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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.

Network241.124.0.0/14
Usable hosts262,142
Subnet mask255.252.0.0
Addresses262,144
Network address
241.124.0.0
Broadcast address
241.127.255.255
First usable
241.124.0.1
Last usable
241.127.255.254
Usable hosts
262,142 (262,144 less the network and broadcast addresses)
Subnet mask
255.252.0.0
Wildcard mask
0.3.255.255 (Cisco ACLs, OSPF)
Prefix length
/14
Type
Reserved 240.0.0.0/4
Future use; not usable on most systems
Old class
E (reserved)
As numbers
Hex F17C0000 · Integer 4051435520 to 4051697663
Reverse DNS zones
124.241.in-addr.arpa
125.241.in-addr.arpa
126.241.in-addr.arpa
127.241.in-addr.arpa
/14 is not on a 8-bit boundary, so it takes 4 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address11110001.01111100.00000000.00000000241.124.0.0
Subnet mask11111111.11111100.00000000.00000000255.252.0.0
Network11110001.01111100.00000000.00000000241.124.0.0
Broadcast11110001.01111111.11111111.11111111241.127.255.255
Split into smaller subnets/20
/15 (2)/16 (4)/17 (8)/18 (16)/19 (32)/20 (64)/21 (128)/22 (256)/23 (512)/24 (1,024)/25 (2,048)/26 (4,096)

241.124.0.0/14 makes 64 subnets of /20.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1241.124.0.0/20241.124.0.1 to 241.124.15.254241.124.15.2554,094
2241.124.16.0/20241.124.16.1 to 241.124.31.254241.124.31.2554,094
3241.124.32.0/20241.124.32.1 to 241.124.47.254241.124.47.2554,094
4241.124.48.0/20241.124.48.1 to 241.124.63.254241.124.63.2554,094
5241.124.64.0/20241.124.64.1 to 241.124.79.254241.124.79.2554,094
6241.124.80.0/20241.124.80.1 to 241.124.95.254241.124.95.2554,094
7241.124.96.0/20241.124.96.1 to 241.124.111.254241.124.111.2554,094
8241.124.112.0/20241.124.112.1 to 241.124.127.254241.124.127.2554,094
9241.124.128.0/20241.124.128.1 to 241.124.143.254241.124.143.2554,094
10241.124.144.0/20241.124.144.1 to 241.124.159.254241.124.159.2554,094
11241.124.160.0/20241.124.160.1 to 241.124.175.254241.124.175.2554,094
12241.124.176.0/20241.124.176.1 to 241.124.191.254241.124.191.2554,094
13241.124.192.0/20241.124.192.1 to 241.124.207.254241.124.207.2554,094
14241.124.208.0/20241.124.208.1 to 241.124.223.254241.124.223.2554,094
15241.124.224.0/20241.124.224.1 to 241.124.239.254241.124.239.2554,094
16241.124.240.0/20241.124.240.1 to 241.124.255.254241.124.255.2554,094
17241.125.0.0/20241.125.0.1 to 241.125.15.254241.125.15.2554,094
18241.125.16.0/20241.125.16.1 to 241.125.31.254241.125.31.2554,094
19241.125.32.0/20241.125.32.1 to 241.125.47.254241.125.47.2554,094
20241.125.48.0/20241.125.48.1 to 241.125.63.254241.125.63.2554,094
21241.125.64.0/20241.125.64.1 to 241.125.79.254241.125.79.2554,094
22241.125.80.0/20241.125.80.1 to 241.125.95.254241.125.95.2554,094
23241.125.96.0/20241.125.96.1 to 241.125.111.254241.125.111.2554,094
24241.125.112.0/20241.125.112.1 to 241.125.127.254241.125.127.2554,094
25241.125.128.0/20241.125.128.1 to 241.125.143.254241.125.143.2554,094
26241.125.144.0/20241.125.144.1 to 241.125.159.254241.125.159.2554,094
27241.125.160.0/20241.125.160.1 to 241.125.175.254241.125.175.2554,094
28241.125.176.0/20241.125.176.1 to 241.125.191.254241.125.191.2554,094
29241.125.192.0/20241.125.192.1 to 241.125.207.254241.125.207.2554,094
30241.125.208.0/20241.125.208.1 to 241.125.223.254241.125.223.2554,094
31241.125.224.0/20241.125.224.1 to 241.125.239.254241.125.239.2554,094
32241.125.240.0/20241.125.240.1 to 241.125.255.254241.125.255.2554,094
33241.126.0.0/20241.126.0.1 to 241.126.15.254241.126.15.2554,094
34241.126.16.0/20241.126.16.1 to 241.126.31.254241.126.31.2554,094
35241.126.32.0/20241.126.32.1 to 241.126.47.254241.126.47.2554,094
36241.126.48.0/20241.126.48.1 to 241.126.63.254241.126.63.2554,094
37241.126.64.0/20241.126.64.1 to 241.126.79.254241.126.79.2554,094
38241.126.80.0/20241.126.80.1 to 241.126.95.254241.126.95.2554,094
39241.126.96.0/20241.126.96.1 to 241.126.111.254241.126.111.2554,094
40241.126.112.0/20241.126.112.1 to 241.126.127.254241.126.127.2554,094
41241.126.128.0/20241.126.128.1 to 241.126.143.254241.126.143.2554,094
42241.126.144.0/20241.126.144.1 to 241.126.159.254241.126.159.2554,094
43241.126.160.0/20241.126.160.1 to 241.126.175.254241.126.175.2554,094
44241.126.176.0/20241.126.176.1 to 241.126.191.254241.126.191.2554,094
45241.126.192.0/20241.126.192.1 to 241.126.207.254241.126.207.2554,094
46241.126.208.0/20241.126.208.1 to 241.126.223.254241.126.223.2554,094
47241.126.224.0/20241.126.224.1 to 241.126.239.254241.126.239.2554,094
48241.126.240.0/20241.126.240.1 to 241.126.255.254241.126.255.2554,094
49241.127.0.0/20241.127.0.1 to 241.127.15.254241.127.15.2554,094
50241.127.16.0/20241.127.16.1 to 241.127.31.254241.127.31.2554,094
51241.127.32.0/20241.127.32.1 to 241.127.47.254241.127.47.2554,094
52241.127.48.0/20241.127.48.1 to 241.127.63.254241.127.63.2554,094
53241.127.64.0/20241.127.64.1 to 241.127.79.254241.127.79.2554,094
54241.127.80.0/20241.127.80.1 to 241.127.95.254241.127.95.2554,094
55241.127.96.0/20241.127.96.1 to 241.127.111.254241.127.111.2554,094
56241.127.112.0/20241.127.112.1 to 241.127.127.254241.127.127.2554,094
57241.127.128.0/20241.127.128.1 to 241.127.143.254241.127.143.2554,094
58241.127.144.0/20241.127.144.1 to 241.127.159.254241.127.159.2554,094
59241.127.160.0/20241.127.160.1 to 241.127.175.254241.127.175.2554,094
60241.127.176.0/20241.127.176.1 to 241.127.191.254241.127.191.2554,094
61241.127.192.0/20241.127.192.1 to 241.127.207.254241.127.207.2554,094
62241.127.208.0/20241.127.208.1 to 241.127.223.254241.127.223.2554,094
63241.127.224.0/20241.127.224.1 to 241.127.239.254241.127.239.2554,094
64241.127.240.0/20241.127.240.1 to 241.127.255.254241.127.255.2554,094

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.