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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.

Network202.2.0.0/19
Usable hosts8,190
Subnet mask255.255.224.0
Addresses8,192
Network address
202.2.0.0
Broadcast address
202.2.31.255
First usable
202.2.0.1
Last usable
202.2.31.254
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 CA020000 · Integer 3389128704 to 3389136895
Reverse DNS zones
0.2.202.in-addr.arpa
1.2.202.in-addr.arpa
2.2.202.in-addr.arpa
3.2.202.in-addr.arpa
4.2.202.in-addr.arpa
5.2.202.in-addr.arpa
6.2.202.in-addr.arpa
7.2.202.in-addr.arpa
8.2.202.in-addr.arpa
9.2.202.in-addr.arpa
10.2.202.in-addr.arpa
11.2.202.in-addr.arpa
12.2.202.in-addr.arpa
13.2.202.in-addr.arpa
14.2.202.in-addr.arpa
15.2.202.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
Address11001010.00000010.00000000.00000000202.2.0.0
Subnet mask11111111.11111111.11100000.00000000255.255.224.0
Network11001010.00000010.00000000.00000000202.2.0.0
Broadcast11001010.00000010.00011111.11111111202.2.31.255
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)

202.2.0.0/19 makes 128 subnets of /26.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1202.2.0.0/26202.2.0.1 to 202.2.0.62202.2.0.6362
2202.2.0.64/26202.2.0.65 to 202.2.0.126202.2.0.12762
3202.2.0.128/26202.2.0.129 to 202.2.0.190202.2.0.19162
4202.2.0.192/26202.2.0.193 to 202.2.0.254202.2.0.25562
5202.2.1.0/26202.2.1.1 to 202.2.1.62202.2.1.6362
6202.2.1.64/26202.2.1.65 to 202.2.1.126202.2.1.12762
7202.2.1.128/26202.2.1.129 to 202.2.1.190202.2.1.19162
8202.2.1.192/26202.2.1.193 to 202.2.1.254202.2.1.25562
9202.2.2.0/26202.2.2.1 to 202.2.2.62202.2.2.6362
10202.2.2.64/26202.2.2.65 to 202.2.2.126202.2.2.12762
11202.2.2.128/26202.2.2.129 to 202.2.2.190202.2.2.19162
12202.2.2.192/26202.2.2.193 to 202.2.2.254202.2.2.25562
13202.2.3.0/26202.2.3.1 to 202.2.3.62202.2.3.6362
14202.2.3.64/26202.2.3.65 to 202.2.3.126202.2.3.12762
15202.2.3.128/26202.2.3.129 to 202.2.3.190202.2.3.19162
16202.2.3.192/26202.2.3.193 to 202.2.3.254202.2.3.25562
17202.2.4.0/26202.2.4.1 to 202.2.4.62202.2.4.6362
18202.2.4.64/26202.2.4.65 to 202.2.4.126202.2.4.12762
19202.2.4.128/26202.2.4.129 to 202.2.4.190202.2.4.19162
20202.2.4.192/26202.2.4.193 to 202.2.4.254202.2.4.25562
21202.2.5.0/26202.2.5.1 to 202.2.5.62202.2.5.6362
22202.2.5.64/26202.2.5.65 to 202.2.5.126202.2.5.12762
23202.2.5.128/26202.2.5.129 to 202.2.5.190202.2.5.19162
24202.2.5.192/26202.2.5.193 to 202.2.5.254202.2.5.25562
25202.2.6.0/26202.2.6.1 to 202.2.6.62202.2.6.6362
26202.2.6.64/26202.2.6.65 to 202.2.6.126202.2.6.12762
27202.2.6.128/26202.2.6.129 to 202.2.6.190202.2.6.19162
28202.2.6.192/26202.2.6.193 to 202.2.6.254202.2.6.25562
29202.2.7.0/26202.2.7.1 to 202.2.7.62202.2.7.6362
30202.2.7.64/26202.2.7.65 to 202.2.7.126202.2.7.12762
31202.2.7.128/26202.2.7.129 to 202.2.7.190202.2.7.19162
