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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.

Network253.80.0.0/13
Usable hosts524,286
Subnet mask255.248.0.0
Addresses524,288
Network address
253.80.0.0
Broadcast address
253.87.255.255
First usable
253.80.0.1
Last usable
253.87.255.254
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
Reserved 240.0.0.0/4
Future use; not usable on most systems
Old class
E (reserved)
As numbers
Hex FD500000 · Integer 4249878528 to 4250402815
Reverse DNS zones
80.253.in-addr.arpa
81.253.in-addr.arpa
82.253.in-addr.arpa
83.253.in-addr.arpa
84.253.in-addr.arpa
85.253.in-addr.arpa
86.253.in-addr.arpa
87.253.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
Address11111101.01010000.00000000.00000000253.80.0.0
Subnet mask11111111.11111000.00000000.00000000255.248.0.0
Network11111101.01010000.00000000.00000000253.80.0.0
Broadcast11111101.01010111.11111111.11111111253.87.255.255
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)

253.80.0.0/13 makes 128 subnets of /20.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1253.80.0.0/20253.80.0.1 to 253.80.15.254253.80.15.2554,094
2253.80.16.0/20253.80.16.1 to 253.80.31.254253.80.31.2554,094
3253.80.32.0/20253.80.32.1 to 253.80.47.254253.80.47.2554,094
4253.80.48.0/20253.80.48.1 to 253.80.63.254253.80.63.2554,094
5253.80.64.0/20253.80.64.1 to 253.80.79.254253.80.79.2554,094
6253.80.80.0/20253.80.80.1 to 253.80.95.254253.80.95.2554,094
7253.80.96.0/20253.80.96.1 to 253.80.111.254253.80.111.2554,094
8253.80.112.0/20253.80.112.1 to 253.80.127.254253.80.127.2554,094
9253.80.128.0/20253.80.128.1 to 253.80.143.254253.80.143.2554,094
10253.80.144.0/20253.80.144.1 to 253.80.159.254253.80.159.2554,094
11253.80.160.0/20253.80.160.1 to 253.80.175.254253.80.175.2554,094
12253.80.176.0/20253.80.176.1 to 253.80.191.254253.80.191.2554,094
13253.80.192.0/20253.80.192.1 to 253.80.207.254253.80.207.2554,094
14253.80.208.0/20253.80.208.1 to 253.80.223.254253.80.223.2554,094
15253.80.224.0/20253.80.224.1 to 253.80.239.254253.80.239.2554,094
16253.80.240.0/20253.80.240.1 to 253.80.255.254253.80.255.2554,094
17253.81.0.0/20253.81.0.1 to 253.81.15.254253.81.15.2554,094
18253.81.16.0/20253.81.16.1 to 253.81.31.254253.81.31.2554,094
19253.81.32.0/20253.81.32.1 to 253.81.47.254253.81.47.2554,094
20253.81.48.0/20253.81.48.1 to 253.81.63.254253.81.63.2554,094
21253.81.64.0/20253.81.64.1 to 253.81.79.254253.81.79.2554,094
22253.81.80.0/20253.81.80.1 to 253.81.95.254253.81.95.2554,094
23253.81.96.0/20253.81.96.1 to 253.81.111.254253.81.111.2554,094
24253.81.112.0/20253.81.112.1 to 253.81.127.254253.81.127.2554,094
25253.81.128.0/20253.81.128.1 to 253.81.143.254253.81.143.2554,094
26253.81.144.0/20253.81.144.1 to 253.81.159.254253.81.159.2554,094
27253.81.160.0/20253.81.160.1 to 253.81.175.254253.81.175.2554,094
28253.81.176.0/20253.81.176.1 to 253.81.191.254253.81.191.2554,094
29253.81.192.0/20253.81.192.1 to 253.81.207.254253.81.207.2554,094
30253.81.208.0/20253.81.208.1 to 253.81.223.254253.81.223.2554,094
31253.81.224.0/20253.81.224.1 to 253.81.239.254253.81.239.2554,094
32253.81.240.0/20253.81.240.1 to 253.81.255.254253.81.255.2554,094
