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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.

Network19.44.0.0/17
Usable hosts32,766
Subnet mask255.255.128.0
Addresses32,768
Network address
19.44.0.0
Broadcast address
19.44.127.255
First usable
19.44.0.1
Last usable
19.44.127.254
Usable hosts
32,766 (32,768 less the network and broadcast addresses)
Subnet mask
255.255.128.0
Wildcard mask
0.0.127.255 (Cisco ACLs, OSPF)
Prefix length
/17
Type
Public public
Old class
A (default /8)
As numbers
Hex 132C0000 · Integer 321650688 to 321683455
Reverse DNS zones
0.44.19.in-addr.arpa
1.44.19.in-addr.arpa
2.44.19.in-addr.arpa
3.44.19.in-addr.arpa
4.44.19.in-addr.arpa
5.44.19.in-addr.arpa
6.44.19.in-addr.arpa
7.44.19.in-addr.arpa
8.44.19.in-addr.arpa
9.44.19.in-addr.arpa
10.44.19.in-addr.arpa
11.44.19.in-addr.arpa
12.44.19.in-addr.arpa
13.44.19.in-addr.arpa
14.44.19.in-addr.arpa
15.44.19.in-addr.arpa
and 112 more
/17 is not on a 8-bit boundary, so it takes 128 /24 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address00010011.00101100.00000000.0000000019.44.0.0
Subnet mask11111111.11111111.10000000.00000000255.255.128.0
Network00010011.00101100.00000000.0000000019.44.0.0
Broadcast00010011.00101100.01111111.1111111119.44.127.255
Split into smaller subnets/25
/18 (2)/19 (4)/20 (8)/21 (16)/22 (32)/23 (64)/24 (128)/25 (256)/26 (512)/27 (1,024)/28 (2,048)/29 (4,096)

19.44.0.0/17 makes 256 subnets of /25.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
119.44.0.0/2519.44.0.1 to 19.44.0.12619.44.0.127126
219.44.0.128/2519.44.0.129 to 19.44.0.25419.44.0.255126
319.44.1.0/2519.44.1.1 to 19.44.1.12619.44.1.127126
419.44.1.128/2519.44.1.129 to 19.44.1.25419.44.1.255126
519.44.2.0/2519.44.2.1 to 19.44.2.12619.44.2.127126
619.44.2.128/2519.44.2.129 to 19.44.2.25419.44.2.255126
719.44.3.0/2519.44.3.1 to 19.44.3.12619.44.3.127126
819.44.3.128/2519.44.3.129 to 19.44.3.25419.44.3.255126
919.44.4.0/2519.44.4.1 to 19.44.4.12619.44.4.127126
1019.44.4.128/2519.44.4.129 to 19.44.4.25419.44.4.255126
1119.44.5.0/2519.44.5.1 to 19.44.5.12619.44.5.127126
1219.44.5.128/2519.44.5.129 to 19.44.5.25419.44.5.255126
1319.44.6.0/2519.44.6.1 to 19.44.6.12619.44.6.127126
1419.44.6.128/2519.44.6.129 to 19.44.6.25419.44.6.255126
1519.44.7.0/2519.44.7.1 to 19.44.7.12619.44.7.127126
1619.44.7.128/2519.44.7.129 to 19.44.7.25419.44.7.255126
1719.44.8.0/2519.44.8.1 to 19.44.8.12619.44.8.127126
1819.44.8.128/2519.44.8.129 to 19.44.8.25419.44.8.255126
1919.44.9.0/2519.44.9.1 to 19.44.9.12619.44.9.127126
2019.44.9.128/2519.44.9.129 to 19.44.9.25419.44.9.255126
2119.44.10.0/2519.44.10.1 to 19.44.10.12619.44.10.127126
