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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.

Network130.64.0.0/11
Usable hosts2,097,150
Subnet mask255.224.0.0
Addresses2,097,152
Network address
130.64.0.0
Broadcast address
130.95.255.255
First usable
130.64.0.1
Last usable
130.95.255.254
Usable hosts
2,097,150 (2,097,152 less the network and broadcast addresses)
Subnet mask
255.224.0.0
Wildcard mask
0.31.255.255 (Cisco ACLs, OSPF)
Prefix length
/11
Type
Public public
Old class
B (default /16)
As numbers
Hex 82400000 · Integer 2185232384 to 2187329535
Reverse DNS zones
64.130.in-addr.arpa
65.130.in-addr.arpa
66.130.in-addr.arpa
67.130.in-addr.arpa
68.130.in-addr.arpa
69.130.in-addr.arpa
70.130.in-addr.arpa
71.130.in-addr.arpa
72.130.in-addr.arpa
73.130.in-addr.arpa
74.130.in-addr.arpa
75.130.in-addr.arpa
76.130.in-addr.arpa
77.130.in-addr.arpa
78.130.in-addr.arpa
79.130.in-addr.arpa
and 16 more
/11 is not on a 8-bit boundary, so it takes 32 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address10000010.01000000.00000000.00000000130.64.0.0
Subnet mask11111111.11100000.00000000.00000000255.224.0.0
Network10000010.01000000.00000000.00000000130.64.0.0
Broadcast10000010.01011111.11111111.11111111130.95.255.255
Split into smaller subnets/18
/12 (2)/13 (4)/14 (8)/15 (16)/16 (32)/17 (64)/18 (128)/19 (256)/20 (512)/21 (1,024)/22 (2,048)/23 (4,096)

130.64.0.0/11 makes 128 subnets of /18.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1130.64.0.0/18130.64.0.1 to 130.64.63.254130.64.63.25516,382
2130.64.64.0/18130.64.64.1 to 130.64.127.254130.64.127.25516,382
3130.64.128.0/18130.64.128.1 to 130.64.191.254130.64.191.25516,382
4130.64.192.0/18130.64.192.1 to 130.64.255.254130.64.255.25516,382
5130.65.0.0/18130.65.0.1 to 130.65.63.254130.65.63.25516,382
6130.65.64.0/18130.65.64.1 to 130.65.127.254130.65.127.25516,382
7130.65.128.0/18130.65.128.1 to 130.65.191.254130.65.191.25516,382
8130.65.192.0/18130.65.192.1 to 130.65.255.254130.65.255.25516,382
9130.66.0.0/18130.66.0.1 to 130.66.63.254130.66.63.25516,382
10130.66.64.0/18130.66.64.1 to 130.66.127.254130.66.127.25516,382
11130.66.128.0/18130.66.128.1 to 130.66.191.254130.66.191.25516,382
12130.66.192.0/18130.66.192.1 to 130.66.255.254130.66.255.25516,382
13130.67.0.0/18130.67.0.1 to 130.67.63.254130.67.63.25516,382
14130.67.64.0/18130.67.64.1 to 130.67.127.254130.67.127.25516,382
15130.67.128.0/18130.67.128.1 to 130.67.191.254130.67.191.25516,382
16130.67.192.0/18130.67.192.1 to 130.67.255.254130.67.255.25516,382
17130.68.0.0/18130.68.0.1 to 130.68.63.254130.68.63.25516,382
18130.68.64.0/18130.68.64.1 to 130.68.127.254130.68.127.25516,382
19130.68.128.0/18130.68.128.1 to 130.68.191.254130.68.191.25516,382
20130.68.192.0/18130.68.192.1 to 130.68.255.254130.68.255.25516,382
21130.69.0.0/18130.69.0.1 to 130.69.63.254130.69.63.25516,382
22130.69.64.0/18130.69.64.1 to 130.69.127.254130.69.127.25516,382
23130.69.128.0/18130.69.128.1 to 130.69.191.254130.69.191.25516,382
24130.69.192.0/18130.69.192.1 to 130.69.255.254130.69.255.25516,382
25130.70.0.0/18130.70.0.1 to 130.70.63.254130.70.63.25516,382
26130.70.64.0/18130.70.64.1 to 130.70.127.254130.70.127.25516,382
27130.70.128.0/18130.70.128.1 to 130.70.191.254130.70.191.25516,382
28130.70.192.0/18130.70.192.1 to 130.70.255.254130.70.255.25516,382
