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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.

Network241.248.0.0/14
Usable hosts262,142
Subnet mask255.252.0.0
Addresses262,144
Network address
241.248.0.0
Broadcast address
241.251.255.255
First usable
241.248.0.1
Last usable
241.251.255.254
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 F1F80000 · Integer 4059561984 to 4059824127
Reverse DNS zones
248.241.in-addr.arpa
249.241.in-addr.arpa
250.241.in-addr.arpa
251.241.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
Address11110001.11111000.00000000.00000000241.248.0.0
Subnet mask11111111.11111100.00000000.00000000255.252.0.0
Network11110001.11111000.00000000.00000000241.248.0.0
Broadcast11110001.11111011.11111111.11111111241.251.255.255
Split into smaller subnets/21
/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)

241.248.0.0/14 makes 128 subnets of /21.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1241.248.0.0/21241.248.0.1 to 241.248.7.254241.248.7.2552,046
2241.248.8.0/21241.248.8.1 to 241.248.15.254241.248.15.2552,046
3241.248.16.0/21241.248.16.1 to 241.248.23.254241.248.23.2552,046
4241.248.24.0/21241.248.24.1 to 241.248.31.254241.248.31.2552,046
5241.248.32.0/21241.248.32.1 to 241.248.39.254241.248.39.2552,046
6241.248.40.0/21241.248.40.1 to 241.248.47.254241.248.47.2552,046
7241.248.48.0/21241.248.48.1 to 241.248.55.254241.248.55.2552,046
8241.248.56.0/21241.248.56.1 to 241.248.63.254241.248.63.2552,046
9241.248.64.0/21241.248.64.1 to 241.248.71.254241.248.71.2552,046
10241.248.72.0/21241.248.72.1 to 241.248.79.254241.248.79.2552,046
11241.248.80.0/21241.248.80.1 to 241.248.87.254241.248.87.2552,046
12241.248.88.0/21241.248.88.1 to 241.248.95.254241.248.95.2552,046
13241.248.96.0/21241.248.96.1 to 241.248.103.254241.248.103.2552,046
14241.248.104.0/21241.248.104.1 to 241.248.111.254241.248.111.2552,046
15241.248.112.0/21241.248.112.1 to 241.248.119.254241.248.119.2552,046
16241.248.120.0/21241.248.120.1 to 241.248.127.254241.248.127.2552,046
17241.248.128.0/21241.248.128.1 to 241.248.135.254241.248.135.2552,046
18241.248.136.0/21241.248.136.1 to 241.248.143.254241.248.143.2552,046
19241.248.144.0/21241.248.144.1 to 241.248.151.254241.248.151.2552,046
20241.248.152.0/21241.248.152.1 to 241.248.159.254241.248.159.2552,046
21241.248.160.0/21241.248.160.1 to 241.248.167.254241.248.167.2552,046
22241.248.168.0/21241.248.168.1 to 241.248.175.254241.248.175.2552,046
23241.248.176.0/21241.248.176.1 to 241.248.183.254241.248.183.2552,046
24241.248.184.0/21241.248.184.1 to 241.248.191.254241.248.191.2552,046
25241.248.192.0/21241.248.192.1 to 241.248.199.254241.248.199.2552,046
26241.248.200.0/21241.248.200.1 to 241.248.207.254241.248.207.2552,046
27241.248.208.0/21241.248.208.1 to 241.248.215.254241.248.215.2552,046
28241.248.216.0/21241.248.216.1 to 241.248.223.254241.248.223.2552,046
29241.248.224.0/21241.248.224.1 to 241.248.231.254241.248.231.2552,046
30241.248.232.0/21241.248.232.1 to 241.248.239.254241.248.239.2552,046
31241.248.240.0/21241.248.240.1 to 241.248.247.254241.248.247.2552,046
32241.248.248.0/21241.248.248.1 to 241.248.255.254241.248.255.2552,046
33241.249.0.0/21241.249.0.1 to 241.249.7.254241.249.7.2552,046
34241.249.8.0/21241.249.8.1 to 241.249.15.254241.249.15.2552,046
