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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.

Network70.0.0.0/11
Usable hosts2,097,150
Subnet mask255.224.0.0
Addresses2,097,152
Network address
70.0.0.0
Broadcast address
70.31.255.255
First usable
70.0.0.1
Last usable
70.31.255.254
Usable hosts
2,097,150 (2,097,152 less the network and broadcast addresses)
Subnet mask
255.224.0.0
Wildcard mask
0.31.255.255 (Cisco ACLs, OSPF)
Prefix length
/11
Type
Public public
Old class
A (default /8)
As numbers
Hex 46000000 · Integer 1174405120 to 1176502271
Reverse DNS zones
0.70.in-addr.arpa
1.70.in-addr.arpa
2.70.in-addr.arpa
3.70.in-addr.arpa
4.70.in-addr.arpa
5.70.in-addr.arpa
6.70.in-addr.arpa
7.70.in-addr.arpa
8.70.in-addr.arpa
9.70.in-addr.arpa
10.70.in-addr.arpa
11.70.in-addr.arpa
12.70.in-addr.arpa
13.70.in-addr.arpa
14.70.in-addr.arpa
15.70.in-addr.arpa
and 16 more
/11 is not on a 8-bit boundary, so it takes 32 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address01000110.00000000.00000000.0000000070.0.0.0
Subnet mask11111111.11100000.00000000.00000000255.224.0.0
Network01000110.00000000.00000000.0000000070.0.0.0
Broadcast01000110.00011111.11111111.1111111170.31.255.255
Split into smaller subnets/18
/12 (2)/13 (4)/14 (8)/15 (16)/16 (32)/17 (64)/18 (128)/19 (256)/20 (512)/21 (1,024)/22 (2,048)/23 (4,096)

70.0.0.0/11 makes 128 subnets of /18.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
170.0.0.0/1870.0.0.1 to 70.0.63.25470.0.63.25516,382
270.0.64.0/1870.0.64.1 to 70.0.127.25470.0.127.25516,382
370.0.128.0/1870.0.128.1 to 70.0.191.25470.0.191.25516,382
470.0.192.0/1870.0.192.1 to 70.0.255.25470.0.255.25516,382
570.1.0.0/1870.1.0.1 to 70.1.63.25470.1.63.25516,382
670.1.64.0/1870.1.64.1 to 70.1.127.25470.1.127.25516,382
770.1.128.0/1870.1.128.1 to 70.1.191.25470.1.191.25516,382
870.1.192.0/1870.1.192.1 to 70.1.255.25470.1.255.25516,382
970.2.0.0/1870.2.0.1 to 70.2.63.25470.2.63.25516,382
1070.2.64.0/1870.2.64.1 to 70.2.127.25470.2.127.25516,382
1170.2.128.0/1870.2.128.1 to 70.2.191.25470.2.191.25516,382
1270.2.192.0/1870.2.192.1 to 70.2.255.25470.2.255.25516,382
1370.3.0.0/1870.3.0.1 to 70.3.63.25470.3.63.25516,382
1470.3.64.0/1870.3.64.1 to 70.3.127.25470.3.127.25516,382
1570.3.128.0/1870.3.128.1 to 70.3.191.25470.3.191.25516,382
1670.3.192.0/1870.3.192.1 to 70.3.255.25470.3.255.25516,382
1770.4.0.0/1870.4.0.1 to 70.4.63.25470.4.63.25516,382
1870.4.64.0/1870.4.64.1 to 70.4.127.25470.4.127.25516,382
1970.4.128.0/1870.4.128.1 to 70.4.191.25470.4.191.25516,382
2070.4.192.0/1870.4.192.1 to 70.4.255.25470.4.255.25516,382
2170.5.0.0/1870.5.0.1 to 70.5.63.25470.5.63.25516,382
2270.5.64.0/1870.5.64.1 to 70.5.127.25470.5.127.25516,382
2370.5.128.0/1870.5.128.1 to 70.5.191.25470.5.191.25516,382
2470.5.192.0/1870.5.192.1 to 70.5.255.25470.5.255.25516,382
2570.6.0.0/1870.6.0.1 to 70.6.63.25470.6.63.25516,382
2670.6.64.0/1870.6.64.1 to 70.6.127.25470.6.127.25516,382
2770.6.128.0/1870.6.128.1 to 70.6.191.25470.6.191.25516,382
2870.6.192.0/1870.6.192.1 to 70.6.255.25470.6.255.25516,382
2970.7.0.0/1870.7.0.1 to 70.7.63.25470.7.63.25516,382
