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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.

Network230.64.0.0/13
Usable hosts524,286
Subnet mask255.248.0.0
Addresses524,288
Network address
230.64.0.0
Broadcast address
230.71.255.255
First usable
230.64.0.1
Last usable
230.71.255.254
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 E6400000 · Integer 3862953984 to 3863478271
Reverse DNS zones
64.230.in-addr.arpa
65.230.in-addr.arpa
66.230.in-addr.arpa
67.230.in-addr.arpa
68.230.in-addr.arpa
69.230.in-addr.arpa
70.230.in-addr.arpa
71.230.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
Address11100110.01000000.00000000.00000000230.64.0.0
Subnet mask11111111.11111000.00000000.00000000255.248.0.0
Network11100110.01000000.00000000.00000000230.64.0.0
Broadcast11100110.01000111.11111111.11111111230.71.255.255
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)

230.64.0.0/13 makes 128 subnets of /20.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1230.64.0.0/20230.64.0.1 to 230.64.15.254230.64.15.2554,094
2230.64.16.0/20230.64.16.1 to 230.64.31.254230.64.31.2554,094
3230.64.32.0/20230.64.32.1 to 230.64.47.254230.64.47.2554,094
4230.64.48.0/20230.64.48.1 to 230.64.63.254230.64.63.2554,094
5230.64.64.0/20230.64.64.1 to 230.64.79.254230.64.79.2554,094
6230.64.80.0/20230.64.80.1 to 230.64.95.254230.64.95.2554,094
7230.64.96.0/20230.64.96.1 to 230.64.111.254230.64.111.2554,094
8230.64.112.0/20230.64.112.1 to 230.64.127.254230.64.127.2554,094
9230.64.128.0/20230.64.128.1 to 230.64.143.254230.64.143.2554,094
10230.64.144.0/20230.64.144.1 to 230.64.159.254230.64.159.2554,094
11230.64.160.0/20230.64.160.1 to 230.64.175.254230.64.175.2554,094
12230.64.176.0/20230.64.176.1 to 230.64.191.254230.64.191.2554,094
13230.64.192.0/20230.64.192.1 to 230.64.207.254230.64.207.2554,094
14230.64.208.0/20230.64.208.1 to 230.64.223.254230.64.223.2554,094
15230.64.224.0/20230.64.224.1 to 230.64.239.254230.64.239.2554,094
16230.64.240.0/20230.64.240.1 to 230.64.255.254230.64.255.2554,094
17230.65.0.0/20230.65.0.1 to 230.65.15.254230.65.15.2554,094
18230.65.16.0/20230.65.16.1 to 230.65.31.254230.65.31.2554,094
19230.65.32.0/20230.65.32.1 to 230.65.47.254230.65.47.2554,094
20230.65.48.0/20230.65.48.1 to 230.65.63.254230.65.63.2554,094
21230.65.64.0/20230.65.64.1 to 230.65.79.254230.65.79.2554,094
22230.65.80.0/20230.65.80.1 to 230.65.95.254230.65.95.2554,094
23230.65.96.0/20230.65.96.1 to 230.65.111.254230.65.111.2554,094
24230.65.112.0/20230.65.112.1 to 230.65.127.254230.65.127.2554,094
25230.65.128.0/20230.65.128.1 to 230.65.143.254230.65.143.2554,094
26230.65.144.0/20230.65.144.1 to 230.65.159.254230.65.159.2554,094
27230.65.160.0/20230.65.160.1 to 230.65.175.254230.65.175.2554,094
28230.65.176.0/20230.65.176.1 to 230.65.191.254230.65.191.2554,094
29230.65.192.0/20230.65.192.1 to 230.65.207.254230.65.207.2554,094
30230.65.208.0/20230.65.208.1 to 230.65.223.254230.65.223.2554,094
31230.65.224.0/20230.65.224.1 to 230.65.239.254230.65.239.2554,094
32230.65.240.0/20230.65.240.1 to 230.65.255.254230.65.255.2554,094
33230.66.0.0/20230.66.0.1 to 230.66.15.254230.66.15.2554,094
