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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.

Network44.167.0.0/17
Usable hosts32,766
Subnet mask255.255.128.0
Addresses32,768
Network address
44.167.0.0
Broadcast address
44.167.127.255
First usable
44.167.0.1
Last usable
44.167.127.254
Usable hosts
32,766 (32,768 less the network and broadcast addresses)
Subnet mask
255.255.128.0
Wildcard mask
0.0.127.255 (Cisco ACLs, OSPF)
Prefix length
/17
Type
Public public
Old class
A (default /8)
As numbers
Hex 2CA70000 · Integer 749142016 to 749174783
Reverse DNS zones
0.167.44.in-addr.arpa
1.167.44.in-addr.arpa
2.167.44.in-addr.arpa
3.167.44.in-addr.arpa
4.167.44.in-addr.arpa
5.167.44.in-addr.arpa
6.167.44.in-addr.arpa
7.167.44.in-addr.arpa
8.167.44.in-addr.arpa
9.167.44.in-addr.arpa
10.167.44.in-addr.arpa
11.167.44.in-addr.arpa
12.167.44.in-addr.arpa
13.167.44.in-addr.arpa
14.167.44.in-addr.arpa
15.167.44.in-addr.arpa
and 112 more
/17 is not on a 8-bit boundary, so it takes 128 /24 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address00101100.10100111.00000000.0000000044.167.0.0
Subnet mask11111111.11111111.10000000.00000000255.255.128.0
Network00101100.10100111.00000000.0000000044.167.0.0
Broadcast00101100.10100111.01111111.1111111144.167.127.255
Split into smaller subnets/24
/18 (2)/19 (4)/20 (8)/21 (16)/22 (32)/23 (64)/24 (128)/25 (256)/26 (512)/27 (1,024)/28 (2,048)/29 (4,096)

44.167.0.0/17 makes 128 subnets of /24.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
144.167.0.0/2444.167.0.1 to 44.167.0.25444.167.0.255254
244.167.1.0/2444.167.1.1 to 44.167.1.25444.167.1.255254
344.167.2.0/2444.167.2.1 to 44.167.2.25444.167.2.255254
444.167.3.0/2444.167.3.1 to 44.167.3.25444.167.3.255254
544.167.4.0/2444.167.4.1 to 44.167.4.25444.167.4.255254
644.167.5.0/2444.167.5.1 to 44.167.5.25444.167.5.255254
744.167.6.0/2444.167.6.1 to 44.167.6.25444.167.6.255254
844.167.7.0/2444.167.7.1 to 44.167.7.25444.167.7.255254
944.167.8.0/2444.167.8.1 to 44.167.8.25444.167.8.255254
1044.167.9.0/2444.167.9.1 to 44.167.9.25444.167.9.255254
1144.167.10.0/2444.167.10.1 to 44.167.10.25444.167.10.255254
1244.167.11.0/2444.167.11.1 to 44.167.11.25444.167.11.255254
1344.167.12.0/2444.167.12.1 to 44.167.12.25444.167.12.255254
1444.167.13.0/2444.167.13.1 to 44.167.13.25444.167.13.255254
1544.167.14.0/2444.167.14.1 to 44.167.14.25444.167.14.255254
1644.167.15.0/2444.167.15.1 to 44.167.15.25444.167.15.255254
1744.167.16.0/2444.167.16.1 to 44.167.16.25444.167.16.255254
1844.167.17.0/2444.167.17.1 to 44.167.17.25444.167.17.255254
1944.167.18.0/2444.167.18.1 to 44.167.18.25444.167.18.255254
2044.167.19.0/2444.167.19.1 to 44.167.19.25444.167.19.255254
2144.167.20.0/2444.167.20.1 to 44.167.20.25444.167.20.255254
2244.167.21.0/2444.167.21.1 to 44.167.21.25444.167.21.255254
2344.167.22.0/2444.167.22.1 to 44.167.22.25444.167.22.255254
2444.167.23.0/2444.167.23.1 to 44.167.23.25444.167.23.255254
2544.167.24.0/2444.167.24.1 to 44.167.24.25444.167.24.255254
2644.167.25.0/2444.167.25.1 to 44.167.25.25444.167.25.255254
2744.167.26.0/2444.167.26.1 to 44.167.26.25444.167.26.255254
2844.167.27.0/2444.167.27.1 to 44.167.27.25444.167.27.255254