3070.7.64.0/1870.7.64.1 to 70.7.127.25470.7.127.25516,382
3170.7.128.0/1870.7.128.1 to 70.7.191.25470.7.191.25516,382
3270.7.192.0/1870.7.192.1 to 70.7.255.25470.7.255.25516,382
3370.8.0.0/1870.8.0.1 to 70.8.63.25470.8.63.25516,382
3470.8.64.0/1870.8.64.1 to 70.8.127.25470.8.127.25516,382
3570.8.128.0/1870.8.128.1 to 70.8.191.25470.8.191.25516,382
3670.8.192.0/1870.8.192.1 to 70.8.255.25470.8.255.25516,382
3770.9.0.0/1870.9.0.1 to 70.9.63.25470.9.63.25516,382
3870.9.64.0/1870.9.64.1 to 70.9.127.25470.9.127.25516,382
3970.9.128.0/1870.9.128.1 to 70.9.191.25470.9.191.25516,382
4070.9.192.0/1870.9.192.1 to 70.9.255.25470.9.255.25516,382
4170.10.0.0/1870.10.0.1 to 70.10.63.25470.10.63.25516,382
4270.10.64.0/1870.10.64.1 to 70.10.127.25470.10.127.25516,382
4370.10.128.0/1870.10.128.1 to 70.10.191.25470.10.191.25516,382
4470.10.192.0/1870.10.192.1 to 70.10.255.25470.10.255.25516,382
4570.11.0.0/1870.11.0.1 to 70.11.63.25470.11.63.25516,382
4670.11.64.0/1870.11.64.1 to 70.11.127.25470.11.127.25516,382
4770.11.128.0/1870.11.128.1 to 70.11.191.25470.11.191.25516,382
4870.11.192.0/1870.11.192.1 to 70.11.255.25470.11.255.25516,382
4970.12.0.0/1870.12.0.1 to 70.12.63.25470.12.63.25516,382
5070.12.64.0/1870.12.64.1 to 70.12.127.25470.12.127.25516,382
5170.12.128.0/1870.12.128.1 to 70.12.191.25470.12.191.25516,382
5270.12.192.0/1870.12.192.1 to 70.12.255.25470.12.255.25516,382
5370.13.0.0/1870.13.0.1 to 70.13.63.25470.13.63.25516,382
5470.13.64.0/1870.13.64.1 to 70.13.127.25470.13.127.25516,382
5570.13.128.0/1870.13.128.1 to 70.13.191.25470.13.191.25516,382
5670.13.192.0/1870.13.192.1 to 70.13.255.25470.13.255.25516,382
5770.14.0.0/1870.14.0.1 to 70.14.63.25470.14.63.25516,382
5870.14.64.0/1870.14.64.1 to 70.14.127.25470.14.127.25516,382
5970.14.128.0/1870.14.128.1 to 70.14.191.25470.14.191.25516,382
6070.14.192.0/1870.14.192.1 to 70.14.255.25470.14.255.25516,382
6170.15.0.0/1870.15.0.1 to 70.15.63.25470.15.63.25516,382
6270.15.64.0/1870.15.64.1 to 70.15.127.25470.15.127.25516,382
6370.15.128.0/1870.15.128.1 to 70.15.191.25470.15.191.25516,382
6470.15.192.0/1870.15.192.1 to 70.15.255.25470.15.255.25516,382
6570.16.0.0/1870.16.0.1 to 70.16.63.25470.16.63.25516,382
6670.16.64.0/1870.16.64.1 to 70.16.127.25470.16.127.25516,382
6770.16.128.0/1870.16.128.1 to 70.16.191.25470.16.191.25516,382
6870.16.192.0/1870.16.192.1 to 70.16.255.25470.16.255.25516,382
6970.17.0.0/1870.17.0.1 to 70.17.63.25470.17.63.25516,382
7070.17.64.0/1870.17.64.1 to 70.17.127.25470.17.127.25516,382
7170.17.128.0/1870.17.128.1 to 70.17.191.25470.17.191.25516,382
7270.17.192.0/1870.17.192.1 to 70.17.255.25470.17.255.25516,382
7370.18.0.0/1870.18.0.1 to 70.18.63.25470.18.63.25516,382
7470.18.64.0/1870.18.64.1 to 70.18.127.25470.18.127.25516,382
7570.18.128.0/1870.18.128.1 to 70.18.191.25470.18.191.25516,382
7670.18.192.0/1870.18.192.1 to 70.18.255.25470.18.255.25516,382
7770.19.0.0/1870.19.0.1 to 70.19.63.25470.19.63.25516,382
7870.19.64.0/1870.19.64.1 to 70.19.127.25470.19.127.25516,382
7970.19.128.0/1870.19.128.1 to 70.19.191.25470.19.191.25516,382
