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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.

Network149.0.0.0/10
Usable hosts4,194,302
Subnet mask255.192.0.0
Addresses4,194,304
Network address
149.0.0.0
Broadcast address
149.63.255.255
First usable
149.0.0.1
Last usable
149.63.255.254
Usable hosts
4,194,302 (4,194,304 less the network and broadcast addresses)
Subnet mask
255.192.0.0
Wildcard mask
0.63.255.255 (Cisco ACLs, OSPF)
Prefix length
/10
Type
Public public
Old class
B (default /16)
As numbers
Hex 95000000 · Integer 2499805184 to 2503999487
Reverse DNS zones
0.149.in-addr.arpa
1.149.in-addr.arpa
2.149.in-addr.arpa
3.149.in-addr.arpa
4.149.in-addr.arpa
5.149.in-addr.arpa
6.149.in-addr.arpa
7.149.in-addr.arpa
8.149.in-addr.arpa
9.149.in-addr.arpa
10.149.in-addr.arpa
11.149.in-addr.arpa
12.149.in-addr.arpa
13.149.in-addr.arpa
14.149.in-addr.arpa
15.149.in-addr.arpa
and 48 more
/10 is not on a 8-bit boundary, so it takes 64 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address10010101.00000000.00000000.00000000149.0.0.0
Subnet mask11111111.11000000.00000000.00000000255.192.0.0
Network10010101.00000000.00000000.00000000149.0.0.0
Broadcast10010101.00111111.11111111.11111111149.63.255.255
Split into smaller subnets/17
/11 (2)/12 (4)/13 (8)/14 (16)/15 (32)/16 (64)/17 (128)/18 (256)/19 (512)/20 (1,024)/21 (2,048)/22 (4,096)

149.0.0.0/10 makes 128 subnets of /17.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1149.0.0.0/17149.0.0.1 to 149.0.127.254149.0.127.25532,766
2149.0.128.0/17149.0.128.1 to 149.0.255.254149.0.255.25532,766
3149.1.0.0/17149.1.0.1 to 149.1.127.254149.1.127.25532,766
4149.1.128.0/17149.1.128.1 to 149.1.255.254149.1.255.25532,766
5149.2.0.0/17149.2.0.1 to 149.2.127.254149.2.127.25532,766
6149.2.128.0/17149.2.128.1 to 149.2.255.254149.2.255.25532,766
7149.3.0.0/17149.3.0.1 to 149.3.127.254149.3.127.25532,766
8149.3.128.0/17149.3.128.1 to 149.3.255.254149.3.255.25532,766
9149.4.0.0/17149.4.0.1 to 149.4.127.254149.4.127.25532,766
10149.4.128.0/17149.4.128.1 to 149.4.255.254149.4.255.25532,766
11149.5.0.0/17149.5.0.1 to 149.5.127.254149.5.127.25532,766
12149.5.128.0/17149.5.128.1 to 149.5.255.254149.5.255.25532,766
13149.6.0.0/17149.6.0.1 to 149.6.127.254149.6.127.25532,766
14149.6.128.0/17149.6.128.1 to 149.6.255.254149.6.255.25532,766
15149.7.0.0/17149.7.0.1 to 149.7.127.254149.7.127.25532,766
16149.7.128.0/17149.7.128.1 to 149.7.255.254149.7.255.25532,766
17149.8.0.0/17149.8.0.1 to 149.8.127.254149.8.127.25532,766
18149.8.128.0/17149.8.128.1 to 149.8.255.254149.8.255.25532,766
19149.9.0.0/17149.9.0.1 to 149.9.127.254149.9.127.25532,766
20149.9.128.0/17149.9.128.1 to 149.9.255.254149.9.255.25532,766
21149.10.0.0/17149.10.0.1 to 149.10.127.254149.10.127.25532,766
22149.10.128.0/17149.10.128.1 to 149.10.255.254149.10.255.25532,766
23149.11.0.0/17149.11.0.1 to 149.11.127.254149.11.127.25532,766
24149.11.128.0/17149.11.128.1 to 149.11.255.254149.11.255.25532,766
25149.12.0.0/17149.12.0.1 to 149.12.127.254149.12.127.25532,766
26149.12.128.0/17149.12.128.1 to 149.12.255.254149.12.255.25532,766
27149.13.0.0/17149.13.0.1 to 149.13.127.254149.13.127.25532,766
28149.13.128.0/17149.13.128.1 to 149.13.255.254149.13.255.25532,766
29149.14.0.0/17149.14.0.1 to 149.14.127.254149.14.127.25532,766
