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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.

Network228.57.80.0/23
Usable hosts510
Subnet mask255.255.254.0
Addresses512
Network address
228.57.80.0
Broadcast address
228.57.81.255
First usable
228.57.80.1
Last usable
228.57.81.254
Usable hosts
510 (512 less the network and broadcast addresses)
Subnet mask
255.255.254.0
Wildcard mask
0.0.1.255 (Cisco ACLs, OSPF)
Prefix length
/23
Type
Multicast 224.0.0.0/4
One-to-many traffic, such as IPTV and routing protocols
Old class
D (multicast)
As numbers
Hex E4395000 · Integer 3828961280 to 3828961791
Reverse DNS zones
80.57.228.in-addr.arpa
81.57.228.in-addr.arpa
/23 is not on a 8-bit boundary, so it takes 2 /24 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address11100100.00111001.01010000.00000000228.57.80.0
Subnet mask11111111.11111111.11111110.00000000255.255.254.0
Network11100100.00111001.01010000.00000000228.57.80.0
Broadcast11100100.00111001.01010001.11111111228.57.81.255
Split into smaller subnets/30
/24 (2)/25 (4)/26 (8)/27 (16)/28 (32)/29 (64)/30 (128)/31 (256)/32 (512)

228.57.80.0/23 makes 128 subnets of /30.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1228.57.80.0/30228.57.80.1 to 228.57.80.2228.57.80.32
2228.57.80.4/30228.57.80.5 to 228.57.80.6228.57.80.72
3228.57.80.8/30228.57.80.9 to 228.57.80.10228.57.80.112
4228.57.80.12/30228.57.80.13 to 228.57.80.14228.57.80.152
5228.57.80.16/30228.57.80.17 to 228.57.80.18228.57.80.192
6228.57.80.20/30228.57.80.21 to 228.57.80.22228.57.80.232
7228.57.80.24/30228.57.80.25 to 228.57.80.26228.57.80.272
8228.57.80.28/30228.57.80.29 to 228.57.80.30228.57.80.312
9228.57.80.32/30228.57.80.33 to 228.57.80.34228.57.80.352
10228.57.80.36/30228.57.80.37 to 228.57.80.38228.57.80.392
11228.57.80.40/30228.57.80.41 to 228.57.80.42228.57.80.432
12228.57.80.44/30228.57.80.45 to 228.57.80.46228.57.80.472
13228.57.80.48/30228.57.80.49 to 228.57.80.50228.57.80.512
14228.57.80.52/30228.57.80.53 to 228.57.80.54228.57.80.552
15228.57.80.56/30228.57.80.57 to 228.57.80.58228.57.80.592
16228.57.80.60/30228.57.80.61 to 228.57.80.62228.57.80.632
17228.57.80.64/30228.57.80.65 to 228.57.80.66228.57.80.672
18228.57.80.68/30228.57.80.69 to 228.57.80.70228.57.80.712
19228.57.80.72/30228.57.80.73 to 228.57.80.74228.57.80.752
20228.57.80.76/30228.57.80.77 to 228.57.80.78228.57.80.792
21228.57.80.80/30228.57.80.81 to 228.57.80.82228.57.80.832
22228.57.80.84/30228.57.80.85 to 228.57.80.86228.57.80.872
23228.57.80.88/30228.57.80.89 to 228.57.80.90228.57.80.912
24228.57.80.92/30228.57.80.93 to 228.57.80.94228.57.80.952
25228.57.80.96/30228.57.80.97 to 228.57.80.98228.57.80.992
26228.57.80.100/30228.57.80.101 to 228.57.80.102228.57.80.1032
27228.57.80.104/30228.57.80.105 to 228.57.80.106228.57.80.1072
28228.57.80.108/30228.57.80.109 to 228.57.80.110228.57.80.1112
29228.57.80.112/30228.57.80.113 to 228.57.80.114228.57.80.1152
30228.57.80.116/30228.57.80.117 to 228.57.80.118228.57.80.1192
31228.57.80.120/30228.57.80.121 to 228.57.80.122228.57.80.1232