2219.44.10.128/2519.44.10.129 to 19.44.10.25419.44.10.255126
2319.44.11.0/2519.44.11.1 to 19.44.11.12619.44.11.127126
2419.44.11.128/2519.44.11.129 to 19.44.11.25419.44.11.255126
2519.44.12.0/2519.44.12.1 to 19.44.12.12619.44.12.127126
2619.44.12.128/2519.44.12.129 to 19.44.12.25419.44.12.255126
2719.44.13.0/2519.44.13.1 to 19.44.13.12619.44.13.127126
2819.44.13.128/2519.44.13.129 to 19.44.13.25419.44.13.255126
2919.44.14.0/2519.44.14.1 to 19.44.14.12619.44.14.127126
3019.44.14.128/2519.44.14.129 to 19.44.14.25419.44.14.255126
3119.44.15.0/2519.44.15.1 to 19.44.15.12619.44.15.127126
3219.44.15.128/2519.44.15.129 to 19.44.15.25419.44.15.255126
3319.44.16.0/2519.44.16.1 to 19.44.16.12619.44.16.127126
3419.44.16.128/2519.44.16.129 to 19.44.16.25419.44.16.255126
3519.44.17.0/2519.44.17.1 to 19.44.17.12619.44.17.127126
3619.44.17.128/2519.44.17.129 to 19.44.17.25419.44.17.255126
3719.44.18.0/2519.44.18.1 to 19.44.18.12619.44.18.127126
3819.44.18.128/2519.44.18.129 to 19.44.18.25419.44.18.255126
3919.44.19.0/2519.44.19.1 to 19.44.19.12619.44.19.127126
4019.44.19.128/2519.44.19.129 to 19.44.19.25419.44.19.255126
4119.44.20.0/2519.44.20.1 to 19.44.20.12619.44.20.127126
4219.44.20.128/2519.44.20.129 to 19.44.20.25419.44.20.255126
4319.44.21.0/2519.44.21.1 to 19.44.21.12619.44.21.127126
4419.44.21.128/2519.44.21.129 to 19.44.21.25419.44.21.255126
4519.44.22.0/2519.44.22.1 to 19.44.22.12619.44.22.127126
4619.44.22.128/2519.44.22.129 to 19.44.22.25419.44.22.255126
4719.44.23.0/2519.44.23.1 to 19.44.23.12619.44.23.127126
4819.44.23.128/2519.44.23.129 to 19.44.23.25419.44.23.255126
4919.44.24.0/2519.44.24.1 to 19.44.24.12619.44.24.127126
5019.44.24.128/2519.44.24.129 to 19.44.24.25419.44.24.255126
5119.44.25.0/2519.44.25.1 to 19.44.25.12619.44.25.127126
5219.44.25.128/2519.44.25.129 to 19.44.25.25419.44.25.255126
5319.44.26.0/2519.44.26.1 to 19.44.26.12619.44.26.127126
5419.44.26.128/2519.44.26.129 to 19.44.26.25419.44.26.255126
5519.44.27.0/2519.44.27.1 to 19.44.27.12619.44.27.127126
5619.44.27.128/2519.44.27.129 to 19.44.27.25419.44.27.255126
5719.44.28.0/2519.44.28.1 to 19.44.28.12619.44.28.127126
5819.44.28.128/2519.44.28.129 to 19.44.28.25419.44.28.255126
5919.44.29.0/2519.44.29.1 to 19.44.29.12619.44.29.127126
6019.44.29.128/2519.44.29.129 to 19.44.29.25419.44.29.255126
6119.44.30.0/2519.44.30.1 to 19.44.30.12619.44.30.127126
6219.44.30.128/2519.44.30.129 to 19.44.30.25419.44.30.255126
6319.44.31.0/2519.44.31.1 to 19.44.31.12619.44.31.127126
6419.44.31.128/2519.44.31.129 to 19.44.31.25419.44.31.255126
6519.44.32.0/2519.44.32.1 to 19.44.32.12619.44.32.127126
6619.44.32.128/2519.44.32.129 to 19.44.32.25419.44.32.255126
6719.44.33.0/2519.44.33.1 to 19.44.33.12619.44.33.127126