29130.71.0.0/18130.71.0.1 to 130.71.63.254130.71.63.25516,382
30130.71.64.0/18130.71.64.1 to 130.71.127.254130.71.127.25516,382
31130.71.128.0/18130.71.128.1 to 130.71.191.254130.71.191.25516,382
32130.71.192.0/18130.71.192.1 to 130.71.255.254130.71.255.25516,382
33130.72.0.0/18130.72.0.1 to 130.72.63.254130.72.63.25516,382
34130.72.64.0/18130.72.64.1 to 130.72.127.254130.72.127.25516,382
35130.72.128.0/18130.72.128.1 to 130.72.191.254130.72.191.25516,382
36130.72.192.0/18130.72.192.1 to 130.72.255.254130.72.255.25516,382
37130.73.0.0/18130.73.0.1 to 130.73.63.254130.73.63.25516,382
38130.73.64.0/18130.73.64.1 to 130.73.127.254130.73.127.25516,382
39130.73.128.0/18130.73.128.1 to 130.73.191.254130.73.191.25516,382
40130.73.192.0/18130.73.192.1 to 130.73.255.254130.73.255.25516,382
41130.74.0.0/18130.74.0.1 to 130.74.63.254130.74.63.25516,382
42130.74.64.0/18130.74.64.1 to 130.74.127.254130.74.127.25516,382
43130.74.128.0/18130.74.128.1 to 130.74.191.254130.74.191.25516,382
44130.74.192.0/18130.74.192.1 to 130.74.255.254130.74.255.25516,382
45130.75.0.0/18130.75.0.1 to 130.75.63.254130.75.63.25516,382
46130.75.64.0/18130.75.64.1 to 130.75.127.254130.75.127.25516,382
47130.75.128.0/18130.75.128.1 to 130.75.191.254130.75.191.25516,382
48130.75.192.0/18130.75.192.1 to 130.75.255.254130.75.255.25516,382
49130.76.0.0/18130.76.0.1 to 130.76.63.254130.76.63.25516,382
50130.76.64.0/18130.76.64.1 to 130.76.127.254130.76.127.25516,382
51130.76.128.0/18130.76.128.1 to 130.76.191.254130.76.191.25516,382
52130.76.192.0/18130.76.192.1 to 130.76.255.254130.76.255.25516,382
53130.77.0.0/18130.77.0.1 to 130.77.63.254130.77.63.25516,382
54130.77.64.0/18130.77.64.1 to 130.77.127.254130.77.127.25516,382
55130.77.128.0/18130.77.128.1 to 130.77.191.254130.77.191.25516,382
56130.77.192.0/18130.77.192.1 to 130.77.255.254130.77.255.25516,382
57130.78.0.0/18130.78.0.1 to 130.78.63.254130.78.63.25516,382
58130.78.64.0/18130.78.64.1 to 130.78.127.254130.78.127.25516,382
59130.78.128.0/18130.78.128.1 to 130.78.191.254130.78.191.25516,382
60130.78.192.0/18130.78.192.1 to 130.78.255.254130.78.255.25516,382
61130.79.0.0/18130.79.0.1 to 130.79.63.254130.79.63.25516,382
62130.79.64.0/18130.79.64.1 to 130.79.127.254130.79.127.25516,382
63130.79.128.0/18130.79.128.1 to 130.79.191.254130.79.191.25516,382
64130.79.192.0/18130.79.192.1 to 130.79.255.254130.79.255.25516,382
65130.80.0.0/18130.80.0.1 to 130.80.63.254130.80.63.25516,382
66130.80.64.0/18130.80.64.1 to 130.80.127.254130.80.127.25516,382
67130.80.128.0/18130.80.128.1 to 130.80.191.254130.80.191.25516,382
68130.80.192.0/18130.80.192.1 to 130.80.255.254130.80.255.25516,382
69130.81.0.0/18130.81.0.1 to 130.81.63.254130.81.63.25516,382
70130.81.64.0/18130.81.64.1 to 130.81.127.254130.81.127.25516,382
71130.81.128.0/18130.81.128.1 to 130.81.191.254130.81.191.25516,382
72130.81.192.0/18130.81.192.1 to 130.81.255.254130.81.255.25516,382
73130.82.0.0/18130.82.0.1 to 130.82.63.254130.82.63.25516,382
74130.82.64.0/18130.82.64.1 to 130.82.127.254130.82.127.25516,382
75130.82.128.0/18130.82.128.1 to 130.82.191.254130.82.191.25516,382
76130.82.192.0/18130.82.192.1 to 130.82.255.254130.82.255.25516,382
77130.83.0.0/18130.83.0.1 to 130.83.63.254130.83.63.25516,382
78130.83.64.0/18130.83.64.1 to 130.83.127.254130.83.127.25516,382
79130.83.128.0/18130.83.128.1 to 130.83.191.254130.83.191.25516,382
