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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.

Network228.24.0.0/13
Usable hosts524,286
Subnet mask255.248.0.0
Addresses524,288
Network address
228.24.0.0
Broadcast address
228.31.255.255
First usable
228.24.0.1
Last usable
228.31.255.254
Usable hosts
524,286 (524,288 less the network and broadcast addresses)
Subnet mask
255.248.0.0
Wildcard mask
0.7.255.255 (Cisco ACLs, OSPF)
Prefix length
/13
Type
Multicast 224.0.0.0/4
One-to-many traffic, such as IPTV and routing protocols
Old class
D (multicast)
As numbers
Hex E4180000 · Integer 3826778112 to 3827302399
Reverse DNS zones
24.228.in-addr.arpa
25.228.in-addr.arpa
26.228.in-addr.arpa
27.228.in-addr.arpa
28.228.in-addr.arpa
29.228.in-addr.arpa
30.228.in-addr.arpa
31.228.in-addr.arpa
/13 is not on a 8-bit boundary, so it takes 8 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address11100100.00011000.00000000.00000000228.24.0.0
Subnet mask11111111.11111000.00000000.00000000255.248.0.0
Network11100100.00011000.00000000.00000000228.24.0.0
Broadcast11100100.00011111.11111111.11111111228.31.255.255
Split into smaller subnets/20
/14 (2)/15 (4)/16 (8)/17 (16)/18 (32)/19 (64)/20 (128)/21 (256)/22 (512)/23 (1,024)/24 (2,048)/25 (4,096)

228.24.0.0/13 makes 128 subnets of /20.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1228.24.0.0/20228.24.0.1 to 228.24.15.254228.24.15.2554,094
2228.24.16.0/20228.24.16.1 to 228.24.31.254228.24.31.2554,094
3228.24.32.0/20228.24.32.1 to 228.24.47.254228.24.47.2554,094
4228.24.48.0/20228.24.48.1 to 228.24.63.254228.24.63.2554,094
5228.24.64.0/20228.24.64.1 to 228.24.79.254228.24.79.2554,094
6228.24.80.0/20228.24.80.1 to 228.24.95.254228.24.95.2554,094
7228.24.96.0/20228.24.96.1 to 228.24.111.254228.24.111.2554,094
8228.24.112.0/20228.24.112.1 to 228.24.127.254228.24.127.2554,094
9228.24.128.0/20228.24.128.1 to 228.24.143.254228.24.143.2554,094
10228.24.144.0/20228.24.144.1 to 228.24.159.254228.24.159.2554,094
11228.24.160.0/20228.24.160.1 to 228.24.175.254228.24.175.2554,094
12228.24.176.0/20228.24.176.1 to 228.24.191.254228.24.191.2554,094
13228.24.192.0/20228.24.192.1 to 228.24.207.254228.24.207.2554,094
14228.24.208.0/20228.24.208.1 to 228.24.223.254228.24.223.2554,094
15228.24.224.0/20228.24.224.1 to 228.24.239.254228.24.239.2554,094
16228.24.240.0/20228.24.240.1 to 228.24.255.254228.24.255.2554,094
17228.25.0.0/20228.25.0.1 to 228.25.15.254228.25.15.2554,094
18228.25.16.0/20228.25.16.1 to 228.25.31.254228.25.31.2554,094
19228.25.32.0/20228.25.32.1 to 228.25.47.254228.25.47.2554,094
20228.25.48.0/20228.25.48.1 to 228.25.63.254228.25.63.2554,094
21228.25.64.0/20228.25.64.1 to 228.25.79.254228.25.79.2554,094
22228.25.80.0/20228.25.80.1 to 228.25.95.254228.25.95.2554,094
23228.25.96.0/20228.25.96.1 to 228.25.111.254228.25.111.2554,094
24228.25.112.0/20228.25.112.1 to 228.25.127.254228.25.127.2554,094
25228.25.128.0/20228.25.128.1 to 228.25.143.254228.25.143.2554,094
26228.25.144.0/20228.25.144.1 to 228.25.159.254228.25.159.2554,094
27228.25.160.0/20228.25.160.1 to 228.25.175.254228.25.175.2554,094
28228.25.176.0/20228.25.176.1 to 228.25.191.254228.25.191.2554,094
29228.25.192.0/20228.25.192.1 to 228.25.207.254228.25.207.2554,094