32228.57.80.124/30228.57.80.125 to 228.57.80.126228.57.80.1272
33228.57.80.128/30228.57.80.129 to 228.57.80.130228.57.80.1312
34228.57.80.132/30228.57.80.133 to 228.57.80.134228.57.80.1352
35228.57.80.136/30228.57.80.137 to 228.57.80.138228.57.80.1392
36228.57.80.140/30228.57.80.141 to 228.57.80.142228.57.80.1432
37228.57.80.144/30228.57.80.145 to 228.57.80.146228.57.80.1472
38228.57.80.148/30228.57.80.149 to 228.57.80.150228.57.80.1512
39228.57.80.152/30228.57.80.153 to 228.57.80.154228.57.80.1552
40228.57.80.156/30228.57.80.157 to 228.57.80.158228.57.80.1592
41228.57.80.160/30228.57.80.161 to 228.57.80.162228.57.80.1632
42228.57.80.164/30228.57.80.165 to 228.57.80.166228.57.80.1672
43228.57.80.168/30228.57.80.169 to 228.57.80.170228.57.80.1712
44228.57.80.172/30228.57.80.173 to 228.57.80.174228.57.80.1752
45228.57.80.176/30228.57.80.177 to 228.57.80.178228.57.80.1792
46228.57.80.180/30228.57.80.181 to 228.57.80.182228.57.80.1832
47228.57.80.184/30228.57.80.185 to 228.57.80.186228.57.80.1872
48228.57.80.188/30228.57.80.189 to 228.57.80.190228.57.80.1912
49228.57.80.192/30228.57.80.193 to 228.57.80.194228.57.80.1952
50228.57.80.196/30228.57.80.197 to 228.57.80.198228.57.80.1992
51228.57.80.200/30228.57.80.201 to 228.57.80.202228.57.80.2032
52228.57.80.204/30228.57.80.205 to 228.57.80.206228.57.80.2072
53228.57.80.208/30228.57.80.209 to 228.57.80.210228.57.80.2112
54228.57.80.212/30228.57.80.213 to 228.57.80.214228.57.80.2152
55228.57.80.216/30228.57.80.217 to 228.57.80.218228.57.80.2192
56228.57.80.220/30228.57.80.221 to 228.57.80.222228.57.80.2232
57228.57.80.224/30228.57.80.225 to 228.57.80.226228.57.80.2272
58228.57.80.228/30228.57.80.229 to 228.57.80.230228.57.80.2312
59228.57.80.232/30228.57.80.233 to 228.57.80.234228.57.80.2352
60228.57.80.236/30228.57.80.237 to 228.57.80.238228.57.80.2392
61228.57.80.240/30228.57.80.241 to 228.57.80.242228.57.80.2432
62228.57.80.244/30228.57.80.245 to 228.57.80.246228.57.80.2472
63228.57.80.248/30228.57.80.249 to 228.57.80.250228.57.80.2512
64228.57.80.252/30228.57.80.253 to 228.57.80.254228.57.80.2552
65228.57.81.0/30228.57.81.1 to 228.57.81.2228.57.81.32
66228.57.81.4/30228.57.81.5 to 228.57.81.6228.57.81.72
67228.57.81.8/30228.57.81.9 to 228.57.81.10228.57.81.112
68228.57.81.12/30228.57.81.13 to 228.57.81.14228.57.81.152
69228.57.81.16/30228.57.81.17 to 228.57.81.18228.57.81.192
70228.57.81.20/30228.57.81.21 to 228.57.81.22228.57.81.232
71228.57.81.24/30228.57.81.25 to 228.57.81.26228.57.81.272
72228.57.81.28/30228.57.81.29 to 228.57.81.30228.57.81.312
73228.57.81.32/30228.57.81.33 to 228.57.81.34228.57.81.352
74228.57.81.36/30228.57.81.37 to 228.57.81.38228.57.81.392
75228.57.81.40/30228.57.81.41 to 228.57.81.42228.57.81.432
76228.57.81.44/30228.57.81.45 to 228.57.81.46228.57.81.472
77228.57.81.48/30228.57.81.49 to 228.57.81.50228.57.81.512
78228.57.81.52/30228.57.81.53 to 228.57.81.54228.57.81.552
79228.57.81.56/30228.57.81.57 to 228.57.81.58228.57.81.592
80228.57.81.60/30228.57.81.61 to 228.57.81.62228.57.81.632
81228.57.81.64/30228.57.81.65 to 228.57.81.66228.57.81.672
