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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.

Network228.0.0.0/12
Usable hosts1,048,574
Subnet mask255.240.0.0
Addresses1,048,576
Network address
228.0.0.0
Broadcast address
228.15.255.255
First usable
228.0.0.1
Last usable
228.15.255.254
Usable hosts
1,048,574 (1,048,576 less the network and broadcast addresses)
Subnet mask
255.240.0.0
Wildcard mask
0.15.255.255 (Cisco ACLs, OSPF)
Prefix length
/12
Type
Multicast 224.0.0.0/4
One-to-many traffic, such as IPTV and routing protocols
Old class
D (multicast)
As numbers
Hex E4000000 · Integer 3825205248 to 3826253823
Reverse DNS zones
0.228.in-addr.arpa
1.228.in-addr.arpa
2.228.in-addr.arpa
3.228.in-addr.arpa
4.228.in-addr.arpa
5.228.in-addr.arpa
6.228.in-addr.arpa
7.228.in-addr.arpa
8.228.in-addr.arpa
9.228.in-addr.arpa
10.228.in-addr.arpa
11.228.in-addr.arpa
12.228.in-addr.arpa
13.228.in-addr.arpa
14.228.in-addr.arpa
15.228.in-addr.arpa
/12 is not on a 8-bit boundary, so it takes 16 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address11100100.00000000.00000000.00000000228.0.0.0
Subnet mask11111111.11110000.00000000.00000000255.240.0.0
Network11100100.00000000.00000000.00000000228.0.0.0
Broadcast11100100.00001111.11111111.11111111228.15.255.255
Split into smaller subnets/19
/13 (2)/14 (4)/15 (8)/16 (16)/17 (32)/18 (64)/19 (128)/20 (256)/21 (512)/22 (1,024)/23 (2,048)/24 (4,096)

228.0.0.0/12 makes 128 subnets of /19.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1228.0.0.0/19228.0.0.1 to 228.0.31.254228.0.31.2558,190
2228.0.32.0/19228.0.32.1 to 228.0.63.254228.0.63.2558,190
3228.0.64.0/19228.0.64.1 to 228.0.95.254228.0.95.2558,190
4228.0.96.0/19228.0.96.1 to 228.0.127.254228.0.127.2558,190
5228.0.128.0/19228.0.128.1 to 228.0.159.254228.0.159.2558,190
6228.0.160.0/19228.0.160.1 to 228.0.191.254228.0.191.2558,190
7228.0.192.0/19228.0.192.1 to 228.0.223.254228.0.223.2558,190
8228.0.224.0/19228.0.224.1 to 228.0.255.254228.0.255.2558,190
9228.1.0.0/19228.1.0.1 to 228.1.31.254228.1.31.2558,190
10228.1.32.0/19228.1.32.1 to 228.1.63.254228.1.63.2558,190
11228.1.64.0/19228.1.64.1 to 228.1.95.254228.1.95.2558,190
12228.1.96.0/19228.1.96.1 to 228.1.127.254228.1.127.2558,190
13228.1.128.0/19228.1.128.1 to 228.1.159.254228.1.159.2558,190
14228.1.160.0/19228.1.160.1 to 228.1.191.254228.1.191.2558,190
15228.1.192.0/19228.1.192.1 to 228.1.223.254228.1.223.2558,190
16228.1.224.0/19228.1.224.1 to 228.1.255.254228.1.255.2558,190
17228.2.0.0/19228.2.0.1 to 228.2.31.254228.2.31.2558,190
18228.2.32.0/19228.2.32.1 to 228.2.63.254228.2.63.2558,190
19228.2.64.0/19228.2.64.1 to 228.2.95.254228.2.95.2558,190
20228.2.96.0/19228.2.96.1 to 228.2.127.254228.2.127.2558,190
21228.2.128.0/19228.2.128.1 to 228.2.159.254228.2.159.2558,190
22228.2.160.0/19228.2.160.1 to 228.2.191.254228.2.191.2558,190
23228.2.192.0/19228.2.192.1 to 228.2.223.254228.2.223.2558,190
24228.2.224.0/19228.2.224.1 to 228.2.255.254228.2.255.2558,190
25228.3.0.0/19228.3.0.1 to 228.3.31.254228.3.31.2558,190
26228.3.32.0/19228.3.32.1 to 228.3.63.254228.3.63.2558,190
27228.3.64.0/19228.3.64.1 to 228.3.95.254228.3.95.2558,190
28228.3.96.0/19228.3.96.1 to 228.3.127.254228.3.127.2558,190
