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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.

Network110.0.0.0/9
Usable hosts8,388,606
Subnet mask255.128.0.0
Addresses8,388,608
Network address
110.0.0.0
Broadcast address
110.127.255.255
First usable
110.0.0.1
Last usable
110.127.255.254
Usable hosts
8,388,606 (8,388,608 less the network and broadcast addresses)
Subnet mask
255.128.0.0
Wildcard mask
0.127.255.255 (Cisco ACLs, OSPF)
Prefix length
/9
Type
Public public
Old class
A (default /8)
As numbers
Hex 6E000000 · Integer 1845493760 to 1853882367
Reverse DNS zones
0.110.in-addr.arpa
1.110.in-addr.arpa
2.110.in-addr.arpa
3.110.in-addr.arpa
4.110.in-addr.arpa
5.110.in-addr.arpa
6.110.in-addr.arpa
7.110.in-addr.arpa
8.110.in-addr.arpa
9.110.in-addr.arpa
10.110.in-addr.arpa
11.110.in-addr.arpa
12.110.in-addr.arpa
13.110.in-addr.arpa
14.110.in-addr.arpa
15.110.in-addr.arpa
and 112 more
/9 is not on a 8-bit boundary, so it takes 128 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address01101110.00000000.00000000.00000000110.0.0.0
Subnet mask11111111.10000000.00000000.00000000255.128.0.0
Network01101110.00000000.00000000.00000000110.0.0.0
Broadcast01101110.01111111.11111111.11111111110.127.255.255
Split into smaller subnets/16
/10 (2)/11 (4)/12 (8)/13 (16)/14 (32)/15 (64)/16 (128)/17 (256)/18 (512)/19 (1,024)/20 (2,048)/21 (4,096)

110.0.0.0/9 makes 128 subnets of /16.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1110.0.0.0/16110.0.0.1 to 110.0.255.254110.0.255.25565,534
2110.1.0.0/16110.1.0.1 to 110.1.255.254110.1.255.25565,534
3110.2.0.0/16110.2.0.1 to 110.2.255.254110.2.255.25565,534
4110.3.0.0/16110.3.0.1 to 110.3.255.254110.3.255.25565,534
5110.4.0.0/16110.4.0.1 to 110.4.255.254110.4.255.25565,534
6110.5.0.0/16110.5.0.1 to 110.5.255.254110.5.255.25565,534
7110.6.0.0/16110.6.0.1 to 110.6.255.254110.6.255.25565,534
8110.7.0.0/16110.7.0.1 to 110.7.255.254110.7.255.25565,534
9110.8.0.0/16110.8.0.1 to 110.8.255.254110.8.255.25565,534
10110.9.0.0/16110.9.0.1 to 110.9.255.254110.9.255.25565,534
11110.10.0.0/16110.10.0.1 to 110.10.255.254110.10.255.25565,534
12110.11.0.0/16110.11.0.1 to 110.11.255.254110.11.255.25565,534
13110.12.0.0/16110.12.0.1 to 110.12.255.254110.12.255.25565,534
14110.13.0.0/16110.13.0.1 to 110.13.255.254110.13.255.25565,534
15110.14.0.0/16110.14.0.1 to 110.14.255.254110.14.255.25565,534
16110.15.0.0/16110.15.0.1 to 110.15.255.254110.15.255.25565,534
17110.16.0.0/16110.16.0.1 to 110.16.255.254110.16.255.25565,534
18110.17.0.0/16110.17.0.1 to 110.17.255.254110.17.255.25565,534
19110.18.0.0/16110.18.0.1 to 110.18.255.254110.18.255.25565,534
20110.19.0.0/16110.19.0.1 to 110.19.255.254110.19.255.25565,534
21110.20.0.0/16110.20.0.1 to 110.20.255.254110.20.255.25565,534
22110.21.0.0/16110.21.0.1 to 110.21.255.254110.21.255.25565,534
23110.22.0.0/16110.22.0.1 to 110.22.255.254110.22.255.25565,534
24110.23.0.0/16110.23.0.1 to 110.23.255.254110.23.255.25565,534
25110.24.0.0/16110.24.0.1 to 110.24.255.254110.24.255.25565,534
26110.25.0.0/16110.25.0.1 to 110.25.255.254110.25.255.25565,534
27110.26.0.0/16110.26.0.1 to 110.26.255.254110.26.255.25565,534
28110.27.0.0/16110.27.0.1 to 110.27.255.254110.27.255.25565,534
29110.28.0.0/16110.28.0.1 to 110.28.255.254110.28.255.25565,534