30228.25.208.0/20228.25.208.1 to 228.25.223.254228.25.223.2554,094
31228.25.224.0/20228.25.224.1 to 228.25.239.254228.25.239.2554,094
32228.25.240.0/20228.25.240.1 to 228.25.255.254228.25.255.2554,094
33228.26.0.0/20228.26.0.1 to 228.26.15.254228.26.15.2554,094
34228.26.16.0/20228.26.16.1 to 228.26.31.254228.26.31.2554,094
35228.26.32.0/20228.26.32.1 to 228.26.47.254228.26.47.2554,094
36228.26.48.0/20228.26.48.1 to 228.26.63.254228.26.63.2554,094
37228.26.64.0/20228.26.64.1 to 228.26.79.254228.26.79.2554,094
38228.26.80.0/20228.26.80.1 to 228.26.95.254228.26.95.2554,094
39228.26.96.0/20228.26.96.1 to 228.26.111.254228.26.111.2554,094
40228.26.112.0/20228.26.112.1 to 228.26.127.254228.26.127.2554,094
41228.26.128.0/20228.26.128.1 to 228.26.143.254228.26.143.2554,094
42228.26.144.0/20228.26.144.1 to 228.26.159.254228.26.159.2554,094
43228.26.160.0/20228.26.160.1 to 228.26.175.254228.26.175.2554,094
44228.26.176.0/20228.26.176.1 to 228.26.191.254228.26.191.2554,094
45228.26.192.0/20228.26.192.1 to 228.26.207.254228.26.207.2554,094
46228.26.208.0/20228.26.208.1 to 228.26.223.254228.26.223.2554,094
47228.26.224.0/20228.26.224.1 to 228.26.239.254228.26.239.2554,094
48228.26.240.0/20228.26.240.1 to 228.26.255.254228.26.255.2554,094
49228.27.0.0/20228.27.0.1 to 228.27.15.254228.27.15.2554,094
50228.27.16.0/20228.27.16.1 to 228.27.31.254228.27.31.2554,094
51228.27.32.0/20228.27.32.1 to 228.27.47.254228.27.47.2554,094
52228.27.48.0/20228.27.48.1 to 228.27.63.254228.27.63.2554,094
53228.27.64.0/20228.27.64.1 to 228.27.79.254228.27.79.2554,094
54228.27.80.0/20228.27.80.1 to 228.27.95.254228.27.95.2554,094
55228.27.96.0/20228.27.96.1 to 228.27.111.254228.27.111.2554,094
56228.27.112.0/20228.27.112.1 to 228.27.127.254228.27.127.2554,094
57228.27.128.0/20228.27.128.1 to 228.27.143.254228.27.143.2554,094
58228.27.144.0/20228.27.144.1 to 228.27.159.254228.27.159.2554,094
59228.27.160.0/20228.27.160.1 to 228.27.175.254228.27.175.2554,094
60228.27.176.0/20228.27.176.1 to 228.27.191.254228.27.191.2554,094
61228.27.192.0/20228.27.192.1 to 228.27.207.254228.27.207.2554,094
62228.27.208.0/20228.27.208.1 to 228.27.223.254228.27.223.2554,094
63228.27.224.0/20228.27.224.1 to 228.27.239.254228.27.239.2554,094
64228.27.240.0/20228.27.240.1 to 228.27.255.254228.27.255.2554,094
65228.28.0.0/20228.28.0.1 to 228.28.15.254228.28.15.2554,094
66228.28.16.0/20228.28.16.1 to 228.28.31.254228.28.31.2554,094
67228.28.32.0/20228.28.32.1 to 228.28.47.254228.28.47.2554,094
68228.28.48.0/20228.28.48.1 to 228.28.63.254228.28.63.2554,094
69228.28.64.0/20228.28.64.1 to 228.28.79.254228.28.79.2554,094
70228.28.80.0/20228.28.80.1 to 228.28.95.254228.28.95.2554,094
71228.28.96.0/20228.28.96.1 to 228.28.111.254228.28.111.2554,094
72228.28.112.0/20228.28.112.1 to 228.28.127.254228.28.127.2554,094
73228.28.128.0/20228.28.128.1 to 228.28.143.254228.28.143.2554,094
74228.28.144.0/20228.28.144.1 to 228.28.159.254228.28.159.2554,094
75228.28.160.0/20228.28.160.1 to 228.28.175.254228.28.175.2554,094
76228.28.176.0/20228.28.176.1 to 228.28.191.254228.28.191.2554,094
77228.28.192.0/20228.28.192.1 to 228.28.207.254228.28.207.2554,094
78228.28.208.0/20228.28.208.1 to 228.28.223.254228.28.223.2554,094
79228.28.224.0/20228.28.224.1 to 228.28.239.254228.28.239.2554,094