8070.19.192.0/1870.19.192.1 to 70.19.255.25470.19.255.25516,382
8170.20.0.0/1870.20.0.1 to 70.20.63.25470.20.63.25516,382
8270.20.64.0/1870.20.64.1 to 70.20.127.25470.20.127.25516,382
8370.20.128.0/1870.20.128.1 to 70.20.191.25470.20.191.25516,382
8470.20.192.0/1870.20.192.1 to 70.20.255.25470.20.255.25516,382
8570.21.0.0/1870.21.0.1 to 70.21.63.25470.21.63.25516,382
8670.21.64.0/1870.21.64.1 to 70.21.127.25470.21.127.25516,382
8770.21.128.0/1870.21.128.1 to 70.21.191.25470.21.191.25516,382
8870.21.192.0/1870.21.192.1 to 70.21.255.25470.21.255.25516,382
8970.22.0.0/1870.22.0.1 to 70.22.63.25470.22.63.25516,382
9070.22.64.0/1870.22.64.1 to 70.22.127.25470.22.127.25516,382
9170.22.128.0/1870.22.128.1 to 70.22.191.25470.22.191.25516,382
9270.22.192.0/1870.22.192.1 to 70.22.255.25470.22.255.25516,382
9370.23.0.0/1870.23.0.1 to 70.23.63.25470.23.63.25516,382
9470.23.64.0/1870.23.64.1 to 70.23.127.25470.23.127.25516,382
9570.23.128.0/1870.23.128.1 to 70.23.191.25470.23.191.25516,382
9670.23.192.0/1870.23.192.1 to 70.23.255.25470.23.255.25516,382
9770.24.0.0/1870.24.0.1 to 70.24.63.25470.24.63.25516,382
9870.24.64.0/1870.24.64.1 to 70.24.127.25470.24.127.25516,382
9970.24.128.0/1870.24.128.1 to 70.24.191.25470.24.191.25516,382
10070.24.192.0/1870.24.192.1 to 70.24.255.25470.24.255.25516,382
10170.25.0.0/1870.25.0.1 to 70.25.63.25470.25.63.25516,382
10270.25.64.0/1870.25.64.1 to 70.25.127.25470.25.127.25516,382
10370.25.128.0/1870.25.128.1 to 70.25.191.25470.25.191.25516,382
10470.25.192.0/1870.25.192.1 to 70.25.255.25470.25.255.25516,382
10570.26.0.0/1870.26.0.1 to 70.26.63.25470.26.63.25516,382
10670.26.64.0/1870.26.64.1 to 70.26.127.25470.26.127.25516,382
10770.26.128.0/1870.26.128.1 to 70.26.191.25470.26.191.25516,382
10870.26.192.0/1870.26.192.1 to 70.26.255.25470.26.255.25516,382
10970.27.0.0/1870.27.0.1 to 70.27.63.25470.27.63.25516,382
11070.27.64.0/1870.27.64.1 to 70.27.127.25470.27.127.25516,382
11170.27.128.0/1870.27.128.1 to 70.27.191.25470.27.191.25516,382
11270.27.192.0/1870.27.192.1 to 70.27.255.25470.27.255.25516,382
11370.28.0.0/1870.28.0.1 to 70.28.63.25470.28.63.25516,382
11470.28.64.0/1870.28.64.1 to 70.28.127.25470.28.127.25516,382
11570.28.128.0/1870.28.128.1 to 70.28.191.25470.28.191.25516,382
11670.28.192.0/1870.28.192.1 to 70.28.255.25470.28.255.25516,382
11770.29.0.0/1870.29.0.1 to 70.29.63.25470.29.63.25516,382
11870.29.64.0/1870.29.64.1 to 70.29.127.25470.29.127.25516,382
11970.29.128.0/1870.29.128.1 to 70.29.191.25470.29.191.25516,382
12070.29.192.0/1870.29.192.1 to 70.29.255.25470.29.255.25516,382
12170.30.0.0/1870.30.0.1 to 70.30.63.25470.30.63.25516,382
12270.30.64.0/1870.30.64.1 to 70.30.127.25470.30.127.25516,382
12370.30.128.0/1870.30.128.1 to 70.30.191.25470.30.191.25516,382
12470.30.192.0/1870.30.192.1 to 70.30.255.25470.30.255.25516,382
12570.31.0.0/1870.31.0.1 to 70.31.63.25470.31.63.25516,382
12670.31.64.0/1870.31.64.1 to 70.31.127.25470.31.127.25516,382
12770.31.128.0/1870.31.128.1 to 70.31.191.25470.31.191.25516,382
12870.31.192.0/1870.31.192.1 to 70.31.255.25470.31.255.25516,382

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.