6819.44.33.128/2519.44.33.129 to 19.44.33.25419.44.33.255126
6919.44.34.0/2519.44.34.1 to 19.44.34.12619.44.34.127126
7019.44.34.128/2519.44.34.129 to 19.44.34.25419.44.34.255126
7119.44.35.0/2519.44.35.1 to 19.44.35.12619.44.35.127126
7219.44.35.128/2519.44.35.129 to 19.44.35.25419.44.35.255126
7319.44.36.0/2519.44.36.1 to 19.44.36.12619.44.36.127126
7419.44.36.128/2519.44.36.129 to 19.44.36.25419.44.36.255126
7519.44.37.0/2519.44.37.1 to 19.44.37.12619.44.37.127126
7619.44.37.128/2519.44.37.129 to 19.44.37.25419.44.37.255126
7719.44.38.0/2519.44.38.1 to 19.44.38.12619.44.38.127126
7819.44.38.128/2519.44.38.129 to 19.44.38.25419.44.38.255126
7919.44.39.0/2519.44.39.1 to 19.44.39.12619.44.39.127126
8019.44.39.128/2519.44.39.129 to 19.44.39.25419.44.39.255126
8119.44.40.0/2519.44.40.1 to 19.44.40.12619.44.40.127126
8219.44.40.128/2519.44.40.129 to 19.44.40.25419.44.40.255126
8319.44.41.0/2519.44.41.1 to 19.44.41.12619.44.41.127126
8419.44.41.128/2519.44.41.129 to 19.44.41.25419.44.41.255126
8519.44.42.0/2519.44.42.1 to 19.44.42.12619.44.42.127126
8619.44.42.128/2519.44.42.129 to 19.44.42.25419.44.42.255126
8719.44.43.0/2519.44.43.1 to 19.44.43.12619.44.43.127126
8819.44.43.128/2519.44.43.129 to 19.44.43.25419.44.43.255126
8919.44.44.0/2519.44.44.1 to 19.44.44.12619.44.44.127126
9019.44.44.128/2519.44.44.129 to 19.44.44.25419.44.44.255126
9119.44.45.0/2519.44.45.1 to 19.44.45.12619.44.45.127126
9219.44.45.128/2519.44.45.129 to 19.44.45.25419.44.45.255126
9319.44.46.0/2519.44.46.1 to 19.44.46.12619.44.46.127126
9419.44.46.128/2519.44.46.129 to 19.44.46.25419.44.46.255126
9519.44.47.0/2519.44.47.1 to 19.44.47.12619.44.47.127126
9619.44.47.128/2519.44.47.129 to 19.44.47.25419.44.47.255126
9719.44.48.0/2519.44.48.1 to 19.44.48.12619.44.48.127126
9819.44.48.128/2519.44.48.129 to 19.44.48.25419.44.48.255126
9919.44.49.0/2519.44.49.1 to 19.44.49.12619.44.49.127126
10019.44.49.128/2519.44.49.129 to 19.44.49.25419.44.49.255126
10119.44.50.0/2519.44.50.1 to 19.44.50.12619.44.50.127126
10219.44.50.128/2519.44.50.129 to 19.44.50.25419.44.50.255126
10319.44.51.0/2519.44.51.1 to 19.44.51.12619.44.51.127126
10419.44.51.128/2519.44.51.129 to 19.44.51.25419.44.51.255126
10519.44.52.0/2519.44.52.1 to 19.44.52.12619.44.52.127126
10619.44.52.128/2519.44.52.129 to 19.44.52.25419.44.52.255126
10719.44.53.0/2519.44.53.1 to 19.44.53.12619.44.53.127126
10819.44.53.128/2519.44.53.129 to 19.44.53.25419.44.53.255126
10919.44.54.0/2519.44.54.1 to 19.44.54.12619.44.54.127126
11019.44.54.128/2519.44.54.129 to 19.44.54.25419.44.54.255126
11119.44.55.0/2519.44.55.1 to 19.44.55.12619.44.55.127126
