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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.

Network200.3.32.0/19
Usable hosts8,190
Subnet mask255.255.224.0
Addresses8,192
Network address
200.3.32.0
Broadcast address
200.3.63.255
First usable
200.3.32.1
Last usable
200.3.63.254
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 C8032000 · Integer 3355648000 to 3355656191
Reverse DNS zones
32.3.200.in-addr.arpa
33.3.200.in-addr.arpa
34.3.200.in-addr.arpa
35.3.200.in-addr.arpa
36.3.200.in-addr.arpa
37.3.200.in-addr.arpa
38.3.200.in-addr.arpa
39.3.200.in-addr.arpa
40.3.200.in-addr.arpa
41.3.200.in-addr.arpa
42.3.200.in-addr.arpa
43.3.200.in-addr.arpa
44.3.200.in-addr.arpa
45.3.200.in-addr.arpa
46.3.200.in-addr.arpa
47.3.200.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
Address11001000.00000011.00100000.00000000200.3.32.0
Subnet mask11111111.11111111.11100000.00000000255.255.224.0
Network11001000.00000011.00100000.00000000200.3.32.0
Broadcast11001000.00000011.00111111.11111111200.3.63.255
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)

200.3.32.0/19 makes 128 subnets of /26.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1200.3.32.0/26200.3.32.1 to 200.3.32.62200.3.32.6362
2200.3.32.64/26200.3.32.65 to 200.3.32.126200.3.32.12762
3200.3.32.128/26200.3.32.129 to 200.3.32.190200.3.32.19162
4200.3.32.192/26200.3.32.193 to 200.3.32.254200.3.32.25562
5200.3.33.0/26200.3.33.1 to 200.3.33.62200.3.33.6362
6200.3.33.64/26200.3.33.65 to 200.3.33.126200.3.33.12762
7200.3.33.128/26200.3.33.129 to 200.3.33.190200.3.33.19162
8200.3.33.192/26200.3.33.193 to 200.3.33.254200.3.33.25562
9200.3.34.0/26200.3.34.1 to 200.3.34.62200.3.34.6362
10200.3.34.64/26200.3.34.65 to 200.3.34.126200.3.34.12762
11200.3.34.128/26200.3.34.129 to 200.3.34.190200.3.34.19162
12200.3.34.192/26200.3.34.193 to 200.3.34.254200.3.34.25562
13200.3.35.0/26200.3.35.1 to 200.3.35.62200.3.35.6362
14200.3.35.64/26200.3.35.65 to 200.3.35.126200.3.35.12762
15200.3.35.128/26200.3.35.129 to 200.3.35.190200.3.35.19162
16200.3.35.192/26200.3.35.193 to 200.3.35.254200.3.35.25562
17200.3.36.0/26200.3.36.1 to 200.3.36.62200.3.36.6362
18200.3.36.64/26200.3.36.65 to 200.3.36.126200.3.36.12762
19200.3.36.128/26200.3.36.129 to 200.3.36.190200.3.36.19162
20200.3.36.192/26200.3.36.193 to 200.3.36.254200.3.36.25562
21200.3.37.0/26200.3.37.1 to 200.3.37.62200.3.37.6362
22200.3.37.64/26200.3.37.65 to 200.3.37.126200.3.37.12762
23200.3.37.128/26200.3.37.129 to 200.3.37.190200.3.37.19162
24200.3.37.192/26200.3.37.193 to 200.3.37.254200.3.37.25562
25200.3.38.0/26200.3.38.1 to 200.3.38.62200.3.38.6362
26200.3.38.64/26200.3.38.65 to 200.3.38.126200.3.38.12762
27200.3.38.128/26200.3.38.129 to 200.3.38.190200.3.38.19162
28200.3.38.192/26200.3.38.193 to 200.3.38.254200.3.38.25562
29200.3.39.0/26200.3.39.1 to 200.3.39.62200.3.39.6362
30200.3.39.64/26200.3.39.65 to 200.3.39.126200.3.39.12762
