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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.

Network230.224.0.0/11
Usable hosts2,097,150
Subnet mask255.224.0.0
Addresses2,097,152
Network address
230.224.0.0
Broadcast address
230.255.255.255
First usable
230.224.0.1
Last usable
230.255.255.254
Usable hosts
2,097,150 (2,097,152 less the network and broadcast addresses)
Subnet mask
255.224.0.0
Wildcard mask
0.31.255.255 (Cisco ACLs, OSPF)
Prefix length
/11
Type
Multicast 224.0.0.0/4
One-to-many traffic, such as IPTV and routing protocols
Old class
D (multicast)
As numbers
Hex E6E00000 · Integer 3873439744 to 3875536895
Reverse DNS zones
224.230.in-addr.arpa
225.230.in-addr.arpa
226.230.in-addr.arpa
227.230.in-addr.arpa
228.230.in-addr.arpa
229.230.in-addr.arpa
230.230.in-addr.arpa
231.230.in-addr.arpa
232.230.in-addr.arpa
233.230.in-addr.arpa
234.230.in-addr.arpa
235.230.in-addr.arpa
236.230.in-addr.arpa
237.230.in-addr.arpa
238.230.in-addr.arpa
239.230.in-addr.arpa
and 16 more
/11 is not on a 8-bit boundary, so it takes 32 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address11100110.11100000.00000000.00000000230.224.0.0
Subnet mask11111111.11100000.00000000.00000000255.224.0.0
Network11100110.11100000.00000000.00000000230.224.0.0
Broadcast11100110.11111111.11111111.11111111230.255.255.255
Split into smaller subnets/17
/12 (2)/13 (4)/14 (8)/15 (16)/16 (32)/17 (64)/18 (128)/19 (256)/20 (512)/21 (1,024)/22 (2,048)/23 (4,096)