11219.44.55.128/2519.44.55.129 to 19.44.55.25419.44.55.255126
11319.44.56.0/2519.44.56.1 to 19.44.56.12619.44.56.127126
11419.44.56.128/2519.44.56.129 to 19.44.56.25419.44.56.255126
11519.44.57.0/2519.44.57.1 to 19.44.57.12619.44.57.127126
11619.44.57.128/2519.44.57.129 to 19.44.57.25419.44.57.255126
11719.44.58.0/2519.44.58.1 to 19.44.58.12619.44.58.127126
11819.44.58.128/2519.44.58.129 to 19.44.58.25419.44.58.255126
11919.44.59.0/2519.44.59.1 to 19.44.59.12619.44.59.127126
12019.44.59.128/2519.44.59.129 to 19.44.59.25419.44.59.255126
12119.44.60.0/2519.44.60.1 to 19.44.60.12619.44.60.127126
12219.44.60.128/2519.44.60.129 to 19.44.60.25419.44.60.255126
12319.44.61.0/2519.44.61.1 to 19.44.61.12619.44.61.127126
12419.44.61.128/2519.44.61.129 to 19.44.61.25419.44.61.255126
12519.44.62.0/2519.44.62.1 to 19.44.62.12619.44.62.127126
12619.44.62.128/2519.44.62.129 to 19.44.62.25419.44.62.255126
12719.44.63.0/2519.44.63.1 to 19.44.63.12619.44.63.127126
12819.44.63.128/2519.44.63.129 to 19.44.63.25419.44.63.255126
12919.44.64.0/2519.44.64.1 to 19.44.64.12619.44.64.127126
13019.44.64.128/2519.44.64.129 to 19.44.64.25419.44.64.255126
13119.44.65.0/2519.44.65.1 to 19.44.65.12619.44.65.127126
13219.44.65.128/2519.44.65.129 to 19.44.65.25419.44.65.255126
13319.44.66.0/2519.44.66.1 to 19.44.66.12619.44.66.127126
13419.44.66.128/2519.44.66.129 to 19.44.66.25419.44.66.255126
13519.44.67.0/2519.44.67.1 to 19.44.67.12619.44.67.127126
13619.44.67.128/2519.44.67.129 to 19.44.67.25419.44.67.255126
13719.44.68.0/2519.44.68.1 to 19.44.68.12619.44.68.127126
13819.44.68.128/2519.44.68.129 to 19.44.68.25419.44.68.255126
13919.44.69.0/2519.44.69.1 to 19.44.69.12619.44.69.127126
14019.44.69.128/2519.44.69.129 to 19.44.69.25419.44.69.255126
14119.44.70.0/2519.44.70.1 to 19.44.70.12619.44.70.127126
14219.44.70.128/2519.44.70.129 to 19.44.70.25419.44.70.255126
14319.44.71.0/2519.44.71.1 to 19.44.71.12619.44.71.127126
14419.44.71.128/2519.44.71.129 to 19.44.71.25419.44.71.255126
14519.44.72.0/2519.44.72.1 to 19.44.72.12619.44.72.127126
14619.44.72.128/2519.44.72.129 to 19.44.72.25419.44.72.255126
14719.44.73.0/2519.44.73.1 to 19.44.73.12619.44.73.127126
14819.44.73.128/2519.44.73.129 to 19.44.73.25419.44.73.255126
14919.44.74.0/2519.44.74.1 to 19.44.74.12619.44.74.127126
15019.44.74.128/2519.44.74.129 to 19.44.74.25419.44.74.255126
15119.44.75.0/2519.44.75.1 to 19.44.75.12619.44.75.127126
15219.44.75.128/2519.44.75.129 to 19.44.75.25419.44.75.255126
15319.44.76.0/2519.44.76.1 to 19.44.76.12619.44.76.127126
15419.44.76.128/2519.44.76.129 to 19.44.76.25419.44.76.255126
15519.44.77.0/2519.44.77.1 to 19.44.77.12619.44.77.127126
15619.44.77.128/2519.44.77.129 to 19.44.77.25419.44.77.255126