35241.249.16.0/21241.249.16.1 to 241.249.23.254241.249.23.2552,046
36241.249.24.0/21241.249.24.1 to 241.249.31.254241.249.31.2552,046
37241.249.32.0/21241.249.32.1 to 241.249.39.254241.249.39.2552,046
38241.249.40.0/21241.249.40.1 to 241.249.47.254241.249.47.2552,046
39241.249.48.0/21241.249.48.1 to 241.249.55.254241.249.55.2552,046
40241.249.56.0/21241.249.56.1 to 241.249.63.254241.249.63.2552,046
41241.249.64.0/21241.249.64.1 to 241.249.71.254241.249.71.2552,046
42241.249.72.0/21241.249.72.1 to 241.249.79.254241.249.79.2552,046
43241.249.80.0/21241.249.80.1 to 241.249.87.254241.249.87.2552,046
44241.249.88.0/21241.249.88.1 to 241.249.95.254241.249.95.2552,046
45241.249.96.0/21241.249.96.1 to 241.249.103.254241.249.103.2552,046
46241.249.104.0/21241.249.104.1 to 241.249.111.254241.249.111.2552,046
47241.249.112.0/21241.249.112.1 to 241.249.119.254241.249.119.2552,046
48241.249.120.0/21241.249.120.1 to 241.249.127.254241.249.127.2552,046
49241.249.128.0/21241.249.128.1 to 241.249.135.254241.249.135.2552,046
50241.249.136.0/21241.249.136.1 to 241.249.143.254241.249.143.2552,046
51241.249.144.0/21241.249.144.1 to 241.249.151.254241.249.151.2552,046
52241.249.152.0/21241.249.152.1 to 241.249.159.254241.249.159.2552,046
53241.249.160.0/21241.249.160.1 to 241.249.167.254241.249.167.2552,046
54241.249.168.0/21241.249.168.1 to 241.249.175.254241.249.175.2552,046
55241.249.176.0/21241.249.176.1 to 241.249.183.254241.249.183.2552,046
56241.249.184.0/21241.249.184.1 to 241.249.191.254241.249.191.2552,046
57241.249.192.0/21241.249.192.1 to 241.249.199.254241.249.199.2552,046
58241.249.200.0/21241.249.200.1 to 241.249.207.254241.249.207.2552,046
59241.249.208.0/21241.249.208.1 to 241.249.215.254241.249.215.2552,046
60241.249.216.0/21241.249.216.1 to 241.249.223.254241.249.223.2552,046
61241.249.224.0/21241.249.224.1 to 241.249.231.254241.249.231.2552,046
62241.249.232.0/21241.249.232.1 to 241.249.239.254241.249.239.2552,046
63241.249.240.0/21241.249.240.1 to 241.249.247.254241.249.247.2552,046
64241.249.248.0/21241.249.248.1 to 241.249.255.254241.249.255.2552,046
65241.250.0.0/21241.250.0.1 to 241.250.7.254241.250.7.2552,046
66241.250.8.0/21241.250.8.1 to 241.250.15.254241.250.15.2552,046
67241.250.16.0/21241.250.16.1 to 241.250.23.254241.250.23.2552,046
68241.250.24.0/21241.250.24.1 to 241.250.31.254241.250.31.2552,046
69241.250.32.0/21241.250.32.1 to 241.250.39.254241.250.39.2552,046
70241.250.40.0/21241.250.40.1 to 241.250.47.254241.250.47.2552,046
71241.250.48.0/21241.250.48.1 to 241.250.55.254241.250.55.2552,046
72241.250.56.0/21241.250.56.1 to 241.250.63.254241.250.63.2552,046
73241.250.64.0/21241.250.64.1 to 241.250.71.254241.250.71.2552,046
74241.250.72.0/21241.250.72.1 to 241.250.79.254241.250.79.2552,046
75241.250.80.0/21241.250.80.1 to 241.250.87.254241.250.87.2552,046
76241.250.88.0/21241.250.88.1 to 241.250.95.254241.250.95.2552,046
77241.250.96.0/21241.250.96.1 to 241.250.103.254241.250.103.2552,046
78241.250.104.0/21241.250.104.1 to 241.250.111.254241.250.111.2552,046
79241.250.112.0/21241.250.112.1 to 241.250.119.254241.250.119.2552,046
80241.250.120.0/21241.250.120.1 to 241.250.127.254241.250.127.2552,046
81241.250.128.0/21241.250.128.1 to 241.250.135.254241.250.135.2552,046
82241.250.136.0/21241.250.136.1 to 241.250.143.254241.250.143.2552,046