29228.3.128.0/19228.3.128.1 to 228.3.159.254228.3.159.2558,190
30228.3.160.0/19228.3.160.1 to 228.3.191.254228.3.191.2558,190
31228.3.192.0/19228.3.192.1 to 228.3.223.254228.3.223.2558,190
32228.3.224.0/19228.3.224.1 to 228.3.255.254228.3.255.2558,190
33228.4.0.0/19228.4.0.1 to 228.4.31.254228.4.31.2558,190
34228.4.32.0/19228.4.32.1 to 228.4.63.254228.4.63.2558,190
35228.4.64.0/19228.4.64.1 to 228.4.95.254228.4.95.2558,190
36228.4.96.0/19228.4.96.1 to 228.4.127.254228.4.127.2558,190
37228.4.128.0/19228.4.128.1 to 228.4.159.254228.4.159.2558,190
38228.4.160.0/19228.4.160.1 to 228.4.191.254228.4.191.2558,190
39228.4.192.0/19228.4.192.1 to 228.4.223.254228.4.223.2558,190
40228.4.224.0/19228.4.224.1 to 228.4.255.254228.4.255.2558,190
41228.5.0.0/19228.5.0.1 to 228.5.31.254228.5.31.2558,190
42228.5.32.0/19228.5.32.1 to 228.5.63.254228.5.63.2558,190
43228.5.64.0/19228.5.64.1 to 228.5.95.254228.5.95.2558,190
44228.5.96.0/19228.5.96.1 to 228.5.127.254228.5.127.2558,190
45228.5.128.0/19228.5.128.1 to 228.5.159.254228.5.159.2558,190
46228.5.160.0/19228.5.160.1 to 228.5.191.254228.5.191.2558,190
47228.5.192.0/19228.5.192.1 to 228.5.223.254228.5.223.2558,190
48228.5.224.0/19228.5.224.1 to 228.5.255.254228.5.255.2558,190
49228.6.0.0/19228.6.0.1 to 228.6.31.254228.6.31.2558,190
50228.6.32.0/19228.6.32.1 to 228.6.63.254228.6.63.2558,190
51228.6.64.0/19228.6.64.1 to 228.6.95.254228.6.95.2558,190
52228.6.96.0/19228.6.96.1 to 228.6.127.254228.6.127.2558,190
53228.6.128.0/19228.6.128.1 to 228.6.159.254228.6.159.2558,190
54228.6.160.0/19228.6.160.1 to 228.6.191.254228.6.191.2558,190
55228.6.192.0/19228.6.192.1 to 228.6.223.254228.6.223.2558,190
56228.6.224.0/19228.6.224.1 to 228.6.255.254228.6.255.2558,190
57228.7.0.0/19228.7.0.1 to 228.7.31.254228.7.31.2558,190
58228.7.32.0/19228.7.32.1 to 228.7.63.254228.7.63.2558,190
59228.7.64.0/19228.7.64.1 to 228.7.95.254228.7.95.2558,190
60228.7.96.0/19228.7.96.1 to 228.7.127.254228.7.127.2558,190
61228.7.128.0/19228.7.128.1 to 228.7.159.254228.7.159.2558,190
62228.7.160.0/19228.7.160.1 to 228.7.191.254228.7.191.2558,190
63228.7.192.0/19228.7.192.1 to 228.7.223.254228.7.223.2558,190
64228.7.224.0/19228.7.224.1 to 228.7.255.254228.7.255.2558,190
65228.8.0.0/19228.8.0.1 to 228.8.31.254228.8.31.2558,190
66228.8.32.0/19228.8.32.1 to 228.8.63.254228.8.63.2558,190
67228.8.64.0/19228.8.64.1 to 228.8.95.254228.8.95.2558,190
68228.8.96.0/19228.8.96.1 to 228.8.127.254228.8.127.2558,190
69228.8.128.0/19228.8.128.1 to 228.8.159.254228.8.159.2558,190
70228.8.160.0/19228.8.160.1 to 228.8.191.254228.8.191.2558,190
71228.8.192.0/19228.8.192.1 to 228.8.223.254228.8.223.2558,190
72228.8.224.0/19228.8.224.1 to 228.8.255.254228.8.255.2558,190
73228.9.0.0/19228.9.0.1 to 228.9.31.254228.9.31.2558,190
74228.9.32.0/19228.9.32.1 to 228.9.63.254228.9.63.2558,190
75228.9.64.0/19228.9.64.1 to 228.9.95.254228.9.95.2558,190
76228.9.96.0/19228.9.96.1 to 228.9.127.254228.9.127.2558,190
77228.9.128.0/19228.9.128.1 to 228.9.159.254228.9.159.2558,190
78228.9.160.0/19228.9.160.1 to 228.9.191.254228.9.191.2558,190
79228.9.192.0/19228.9.192.1 to 228.9.223.254228.9.223.2558,190
80228.9.224.0/19228.9.224.1 to 228.9.255.254228.9.255.2558,190