34230.66.16.0/20230.66.16.1 to 230.66.31.254230.66.31.2554,094
35230.66.32.0/20230.66.32.1 to 230.66.47.254230.66.47.2554,094
36230.66.48.0/20230.66.48.1 to 230.66.63.254230.66.63.2554,094
37230.66.64.0/20230.66.64.1 to 230.66.79.254230.66.79.2554,094
38230.66.80.0/20230.66.80.1 to 230.66.95.254230.66.95.2554,094
39230.66.96.0/20230.66.96.1 to 230.66.111.254230.66.111.2554,094
40230.66.112.0/20230.66.112.1 to 230.66.127.254230.66.127.2554,094
41230.66.128.0/20230.66.128.1 to 230.66.143.254230.66.143.2554,094
42230.66.144.0/20230.66.144.1 to 230.66.159.254230.66.159.2554,094
43230.66.160.0/20230.66.160.1 to 230.66.175.254230.66.175.2554,094
44230.66.176.0/20230.66.176.1 to 230.66.191.254230.66.191.2554,094
45230.66.192.0/20230.66.192.1 to 230.66.207.254230.66.207.2554,094
46230.66.208.0/20230.66.208.1 to 230.66.223.254230.66.223.2554,094
47230.66.224.0/20230.66.224.1 to 230.66.239.254230.66.239.2554,094
48230.66.240.0/20230.66.240.1 to 230.66.255.254230.66.255.2554,094
49230.67.0.0/20230.67.0.1 to 230.67.15.254230.67.15.2554,094
50230.67.16.0/20230.67.16.1 to 230.67.31.254230.67.31.2554,094
51230.67.32.0/20230.67.32.1 to 230.67.47.254230.67.47.2554,094
52230.67.48.0/20230.67.48.1 to 230.67.63.254230.67.63.2554,094
53230.67.64.0/20230.67.64.1 to 230.67.79.254230.67.79.2554,094
54230.67.80.0/20230.67.80.1 to 230.67.95.254230.67.95.2554,094
55230.67.96.0/20230.67.96.1 to 230.67.111.254230.67.111.2554,094
56230.67.112.0/20230.67.112.1 to 230.67.127.254230.67.127.2554,094
57230.67.128.0/20230.67.128.1 to 230.67.143.254230.67.143.2554,094
58230.67.144.0/20230.67.144.1 to 230.67.159.254230.67.159.2554,094
59230.67.160.0/20230.67.160.1 to 230.67.175.254230.67.175.2554,094
60230.67.176.0/20230.67.176.1 to 230.67.191.254230.67.191.2554,094
61230.67.192.0/20230.67.192.1 to 230.67.207.254230.67.207.2554,094
62230.67.208.0/20230.67.208.1 to 230.67.223.254230.67.223.2554,094
63230.67.224.0/20230.67.224.1 to 230.67.239.254230.67.239.2554,094
64230.67.240.0/20230.67.240.1 to 230.67.255.254230.67.255.2554,094
65230.68.0.0/20230.68.0.1 to 230.68.15.254230.68.15.2554,094
66230.68.16.0/20230.68.16.1 to 230.68.31.254230.68.31.2554,094
67230.68.32.0/20230.68.32.1 to 230.68.47.254230.68.47.2554,094
68230.68.48.0/20230.68.48.1 to 230.68.63.254230.68.63.2554,094
69230.68.64.0/20230.68.64.1 to 230.68.79.254230.68.79.2554,094
70230.68.80.0/20230.68.80.1 to 230.68.95.254230.68.95.2554,094
71230.68.96.0/20230.68.96.1 to 230.68.111.254230.68.111.2554,094
72230.68.112.0/20230.68.112.1 to 230.68.127.254230.68.127.2554,094
73230.68.128.0/20230.68.128.1 to 230.68.143.254230.68.143.2554,094
74230.68.144.0/20230.68.144.1 to 230.68.159.254230.68.159.2554,094
75230.68.160.0/20230.68.160.1 to 230.68.175.254230.68.175.2554,094
76230.68.176.0/20230.68.176.1 to 230.68.191.254230.68.191.2554,094
77230.68.192.0/20230.68.192.1 to 230.68.207.254230.68.207.2554,094
78230.68.208.0/20230.68.208.1 to 230.68.223.254230.68.223.2554,094
79230.68.224.0/20230.68.224.1 to 230.68.239.254230.68.239.2554,094
80230.68.240.0/20230.68.240.1 to 230.68.255.254230.68.255.2554,094
81230.69.0.0/20230.69.0.1 to 230.69.15.254230.69.15.2554,094