230.224.0.0/11 makes 64 subnets of /17.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1230.224.0.0/17230.224.0.1 to 230.224.127.254230.224.127.25532,766
2230.224.128.0/17230.224.128.1 to 230.224.255.254230.224.255.25532,766
3230.225.0.0/17230.225.0.1 to 230.225.127.254230.225.127.25532,766
4230.225.128.0/17230.225.128.1 to 230.225.255.254230.225.255.25532,766
5230.226.0.0/17230.226.0.1 to 230.226.127.254230.226.127.25532,766
6230.226.128.0/17230.226.128.1 to 230.226.255.254230.226.255.25532,766
7230.227.0.0/17230.227.0.1 to 230.227.127.254230.227.127.25532,766
8230.227.128.0/17230.227.128.1 to 230.227.255.254230.227.255.25532,766
9230.228.0.0/17230.228.0.1 to 230.228.127.254230.228.127.25532,766
10230.228.128.0/17230.228.128.1 to 230.228.255.254230.228.255.25532,766
11230.229.0.0/17230.229.0.1 to 230.229.127.254230.229.127.25532,766
12230.229.128.0/17230.229.128.1 to 230.229.255.254230.229.255.25532,766
13230.230.0.0/17230.230.0.1 to 230.230.127.254230.230.127.25532,766
14230.230.128.0/17230.230.128.1 to 230.230.255.254230.230.255.25532,766
15230.231.0.0/17230.231.0.1 to 230.231.127.254230.231.127.25532,766
16230.231.128.0/17230.231.128.1 to 230.231.255.254230.231.255.25532,766
17230.232.0.0/17230.232.0.1 to 230.232.127.254230.232.127.25532,766
18230.232.128.0/17230.232.128.1 to 230.232.255.254230.232.255.25532,766
19230.233.0.0/17230.233.0.1 to 230.233.127.254230.233.127.25532,766
20230.233.128.0/17230.233.128.1 to 230.233.255.254230.233.255.25532,766
21230.234.0.0/17230.234.0.1 to 230.234.127.254230.234.127.25532,766
22230.234.128.0/17230.234.128.1 to 230.234.255.254230.234.255.25532,766
23230.235.0.0/17230.235.0.1 to 230.235.127.254230.235.127.25532,766
24230.235.128.0/17230.235.128.1 to 230.235.255.254230.235.255.25532,766
25230.236.0.0/17230.236.0.1 to 230.236.127.254230.236.127.25532,766
26230.236.128.0/17230.236.128.1 to 230.236.255.254230.236.255.25532,766
27230.237.0.0/17230.237.0.1 to 230.237.127.254230.237.127.25532,766
28230.237.128.0/17230.237.128.1 to 230.237.255.254230.237.255.25532,766
29230.238.0.0/17230.238.0.1 to 230.238.127.254230.238.127.25532,766
30230.238.128.0/17230.238.128.1 to 230.238.255.254230.238.255.25532,766
31230.239.0.0/17230.239.0.1 to 230.239.127.254230.239.127.25532,766
32230.239.128.0/17230.239.128.1 to 230.239.255.254230.239.255.25532,766
33230.240.0.0/17230.240.0.1 to 230.240.127.254230.240.127.25532,766
34230.240.128.0/17230.240.128.1 to 230.240.255.254230.240.255.25532,766
35230.241.0.0/17230.241.0.1 to 230.241.127.254230.241.127.25532,766
36230.241.128.0/17230.241.128.1 to 230.241.255.254230.241.255.25532,766
37230.242.0.0/17230.242.0.1 to 230.242.127.254230.242.127.25532,766
38230.242.128.0/17230.242.128.1 to 230.242.255.254230.242.255.25532,766
39230.243.0.0/17230.243.0.1 to 230.243.127.254230.243.127.25532,766
40230.243.128.0/17230.243.128.1 to 230.243.255.254230.243.255.25532,766
41230.244.0.0/17230.244.0.1 to 230.244.127.254230.244.127.25532,766
42230.244.128.0/17230.244.128.1 to 230.244.255.254230.244.255.25532,766
43230.245.0.0/17230.245.0.1 to 230.245.127.254230.245.127.25532,766
44230.245.128.0/17230.245.128.1 to 230.245.255.254230.245.255.25532,766
45230.246.0.0/17230.246.0.1 to 230.246.127.254230.246.127.25532,766
46230.246.128.0/17230.246.128.1 to 230.246.255.254230.246.255.25532,766
47230.247.0.0/17230.247.0.1 to 230.247.127.254230.247.127.25532,766
48230.247.128.0/17230.247.128.1 to 230.247.255.254230.247.255.25532,766
49230.248.0.0/17230.248.0.1 to 230.248.127.254230.248.127.25532,766
50230.248.128.0/17230.248.128.1 to 230.248.255.254230.248.255.25532,766
51230.249.0.0/17230.249.0.1 to 230.249.127.254230.249.127.25532,766
52230.249.128.0/17230.249.128.1 to 230.249.255.254230.249.255.25532,766
53230.250.0.0/17230.250.0.1 to 230.250.127.254230.250.127.25532,766
54230.250.128.0/17230.250.128.1 to 230.250.255.254230.250.255.25532,766
55230.251.0.0/17230.251.0.1 to 230.251.127.254230.251.127.25532,766
56230.251.128.0/17230.251.128.1 to 230.251.255.254230.251.255.25532,766
57230.252.0.0/17230.252.0.1 to 230.252.127.254230.252.127.25532,766
58230.252.128.0/17230.252.128.1 to 230.252.255.254230.252.255.25532,766
59230.253.0.0/17230.253.0.1 to 230.253.127.254230.253.127.25532,766
60230.253.128.0/17230.253.128.1 to 230.253.255.254230.253.255.25532,766
61230.254.0.0/17230.254.0.1 to 230.254.127.254230.254.127.25532,766
62230.254.128.0/17230.254.128.1 to 230.254.255.254230.254.255.25532,766
63230.255.0.0/17230.255.0.1 to 230.255.127.254230.255.127.25532,766
64230.255.128.0/17230.255.128.1 to 230.255.255.254230.255.255.25532,766

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.