2944.167.28.0/2444.167.28.1 to 44.167.28.25444.167.28.255254
3044.167.29.0/2444.167.29.1 to 44.167.29.25444.167.29.255254
3144.167.30.0/2444.167.30.1 to 44.167.30.25444.167.30.255254
3244.167.31.0/2444.167.31.1 to 44.167.31.25444.167.31.255254
3344.167.32.0/2444.167.32.1 to 44.167.32.25444.167.32.255254
3444.167.33.0/2444.167.33.1 to 44.167.33.25444.167.33.255254
3544.167.34.0/2444.167.34.1 to 44.167.34.25444.167.34.255254
3644.167.35.0/2444.167.35.1 to 44.167.35.25444.167.35.255254
3744.167.36.0/2444.167.36.1 to 44.167.36.25444.167.36.255254
3844.167.37.0/2444.167.37.1 to 44.167.37.25444.167.37.255254
3944.167.38.0/2444.167.38.1 to 44.167.38.25444.167.38.255254
4044.167.39.0/2444.167.39.1 to 44.167.39.25444.167.39.255254
4144.167.40.0/2444.167.40.1 to 44.167.40.25444.167.40.255254
4244.167.41.0/2444.167.41.1 to 44.167.41.25444.167.41.255254
4344.167.42.0/2444.167.42.1 to 44.167.42.25444.167.42.255254
4444.167.43.0/2444.167.43.1 to 44.167.43.25444.167.43.255254
4544.167.44.0/2444.167.44.1 to 44.167.44.25444.167.44.255254
4644.167.45.0/2444.167.45.1 to 44.167.45.25444.167.45.255254
4744.167.46.0/2444.167.46.1 to 44.167.46.25444.167.46.255254
4844.167.47.0/2444.167.47.1 to 44.167.47.25444.167.47.255254
4944.167.48.0/2444.167.48.1 to 44.167.48.25444.167.48.255254
5044.167.49.0/2444.167.49.1 to 44.167.49.25444.167.49.255254
5144.167.50.0/2444.167.50.1 to 44.167.50.25444.167.50.255254
5244.167.51.0/2444.167.51.1 to 44.167.51.25444.167.51.255254
5344.167.52.0/2444.167.52.1 to 44.167.52.25444.167.52.255254
5444.167.53.0/2444.167.53.1 to 44.167.53.25444.167.53.255254
5544.167.54.0/2444.167.54.1 to 44.167.54.25444.167.54.255254
5644.167.55.0/2444.167.55.1 to 44.167.55.25444.167.55.255254
5744.167.56.0/2444.167.56.1 to 44.167.56.25444.167.56.255254
5844.167.57.0/2444.167.57.1 to 44.167.57.25444.167.57.255254
5944.167.58.0/2444.167.58.1 to 44.167.58.25444.167.58.255254
6044.167.59.0/2444.167.59.1 to 44.167.59.25444.167.59.255254
6144.167.60.0/2444.167.60.1 to 44.167.60.25444.167.60.255254
6244.167.61.0/2444.167.61.1 to 44.167.61.25444.167.61.255254
6344.167.62.0/2444.167.62.1 to 44.167.62.25444.167.62.255254
6444.167.63.0/2444.167.63.1 to 44.167.63.25444.167.63.255254
6544.167.64.0/2444.167.64.1 to 44.167.64.25444.167.64.255254
6644.167.65.0/2444.167.65.1 to 44.167.65.25444.167.65.255254
6744.167.66.0/2444.167.66.1 to 44.167.66.25444.167.66.255254
6844.167.67.0/2444.167.67.1 to 44.167.67.25444.167.67.255254
6944.167.68.0/2444.167.68.1 to 44.167.68.25444.167.68.255254
7044.167.69.0/2444.167.69.1 to 44.167.69.25444.167.69.255254
7144.167.70.0/2444.167.70.1 to 44.167.70.25444.167.70.255254
7244.167.71.0/2444.167.71.1 to 44.167.71.25444.167.71.255254
7344.167.72.0/2444.167.72.1 to 44.167.72.25444.167.72.255254
7444.167.73.0/2444.167.73.1 to 44.167.73.25444.167.73.255254
7544.167.74.0/2444.167.74.1 to 44.167.74.25444.167.74.255254
7644.167.75.0/2444.167.75.1 to 44.167.75.25444.167.75.255254
7744.167.76.0/2444.167.76.1 to 44.167.76.25444.167.76.255254
7844.167.77.0/2444.167.77.1 to 44.167.77.25444.167.77.255254
7944.167.78.0/2444.167.78.1 to 44.167.78.25444.167.78.255254