82228.57.81.68/30228.57.81.69 to 228.57.81.70228.57.81.712
83228.57.81.72/30228.57.81.73 to 228.57.81.74228.57.81.752
84228.57.81.76/30228.57.81.77 to 228.57.81.78228.57.81.792
85228.57.81.80/30228.57.81.81 to 228.57.81.82228.57.81.832
86228.57.81.84/30228.57.81.85 to 228.57.81.86228.57.81.872
87228.57.81.88/30228.57.81.89 to 228.57.81.90228.57.81.912
88228.57.81.92/30228.57.81.93 to 228.57.81.94228.57.81.952
89228.57.81.96/30228.57.81.97 to 228.57.81.98228.57.81.992
90228.57.81.100/30228.57.81.101 to 228.57.81.102228.57.81.1032
91228.57.81.104/30228.57.81.105 to 228.57.81.106228.57.81.1072
92228.57.81.108/30228.57.81.109 to 228.57.81.110228.57.81.1112
93228.57.81.112/30228.57.81.113 to 228.57.81.114228.57.81.1152
94228.57.81.116/30228.57.81.117 to 228.57.81.118228.57.81.1192
95228.57.81.120/30228.57.81.121 to 228.57.81.122228.57.81.1232
96228.57.81.124/30228.57.81.125 to 228.57.81.126228.57.81.1272
97228.57.81.128/30228.57.81.129 to 228.57.81.130228.57.81.1312
98228.57.81.132/30228.57.81.133 to 228.57.81.134228.57.81.1352
99228.57.81.136/30228.57.81.137 to 228.57.81.138228.57.81.1392
100228.57.81.140/30228.57.81.141 to 228.57.81.142228.57.81.1432
101228.57.81.144/30228.57.81.145 to 228.57.81.146228.57.81.1472
102228.57.81.148/30228.57.81.149 to 228.57.81.150228.57.81.1512
103228.57.81.152/30228.57.81.153 to 228.57.81.154228.57.81.1552
104228.57.81.156/30228.57.81.157 to 228.57.81.158228.57.81.1592
105228.57.81.160/30228.57.81.161 to 228.57.81.162228.57.81.1632
106228.57.81.164/30228.57.81.165 to 228.57.81.166228.57.81.1672
107228.57.81.168/30228.57.81.169 to 228.57.81.170228.57.81.1712
108228.57.81.172/30228.57.81.173 to 228.57.81.174228.57.81.1752
109228.57.81.176/30228.57.81.177 to 228.57.81.178228.57.81.1792
110228.57.81.180/30228.57.81.181 to 228.57.81.182228.57.81.1832
111228.57.81.184/30228.57.81.185 to 228.57.81.186228.57.81.1872
112228.57.81.188/30228.57.81.189 to 228.57.81.190228.57.81.1912
113228.57.81.192/30228.57.81.193 to 228.57.81.194228.57.81.1952
114228.57.81.196/30228.57.81.197 to 228.57.81.198228.57.81.1992
115228.57.81.200/30228.57.81.201 to 228.57.81.202228.57.81.2032
116228.57.81.204/30228.57.81.205 to 228.57.81.206228.57.81.2072
117228.57.81.208/30228.57.81.209 to 228.57.81.210228.57.81.2112
118228.57.81.212/30228.57.81.213 to 228.57.81.214228.57.81.2152
119228.57.81.216/30228.57.81.217 to 228.57.81.218228.57.81.2192
120228.57.81.220/30228.57.81.221 to 228.57.81.222228.57.81.2232
121228.57.81.224/30228.57.81.225 to 228.57.81.226228.57.81.2272
122228.57.81.228/30228.57.81.229 to 228.57.81.230228.57.81.2312
123228.57.81.232/30228.57.81.233 to 228.57.81.234228.57.81.2352
124228.57.81.236/30228.57.81.237 to 228.57.81.238228.57.81.2392
125228.57.81.240/30228.57.81.241 to 228.57.81.242228.57.81.2432
126228.57.81.244/30228.57.81.245 to 228.57.81.246228.57.81.2472
127228.57.81.248/30228.57.81.249 to 228.57.81.250228.57.81.2512
128228.57.81.252/30228.57.81.253 to 228.57.81.254228.57.81.2552

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.