80228.28.240.0/20228.28.240.1 to 228.28.255.254228.28.255.2554,094
81228.29.0.0/20228.29.0.1 to 228.29.15.254228.29.15.2554,094
82228.29.16.0/20228.29.16.1 to 228.29.31.254228.29.31.2554,094
83228.29.32.0/20228.29.32.1 to 228.29.47.254228.29.47.2554,094
84228.29.48.0/20228.29.48.1 to 228.29.63.254228.29.63.2554,094
85228.29.64.0/20228.29.64.1 to 228.29.79.254228.29.79.2554,094
86228.29.80.0/20228.29.80.1 to 228.29.95.254228.29.95.2554,094
87228.29.96.0/20228.29.96.1 to 228.29.111.254228.29.111.2554,094
88228.29.112.0/20228.29.112.1 to 228.29.127.254228.29.127.2554,094
89228.29.128.0/20228.29.128.1 to 228.29.143.254228.29.143.2554,094
90228.29.144.0/20228.29.144.1 to 228.29.159.254228.29.159.2554,094
91228.29.160.0/20228.29.160.1 to 228.29.175.254228.29.175.2554,094
92228.29.176.0/20228.29.176.1 to 228.29.191.254228.29.191.2554,094
93228.29.192.0/20228.29.192.1 to 228.29.207.254228.29.207.2554,094
94228.29.208.0/20228.29.208.1 to 228.29.223.254228.29.223.2554,094
95228.29.224.0/20228.29.224.1 to 228.29.239.254228.29.239.2554,094
96228.29.240.0/20228.29.240.1 to 228.29.255.254228.29.255.2554,094
97228.30.0.0/20228.30.0.1 to 228.30.15.254228.30.15.2554,094
98228.30.16.0/20228.30.16.1 to 228.30.31.254228.30.31.2554,094
99228.30.32.0/20228.30.32.1 to 228.30.47.254228.30.47.2554,094
100228.30.48.0/20228.30.48.1 to 228.30.63.254228.30.63.2554,094
101228.30.64.0/20228.30.64.1 to 228.30.79.254228.30.79.2554,094
102228.30.80.0/20228.30.80.1 to 228.30.95.254228.30.95.2554,094
103228.30.96.0/20228.30.96.1 to 228.30.111.254228.30.111.2554,094
104228.30.112.0/20228.30.112.1 to 228.30.127.254228.30.127.2554,094
105228.30.128.0/20228.30.128.1 to 228.30.143.254228.30.143.2554,094
106228.30.144.0/20228.30.144.1 to 228.30.159.254228.30.159.2554,094
107228.30.160.0/20228.30.160.1 to 228.30.175.254228.30.175.2554,094
108228.30.176.0/20228.30.176.1 to 228.30.191.254228.30.191.2554,094
109228.30.192.0/20228.30.192.1 to 228.30.207.254228.30.207.2554,094
110228.30.208.0/20228.30.208.1 to 228.30.223.254228.30.223.2554,094
111228.30.224.0/20228.30.224.1 to 228.30.239.254228.30.239.2554,094
112228.30.240.0/20228.30.240.1 to 228.30.255.254228.30.255.2554,094
113228.31.0.0/20228.31.0.1 to 228.31.15.254228.31.15.2554,094
114228.31.16.0/20228.31.16.1 to 228.31.31.254228.31.31.2554,094
115228.31.32.0/20228.31.32.1 to 228.31.47.254228.31.47.2554,094
116228.31.48.0/20228.31.48.1 to 228.31.63.254228.31.63.2554,094
117228.31.64.0/20228.31.64.1 to 228.31.79.254228.31.79.2554,094
118228.31.80.0/20228.31.80.1 to 228.31.95.254228.31.95.2554,094
119228.31.96.0/20228.31.96.1 to 228.31.111.254228.31.111.2554,094
120228.31.112.0/20228.31.112.1 to 228.31.127.254228.31.127.2554,094
121228.31.128.0/20228.31.128.1 to 228.31.143.254228.31.143.2554,094
122228.31.144.0/20228.31.144.1 to 228.31.159.254228.31.159.2554,094
123228.31.160.0/20228.31.160.1 to 228.31.175.254228.31.175.2554,094
124228.31.176.0/20228.31.176.1 to 228.31.191.254228.31.191.2554,094
125228.31.192.0/20228.31.192.1 to 228.31.207.254228.31.207.2554,094
126228.31.208.0/20228.31.208.1 to 228.31.223.254228.31.223.2554,094
127228.31.224.0/20228.31.224.1 to 228.31.239.254228.31.239.2554,094
128228.31.240.0/20228.31.240.1 to 228.31.255.254228.31.255.2554,094

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.