82230.69.16.0/20230.69.16.1 to 230.69.31.254230.69.31.2554,094
83230.69.32.0/20230.69.32.1 to 230.69.47.254230.69.47.2554,094
84230.69.48.0/20230.69.48.1 to 230.69.63.254230.69.63.2554,094
85230.69.64.0/20230.69.64.1 to 230.69.79.254230.69.79.2554,094
86230.69.80.0/20230.69.80.1 to 230.69.95.254230.69.95.2554,094
87230.69.96.0/20230.69.96.1 to 230.69.111.254230.69.111.2554,094
88230.69.112.0/20230.69.112.1 to 230.69.127.254230.69.127.2554,094
89230.69.128.0/20230.69.128.1 to 230.69.143.254230.69.143.2554,094
90230.69.144.0/20230.69.144.1 to 230.69.159.254230.69.159.2554,094
91230.69.160.0/20230.69.160.1 to 230.69.175.254230.69.175.2554,094
92230.69.176.0/20230.69.176.1 to 230.69.191.254230.69.191.2554,094
93230.69.192.0/20230.69.192.1 to 230.69.207.254230.69.207.2554,094
94230.69.208.0/20230.69.208.1 to 230.69.223.254230.69.223.2554,094
95230.69.224.0/20230.69.224.1 to 230.69.239.254230.69.239.2554,094
96230.69.240.0/20230.69.240.1 to 230.69.255.254230.69.255.2554,094
97230.70.0.0/20230.70.0.1 to 230.70.15.254230.70.15.2554,094
98230.70.16.0/20230.70.16.1 to 230.70.31.254230.70.31.2554,094
99230.70.32.0/20230.70.32.1 to 230.70.47.254230.70.47.2554,094
100230.70.48.0/20230.70.48.1 to 230.70.63.254230.70.63.2554,094
101230.70.64.0/20230.70.64.1 to 230.70.79.254230.70.79.2554,094
102230.70.80.0/20230.70.80.1 to 230.70.95.254230.70.95.2554,094
103230.70.96.0/20230.70.96.1 to 230.70.111.254230.70.111.2554,094
104230.70.112.0/20230.70.112.1 to 230.70.127.254230.70.127.2554,094
105230.70.128.0/20230.70.128.1 to 230.70.143.254230.70.143.2554,094
106230.70.144.0/20230.70.144.1 to 230.70.159.254230.70.159.2554,094
107230.70.160.0/20230.70.160.1 to 230.70.175.254230.70.175.2554,094
108230.70.176.0/20230.70.176.1 to 230.70.191.254230.70.191.2554,094
109230.70.192.0/20230.70.192.1 to 230.70.207.254230.70.207.2554,094
110230.70.208.0/20230.70.208.1 to 230.70.223.254230.70.223.2554,094
111230.70.224.0/20230.70.224.1 to 230.70.239.254230.70.239.2554,094
112230.70.240.0/20230.70.240.1 to 230.70.255.254230.70.255.2554,094
113230.71.0.0/20230.71.0.1 to 230.71.15.254230.71.15.2554,094
114230.71.16.0/20230.71.16.1 to 230.71.31.254230.71.31.2554,094
115230.71.32.0/20230.71.32.1 to 230.71.47.254230.71.47.2554,094
116230.71.48.0/20230.71.48.1 to 230.71.63.254230.71.63.2554,094
117230.71.64.0/20230.71.64.1 to 230.71.79.254230.71.79.2554,094
118230.71.80.0/20230.71.80.1 to 230.71.95.254230.71.95.2554,094
119230.71.96.0/20230.71.96.1 to 230.71.111.254230.71.111.2554,094
120230.71.112.0/20230.71.112.1 to 230.71.127.254230.71.127.2554,094
121230.71.128.0/20230.71.128.1 to 230.71.143.254230.71.143.2554,094
122230.71.144.0/20230.71.144.1 to 230.71.159.254230.71.159.2554,094
123230.71.160.0/20230.71.160.1 to 230.71.175.254230.71.175.2554,094
124230.71.176.0/20230.71.176.1 to 230.71.191.254230.71.191.2554,094
125230.71.192.0/20230.71.192.1 to 230.71.207.254230.71.207.2554,094
126230.71.208.0/20230.71.208.1 to 230.71.223.254230.71.223.2554,094
127230.71.224.0/20230.71.224.1 to 230.71.239.254230.71.239.2554,094
128230.71.240.0/20230.71.240.1 to 230.71.255.254230.71.255.2554,094

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.