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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.

Network152.152.0.0/13
Usable hosts524,286
Subnet mask255.248.0.0
Addresses524,288
Network address
152.152.0.0
Broadcast address
152.159.255.255
First usable
152.152.0.1
Last usable
152.159.255.254
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
Public public
Old class
B (default /16)
As numbers
Hex 98980000 · Integer 2560098304 to 2560622591
Reverse DNS zones
152.152.in-addr.arpa
153.152.in-addr.arpa
154.152.in-addr.arpa
155.152.in-addr.arpa
156.152.in-addr.arpa
157.152.in-addr.arpa
158.152.in-addr.arpa
159.152.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
Address10011000.10011000.00000000.00000000152.152.0.0
Subnet mask11111111.11111000.00000000.00000000255.248.0.0
Network10011000.10011000.00000000.00000000152.152.0.0
Broadcast10011000.10011111.11111111.11111111152.159.255.255
Split into smaller subnets/19
/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)

152.152.0.0/13 makes 64 subnets of /19.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1152.152.0.0/19152.152.0.1 to 152.152.31.254152.152.31.2558,190
2152.152.32.0/19152.152.32.1 to 152.152.63.254152.152.63.2558,190
3152.152.64.0/19152.152.64.1 to 152.152.95.254152.152.95.2558,190
4152.152.96.0/19152.152.96.1 to 152.152.127.254152.152.127.2558,190
5152.152.128.0/19152.152.128.1 to 152.152.159.254152.152.159.2558,190
6152.152.160.0/19152.152.160.1 to 152.152.191.254152.152.191.2558,190
7152.152.192.0/19152.152.192.1 to 152.152.223.254152.152.223.2558,190
8152.152.224.0/19152.152.224.1 to 152.152.255.254152.152.255.2558,190
9152.153.0.0/19152.153.0.1 to 152.153.31.254152.153.31.2558,190
10152.153.32.0/19152.153.32.1 to 152.153.63.254152.153.63.2558,190
11152.153.64.0/19152.153.64.1 to 152.153.95.254152.153.95.2558,190
12152.153.96.0/19152.153.96.1 to 152.153.127.254152.153.127.2558,190
13152.153.128.0/19152.153.128.1 to 152.153.159.254152.153.159.2558,190
14152.153.160.0/19152.153.160.1 to 152.153.191.254152.153.191.2558,190
15152.153.192.0/19152.153.192.1 to 152.153.223.254152.153.223.2558,190
16152.153.224.0/19152.153.224.1 to 152.153.255.254152.153.255.2558,190
17152.154.0.0/19152.154.0.1 to 152.154.31.254152.154.31.2558,190
18152.154.32.0/19152.154.32.1 to 152.154.63.254152.154.63.2558,190
19152.154.64.0/19152.154.64.1 to 152.154.95.254152.154.95.2558,190
20152.154.96.0/19152.154.96.1 to 152.154.127.254152.154.127.2558,190
21152.154.128.0/19152.154.128.1 to 152.154.159.254152.154.159.2558,190
22152.154.160.0/19152.154.160.1 to 152.154.191.254152.154.191.2558,190
23152.154.192.0/19152.154.192.1 to 152.154.223.254152.154.223.2558,190
24152.154.224.0/19152.154.224.1 to 152.154.255.254152.154.255.2558,190
25152.155.0.0/19152.155.0.1 to 152.155.31.254152.155.31.2558,190
26152.155.32.0/19152.155.32.1 to 152.155.63.254152.155.63.2558,190
27152.155.64.0/19152.155.64.1 to 152.155.95.254152.155.95.2558,190
28152.155.96.0/19152.155.96.1 to 152.155.127.254152.155.127.2558,190
29152.155.128.0/19152.155.128.1 to 152.155.159.254152.155.159.2558,190
30152.155.160.0/19152.155.160.1 to 152.155.191.254152.155.191.2558,190
31152.155.192.0/19152.155.192.1 to 152.155.223.254152.155.223.2558,190
32152.155.224.0/19152.155.224.1 to 152.155.255.254152.155.255.2558,190
33152.156.0.0/19152.156.0.1 to 152.156.31.254152.156.31.2558,190
34152.156.32.0/19152.156.32.1 to 152.156.63.254152.156.63.2558,190
35152.156.64.0/19152.156.64.1 to 152.156.95.254152.156.95.2558,190
36152.156.96.0/19152.156.96.1 to 152.156.127.254152.156.127.2558,190
37152.156.128.0/19152.156.128.1 to 152.156.159.254152.156.159.2558,190
38152.156.160.0/19152.156.160.1 to 152.156.191.254152.156.191.2558,190
39152.156.192.0/19152.156.192.1 to 152.156.223.254152.156.223.2558,190
40152.156.224.0/19152.156.224.1 to 152.156.255.254152.156.255.2558,190
41152.157.0.0/19152.157.0.1 to 152.157.31.254152.157.31.2558,190
42152.157.32.0/19152.157.32.1 to 152.157.63.254152.157.63.2558,190
43152.157.64.0/19152.157.64.1 to 152.157.95.254152.157.95.2558,190
44152.157.96.0/19152.157.96.1 to 152.157.127.254152.157.127.2558,190
45152.157.128.0/19152.157.128.1 to 152.157.159.254152.157.159.2558,190
46152.157.160.0/19152.157.160.1 to 152.157.191.254152.157.191.2558,190
47152.157.192.0/19152.157.192.1 to 152.157.223.254152.157.223.2558,190
48152.157.224.0/19152.157.224.1 to 152.157.255.254152.157.255.2558,190
49152.158.0.0/19152.158.0.1 to 152.158.31.254152.158.31.2558,190
50152.158.32.0/19152.158.32.1 to 152.158.63.254152.158.63.2558,190
51152.158.64.0/19152.158.64.1 to 152.158.95.254152.158.95.2558,190
52152.158.96.0/19152.158.96.1 to 152.158.127.254152.158.127.2558,190
53152.158.128.0/19152.158.128.1 to 152.158.159.254152.158.159.2558,190
54152.158.160.0/19152.158.160.1 to 152.158.191.254152.158.191.2558,190
55152.158.192.0/19152.158.192.1 to 152.158.223.254152.158.223.2558,190
56152.158.224.0/19152.158.224.1 to 152.158.255.254152.158.255.2558,190
57152.159.0.0/19152.159.0.1 to 152.159.31.254152.159.31.2558,190
58152.159.32.0/19152.159.32.1 to 152.159.63.254152.159.63.2558,190
59152.159.64.0/19152.159.64.1 to 152.159.95.254152.159.95.2558,190
60152.159.96.0/19152.159.96.1 to 152.159.127.254152.159.127.2558,190
61152.159.128.0/19152.159.128.1 to 152.159.159.254152.159.159.2558,190
62152.159.160.0/19152.159.160.1 to 152.159.191.254152.159.191.2558,190
63152.159.192.0/19152.159.192.1 to 152.159.223.254152.159.223.2558,190
64152.159.224.0/19152.159.224.1 to 152.159.255.254152.159.255.2558,190

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.