32202.2.7.192/26202.2.7.193 to 202.2.7.254202.2.7.25562
33202.2.8.0/26202.2.8.1 to 202.2.8.62202.2.8.6362
34202.2.8.64/26202.2.8.65 to 202.2.8.126202.2.8.12762
35202.2.8.128/26202.2.8.129 to 202.2.8.190202.2.8.19162
36202.2.8.192/26202.2.8.193 to 202.2.8.254202.2.8.25562
37202.2.9.0/26202.2.9.1 to 202.2.9.62202.2.9.6362
38202.2.9.64/26202.2.9.65 to 202.2.9.126202.2.9.12762
39202.2.9.128/26202.2.9.129 to 202.2.9.190202.2.9.19162
40202.2.9.192/26202.2.9.193 to 202.2.9.254202.2.9.25562
41202.2.10.0/26202.2.10.1 to 202.2.10.62202.2.10.6362
42202.2.10.64/26202.2.10.65 to 202.2.10.126202.2.10.12762
43202.2.10.128/26202.2.10.129 to 202.2.10.190202.2.10.19162
44202.2.10.192/26202.2.10.193 to 202.2.10.254202.2.10.25562
45202.2.11.0/26202.2.11.1 to 202.2.11.62202.2.11.6362
46202.2.11.64/26202.2.11.65 to 202.2.11.126202.2.11.12762
47202.2.11.128/26202.2.11.129 to 202.2.11.190202.2.11.19162
48202.2.11.192/26202.2.11.193 to 202.2.11.254202.2.11.25562
49202.2.12.0/26202.2.12.1 to 202.2.12.62202.2.12.6362
50202.2.12.64/26202.2.12.65 to 202.2.12.126202.2.12.12762
51202.2.12.128/26202.2.12.129 to 202.2.12.190202.2.12.19162
52202.2.12.192/26202.2.12.193 to 202.2.12.254202.2.12.25562
53202.2.13.0/26202.2.13.1 to 202.2.13.62202.2.13.6362
54202.2.13.64/26202.2.13.65 to 202.2.13.126202.2.13.12762
55202.2.13.128/26202.2.13.129 to 202.2.13.190202.2.13.19162
56202.2.13.192/26202.2.13.193 to 202.2.13.254202.2.13.25562
57202.2.14.0/26202.2.14.1 to 202.2.14.62202.2.14.6362
58202.2.14.64/26202.2.14.65 to 202.2.14.126202.2.14.12762
59202.2.14.128/26202.2.14.129 to 202.2.14.190202.2.14.19162
60202.2.14.192/26202.2.14.193 to 202.2.14.254202.2.14.25562
61202.2.15.0/26202.2.15.1 to 202.2.15.62202.2.15.6362
62202.2.15.64/26202.2.15.65 to 202.2.15.126202.2.15.12762
63202.2.15.128/26202.2.15.129 to 202.2.15.190202.2.15.19162
64202.2.15.192/26202.2.15.193 to 202.2.15.254202.2.15.25562
65202.2.16.0/26202.2.16.1 to 202.2.16.62202.2.16.6362
66202.2.16.64/26202.2.16.65 to 202.2.16.126202.2.16.12762
67202.2.16.128/26202.2.16.129 to 202.2.16.190202.2.16.19162
68202.2.16.192/26202.2.16.193 to 202.2.16.254202.2.16.25562
69202.2.17.0/26202.2.17.1 to 202.2.17.62202.2.17.6362
70202.2.17.64/26202.2.17.65 to 202.2.17.126202.2.17.12762
71202.2.17.128/26202.2.17.129 to 202.2.17.190202.2.17.19162
72202.2.17.192/26202.2.17.193 to 202.2.17.254202.2.17.25562
73202.2.18.0/26202.2.18.1 to 202.2.18.62202.2.18.6362
74202.2.18.64/26202.2.18.65 to 202.2.18.126202.2.18.12762
75202.2.18.128/26202.2.18.129 to 202.2.18.190202.2.18.19162
76202.2.18.192/26202.2.18.193 to 202.2.18.254202.2.18.25562
77202.2.19.0/26202.2.19.1 to 202.2.19.62202.2.19.6362
78202.2.19.64/26202.2.19.65 to 202.2.19.126202.2.19.12762
79202.2.19.128/26202.2.19.129 to 202.2.19.190202.2.19.19162
80202.2.19.192/26202.2.19.193 to 202.2.19.254202.2.19.25562
81202.2.20.0/26202.2.20.1 to 202.2.20.62202.2.20.6362