30149.14.128.0/17149.14.128.1 to 149.14.255.254149.14.255.25532,766
31149.15.0.0/17149.15.0.1 to 149.15.127.254149.15.127.25532,766
32149.15.128.0/17149.15.128.1 to 149.15.255.254149.15.255.25532,766
33149.16.0.0/17149.16.0.1 to 149.16.127.254149.16.127.25532,766
34149.16.128.0/17149.16.128.1 to 149.16.255.254149.16.255.25532,766
35149.17.0.0/17149.17.0.1 to 149.17.127.254149.17.127.25532,766
36149.17.128.0/17149.17.128.1 to 149.17.255.254149.17.255.25532,766
37149.18.0.0/17149.18.0.1 to 149.18.127.254149.18.127.25532,766
38149.18.128.0/17149.18.128.1 to 149.18.255.254149.18.255.25532,766
39149.19.0.0/17149.19.0.1 to 149.19.127.254149.19.127.25532,766
40149.19.128.0/17149.19.128.1 to 149.19.255.254149.19.255.25532,766
41149.20.0.0/17149.20.0.1 to 149.20.127.254149.20.127.25532,766
42149.20.128.0/17149.20.128.1 to 149.20.255.254149.20.255.25532,766
43149.21.0.0/17149.21.0.1 to 149.21.127.254149.21.127.25532,766
44149.21.128.0/17149.21.128.1 to 149.21.255.254149.21.255.25532,766
45149.22.0.0/17149.22.0.1 to 149.22.127.254149.22.127.25532,766
46149.22.128.0/17149.22.128.1 to 149.22.255.254149.22.255.25532,766
47149.23.0.0/17149.23.0.1 to 149.23.127.254149.23.127.25532,766
48149.23.128.0/17149.23.128.1 to 149.23.255.254149.23.255.25532,766
49149.24.0.0/17149.24.0.1 to 149.24.127.254149.24.127.25532,766
50149.24.128.0/17149.24.128.1 to 149.24.255.254149.24.255.25532,766
51149.25.0.0/17149.25.0.1 to 149.25.127.254149.25.127.25532,766
52149.25.128.0/17149.25.128.1 to 149.25.255.254149.25.255.25532,766
53149.26.0.0/17149.26.0.1 to 149.26.127.254149.26.127.25532,766
54149.26.128.0/17149.26.128.1 to 149.26.255.254149.26.255.25532,766
55149.27.0.0/17149.27.0.1 to 149.27.127.254149.27.127.25532,766
56149.27.128.0/17149.27.128.1 to 149.27.255.254149.27.255.25532,766
57149.28.0.0/17149.28.0.1 to 149.28.127.254149.28.127.25532,766
58149.28.128.0/17149.28.128.1 to 149.28.255.254149.28.255.25532,766
59149.29.0.0/17149.29.0.1 to 149.29.127.254149.29.127.25532,766
60149.29.128.0/17149.29.128.1 to 149.29.255.254149.29.255.25532,766
61149.30.0.0/17149.30.0.1 to 149.30.127.254149.30.127.25532,766
62149.30.128.0/17149.30.128.1 to 149.30.255.254149.30.255.25532,766
63149.31.0.0/17149.31.0.1 to 149.31.127.254149.31.127.25532,766
64149.31.128.0/17149.31.128.1 to 149.31.255.254149.31.255.25532,766
65149.32.0.0/17149.32.0.1 to 149.32.127.254149.32.127.25532,766
66149.32.128.0/17149.32.128.1 to 149.32.255.254149.32.255.25532,766
67149.33.0.0/17149.33.0.1 to 149.33.127.254149.33.127.25532,766
68149.33.128.0/17149.33.128.1 to 149.33.255.254149.33.255.25532,766
69149.34.0.0/17149.34.0.1 to 149.34.127.254149.34.127.25532,766
70149.34.128.0/17149.34.128.1 to 149.34.255.254149.34.255.25532,766
71149.35.0.0/17149.35.0.1 to 149.35.127.254149.35.127.25532,766
72149.35.128.0/17149.35.128.1 to 149.35.255.254149.35.255.25532,766
73149.36.0.0/17149.36.0.1 to 149.36.127.254149.36.127.25532,766
74149.36.128.0/17149.36.128.1 to 149.36.255.254149.36.255.25532,766
75149.37.0.0/17149.37.0.1 to 149.37.127.254149.37.127.25532,766
76149.37.128.0/17149.37.128.1 to 149.37.255.254149.37.255.25532,766
77149.38.0.0/17149.38.0.1 to 149.38.127.254149.38.127.25532,766
78149.38.128.0/17149.38.128.1 to 149.38.255.254149.38.255.25532,766
79149.39.0.0/17149.39.0.1 to 149.39.127.254149.39.127.25532,766
