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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.

Network52.0.0.0/9
Usable hosts8,388,606
Subnet mask255.128.0.0
Addresses8,388,608
Network address
52.0.0.0
Broadcast address
52.127.255.255
First usable
52.0.0.1
Last usable
52.127.255.254
Usable hosts
8,388,606 (8,388,608 less the network and broadcast addresses)
Subnet mask
255.128.0.0
Wildcard mask
0.127.255.255 (Cisco ACLs, OSPF)
Prefix length
/9
Type
Public public
Old class
A (default /8)
As numbers
Hex 34000000 · Integer 872415232 to 880803839
Reverse DNS zones
0.52.in-addr.arpa
1.52.in-addr.arpa
2.52.in-addr.arpa
3.52.in-addr.arpa
4.52.in-addr.arpa
5.52.in-addr.arpa
6.52.in-addr.arpa
7.52.in-addr.arpa
8.52.in-addr.arpa
9.52.in-addr.arpa
10.52.in-addr.arpa
11.52.in-addr.arpa
12.52.in-addr.arpa
13.52.in-addr.arpa
14.52.in-addr.arpa
15.52.in-addr.arpa
and 112 more
/9 is not on a 8-bit boundary, so it takes 128 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address00110100.00000000.00000000.0000000052.0.0.0
Subnet mask11111111.10000000.00000000.00000000255.128.0.0
Network00110100.00000000.00000000.0000000052.0.0.0
Broadcast00110100.01111111.11111111.1111111152.127.255.255
Split into smaller subnets/15
/10 (2)/11 (4)/12 (8)/13 (16)/14 (32)/15 (64)/16 (128)/17 (256)/18 (512)/19 (1,024)/20 (2,048)/21 (4,096)