33253.82.0.0/20253.82.0.1 to 253.82.15.254253.82.15.2554,094
34253.82.16.0/20253.82.16.1 to 253.82.31.254253.82.31.2554,094
35253.82.32.0/20253.82.32.1 to 253.82.47.254253.82.47.2554,094
36253.82.48.0/20253.82.48.1 to 253.82.63.254253.82.63.2554,094
37253.82.64.0/20253.82.64.1 to 253.82.79.254253.82.79.2554,094
38253.82.80.0/20253.82.80.1 to 253.82.95.254253.82.95.2554,094
39253.82.96.0/20253.82.96.1 to 253.82.111.254253.82.111.2554,094
40253.82.112.0/20253.82.112.1 to 253.82.127.254253.82.127.2554,094
41253.82.128.0/20253.82.128.1 to 253.82.143.254253.82.143.2554,094
42253.82.144.0/20253.82.144.1 to 253.82.159.254253.82.159.2554,094
43253.82.160.0/20253.82.160.1 to 253.82.175.254253.82.175.2554,094
44253.82.176.0/20253.82.176.1 to 253.82.191.254253.82.191.2554,094
45253.82.192.0/20253.82.192.1 to 253.82.207.254253.82.207.2554,094
46253.82.208.0/20253.82.208.1 to 253.82.223.254253.82.223.2554,094
47253.82.224.0/20253.82.224.1 to 253.82.239.254253.82.239.2554,094
48253.82.240.0/20253.82.240.1 to 253.82.255.254253.82.255.2554,094
49253.83.0.0/20253.83.0.1 to 253.83.15.254253.83.15.2554,094
50253.83.16.0/20253.83.16.1 to 253.83.31.254253.83.31.2554,094
51253.83.32.0/20253.83.32.1 to 253.83.47.254253.83.47.2554,094
52253.83.48.0/20253.83.48.1 to 253.83.63.254253.83.63.2554,094
53253.83.64.0/20253.83.64.1 to 253.83.79.254253.83.79.2554,094
54253.83.80.0/20253.83.80.1 to 253.83.95.254253.83.95.2554,094
55253.83.96.0/20253.83.96.1 to 253.83.111.254253.83.111.2554,094
56253.83.112.0/20253.83.112.1 to 253.83.127.254253.83.127.2554,094
57253.83.128.0/20253.83.128.1 to 253.83.143.254253.83.143.2554,094
58253.83.144.0/20253.83.144.1 to 253.83.159.254253.83.159.2554,094
59253.83.160.0/20253.83.160.1 to 253.83.175.254253.83.175.2554,094
60253.83.176.0/20253.83.176.1 to 253.83.191.254253.83.191.2554,094
61253.83.192.0/20253.83.192.1 to 253.83.207.254253.83.207.2554,094
62253.83.208.0/20253.83.208.1 to 253.83.223.254253.83.223.2554,094
63253.83.224.0/20253.83.224.1 to 253.83.239.254253.83.239.2554,094
64253.83.240.0/20253.83.240.1 to 253.83.255.254253.83.255.2554,094
65253.84.0.0/20253.84.0.1 to 253.84.15.254253.84.15.2554,094
66253.84.16.0/20253.84.16.1 to 253.84.31.254253.84.31.2554,094
67253.84.32.0/20253.84.32.1 to 253.84.47.254253.84.47.2554,094
68253.84.48.0/20253.84.48.1 to 253.84.63.254253.84.63.2554,094
69253.84.64.0/20253.84.64.1 to 253.84.79.254253.84.79.2554,094
70253.84.80.0/20253.84.80.1 to 253.84.95.254253.84.95.2554,094
71253.84.96.0/20253.84.96.1 to 253.84.111.254253.84.111.2554,094
72253.84.112.0/20253.84.112.1 to 253.84.127.254253.84.127.2554,094
73253.84.128.0/20253.84.128.1 to 253.84.143.254253.84.143.2554,094
74253.84.144.0/20253.84.144.1 to 253.84.159.254253.84.159.2554,094
75253.84.160.0/20253.84.160.1 to 253.84.175.254253.84.175.2554,094
76253.84.176.0/20253.84.176.1 to 253.84.191.254253.84.191.2554,094
77253.84.192.0/20253.84.192.1 to 253.84.207.254253.84.207.2554,094
78253.84.208.0/20253.84.208.1 to 253.84.223.254253.84.223.2554,094
79253.84.224.0/20253.84.224.1 to 253.84.239.254253.84.239.2554,094
80253.84.240.0/20253.84.240.1 to 253.84.255.254253.84.255.2554,094
81253.85.0.0/20253.85.0.1 to 253.85.15.254253.85.15.2554,094
