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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.

Network10.136.0.0/14
Usable hosts262,142
Subnet mask255.252.0.0
Addresses262,144
Network address
10.136.0.0
Broadcast address
10.139.255.255
First usable
10.136.0.1
Last usable
10.139.255.254
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
Private (RFC 1918) 10.0.0.0/8
Office and home networks; not routed on the internet
Old class
A (default /8)
As numbers
Hex 0A880000 · Integer 176685056 to 176947199
Reverse DNS zones
136.10.in-addr.arpa
137.10.in-addr.arpa
138.10.in-addr.arpa
139.10.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
Address00001010.10001000.00000000.0000000010.136.0.0
Subnet mask11111111.11111100.00000000.00000000255.252.0.0
Network00001010.10001000.00000000.0000000010.136.0.0
Broadcast00001010.10001011.11111111.1111111110.139.255.255
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)

10.136.0.0/14 makes 64 subnets of /20.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
110.136.0.0/2010.136.0.1 to 10.136.15.25410.136.15.2554,094
210.136.16.0/2010.136.16.1 to 10.136.31.25410.136.31.2554,094
310.136.32.0/2010.136.32.1 to 10.136.47.25410.136.47.2554,094
410.136.48.0/2010.136.48.1 to 10.136.63.25410.136.63.2554,094
510.136.64.0/2010.136.64.1 to 10.136.79.25410.136.79.2554,094
610.136.80.0/2010.136.80.1 to 10.136.95.25410.136.95.2554,094
710.136.96.0/2010.136.96.1 to 10.136.111.25410.136.111.2554,094
810.136.112.0/2010.136.112.1 to 10.136.127.25410.136.127.2554,094
910.136.128.0/2010.136.128.1 to 10.136.143.25410.136.143.2554,094
1010.136.144.0/2010.136.144.1 to 10.136.159.25410.136.159.2554,094
1110.136.160.0/2010.136.160.1 to 10.136.175.25410.136.175.2554,094
1210.136.176.0/2010.136.176.1 to 10.136.191.25410.136.191.2554,094
1310.136.192.0/2010.136.192.1 to 10.136.207.25410.136.207.2554,094
1410.136.208.0/2010.136.208.1 to 10.136.223.25410.136.223.2554,094
1510.136.224.0/2010.136.224.1 to 10.136.239.25410.136.239.2554,094
1610.136.240.0/2010.136.240.1 to 10.136.255.25410.136.255.2554,094
1710.137.0.0/2010.137.0.1 to 10.137.15.25410.137.15.2554,094
1810.137.16.0/2010.137.16.1 to 10.137.31.25410.137.31.2554,094
1910.137.32.0/2010.137.32.1 to 10.137.47.25410.137.47.2554,094
2010.137.48.0/2010.137.48.1 to 10.137.63.25410.137.63.2554,094
2110.137.64.0/2010.137.64.1 to 10.137.79.25410.137.79.2554,094
2210.137.80.0/2010.137.80.1 to 10.137.95.25410.137.95.2554,094
2310.137.96.0/2010.137.96.1 to 10.137.111.25410.137.111.2554,094
2410.137.112.0/2010.137.112.1 to 10.137.127.25410.137.127.2554,094
2510.137.128.0/2010.137.128.1 to 10.137.143.25410.137.143.2554,094
2610.137.144.0/2010.137.144.1 to 10.137.159.25410.137.159.2554,094
2710.137.160.0/2010.137.160.1 to 10.137.175.25410.137.175.2554,094
2810.137.176.0/2010.137.176.1 to 10.137.191.25410.137.191.2554,094
2910.137.192.0/2010.137.192.1 to 10.137.207.25410.137.207.2554,094
3010.137.208.0/2010.137.208.1 to 10.137.223.25410.137.223.2554,094
3110.137.224.0/2010.137.224.1 to 10.137.239.25410.137.239.2554,094
3210.137.240.0/2010.137.240.1 to 10.137.255.25410.137.255.2554,094
3310.138.0.0/2010.138.0.1 to 10.138.15.25410.138.15.2554,094
3410.138.16.0/2010.138.16.1 to 10.138.31.25410.138.31.2554,094
3510.138.32.0/2010.138.32.1 to 10.138.47.25410.138.47.2554,094
3610.138.48.0/2010.138.48.1 to 10.138.63.25410.138.63.2554,094
3710.138.64.0/2010.138.64.1 to 10.138.79.25410.138.79.2554,094
3810.138.80.0/2010.138.80.1 to 10.138.95.25410.138.95.2554,094
3910.138.96.0/2010.138.96.1 to 10.138.111.25410.138.111.2554,094
4010.138.112.0/2010.138.112.1 to 10.138.127.25410.138.127.2554,094
4110.138.128.0/2010.138.128.1 to 10.138.143.25410.138.143.2554,094
4210.138.144.0/2010.138.144.1 to 10.138.159.25410.138.159.2554,094
4310.138.160.0/2010.138.160.1 to 10.138.175.25410.138.175.2554,094
4410.138.176.0/2010.138.176.1 to 10.138.191.25410.138.191.2554,094
4510.138.192.0/2010.138.192.1 to 10.138.207.25410.138.207.2554,094
4610.138.208.0/2010.138.208.1 to 10.138.223.25410.138.223.2554,094
4710.138.224.0/2010.138.224.1 to 10.138.239.25410.138.239.2554,094
4810.138.240.0/2010.138.240.1 to 10.138.255.25410.138.255.2554,094
4910.139.0.0/2010.139.0.1 to 10.139.15.25410.139.15.2554,094
5010.139.16.0/2010.139.16.1 to 10.139.31.25410.139.31.2554,094
5110.139.32.0/2010.139.32.1 to 10.139.47.25410.139.47.2554,094
5210.139.48.0/2010.139.48.1 to 10.139.63.25410.139.63.2554,094
5310.139.64.0/2010.139.64.1 to 10.139.79.25410.139.79.2554,094
5410.139.80.0/2010.139.80.1 to 10.139.95.25410.139.95.2554,094
5510.139.96.0/2010.139.96.1 to 10.139.111.25410.139.111.2554,094
5610.139.112.0/2010.139.112.1 to 10.139.127.25410.139.127.2554,094
5710.139.128.0/2010.139.128.1 to 10.139.143.25410.139.143.2554,094
5810.139.144.0/2010.139.144.1 to 10.139.159.25410.139.159.2554,094
5910.139.160.0/2010.139.160.1 to 10.139.175.25410.139.175.2554,094
6010.139.176.0/2010.139.176.1 to 10.139.191.25410.139.191.2554,094
6110.139.192.0/2010.139.192.1 to 10.139.207.25410.139.207.2554,094
6210.139.208.0/2010.139.208.1 to 10.139.223.25410.139.223.2554,094
6310.139.224.0/2010.139.224.1 to 10.139.239.25410.139.239.2554,094
6410.139.240.0/2010.139.240.1 to 10.139.255.25410.139.255.2554,094

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.