80130.83.192.0/18130.83.192.1 to 130.83.255.254130.83.255.25516,382
81130.84.0.0/18130.84.0.1 to 130.84.63.254130.84.63.25516,382
82130.84.64.0/18130.84.64.1 to 130.84.127.254130.84.127.25516,382
83130.84.128.0/18130.84.128.1 to 130.84.191.254130.84.191.25516,382
84130.84.192.0/18130.84.192.1 to 130.84.255.254130.84.255.25516,382
85130.85.0.0/18130.85.0.1 to 130.85.63.254130.85.63.25516,382
86130.85.64.0/18130.85.64.1 to 130.85.127.254130.85.127.25516,382
87130.85.128.0/18130.85.128.1 to 130.85.191.254130.85.191.25516,382
88130.85.192.0/18130.85.192.1 to 130.85.255.254130.85.255.25516,382
89130.86.0.0/18130.86.0.1 to 130.86.63.254130.86.63.25516,382
90130.86.64.0/18130.86.64.1 to 130.86.127.254130.86.127.25516,382
91130.86.128.0/18130.86.128.1 to 130.86.191.254130.86.191.25516,382
92130.86.192.0/18130.86.192.1 to 130.86.255.254130.86.255.25516,382
93130.87.0.0/18130.87.0.1 to 130.87.63.254130.87.63.25516,382
94130.87.64.0/18130.87.64.1 to 130.87.127.254130.87.127.25516,382
95130.87.128.0/18130.87.128.1 to 130.87.191.254130.87.191.25516,382
96130.87.192.0/18130.87.192.1 to 130.87.255.254130.87.255.25516,382
97130.88.0.0/18130.88.0.1 to 130.88.63.254130.88.63.25516,382
98130.88.64.0/18130.88.64.1 to 130.88.127.254130.88.127.25516,382
99130.88.128.0/18130.88.128.1 to 130.88.191.254130.88.191.25516,382
100130.88.192.0/18130.88.192.1 to 130.88.255.254130.88.255.25516,382
101130.89.0.0/18130.89.0.1 to 130.89.63.254130.89.63.25516,382
102130.89.64.0/18130.89.64.1 to 130.89.127.254130.89.127.25516,382
103130.89.128.0/18130.89.128.1 to 130.89.191.254130.89.191.25516,382
104130.89.192.0/18130.89.192.1 to 130.89.255.254130.89.255.25516,382
105130.90.0.0/18130.90.0.1 to 130.90.63.254130.90.63.25516,382
106130.90.64.0/18130.90.64.1 to 130.90.127.254130.90.127.25516,382
107130.90.128.0/18130.90.128.1 to 130.90.191.254130.90.191.25516,382
108130.90.192.0/18130.90.192.1 to 130.90.255.254130.90.255.25516,382
109130.91.0.0/18130.91.0.1 to 130.91.63.254130.91.63.25516,382
110130.91.64.0/18130.91.64.1 to 130.91.127.254130.91.127.25516,382
111130.91.128.0/18130.91.128.1 to 130.91.191.254130.91.191.25516,382
112130.91.192.0/18130.91.192.1 to 130.91.255.254130.91.255.25516,382
113130.92.0.0/18130.92.0.1 to 130.92.63.254130.92.63.25516,382
114130.92.64.0/18130.92.64.1 to 130.92.127.254130.92.127.25516,382
115130.92.128.0/18130.92.128.1 to 130.92.191.254130.92.191.25516,382
116130.92.192.0/18130.92.192.1 to 130.92.255.254130.92.255.25516,382
117130.93.0.0/18130.93.0.1 to 130.93.63.254130.93.63.25516,382
118130.93.64.0/18130.93.64.1 to 130.93.127.254130.93.127.25516,382
119130.93.128.0/18130.93.128.1 to 130.93.191.254130.93.191.25516,382
120130.93.192.0/18130.93.192.1 to 130.93.255.254130.93.255.25516,382
121130.94.0.0/18130.94.0.1 to 130.94.63.254130.94.63.25516,382
122130.94.64.0/18130.94.64.1 to 130.94.127.254130.94.127.25516,382
123130.94.128.0/18130.94.128.1 to 130.94.191.254130.94.191.25516,382
124130.94.192.0/18130.94.192.1 to 130.94.255.254130.94.255.25516,382
125130.95.0.0/18130.95.0.1 to 130.95.63.254130.95.63.25516,382
126130.95.64.0/18130.95.64.1 to 130.95.127.254130.95.127.25516,382
127130.95.128.0/18130.95.128.1 to 130.95.191.254130.95.191.25516,382
128130.95.192.0/18130.95.192.1 to 130.95.255.254130.95.255.25516,382

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.