37.19162
24213.2.37.192/26213.2.37.193 to 213.2.37.254213.2.37.25562
25213.2.38.0/26213.2.38.1 to 213.2.38.62213.2.38.6362
26213.2.38.64/26213.2.38.65 to 213.2.38.126213.2.38.12762
27213.2.38.128/26213.2.38.129 to 213.2.38.190213.2.38.19162
28213.2.38.192/26213.2.38.193 to 213.2.38.254213.2.38.25562
29213.2.39.0/26213.2.39.1 to 213.2.39.62213.2.39.6362
30213.2.39.64/26213.2.39.65 to 213.2.39.126213.2.39.12762
31213.2.39.128/26213.2.39.129 to 213.2.39.190213.2.39.19162
32213.2.39.192/26213.2.39.193 to 213.2.39.254213.2.39.25562
33213.2.40.0/26213.2.40.1 to 213.2.40.62213.2.40.6362
34213.2.40.64/26213.2.40.65 to 213.2.40.126213.2.40.12762
35213.2.40.128/26213.2.40.129 to 213.2.40.190213.2.40.19162
36213.2.40.192/26213.2.40.193 to 213.2.40.254213.2.40.25562
37213.2.41.0/26213.2.41.1 to 213.2.41.62213.2.41.6362
38213.2.41.64/26213.2.41.65 to 213.2.41.126213.2.41.12762
39213.2.41.128/26213.2.41.129 to 213.2.41.190213.2.41.19162
40213.2.41.192/26213.2.41.193 to 213.2.41.254213.2.41.25562
41213.2.42.0/26213.2.42.1 to 213.2.42.62213.2.42.6362
42213.2.42.64/26213.2.42.65 to 213.2.42.126213.2.42.12762
43213.2.42.128/26213.2.42.129 to 213.2.42.190213.2.42.19162
44213.2.42.192/26213.2.42.193 to 213.2.42.254213.2.42.25562
45213.2.43.0/26213.2.43.1 to 213.2.43.62213.2.43.6362
46213.2.43.64/26213.2.43.65 to 213.2.43.126213.2.43.12762
47213.2.43.128/26213.2.43.129 to 213.2.43.190213.2.43.19162
48213.2.43.192/26213.2.43.193 to 213.2.43.254213.2.43.25562
49213.2.44.0/26213.2.44.1 to 213.2.44.62213.2.44.6362
50213.2.44.64/26213.2.44.65 to 213.2.44.126213.2.44.12762
51213.2.44.128/26213.2.44.129 to 213.2.44.190213.2.44.19162
52213.2.44.192/26213.2.44.193 to 213.2.44.254213.2.44.25562
53213.2.45.0/26213.2.45.1 to 213.2.45.62213.2.45.6362
54213.2.45.64/26213.2.45.65 to 213.2.45.126213.2.45.12762
55213.2.45.128/26213.2.45.129 to 213.2.45.190213.2.45.19162
56213.2.45.192/26213.2.45.193 to 213.2.45.254213.2.45.25562
57213.2.46.0/26213.2.46.1 to 213.2.46.62213.2.46.6362
58213.2.46.64/26213.2.46.65 to 213.2.46.126213.2.46.12762
59213.2.46.128/26213.2.46.129 to 213.2.46.190213.2.46.19162
60213.2.46.192/26213.2.46.193 to 213.2.46.254213.2.46.25562
61213.2.47.0/26213.2.47.1 to 213.2.47.62213.2.47.6362
62213.2.47.64/26213.2.47.65 to 213.2.47.126213.2.47.12762
63213.2.47.128/26213.2.47.129 to 213.2.47.190213.2.47.19162
64213.2.47.192/26213.2.47.193 to 213.2.47.254213.2.47.25562
65213.2.48.0/26213.2.48.1 to 213.2.48.62213.2.48.6362
66213.2.48.64/26213.2.48.65 to 213.2.48.126213.2.48.12762
67213.2.48.128/26213.2.48.129 to 213.2.48.190213.2.48.19162
68213.2.48.192/26213.2.48.193 to 213.2.48.254213.2.48.25562
69213.2.49.0/26213.2.49.1 to 213.2.49.62213.2.49.6362
70213.2.49.64/26213.2.49.65 to 213.2.49.126213.2.49.12762
71213.2.49.128/26213.2.49.129 to 213.2.49.190213.2.49.19162
72213.2.49.192/26213.2.49.193 to 213.2.49.254213.2.49.25562
73213.2.50.0/26213.2.50.1 to 213.2.50.62213.2.50.6362
74213.2.50.64/26213.2.50.65 to 213.2.50.126213.2.50.12762
75213.2.50.128/26213.2.50.129 to 213.2.50.190213.2.50.19162
76213.2.50.192/26213.2.50.193 to 213.2.50.254213.2.50.25562