52.0.0.0/9 makes 64 subnets of /15.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
152.0.0.0/1552.0.0.1 to 52.1.255.25452.1.255.255131,070
252.2.0.0/1552.2.0.1 to 52.3.255.25452.3.255.255131,070
352.4.0.0/1552.4.0.1 to 52.5.255.25452.5.255.255131,070
452.6.0.0/1552.6.0.1 to 52.7.255.25452.7.255.255131,070
552.8.0.0/1552.8.0.1 to 52.9.255.25452.9.255.255131,070
652.10.0.0/1552.10.0.1 to 52.11.255.25452.11.255.255131,070
752.12.0.0/1552.12.0.1 to 52.13.255.25452.13.255.255131,070
852.14.0.0/1552.14.0.1 to 52.15.255.25452.15.255.255131,070
952.16.0.0/1552.16.0.1 to 52.17.255.25452.17.255.255131,070
1052.18.0.0/1552.18.0.1 to 52.19.255.25452.19.255.255131,070
1152.20.0.0/1552.20.0.1 to 52.21.255.25452.21.255.255131,070
1252.22.0.0/1552.22.0.1 to 52.23.255.25452.23.255.255131,070
1352.24.0.0/1552.24.0.1 to 52.25.255.25452.25.255.255131,070
1452.26.0.0/1552.26.0.1 to 52.27.255.25452.27.255.255131,070
1552.28.0.0/1552.28.0.1 to 52.29.255.25452.29.255.255131,070
1652.30.0.0/1552.30.0.1 to 52.31.255.25452.31.255.255131,070
1752.32.0.0/1552.32.0.1 to 52.33.255.25452.33.255.255131,070
1852.34.0.0/1552.34.0.1 to 52.35.255.25452.35.255.255131,070
1952.36.0.0/1552.36.0.1 to 52.37.255.25452.37.255.255131,070
2052.38.0.0/1552.38.0.1 to 52.39.255.25452.39.255.255131,070
2152.40.0.0/1552.40.0.1 to 52.41.255.25452.41.255.255131,070
2252.42.0.0/1552.42.0.1 to 52.43.255.25452.43.255.255131,070
2352.44.0.0/1552.44.0.1 to 52.45.255.25452.45.255.255131,070
2452.46.0.0/1552.46.0.1 to 52.47.255.25452.47.255.255131,070
2552.48.0.0/1552.48.0.1 to 52.49.255.25452.49.255.255131,070
2652.50.0.0/1552.50.0.1 to 52.51.255.25452.51.255.255131,070
2752.52.0.0/1552.52.0.1 to 52.53.255.25452.53.255.255131,070
2852.54.0.0/1552.54.0.1 to 52.55.255.25452.55.255.255131,070
2952.56.0.0/1552.56.0.1 to 52.57.255.25452.57.255.255131,070
3052.58.0.0/1552.58.0.1 to 52.59.255.25452.59.255.255131,070
3152.60.0.0/1552.60.0.1 to 52.61.255.25452.61.255.255131,070
3252.62.0.0/1552.62.0.1 to 52.63.255.25452.63.255.255131,070
3352.64.0.0/1552.64.0.1 to 52.65.255.25452.65.255.255131,070
3452.66.0.0/1552.66.0.1 to 52.67.255.25452.67.255.255131,070
3552.68.0.0/1552.68.0.1 to 52.69.255.25452.69.255.255131,070
3652.70.0.0/1552.70.0.1 to 52.71.255.25452.71.255.255131,070
3752.72.0.0/1552.72.0.1 to 52.73.255.25452.73.255.255131,070
3852.74.0.0/1552.74.0.1 to 52.75.255.25452.75.255.255131,070
3952.76.0.0/1552.76.0.1 to 52.77.255.25452.77.255.255131,070
4052.78.0.0/1552.78.0.1 to 52.79.255.25452.79.255.255131,070
4152.80.0.0/1552.80.0.1 to 52.81.255.25452.81.255.255131,070
4252.82.0.0/1552.82.0.1 to 52.83.255.25452.83.255.255131,070
4352.84.0.0/1552.84.0.1 to 52.85.255.25452.85.255.255131,070
4452.86.0.0/1552.86.0.1 to 52.87.255.25452.87.255.255131,070
4552.88.0.0/1552.88.0.1 to 52.89.255.25452.89.255.255131,070
4652.90.0.0/1552.90.0.1 to 52.91.255.25452.91.255.255131,070
4752.92.0.0/1552.92.0.1 to 52.93.255.25452.93.255.255131,070
4852.94.0.0/1552.94.0.1 to 52.95.255.25452.95.255.255131,070
4952.96.0.0/1552.96.0.1 to 52.97.255.25452.97.255.255131,070
5052.98.0.0/1552.98.0.1 to 52.99.255.25452.99.255.255131,070
5152.100.0.0/1552.100.0.1 to 52.101.255.25452.101.255.255131,070
5252.102.0.0/1552.102.0.1 to 52.103.255.25452.103.255.255131,070
5352.104.0.0/1552.104.0.1 to 52.105.255.25452.105.255.255131,070
5452.106.0.0/1552.106.0.1 to 52.107.255.25452.107.255.255131,070
5552.108.0.0/1552.108.0.1 to 52.109.255.25452.109.255.255131,070
5652.110.0.0/1552.110.0.1 to 52.111.255.25452.111.255.255131,070
5752.112.0.0/1552.112.0.1 to 52.113.255.25452.113.255.255131,070
5852.114.0.0/1552.114.0.1 to 52.115.255.25452.115.255.255131,070
5952.116.0.0/1552.116.0.1 to 52.117.255.25452.117.255.255131,070
6052.118.0.0/1552.118.0.1 to 52.119.255.25452.119.255.255131,070
6152.120.0.0/1552.120.0.1 to 52.121.255.25452.121.255.255131,070
6252.122.0.0/1552.122.0.1 to 52.123.255.25452.123.255.255131,070
6352.124.0.0/1552.124.0.1 to 52.125.255.25452.125.255.255131,070
6452.126.0.0/1552.126.0.1 to 52.127.255.25452.127.255.255131,070

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.