31200.3.39.128/26200.3.39.129 to 200.3.39.190200.3.39.19162
32200.3.39.192/26200.3.39.193 to 200.3.39.254200.3.39.25562
33200.3.40.0/26200.3.40.1 to 200.3.40.62200.3.40.6362
34200.3.40.64/26200.3.40.65 to 200.3.40.126200.3.40.12762
35200.3.40.128/26200.3.40.129 to 200.3.40.190200.3.40.19162
36200.3.40.192/26200.3.40.193 to 200.3.40.254200.3.40.25562
37200.3.41.0/26200.3.41.1 to 200.3.41.62200.3.41.6362
38200.3.41.64/26200.3.41.65 to 200.3.41.126200.3.41.12762
39200.3.41.128/26200.3.41.129 to 200.3.41.190200.3.41.19162
40200.3.41.192/26200.3.41.193 to 200.3.41.254200.3.41.25562
41200.3.42.0/26200.3.42.1 to 200.3.42.62200.3.42.6362
42200.3.42.64/26200.3.42.65 to 200.3.42.126200.3.42.12762
43200.3.42.128/26200.3.42.129 to 200.3.42.190200.3.42.19162
44200.3.42.192/26200.3.42.193 to 200.3.42.254200.3.42.25562
45200.3.43.0/26200.3.43.1 to 200.3.43.62200.3.43.6362
46200.3.43.64/26200.3.43.65 to 200.3.43.126200.3.43.12762
47200.3.43.128/26200.3.43.129 to 200.3.43.190200.3.43.19162
48200.3.43.192/26200.3.43.193 to 200.3.43.254200.3.43.25562
49200.3.44.0/26200.3.44.1 to 200.3.44.62200.3.44.6362
50200.3.44.64/26200.3.44.65 to 200.3.44.126200.3.44.12762
51200.3.44.128/26200.3.44.129 to 200.3.44.190200.3.44.19162
52200.3.44.192/26200.3.44.193 to 200.3.44.254200.3.44.25562
53200.3.45.0/26200.3.45.1 to 200.3.45.62200.3.45.6362
54200.3.45.64/26200.3.45.65 to 200.3.45.126200.3.45.12762
55200.3.45.128/26200.3.45.129 to 200.3.45.190200.3.45.19162
56200.3.45.192/26200.3.45.193 to 200.3.45.254200.3.45.25562
57200.3.46.0/26200.3.46.1 to 200.3.46.62200.3.46.6362
58200.3.46.64/26200.3.46.65 to 200.3.46.126200.3.46.12762
59200.3.46.128/26200.3.46.129 to 200.3.46.190200.3.46.19162
60200.3.46.192/26200.3.46.193 to 200.3.46.254200.3.46.25562
61200.3.47.0/26200.3.47.1 to 200.3.47.62200.3.47.6362
62200.3.47.64/26200.3.47.65 to 200.3.47.126200.3.47.12762
63200.3.47.128/26200.3.47.129 to 200.3.47.190200.3.47.19162
64200.3.47.192/26200.3.47.193 to 200.3.47.254200.3.47.25562
65200.3.48.0/26200.3.48.1 to 200.3.48.62200.3.48.6362
66200.3.48.64/26200.3.48.65 to 200.3.48.126200.3.48.12762
67200.3.48.128/26200.3.48.129 to 200.3.48.190200.3.48.19162
68200.3.48.192/26200.3.48.193 to 200.3.48.254200.3.48.25562
69200.3.49.0/26200.3.49.1 to 200.3.49.62200.3.49.6362
70200.3.49.64/26200.3.49.65 to 200.3.49.126200.3.49.12762
71200.3.49.128/26200.3.49.129 to 200.3.49.190200.3.49.19162
72200.3.49.192/26200.3.49.193 to 200.3.49.254200.3.49.25562
73200.3.50.0/26200.3.50.1 to 200.3.50.62200.3.50.6362
74200.3.50.64/26200.3.50.65 to 200.3.50.126200.3.50.12762
75200.3.50.128/26200.3.50.129 to 200.3.50.190200.3.50.19162
76200.3.50.192/26200.3.50.193 to 200.3.50.254200.3.50.25562
77200.3.51.0/26200.3.51.1 to 200.3.51.62200.3.51.6362
78200.3.51.64/26200.3.51.65 to 200.3.51.126200.3.51.12762
79200.3.51.128/26200.3.51.129 to 200.3.51.190200.3.51.19162
80200.3.51.192/26200.3.51.193 to 200.3.51.254200.3.51.25562