82253.85.16.0/20253.85.16.1 to 253.85.31.254253.85.31.2554,094
83253.85.32.0/20253.85.32.1 to 253.85.47.254253.85.47.2554,094
84253.85.48.0/20253.85.48.1 to 253.85.63.254253.85.63.2554,094
85253.85.64.0/20253.85.64.1 to 253.85.79.254253.85.79.2554,094
86253.85.80.0/20253.85.80.1 to 253.85.95.254253.85.95.2554,094
87253.85.96.0/20253.85.96.1 to 253.85.111.254253.85.111.2554,094
88253.85.112.0/20253.85.112.1 to 253.85.127.254253.85.127.2554,094
89253.85.128.0/20253.85.128.1 to 253.85.143.254253.85.143.2554,094
90253.85.144.0/20253.85.144.1 to 253.85.159.254253.85.159.2554,094
91253.85.160.0/20253.85.160.1 to 253.85.175.254253.85.175.2554,094
92253.85.176.0/20253.85.176.1 to 253.85.191.254253.85.191.2554,094
93253.85.192.0/20253.85.192.1 to 253.85.207.254253.85.207.2554,094
94253.85.208.0/20253.85.208.1 to 253.85.223.254253.85.223.2554,094
95253.85.224.0/20253.85.224.1 to 253.85.239.254253.85.239.2554,094
96253.85.240.0/20253.85.240.1 to 253.85.255.254253.85.255.2554,094
97253.86.0.0/20253.86.0.1 to 253.86.15.254253.86.15.2554,094
98253.86.16.0/20253.86.16.1 to 253.86.31.254253.86.31.2554,094
99253.86.32.0/20253.86.32.1 to 253.86.47.254253.86.47.2554,094
100253.86.48.0/20253.86.48.1 to 253.86.63.254253.86.63.2554,094
101253.86.64.0/20253.86.64.1 to 253.86.79.254253.86.79.2554,094
102253.86.80.0/20253.86.80.1 to 253.86.95.254253.86.95.2554,094
103253.86.96.0/20253.86.96.1 to 253.86.111.254253.86.111.2554,094
104253.86.112.0/20253.86.112.1 to 253.86.127.254253.86.127.2554,094
105253.86.128.0/20253.86.128.1 to 253.86.143.254253.86.143.2554,094
106253.86.144.0/20253.86.144.1 to 253.86.159.254253.86.159.2554,094
107253.86.160.0/20253.86.160.1 to 253.86.175.254253.86.175.2554,094
108253.86.176.0/20253.86.176.1 to 253.86.191.254253.86.191.2554,094
109253.86.192.0/20253.86.192.1 to 253.86.207.254253.86.207.2554,094
110253.86.208.0/20253.86.208.1 to 253.86.223.254253.86.223.2554,094
111253.86.224.0/20253.86.224.1 to 253.86.239.254253.86.239.2554,094
112253.86.240.0/20253.86.240.1 to 253.86.255.254253.86.255.2554,094
113253.87.0.0/20253.87.0.1 to 253.87.15.254253.87.15.2554,094
114253.87.16.0/20253.87.16.1 to 253.87.31.254253.87.31.2554,094
115253.87.32.0/20253.87.32.1 to 253.87.47.254253.87.47.2554,094
116253.87.48.0/20253.87.48.1 to 253.87.63.254253.87.63.2554,094
117253.87.64.0/20253.87.64.1 to 253.87.79.254253.87.79.2554,094
118253.87.80.0/20253.87.80.1 to 253.87.95.254253.87.95.2554,094
119253.87.96.0/20253.87.96.1 to 253.87.111.254253.87.111.2554,094
120253.87.112.0/20253.87.112.1 to 253.87.127.254253.87.127.2554,094
121253.87.128.0/20253.87.128.1 to 253.87.143.254253.87.143.2554,094
122253.87.144.0/20253.87.144.1 to 253.87.159.254253.87.159.2554,094
123253.87.160.0/20253.87.160.1 to 253.87.175.254253.87.175.2554,094
124253.87.176.0/20253.87.176.1 to 253.87.191.254253.87.191.2554,094
125253.87.192.0/20253.87.192.1 to 253.87.207.254253.87.207.2554,094
126253.87.208.0/20253.87.208.1 to 253.87.223.254253.87.223.2554,094
127253.87.224.0/20253.87.224.1 to 253.87.239.254253.87.239.2554,094
128253.87.240.0/20253.87.240.1 to 253.87.255.254253.87.255.2554,094

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.