30110.29.0.0/16110.29.0.1 to 110.29.255.254110.29.255.25565,534
31110.30.0.0/16110.30.0.1 to 110.30.255.254110.30.255.25565,534
32110.31.0.0/16110.31.0.1 to 110.31.255.254110.31.255.25565,534
33110.32.0.0/16110.32.0.1 to 110.32.255.254110.32.255.25565,534
34110.33.0.0/16110.33.0.1 to 110.33.255.254110.33.255.25565,534
35110.34.0.0/16110.34.0.1 to 110.34.255.254110.34.255.25565,534
36110.35.0.0/16110.35.0.1 to 110.35.255.254110.35.255.25565,534
37110.36.0.0/16110.36.0.1 to 110.36.255.254110.36.255.25565,534
38110.37.0.0/16110.37.0.1 to 110.37.255.254110.37.255.25565,534
39110.38.0.0/16110.38.0.1 to 110.38.255.254110.38.255.25565,534
40110.39.0.0/16110.39.0.1 to 110.39.255.254110.39.255.25565,534
41110.40.0.0/16110.40.0.1 to 110.40.255.254110.40.255.25565,534
42110.41.0.0/16110.41.0.1 to 110.41.255.254110.41.255.25565,534
43110.42.0.0/16110.42.0.1 to 110.42.255.254110.42.255.25565,534
44110.43.0.0/16110.43.0.1 to 110.43.255.254110.43.255.25565,534
45110.44.0.0/16110.44.0.1 to 110.44.255.254110.44.255.25565,534
46110.45.0.0/16110.45.0.1 to 110.45.255.254110.45.255.25565,534
47110.46.0.0/16110.46.0.1 to 110.46.255.254110.46.255.25565,534
48110.47.0.0/16110.47.0.1 to 110.47.255.254110.47.255.25565,534
49110.48.0.0/16110.48.0.1 to 110.48.255.254110.48.255.25565,534
50110.49.0.0/16110.49.0.1 to 110.49.255.254110.49.255.25565,534
51110.50.0.0/16110.50.0.1 to 110.50.255.254110.50.255.25565,534
52110.51.0.0/16110.51.0.1 to 110.51.255.254110.51.255.25565,534
53110.52.0.0/16110.52.0.1 to 110.52.255.254110.52.255.25565,534
54110.53.0.0/16110.53.0.1 to 110.53.255.254110.53.255.25565,534
55110.54.0.0/16110.54.0.1 to 110.54.255.254110.54.255.25565,534
56110.55.0.0/16110.55.0.1 to 110.55.255.254110.55.255.25565,534
57110.56.0.0/16110.56.0.1 to 110.56.255.254110.56.255.25565,534
58110.57.0.0/16110.57.0.1 to 110.57.255.254110.57.255.25565,534
59110.58.0.0/16110.58.0.1 to 110.58.255.254110.58.255.25565,534
60110.59.0.0/16110.59.0.1 to 110.59.255.254110.59.255.25565,534
61110.60.0.0/16110.60.0.1 to 110.60.255.254110.60.255.25565,534
62110.61.0.0/16110.61.0.1 to 110.61.255.254110.61.255.25565,534
63110.62.0.0/16110.62.0.1 to 110.62.255.254110.62.255.25565,534
64110.63.0.0/16110.63.0.1 to 110.63.255.254110.63.255.25565,534
65110.64.0.0/16110.64.0.1 to 110.64.255.254110.64.255.25565,534
66110.65.0.0/16110.65.0.1 to 110.65.255.254110.65.255.25565,534
67110.66.0.0/16110.66.0.1 to 110.66.255.254110.66.255.25565,534
68110.67.0.0/16110.67.0.1 to 110.67.255.254110.67.255.25565,534
69110.68.0.0/16110.68.0.1 to 110.68.255.254110.68.255.25565,534
70110.69.0.0/16110.69.0.1 to 110.69.255.254110.69.255.25565,534
71110.70.0.0/16110.70.0.1 to 110.70.255.254110.70.255.25565,534
72110.71.0.0/16110.71.0.1 to 110.71.255.254110.71.255.25565,534
73110.72.0.0/16110.72.0.1 to 110.72.255.254110.72.255.25565,534
74110.73.0.0/16110.73.0.1 to 110.73.255.254110.73.255.25565,534
75110.74.0.0/16110.74.0.1 to 110.74.255.254110.74.255.25565,534
76110.75.0.0/16110.75.0.1 to 110.75.255.254110.75.255.25565,534
77110.76.0.0/16110.76.0.1 to 110.76.255.254110.76.255.25565,534
78110.77.0.0/16110.77.0.1 to 110.77.255.254110.77.255.25565,534
79110.78.0.0/16110.78.0.1 to 110.78.255.254110.78.255.25565,534
80110.79.0.0/16110.79.0.1 to 110.79.255.254110.79.255.25565,534