81200.3.52.0/26200.3.52.1 to 200.3.52.62200.3.52.6362
82200.3.52.64/26200.3.52.65 to 200.3.52.126200.3.52.12762
83200.3.52.128/26200.3.52.129 to 200.3.52.190200.3.52.19162
84200.3.52.192/26200.3.52.193 to 200.3.52.254200.3.52.25562
85200.3.53.0/26200.3.53.1 to 200.3.53.62200.3.53.6362
86200.3.53.64/26200.3.53.65 to 200.3.53.126200.3.53.12762
87200.3.53.128/26200.3.53.129 to 200.3.53.190200.3.53.19162
88200.3.53.192/26200.3.53.193 to 200.3.53.254200.3.53.25562
89200.3.54.0/26200.3.54.1 to 200.3.54.62200.3.54.6362
90200.3.54.64/26200.3.54.65 to 200.3.54.126200.3.54.12762
91200.3.54.128/26200.3.54.129 to 200.3.54.190200.3.54.19162
92200.3.54.192/26200.3.54.193 to 200.3.54.254200.3.54.25562
93200.3.55.0/26200.3.55.1 to 200.3.55.62200.3.55.6362
94200.3.55.64/26200.3.55.65 to 200.3.55.126200.3.55.12762
95200.3.55.128/26200.3.55.129 to 200.3.55.190200.3.55.19162
96200.3.55.192/26200.3.55.193 to 200.3.55.254200.3.55.25562
97200.3.56.0/26200.3.56.1 to 200.3.56.62200.3.56.6362
98200.3.56.64/26200.3.56.65 to 200.3.56.126200.3.56.12762
99200.3.56.128/26200.3.56.129 to 200.3.56.190200.3.56.19162
100200.3.56.192/26200.3.56.193 to 200.3.56.254200.3.56.25562
101200.3.57.0/26200.3.57.1 to 200.3.57.62200.3.57.6362
102200.3.57.64/26200.3.57.65 to 200.3.57.126200.3.57.12762
103200.3.57.128/26200.3.57.129 to 200.3.57.190200.3.57.19162
104200.3.57.192/26200.3.57.193 to 200.3.57.254200.3.57.25562
105200.3.58.0/26200.3.58.1 to 200.3.58.62200.3.58.6362
106200.3.58.64/26200.3.58.65 to 200.3.58.126200.3.58.12762
107200.3.58.128/26200.3.58.129 to 200.3.58.190200.3.58.19162
108200.3.58.192/26200.3.58.193 to 200.3.58.254200.3.58.25562
109200.3.59.0/26200.3.59.1 to 200.3.59.62200.3.59.6362
110200.3.59.64/26200.3.59.65 to 200.3.59.126200.3.59.12762
111200.3.59.128/26200.3.59.129 to 200.3.59.190200.3.59.19162
112200.3.59.192/26200.3.59.193 to 200.3.59.254200.3.59.25562
113200.3.60.0/26200.3.60.1 to 200.3.60.62200.3.60.6362
114200.3.60.64/26200.3.60.65 to 200.3.60.126200.3.60.12762
115200.3.60.128/26200.3.60.129 to 200.3.60.190200.3.60.19162
116200.3.60.192/26200.3.60.193 to 200.3.60.254200.3.60.25562
117200.3.61.0/26200.3.61.1 to 200.3.61.62200.3.61.6362
118200.3.61.64/26200.3.61.65 to 200.3.61.126200.3.61.12762
119200.3.61.128/26200.3.61.129 to 200.3.61.190200.3.61.19162
120200.3.61.192/26200.3.61.193 to 200.3.61.254200.3.61.25562
121200.3.62.0/26200.3.62.1 to 200.3.62.62200.3.62.6362
122200.3.62.64/26200.3.62.65 to 200.3.62.126200.3.62.12762
123200.3.62.128/26200.3.62.129 to 200.3.62.190200.3.62.19162
124200.3.62.192/26200.3.62.193 to 200.3.62.254200.3.62.25562
125200.3.63.0/26200.3.63.1 to 200.3.63.62200.3.63.6362
126200.3.63.64/26200.3.63.65 to 200.3.63.126200.3.63.12762
127200.3.63.128/26200.3.63.129 to 200.3.63.190200.3.63.19162
128200.3.63.192/26200.3.63.193 to 200.3.63.254200.3.63.25562

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.