83241.250.144.0/21241.250.144.1 to 241.250.151.254241.250.151.2552,046
84241.250.152.0/21241.250.152.1 to 241.250.159.254241.250.159.2552,046
85241.250.160.0/21241.250.160.1 to 241.250.167.254241.250.167.2552,046
86241.250.168.0/21241.250.168.1 to 241.250.175.254241.250.175.2552,046
87241.250.176.0/21241.250.176.1 to 241.250.183.254241.250.183.2552,046
88241.250.184.0/21241.250.184.1 to 241.250.191.254241.250.191.2552,046
89241.250.192.0/21241.250.192.1 to 241.250.199.254241.250.199.2552,046
90241.250.200.0/21241.250.200.1 to 241.250.207.254241.250.207.2552,046
91241.250.208.0/21241.250.208.1 to 241.250.215.254241.250.215.2552,046
92241.250.216.0/21241.250.216.1 to 241.250.223.254241.250.223.2552,046
93241.250.224.0/21241.250.224.1 to 241.250.231.254241.250.231.2552,046
94241.250.232.0/21241.250.232.1 to 241.250.239.254241.250.239.2552,046
95241.250.240.0/21241.250.240.1 to 241.250.247.254241.250.247.2552,046
96241.250.248.0/21241.250.248.1 to 241.250.255.254241.250.255.2552,046
97241.251.0.0/21241.251.0.1 to 241.251.7.254241.251.7.2552,046
98241.251.8.0/21241.251.8.1 to 241.251.15.254241.251.15.2552,046
99241.251.16.0/21241.251.16.1 to 241.251.23.254241.251.23.2552,046
100241.251.24.0/21241.251.24.1 to 241.251.31.254241.251.31.2552,046
101241.251.32.0/21241.251.32.1 to 241.251.39.254241.251.39.2552,046
102241.251.40.0/21241.251.40.1 to 241.251.47.254241.251.47.2552,046
103241.251.48.0/21241.251.48.1 to 241.251.55.254241.251.55.2552,046
104241.251.56.0/21241.251.56.1 to 241.251.63.254241.251.63.2552,046
105241.251.64.0/21241.251.64.1 to 241.251.71.254241.251.71.2552,046
106241.251.72.0/21241.251.72.1 to 241.251.79.254241.251.79.2552,046
107241.251.80.0/21241.251.80.1 to 241.251.87.254241.251.87.2552,046
108241.251.88.0/21241.251.88.1 to 241.251.95.254241.251.95.2552,046
109241.251.96.0/21241.251.96.1 to 241.251.103.254241.251.103.2552,046
110241.251.104.0/21241.251.104.1 to 241.251.111.254241.251.111.2552,046
111241.251.112.0/21241.251.112.1 to 241.251.119.254241.251.119.2552,046
112241.251.120.0/21241.251.120.1 to 241.251.127.254241.251.127.2552,046
113241.251.128.0/21241.251.128.1 to 241.251.135.254241.251.135.2552,046
114241.251.136.0/21241.251.136.1 to 241.251.143.254241.251.143.2552,046
115241.251.144.0/21241.251.144.1 to 241.251.151.254241.251.151.2552,046
116241.251.152.0/21241.251.152.1 to 241.251.159.254241.251.159.2552,046
117241.251.160.0/21241.251.160.1 to 241.251.167.254241.251.167.2552,046
118241.251.168.0/21241.251.168.1 to 241.251.175.254241.251.175.2552,046
119241.251.176.0/21241.251.176.1 to 241.251.183.254241.251.183.2552,046
120241.251.184.0/21241.251.184.1 to 241.251.191.254241.251.191.2552,046
121241.251.192.0/21241.251.192.1 to 241.251.199.254241.251.199.2552,046
122241.251.200.0/21241.251.200.1 to 241.251.207.254241.251.207.2552,046
123241.251.208.0/21241.251.208.1 to 241.251.215.254241.251.215.2552,046
124241.251.216.0/21241.251.216.1 to 241.251.223.254241.251.223.2552,046
125241.251.224.0/21241.251.224.1 to 241.251.231.254241.251.231.2552,046
126241.251.232.0/21241.251.232.1 to 241.251.239.254241.251.239.2552,046
127241.251.240.0/21241.251.240.1 to 241.251.247.254241.251.247.2552,046
128241.251.248.0/21241.251.248.1 to 241.251.255.254241.251.255.2552,046

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.