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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.

Network115.136.0.0/14
Usable hosts262,142
Subnet mask255.252.0.0
Addresses262,144
Network address
115.136.0.0
Broadcast address
115.139.255.255
First usable
115.136.0.1
Last usable
115.139.255.254
Usable hosts
262,142 (262,144 less the network and broadcast addresses)
Subnet mask
255.252.0.0
Wildcard mask
0.3.255.255 (Cisco ACLs, OSPF)
Prefix length
/14
Type
Public public
Old class
A (default /8)
As numbers
Hex 73880000 · Integer 1938292736 to 1938554879
Reverse DNS zones
136.115.in-addr.arpa
137.115.in-addr.arpa
138.115.in-addr.arpa
139.115.in-addr.arpa
/14 is not on a 8-bit boundary, so it takes 4 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address01110011.10001000.00000000.00000000115.136.0.0
Subnet mask11111111.11111100.00000000.00000000255.252.0.0
Network01110011.10001000.00000000.00000000115.136.0.0
Broadcast01110011.10001011.11111111.11111111115.139.255.255
Split into smaller subnets/20
/15 (2)/16 (4)/17 (8)/18 (16)/19 (32)/20 (64)/21 (128)/22 (256)/23 (512)/24 (1,024)/25 (2,048)/26 (4,096)

115.136.0.0/14 makes 64 subnets of /20.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1115.136.0.0/20115.136.0.1 to 115.136.15.254115.136.15.2554,094
2115.136.16.0/20115.136.16.1 to 115.136.31.254115.136.31.2554,094
3115.136.32.0/20115.136.32.1 to 115.136.47.254115.136.47.2554,094
4115.136.48.0/20115.136.48.1 to 115.136.63.254115.136.63.2554,094
5115.136.64.0/20115.136.64.1 to 115.136.79.254115.136.79.2554,094
6115.136.80.0/20115.136.80.1 to 115.136.95.254115.136.95.2554,094
7115.136.96.0/20115.136.96.1 to 115.136.111.254115.136.111.2554,094
8115.136.112.0/20115.136.112.1 to 115.136.127.254115.136.127.2554,094
9115.136.128.0/20115.136.128.1 to 115.136.143.254115.136.143.2554,094
10115.136.144.0/20115.136.144.1 to 115.136.159.254115.136.159.2554,094
11115.136.160.0/20115.136.160.1 to 115.136.175.254115.136.175.2554,094
12115.136.176.0/20115.136.176.1 to 115.136.191.254115.136.191.2554,094
13115.136.192.0/20115.136.192.1 to 115.136.207.254115.136.207.2554,094
14115.136.208.0/20115.136.208.1 to 115.136.223.254115.136.223.2554,094
15115.136.224.0/20115.136.224.1 to 115.136.239.254115.136.239.2554,094
16115.136.240.0/20115.136.240.1 to 115.136.255.254115.136.255.2554,094
17115.137.0.0/20115.137.0.1 to 115.137.15.254115.137.15.2554,094
18115.137.16.0/20115.137.16.1 to 115.137.31.254115.137.31.2554,094
19115.137.32.0/20115.137.32.1 to 115.137.47.254115.137.47.2554,094
20115.137.48.0/20115.137.48.1 to 115.137.63.254115.137.63.2554,094
21115.137.64.0/20115.137.64.1 to 115.137.79.254115.137.79.2554,094
22115.137.80.0/20115.137.80.1 to 115.137.95.254115.137.95.2554,094
23115.137.96.0/20115.137.96.1 to 115.137.111.254115.137.111.2554,094
24115.137.112.0/20115.137.112.1 to 115.137.127.254115.137.127.2554,094
25115.137.128.0/20115.137.128.1 to 115.137.143.254115.137.143.2554,094
26115.137.144.0/20115.137.144.1 to 115.137.159.254115.137.159.2554,094
27115.137.160.0/20115.137.160.1 to 115.137.175.254115.137.175.2554,094
28115.137.176.0/20115.137.176.1 to 115.137.191.254115.137.191.2554,094
29115.137.192.0/20115.137.192.1 to 115.137.207.254115.137.207.2554,094
30115.137.208.0/20115.137.208.1 to 115.137.223.254115.137.223.2554,094
31115.137.224.0/20115.137.224.1 to 115.137.239.254115.137.239.2554,094
32115.137.240.0/20115.137.240.1 to 115.137.255.254115.137.255.2554,094
33115.138.0.0/20115.138.0.1 to 115.138.15.254115.138.15.2554,094
34115.138.16.0/20115.138.16.1 to 115.138.31.254115.138.31.2554,094
35115.138.32.0/20115.138.32.1 to 115.138.47.254115.138.47.2554,094
36115.138.48.0/20115.138.48.1 to 115.138.63.254115.138.63.2554,094
37115.138.64.0/20115.138.64.1 to 115.138.79.254115.138.79.2554,094
38115.138.80.0/20115.138.80.1 to 115.138.95.254115.138.95.2554,094
39115.138.96.0/20115.138.96.1 to 115.138.111.254115.138.111.2554,094
40115.138.112.0/20115.138.112.1 to 115.138.127.254115.138.127.2554,094
41115.138.128.0/20115.138.128.1 to 115.138.143.254115.138.143.2554,094
42115.138.144.0/20115.138.144.1 to 115.138.159.254115.138.159.2554,094
43115.138.160.0/20115.138.160.1 to 115.138.175.254115.138.175.2554,094
44115.138.176.0/20115.138.176.1 to 115.138.191.254115.138.191.2554,094
45115.138.192.0/20115.138.192.1 to 115.138.207.254115.138.207.2554,094
46115.138.208.0/20115.138.208.1 to 115.138.223.254115.138.223.2554,094
47115.138.224.0/20115.138.224.1 to 115.138.239.254115.138.239.2554,094
48115.138.240.0/20115.138.240.1 to 115.138.255.254115.138.255.2554,094
49115.139.0.0/20115.139.0.1 to 115.139.15.254115.139.15.2554,094
50115.139.16.0/20115.139.16.1 to 115.139.31.254115.139.31.2554,094
51115.139.32.0/20115.139.32.1 to 115.139.47.254115.139.47.2554,094
52115.139.48.0/20115.139.48.1 to 115.139.63.254115.139.63.2554,094
53115.139.64.0/20115.139.64.1 to 115.139.79.254115.139.79.2554,094
54115.139.80.0/20115.139.80.1 to 115.139.95.254115.139.95.2554,094
55115.139.96.0/20115.139.96.1 to 115.139.111.254115.139.111.2554,094
56115.139.112.0/20115.139.112.1 to 115.139.127.254115.139.127.2554,094
57115.139.128.0/20115.139.128.1 to 115.139.143.254115.139.143.2554,094
58115.139.144.0/20115.139.144.1 to 115.139.159.254115.139.159.2554,094
59115.139.160.0/20115.139.160.1 to 115.139.175.254115.139.175.2554,094
60115.139.176.0/20115.139.176.1 to 115.139.191.254115.139.191.2554,094
61115.139.192.0/20115.139.192.1 to 115.139.207.254115.139.207.2554,094
62115.139.208.0/20115.139.208.1 to 115.139.223.254115.139.223.2554,094
63115.139.224.0/20115.139.224.1 to 115.139.239.254115.139.239.2554,094
64115.139.240.0/20115.139.240.1 to 115.139.255.254115.139.255.2554,094

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.