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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.

Network225.166.2.192/26
Usable hosts62
Subnet mask255.255.255.192
Addresses64
Network address
225.166.2.192
Broadcast address
225.166.2.255
First usable
225.166.2.193
Last usable
225.166.2.254
Usable hosts
62 (64 less the network and broadcast addresses)
Subnet mask
255.255.255.192
Wildcard mask
0.0.0.63 (Cisco ACLs, OSPF)
Prefix length
/26
Type
Multicast 224.0.0.0/4
One-to-many traffic, such as IPTV and routing protocols
Old class
D (multicast)
As numbers
Hex E1A602C0 · Integer 3785753280 to 3785753343
Reverse DNS zone
2.166.225.in-addr.arpa
Smaller than a /24: the provider delegates it inside the /24 zone (RFC 2317), or sets each PTR record for you.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address11100001.10100110.00000010.11000000225.166.2.192
Subnet mask11111111.11111111.11111111.11000000255.255.255.192
Network11100001.10100110.00000010.11000000225.166.2.192
Broadcast11100001.10100110.00000010.11111111225.166.2.255
Split into smaller subnets/32
/27 (2)/28 (4)/29 (8)/30 (16)/31 (32)/32 (64)

225.166.2.192/26 makes 64 subnets of /32.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1225.166.2.192/32225.166.2.192 to 225.166.2.192—1
2225.166.2.193/32225.166.2.193 to 225.166.2.193—1
3225.166.2.194/32225.166.2.194 to 225.166.2.194—1
4225.166.2.195/32225.166.2.195 to 225.166.2.195—1
5225.166.2.196/32225.166.2.196 to 225.166.2.196—1
6225.166.2.197/32225.166.2.197 to 225.166.2.197—1
7225.166.2.198/32225.166.2.198 to 225.166.2.198—1
8225.166.2.199/32225.166.2.199 to 225.166.2.199—1
9225.166.2.200/32225.166.2.200 to 225.166.2.200—1
10225.166.2.201/32225.166.2.201 to 225.166.2.201—1
11225.166.2.202/32225.166.2.202 to 225.166.2.202—1
12225.166.2.203/32225.166.2.203 to 225.166.2.203—1
13225.166.2.204/32225.166.2.204 to 225.166.2.204—1
14225.166.2.205/32225.166.2.205 to 225.166.2.205—1
15225.166.2.206/32225.166.2.206 to 225.166.2.206—1
16225.166.2.207/32225.166.2.207 to 225.166.2.207—1
17225.166.2.208/32225.166.2.208 to 225.166.2.208—1
18225.166.2.209/32225.166.2.209 to 225.166.2.209—1
19225.166.2.210/32225.166.2.210 to 225.166.2.210—1
20225.166.2.211/32225.166.2.211 to 225.166.2.211—1
21225.166.2.212/32225.166.2.212 to 225.166.2.212—1
22225.166.2.213/32225.166.2.213 to 225.166.2.213—1
23225.166.2.214/32225.166.2.214 to 225.166.2.214—1
24225.166.2.215/32225.166.2.215 to 225.166.2.215—1
25225.166.2.216/32225.166.2.216 to 225.166.2.216—1
26225.166.2.217/32225.166.2.217 to 225.166.2.217—1
27225.166.2.218/32225.166.2.218 to 225.166.2.218—1
28225.166.2.219/32225.166.2.219 to 225.166.2.219—1
29225.166.2.220/32225.166.2.220 to 225.166.2.220—1
30225.166.2.221/32225.166.2.221 to 225.166.2.221—1
31225.166.2.222/32225.166.2.222 to 225.166.2.222—1
32225.166.2.223/32225.166.2.223 to 225.166.2.223—1
33225.166.2.224/32225.166.2.224 to 225.166.2.224—1
34225.166.2.225/32225.166.2.225 to 225.166.2.225—1
35225.166.2.226/32225.166.2.226 to 225.166.2.226—1
36225.166.2.227/32225.166.2.227 to 225.166.2.227—1
37225.166.2.228/32225.166.2.228 to 225.166.2.228—1
38225.166.2.229/32225.166.2.229 to 225.166.2.229—1
39225.166.2.230/32225.166.2.230 to 225.166.2.230—1
40225.166.2.231/32225.166.2.231 to 225.166.2.231—1
41225.166.2.232/32225.166.2.232 to 225.166.2.232—1
42225.166.2.233/32225.166.2.233 to 225.166.2.233—1
43225.166.2.234/32225.166.2.234 to 225.166.2.234—1
44225.166.2.235/32225.166.2.235 to 225.166.2.235—1
45225.166.2.236/32225.166.2.236 to 225.166.2.236—1
46225.166.2.237/32225.166.2.237 to 225.166.2.237—1
47225.166.2.238/32225.166.2.238 to 225.166.2.238—1
48225.166.2.239/32225.166.2.239 to 225.166.2.239—1
49225.166.2.240/32225.166.2.240 to 225.166.2.240—1
50225.166.2.241/32225.166.2.241 to 225.166.2.241—1
51225.166.2.242/32225.166.2.242 to 225.166.2.242—1
52225.166.2.243/32225.166.2.243 to 225.166.2.243—1
53225.166.2.244/32225.166.2.244 to 225.166.2.244—1
54225.166.2.245/32225.166.2.245 to 225.166.2.245—1
55225.166.2.246/32225.166.2.246 to 225.166.2.246—1
56225.166.2.247/32225.166.2.247 to 225.166.2.247—1
57225.166.2.248/32225.166.2.248 to 225.166.2.248—1
58225.166.2.249/32225.166.2.249 to 225.166.2.249—1
59225.166.2.250/32225.166.2.250 to 225.166.2.250—1
60225.166.2.251/32225.166.2.251 to 225.166.2.251—1
61225.166.2.252/32225.166.2.252 to 225.166.2.252—1
62225.166.2.253/32225.166.2.253 to 225.166.2.253—1
63225.166.2.254/32225.166.2.254 to 225.166.2.254—1
64225.166.2.255/32225.166.2.255 to 225.166.2.255—1

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.