81228.10.0.0/19228.10.0.1 to 228.10.31.254228.10.31.2558,190
82228.10.32.0/19228.10.32.1 to 228.10.63.254228.10.63.2558,190
83228.10.64.0/19228.10.64.1 to 228.10.95.254228.10.95.2558,190
84228.10.96.0/19228.10.96.1 to 228.10.127.254228.10.127.2558,190
85228.10.128.0/19228.10.128.1 to 228.10.159.254228.10.159.2558,190
86228.10.160.0/19228.10.160.1 to 228.10.191.254228.10.191.2558,190
87228.10.192.0/19228.10.192.1 to 228.10.223.254228.10.223.2558,190
88228.10.224.0/19228.10.224.1 to 228.10.255.254228.10.255.2558,190
89228.11.0.0/19228.11.0.1 to 228.11.31.254228.11.31.2558,190
90228.11.32.0/19228.11.32.1 to 228.11.63.254228.11.63.2558,190
91228.11.64.0/19228.11.64.1 to 228.11.95.254228.11.95.2558,190
92228.11.96.0/19228.11.96.1 to 228.11.127.254228.11.127.2558,190
93228.11.128.0/19228.11.128.1 to 228.11.159.254228.11.159.2558,190
94228.11.160.0/19228.11.160.1 to 228.11.191.254228.11.191.2558,190
95228.11.192.0/19228.11.192.1 to 228.11.223.254228.11.223.2558,190
96228.11.224.0/19228.11.224.1 to 228.11.255.254228.11.255.2558,190
97228.12.0.0/19228.12.0.1 to 228.12.31.254228.12.31.2558,190
98228.12.32.0/19228.12.32.1 to 228.12.63.254228.12.63.2558,190
99228.12.64.0/19228.12.64.1 to 228.12.95.254228.12.95.2558,190
100228.12.96.0/19228.12.96.1 to 228.12.127.254228.12.127.2558,190
101228.12.128.0/19228.12.128.1 to 228.12.159.254228.12.159.2558,190
102228.12.160.0/19228.12.160.1 to 228.12.191.254228.12.191.2558,190
103228.12.192.0/19228.12.192.1 to 228.12.223.254228.12.223.2558,190
104228.12.224.0/19228.12.224.1 to 228.12.255.254228.12.255.2558,190
105228.13.0.0/19228.13.0.1 to 228.13.31.254228.13.31.2558,190
106228.13.32.0/19228.13.32.1 to 228.13.63.254228.13.63.2558,190
107228.13.64.0/19228.13.64.1 to 228.13.95.254228.13.95.2558,190
108228.13.96.0/19228.13.96.1 to 228.13.127.254228.13.127.2558,190
109228.13.128.0/19228.13.128.1 to 228.13.159.254228.13.159.2558,190
110228.13.160.0/19228.13.160.1 to 228.13.191.254228.13.191.2558,190
111228.13.192.0/19228.13.192.1 to 228.13.223.254228.13.223.2558,190
112228.13.224.0/19228.13.224.1 to 228.13.255.254228.13.255.2558,190
113228.14.0.0/19228.14.0.1 to 228.14.31.254228.14.31.2558,190
114228.14.32.0/19228.14.32.1 to 228.14.63.254228.14.63.2558,190
115228.14.64.0/19228.14.64.1 to 228.14.95.254228.14.95.2558,190
116228.14.96.0/19228.14.96.1 to 228.14.127.254228.14.127.2558,190
117228.14.128.0/19228.14.128.1 to 228.14.159.254228.14.159.2558,190
118228.14.160.0/19228.14.160.1 to 228.14.191.254228.14.191.2558,190
119228.14.192.0/19228.14.192.1 to 228.14.223.254228.14.223.2558,190
120228.14.224.0/19228.14.224.1 to 228.14.255.254228.14.255.2558,190
121228.15.0.0/19228.15.0.1 to 228.15.31.254228.15.31.2558,190
122228.15.32.0/19228.15.32.1 to 228.15.63.254228.15.63.2558,190
123228.15.64.0/19228.15.64.1 to 228.15.95.254228.15.95.2558,190
124228.15.96.0/19228.15.96.1 to 228.15.127.254228.15.127.2558,190
125228.15.128.0/19228.15.128.1 to 228.15.159.254228.15.159.2558,190
126228.15.160.0/19228.15.160.1 to 228.15.191.254228.15.191.2558,190
127228.15.192.0/19228.15.192.1 to 228.15.223.254228.15.223.2558,190
128228.15.224.0/19228.15.224.1 to 228.15.255.254228.15.255.2558,190

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.