15719.44.78.0/2519.44.78.1 to 19.44.78.12619.44.78.127126
15819.44.78.128/2519.44.78.129 to 19.44.78.25419.44.78.255126
15919.44.79.0/2519.44.79.1 to 19.44.79.12619.44.79.127126
16019.44.79.128/2519.44.79.129 to 19.44.79.25419.44.79.255126
16119.44.80.0/2519.44.80.1 to 19.44.80.12619.44.80.127126
16219.44.80.128/2519.44.80.129 to 19.44.80.25419.44.80.255126
16319.44.81.0/2519.44.81.1 to 19.44.81.12619.44.81.127126
16419.44.81.128/2519.44.81.129 to 19.44.81.25419.44.81.255126
16519.44.82.0/2519.44.82.1 to 19.44.82.12619.44.82.127126
16619.44.82.128/2519.44.82.129 to 19.44.82.25419.44.82.255126
16719.44.83.0/2519.44.83.1 to 19.44.83.12619.44.83.127126
16819.44.83.128/2519.44.83.129 to 19.44.83.25419.44.83.255126
16919.44.84.0/2519.44.84.1 to 19.44.84.12619.44.84.127126
17019.44.84.128/2519.44.84.129 to 19.44.84.25419.44.84.255126
17119.44.85.0/2519.44.85.1 to 19.44.85.12619.44.85.127126
17219.44.85.128/2519.44.85.129 to 19.44.85.25419.44.85.255126
17319.44.86.0/2519.44.86.1 to 19.44.86.12619.44.86.127126
17419.44.86.128/2519.44.86.129 to 19.44.86.25419.44.86.255126
17519.44.87.0/2519.44.87.1 to 19.44.87.12619.44.87.127126
17619.44.87.128/2519.44.87.129 to 19.44.87.25419.44.87.255126
17719.44.88.0/2519.44.88.1 to 19.44.88.12619.44.88.127126
17819.44.88.128/2519.44.88.129 to 19.44.88.25419.44.88.255126
17919.44.89.0/2519.44.89.1 to 19.44.89.12619.44.89.127126
18019.44.89.128/2519.44.89.129 to 19.44.89.25419.44.89.255126
18119.44.90.0/2519.44.90.1 to 19.44.90.12619.44.90.127126
18219.44.90.128/2519.44.90.129 to 19.44.90.25419.44.90.255126
18319.44.91.0/2519.44.91.1 to 19.44.91.12619.44.91.127126
18419.44.91.128/2519.44.91.129 to 19.44.91.25419.44.91.255126
18519.44.92.0/2519.44.92.1 to 19.44.92.12619.44.92.127126
18619.44.92.128/2519.44.92.129 to 19.44.92.25419.44.92.255126
18719.44.93.0/2519.44.93.1 to 19.44.93.12619.44.93.127126
18819.44.93.128/2519.44.93.129 to 19.44.93.25419.44.93.255126
18919.44.94.0/2519.44.94.1 to 19.44.94.12619.44.94.127126
19019.44.94.128/2519.44.94.129 to 19.44.94.25419.44.94.255126
19119.44.95.0/2519.44.95.1 to 19.44.95.12619.44.95.127126
19219.44.95.128/2519.44.95.129 to 19.44.95.25419.44.95.255126
19319.44.96.0/2519.44.96.1 to 19.44.96.12619.44.96.127126
19419.44.96.128/2519.44.96.129 to 19.44.96.25419.44.96.255126
19519.44.97.0/2519.44.97.1 to 19.44.97.12619.44.97.127126
19619.44.97.128/2519.44.97.129 to 19.44.97.25419.44.97.255126
19719.44.98.0/2519.44.98.1 to 19.44.98.12619.44.98.127126
19819.44.98.128/2519.44.98.129 to 19.44.98.25419.44.98.255126
19919.44.99.0/2519.44.99.1 to 19.44.99.12619.44.99.127126
20019.44.99.128/2519.44.99.129 to 19.44.99.25419.44.99.255126