80149.39.128.0/17149.39.128.1 to 149.39.255.254149.39.255.25532,766
81149.40.0.0/17149.40.0.1 to 149.40.127.254149.40.127.25532,766
82149.40.128.0/17149.40.128.1 to 149.40.255.254149.40.255.25532,766
83149.41.0.0/17149.41.0.1 to 149.41.127.254149.41.127.25532,766
84149.41.128.0/17149.41.128.1 to 149.41.255.254149.41.255.25532,766
85149.42.0.0/17149.42.0.1 to 149.42.127.254149.42.127.25532,766
86149.42.128.0/17149.42.128.1 to 149.42.255.254149.42.255.25532,766
87149.43.0.0/17149.43.0.1 to 149.43.127.254149.43.127.25532,766
88149.43.128.0/17149.43.128.1 to 149.43.255.254149.43.255.25532,766
89149.44.0.0/17149.44.0.1 to 149.44.127.254149.44.127.25532,766
90149.44.128.0/17149.44.128.1 to 149.44.255.254149.44.255.25532,766
91149.45.0.0/17149.45.0.1 to 149.45.127.254149.45.127.25532,766
92149.45.128.0/17149.45.128.1 to 149.45.255.254149.45.255.25532,766
93149.46.0.0/17149.46.0.1 to 149.46.127.254149.46.127.25532,766
94149.46.128.0/17149.46.128.1 to 149.46.255.254149.46.255.25532,766
95149.47.0.0/17149.47.0.1 to 149.47.127.254149.47.127.25532,766
96149.47.128.0/17149.47.128.1 to 149.47.255.254149.47.255.25532,766
97149.48.0.0/17149.48.0.1 to 149.48.127.254149.48.127.25532,766
98149.48.128.0/17149.48.128.1 to 149.48.255.254149.48.255.25532,766
99149.49.0.0/17149.49.0.1 to 149.49.127.254149.49.127.25532,766
100149.49.128.0/17149.49.128.1 to 149.49.255.254149.49.255.25532,766
101149.50.0.0/17149.50.0.1 to 149.50.127.254149.50.127.25532,766
102149.50.128.0/17149.50.128.1 to 149.50.255.254149.50.255.25532,766
103149.51.0.0/17149.51.0.1 to 149.51.127.254149.51.127.25532,766
104149.51.128.0/17149.51.128.1 to 149.51.255.254149.51.255.25532,766
105149.52.0.0/17149.52.0.1 to 149.52.127.254149.52.127.25532,766
106149.52.128.0/17149.52.128.1 to 149.52.255.254149.52.255.25532,766
107149.53.0.0/17149.53.0.1 to 149.53.127.254149.53.127.25532,766
108149.53.128.0/17149.53.128.1 to 149.53.255.254149.53.255.25532,766
109149.54.0.0/17149.54.0.1 to 149.54.127.254149.54.127.25532,766
110149.54.128.0/17149.54.128.1 to 149.54.255.254149.54.255.25532,766
111149.55.0.0/17149.55.0.1 to 149.55.127.254149.55.127.25532,766
112149.55.128.0/17149.55.128.1 to 149.55.255.254149.55.255.25532,766
113149.56.0.0/17149.56.0.1 to 149.56.127.254149.56.127.25532,766
114149.56.128.0/17149.56.128.1 to 149.56.255.254149.56.255.25532,766
115149.57.0.0/17149.57.0.1 to 149.57.127.254149.57.127.25532,766
116149.57.128.0/17149.57.128.1 to 149.57.255.254149.57.255.25532,766
117149.58.0.0/17149.58.0.1 to 149.58.127.254149.58.127.25532,766
118149.58.128.0/17149.58.128.1 to 149.58.255.254149.58.255.25532,766
119149.59.0.0/17149.59.0.1 to 149.59.127.254149.59.127.25532,766
120149.59.128.0/17149.59.128.1 to 149.59.255.254149.59.255.25532,766
121149.60.0.0/17149.60.0.1 to 149.60.127.254149.60.127.25532,766
122149.60.128.0/17149.60.128.1 to 149.60.255.254149.60.255.25532,766
123149.61.0.0/17149.61.0.1 to 149.61.127.254149.61.127.25532,766
124149.61.128.0/17149.61.128.1 to 149.61.255.254149.61.255.25532,766
125149.62.0.0/17149.62.0.1 to 149.62.127.254149.62.127.25532,766
126149.62.128.0/17149.62.128.1 to 149.62.255.254149.62.255.25532,766
127149.63.0.0/17149.63.0.1 to 149.63.127.254149.63.127.25532,766
128149.63.128.0/17149.63.128.1 to 149.63.255.254149.63.255.25532,766

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.