8044.167.79.0/2444.167.79.1 to 44.167.79.25444.167.79.255254
8144.167.80.0/2444.167.80.1 to 44.167.80.25444.167.80.255254
8244.167.81.0/2444.167.81.1 to 44.167.81.25444.167.81.255254
8344.167.82.0/2444.167.82.1 to 44.167.82.25444.167.82.255254
8444.167.83.0/2444.167.83.1 to 44.167.83.25444.167.83.255254
8544.167.84.0/2444.167.84.1 to 44.167.84.25444.167.84.255254
8644.167.85.0/2444.167.85.1 to 44.167.85.25444.167.85.255254
8744.167.86.0/2444.167.86.1 to 44.167.86.25444.167.86.255254
8844.167.87.0/2444.167.87.1 to 44.167.87.25444.167.87.255254
8944.167.88.0/2444.167.88.1 to 44.167.88.25444.167.88.255254
9044.167.89.0/2444.167.89.1 to 44.167.89.25444.167.89.255254
9144.167.90.0/2444.167.90.1 to 44.167.90.25444.167.90.255254
9244.167.91.0/2444.167.91.1 to 44.167.91.25444.167.91.255254
9344.167.92.0/2444.167.92.1 to 44.167.92.25444.167.92.255254
9444.167.93.0/2444.167.93.1 to 44.167.93.25444.167.93.255254
9544.167.94.0/2444.167.94.1 to 44.167.94.25444.167.94.255254
9644.167.95.0/2444.167.95.1 to 44.167.95.25444.167.95.255254
9744.167.96.0/2444.167.96.1 to 44.167.96.25444.167.96.255254
9844.167.97.0/2444.167.97.1 to 44.167.97.25444.167.97.255254
9944.167.98.0/2444.167.98.1 to 44.167.98.25444.167.98.255254
10044.167.99.0/2444.167.99.1 to 44.167.99.25444.167.99.255254
10144.167.100.0/2444.167.100.1 to 44.167.100.25444.167.100.255254
10244.167.101.0/2444.167.101.1 to 44.167.101.25444.167.101.255254
10344.167.102.0/2444.167.102.1 to 44.167.102.25444.167.102.255254
10444.167.103.0/2444.167.103.1 to 44.167.103.25444.167.103.255254
10544.167.104.0/2444.167.104.1 to 44.167.104.25444.167.104.255254
10644.167.105.0/2444.167.105.1 to 44.167.105.25444.167.105.255254
10744.167.106.0/2444.167.106.1 to 44.167.106.25444.167.106.255254
10844.167.107.0/2444.167.107.1 to 44.167.107.25444.167.107.255254
10944.167.108.0/2444.167.108.1 to 44.167.108.25444.167.108.255254
11044.167.109.0/2444.167.109.1 to 44.167.109.25444.167.109.255254
11144.167.110.0/2444.167.110.1 to 44.167.110.25444.167.110.255254
11244.167.111.0/2444.167.111.1 to 44.167.111.25444.167.111.255254
11344.167.112.0/2444.167.112.1 to 44.167.112.25444.167.112.255254
11444.167.113.0/2444.167.113.1 to 44.167.113.25444.167.113.255254
11544.167.114.0/2444.167.114.1 to 44.167.114.25444.167.114.255254
11644.167.115.0/2444.167.115.1 to 44.167.115.25444.167.115.255254
11744.167.116.0/2444.167.116.1 to 44.167.116.25444.167.116.255254
11844.167.117.0/2444.167.117.1 to 44.167.117.25444.167.117.255254
11944.167.118.0/2444.167.118.1 to 44.167.118.25444.167.118.255254
12044.167.119.0/2444.167.119.1 to 44.167.119.25444.167.119.255254
12144.167.120.0/2444.167.120.1 to 44.167.120.25444.167.120.255254
12244.167.121.0/2444.167.121.1 to 44.167.121.25444.167.121.255254
12344.167.122.0/2444.167.122.1 to 44.167.122.25444.167.122.255254
12444.167.123.0/2444.167.123.1 to 44.167.123.25444.167.123.255254
12544.167.124.0/2444.167.124.1 to 44.167.124.25444.167.124.255254
12644.167.125.0/2444.167.125.1 to 44.167.125.25444.167.125.255254
12744.167.126.0/2444.167.126.1 to 44.167.126.25444.167.126.255254
12844.167.127.0/2444.167.127.1 to 44.167.127.25444.167.127.255254

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.