81110.80.0.0/16110.80.0.1 to 110.80.255.254110.80.255.25565,534
82110.81.0.0/16110.81.0.1 to 110.81.255.254110.81.255.25565,534
83110.82.0.0/16110.82.0.1 to 110.82.255.254110.82.255.25565,534
84110.83.0.0/16110.83.0.1 to 110.83.255.254110.83.255.25565,534
85110.84.0.0/16110.84.0.1 to 110.84.255.254110.84.255.25565,534
86110.85.0.0/16110.85.0.1 to 110.85.255.254110.85.255.25565,534
87110.86.0.0/16110.86.0.1 to 110.86.255.254110.86.255.25565,534
88110.87.0.0/16110.87.0.1 to 110.87.255.254110.87.255.25565,534
89110.88.0.0/16110.88.0.1 to 110.88.255.254110.88.255.25565,534
90110.89.0.0/16110.89.0.1 to 110.89.255.254110.89.255.25565,534
91110.90.0.0/16110.90.0.1 to 110.90.255.254110.90.255.25565,534
92110.91.0.0/16110.91.0.1 to 110.91.255.254110.91.255.25565,534
93110.92.0.0/16110.92.0.1 to 110.92.255.254110.92.255.25565,534
94110.93.0.0/16110.93.0.1 to 110.93.255.254110.93.255.25565,534
95110.94.0.0/16110.94.0.1 to 110.94.255.254110.94.255.25565,534
96110.95.0.0/16110.95.0.1 to 110.95.255.254110.95.255.25565,534
97110.96.0.0/16110.96.0.1 to 110.96.255.254110.96.255.25565,534
98110.97.0.0/16110.97.0.1 to 110.97.255.254110.97.255.25565,534
99110.98.0.0/16110.98.0.1 to 110.98.255.254110.98.255.25565,534
100110.99.0.0/16110.99.0.1 to 110.99.255.254110.99.255.25565,534
101110.100.0.0/16110.100.0.1 to 110.100.255.254110.100.255.25565,534
102110.101.0.0/16110.101.0.1 to 110.101.255.254110.101.255.25565,534
103110.102.0.0/16110.102.0.1 to 110.102.255.254110.102.255.25565,534
104110.103.0.0/16110.103.0.1 to 110.103.255.254110.103.255.25565,534
105110.104.0.0/16110.104.0.1 to 110.104.255.254110.104.255.25565,534
106110.105.0.0/16110.105.0.1 to 110.105.255.254110.105.255.25565,534
107110.106.0.0/16110.106.0.1 to 110.106.255.254110.106.255.25565,534
108110.107.0.0/16110.107.0.1 to 110.107.255.254110.107.255.25565,534
109110.108.0.0/16110.108.0.1 to 110.108.255.254110.108.255.25565,534
110110.109.0.0/16110.109.0.1 to 110.109.255.254110.109.255.25565,534
111110.110.0.0/16110.110.0.1 to 110.110.255.254110.110.255.25565,534
112110.111.0.0/16110.111.0.1 to 110.111.255.254110.111.255.25565,534
113110.112.0.0/16110.112.0.1 to 110.112.255.254110.112.255.25565,534
114110.113.0.0/16110.113.0.1 to 110.113.255.254110.113.255.25565,534
115110.114.0.0/16110.114.0.1 to 110.114.255.254110.114.255.25565,534
116110.115.0.0/16110.115.0.1 to 110.115.255.254110.115.255.25565,534
117110.116.0.0/16110.116.0.1 to 110.116.255.254110.116.255.25565,534
118110.117.0.0/16110.117.0.1 to 110.117.255.254110.117.255.25565,534
119110.118.0.0/16110.118.0.1 to 110.118.255.254110.118.255.25565,534
120110.119.0.0/16110.119.0.1 to 110.119.255.254110.119.255.25565,534
121110.120.0.0/16110.120.0.1 to 110.120.255.254110.120.255.25565,534
122110.121.0.0/16110.121.0.1 to 110.121.255.254110.121.255.25565,534
123110.122.0.0/16110.122.0.1 to 110.122.255.254110.122.255.25565,534
124110.123.0.0/16110.123.0.1 to 110.123.255.254110.123.255.25565,534
125110.124.0.0/16110.124.0.1 to 110.124.255.254110.124.255.25565,534
126110.125.0.0/16110.125.0.1 to 110.125.255.254110.125.255.25565,534
127110.126.0.0/16110.126.0.1 to 110.126.255.254110.126.255.25565,534
128110.127.0.0/16110.127.0.1 to 110.127.255.254110.127.255.25565,534

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.