77213.2.51.0/26213.2.51.1 to 213.2.51.62213.2.51.6362
78213.2.51.64/26213.2.51.65 to 213.2.51.126213.2.51.12762
79213.2.51.128/26213.2.51.129 to 213.2.51.190213.2.51.19162
80213.2.51.192/26213.2.51.193 to 213.2.51.254213.2.51.25562
81213.2.52.0/26213.2.52.1 to 213.2.52.62213.2.52.6362
82213.2.52.64/26213.2.52.65 to 213.2.52.126213.2.52.12762
83213.2.52.128/26213.2.52.129 to 213.2.52.190213.2.52.19162
84213.2.52.192/26213.2.52.193 to 213.2.52.254213.2.52.25562
85213.2.53.0/26213.2.53.1 to 213.2.53.62213.2.53.6362
86213.2.53.64/26213.2.53.65 to 213.2.53.126213.2.53.12762
87213.2.53.128/26213.2.53.129 to 213.2.53.190213.2.53.19162
88213.2.53.192/26213.2.53.193 to 213.2.53.254213.2.53.25562
89213.2.54.0/26213.2.54.1 to 213.2.54.62213.2.54.6362
90213.2.54.64/26213.2.54.65 to 213.2.54.126213.2.54.12762
91213.2.54.128/26213.2.54.129 to 213.2.54.190213.2.54.19162
92213.2.54.192/26213.2.54.193 to 213.2.54.254213.2.54.25562
93213.2.55.0/26213.2.55.1 to 213.2.55.62213.2.55.6362
94213.2.55.64/26213.2.55.65 to 213.2.55.126213.2.55.12762
95213.2.55.128/26213.2.55.129 to 213.2.55.190213.2.55.19162
96213.2.55.192/26213.2.55.193 to 213.2.55.254213.2.55.25562
97213.2.56.0/26213.2.56.1 to 213.2.56.62213.2.56.6362
98213.2.56.64/26213.2.56.65 to 213.2.56.126213.2.56.12762
99213.2.56.128/26213.2.56.129 to 213.2.56.190213.2.56.19162
100213.2.56.192/26213.2.56.193 to 213.2.56.254213.2.56.25562
101213.2.57.0/26213.2.57.1 to 213.2.57.62213.2.57.6362
102213.2.57.64/26213.2.57.65 to 213.2.57.126213.2.57.12762
103213.2.57.128/26213.2.57.129 to 213.2.57.190213.2.57.19162
104213.2.57.192/26213.2.57.193 to 213.2.57.254213.2.57.25562
105213.2.58.0/26213.2.58.1 to 213.2.58.62213.2.58.6362
106213.2.58.64/26213.2.58.65 to 213.2.58.126213.2.58.12762
107213.2.58.128/26213.2.58.129 to 213.2.58.190213.2.58.19162
108213.2.58.192/26213.2.58.193 to 213.2.58.254213.2.58.25562
109213.2.59.0/26213.2.59.1 to 213.2.59.62213.2.59.6362
110213.2.59.64/26213.2.59.65 to 213.2.59.126213.2.59.12762
111213.2.59.128/26213.2.59.129 to 213.2.59.190213.2.59.19162
112213.2.59.192/26213.2.59.193 to 213.2.59.254213.2.59.25562
113213.2.60.0/26213.2.60.1 to 213.2.60.62213.2.60.6362
114213.2.60.64/26213.2.60.65 to 213.2.60.126213.2.60.12762
115213.2.60.128/26213.2.60.129 to 213.2.60.190213.2.60.19162
116213.2.60.192/26213.2.60.193 to 213.2.60.254213.2.60.25562
117213.2.61.0/26213.2.61.1 to 213.2.61.62213.2.61.6362
118213.2.61.64/26213.2.61.65 to 213.2.61.126213.2.61.12762
119213.2.61.128/26213.2.61.129 to 213.2.61.190213.2.61.19162
120213.2.61.192/26213.2.61.193 to 213.2.61.254213.2.61.25562
121213.2.62.0/26213.2.62.1 to 213.2.62.62213.2.62.6362
122213.2.62.64/26213.2.62.65 to 213.2.62.126213.2.62.12762
123213.2.62.128/26213.2.62.129 to 213.2.62.190213.2.62.19162
124213.2.62.192/26213.2.62.193 to 213.2.62.254213.2.62.25562
125213.2.63.0/26213.2.63.1 to 213.2.63.62213.2.63.6362
126213.2.63.64/26213.2.63.65 to 213.2.63.126213.2.63.12762
127213.2.63.128/26213.2.63.129 to 213.2.63.190213.2.63.19162
128213.2.63.192/26213.2.63.193 to 213.2.63.254213.2.63.25562

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.