82202.2.20.64/26202.2.20.65 to 202.2.20.126202.2.20.12762
83202.2.20.128/26202.2.20.129 to 202.2.20.190202.2.20.19162
84202.2.20.192/26202.2.20.193 to 202.2.20.254202.2.20.25562
85202.2.21.0/26202.2.21.1 to 202.2.21.62202.2.21.6362
86202.2.21.64/26202.2.21.65 to 202.2.21.126202.2.21.12762
87202.2.21.128/26202.2.21.129 to 202.2.21.190202.2.21.19162
88202.2.21.192/26202.2.21.193 to 202.2.21.254202.2.21.25562
89202.2.22.0/26202.2.22.1 to 202.2.22.62202.2.22.6362
90202.2.22.64/26202.2.22.65 to 202.2.22.126202.2.22.12762
91202.2.22.128/26202.2.22.129 to 202.2.22.190202.2.22.19162
92202.2.22.192/26202.2.22.193 to 202.2.22.254202.2.22.25562
93202.2.23.0/26202.2.23.1 to 202.2.23.62202.2.23.6362
94202.2.23.64/26202.2.23.65 to 202.2.23.126202.2.23.12762
95202.2.23.128/26202.2.23.129 to 202.2.23.190202.2.23.19162
96202.2.23.192/26202.2.23.193 to 202.2.23.254202.2.23.25562
97202.2.24.0/26202.2.24.1 to 202.2.24.62202.2.24.6362
98202.2.24.64/26202.2.24.65 to 202.2.24.126202.2.24.12762
99202.2.24.128/26202.2.24.129 to 202.2.24.190202.2.24.19162
100202.2.24.192/26202.2.24.193 to 202.2.24.254202.2.24.25562
101202.2.25.0/26202.2.25.1 to 202.2.25.62202.2.25.6362
102202.2.25.64/26202.2.25.65 to 202.2.25.126202.2.25.12762
103202.2.25.128/26202.2.25.129 to 202.2.25.190202.2.25.19162
104202.2.25.192/26202.2.25.193 to 202.2.25.254202.2.25.25562
105202.2.26.0/26202.2.26.1 to 202.2.26.62202.2.26.6362
106202.2.26.64/26202.2.26.65 to 202.2.26.126202.2.26.12762
107202.2.26.128/26202.2.26.129 to 202.2.26.190202.2.26.19162
108202.2.26.192/26202.2.26.193 to 202.2.26.254202.2.26.25562
109202.2.27.0/26202.2.27.1 to 202.2.27.62202.2.27.6362
110202.2.27.64/26202.2.27.65 to 202.2.27.126202.2.27.12762
111202.2.27.128/26202.2.27.129 to 202.2.27.190202.2.27.19162
112202.2.27.192/26202.2.27.193 to 202.2.27.254202.2.27.25562
113202.2.28.0/26202.2.28.1 to 202.2.28.62202.2.28.6362
114202.2.28.64/26202.2.28.65 to 202.2.28.126202.2.28.12762
115202.2.28.128/26202.2.28.129 to 202.2.28.190202.2.28.19162
116202.2.28.192/26202.2.28.193 to 202.2.28.254202.2.28.25562
117202.2.29.0/26202.2.29.1 to 202.2.29.62202.2.29.6362
118202.2.29.64/26202.2.29.65 to 202.2.29.126202.2.29.12762
119202.2.29.128/26202.2.29.129 to 202.2.29.190202.2.29.19162
120202.2.29.192/26202.2.29.193 to 202.2.29.254202.2.29.25562
121202.2.30.0/26202.2.30.1 to 202.2.30.62202.2.30.6362
122202.2.30.64/26202.2.30.65 to 202.2.30.126202.2.30.12762
123202.2.30.128/26202.2.30.129 to 202.2.30.190202.2.30.19162
124202.2.30.192/26202.2.30.193 to 202.2.30.254202.2.30.25562
125202.2.31.0/26202.2.31.1 to 202.2.31.62202.2.31.6362
126202.2.31.64/26202.2.31.65 to 202.2.31.126202.2.31.12762
127202.2.31.128/26202.2.31.129 to 202.2.31.190202.2.31.19162
128202.2.31.192/26202.2.31.193 to 202.2.31.254202.2.31.25562

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.