20119.44.100.0/2519.44.100.1 to 19.44.100.12619.44.100.127126
20219.44.100.128/2519.44.100.129 to 19.44.100.25419.44.100.255126
20319.44.101.0/2519.44.101.1 to 19.44.101.12619.44.101.127126
20419.44.101.128/2519.44.101.129 to 19.44.101.25419.44.101.255126
20519.44.102.0/2519.44.102.1 to 19.44.102.12619.44.102.127126
20619.44.102.128/2519.44.102.129 to 19.44.102.25419.44.102.255126
20719.44.103.0/2519.44.103.1 to 19.44.103.12619.44.103.127126
20819.44.103.128/2519.44.103.129 to 19.44.103.25419.44.103.255126
20919.44.104.0/2519.44.104.1 to 19.44.104.12619.44.104.127126
21019.44.104.128/2519.44.104.129 to 19.44.104.25419.44.104.255126
21119.44.105.0/2519.44.105.1 to 19.44.105.12619.44.105.127126
21219.44.105.128/2519.44.105.129 to 19.44.105.25419.44.105.255126
21319.44.106.0/2519.44.106.1 to 19.44.106.12619.44.106.127126
21419.44.106.128/2519.44.106.129 to 19.44.106.25419.44.106.255126
21519.44.107.0/2519.44.107.1 to 19.44.107.12619.44.107.127126
21619.44.107.128/2519.44.107.129 to 19.44.107.25419.44.107.255126
21719.44.108.0/2519.44.108.1 to 19.44.108.12619.44.108.127126
21819.44.108.128/2519.44.108.129 to 19.44.108.25419.44.108.255126
21919.44.109.0/2519.44.109.1 to 19.44.109.12619.44.109.127126
22019.44.109.128/2519.44.109.129 to 19.44.109.25419.44.109.255126
22119.44.110.0/2519.44.110.1 to 19.44.110.12619.44.110.127126
22219.44.110.128/2519.44.110.129 to 19.44.110.25419.44.110.255126
22319.44.111.0/2519.44.111.1 to 19.44.111.12619.44.111.127126
22419.44.111.128/2519.44.111.129 to 19.44.111.25419.44.111.255126
22519.44.112.0/2519.44.112.1 to 19.44.112.12619.44.112.127126
22619.44.112.128/2519.44.112.129 to 19.44.112.25419.44.112.255126
22719.44.113.0/2519.44.113.1 to 19.44.113.12619.44.113.127126
22819.44.113.128/2519.44.113.129 to 19.44.113.25419.44.113.255126
22919.44.114.0/2519.44.114.1 to 19.44.114.12619.44.114.127126
23019.44.114.128/2519.44.114.129 to 19.44.114.25419.44.114.255126
23119.44.115.0/2519.44.115.1 to 19.44.115.12619.44.115.127126
23219.44.115.128/2519.44.115.129 to 19.44.115.25419.44.115.255126
23319.44.116.0/2519.44.116.1 to 19.44.116.12619.44.116.127126
23419.44.116.128/2519.44.116.129 to 19.44.116.25419.44.116.255126
23519.44.117.0/2519.44.117.1 to 19.44.117.12619.44.117.127126
23619.44.117.128/2519.44.117.129 to 19.44.117.25419.44.117.255126
23719.44.118.0/2519.44.118.1 to 19.44.118.12619.44.118.127126
23819.44.118.128/2519.44.118.129 to 19.44.118.25419.44.118.255126
23919.44.119.0/2519.44.119.1 to 19.44.119.12619.44.119.127126
24019.44.119.128/2519.44.119.129 to 19.44.119.25419.44.119.255126
24119.44.120.0/2519.44.120.1 to 19.44.120.12619.44.120.127126
24219.44.120.128/2519.44.120.129 to 19.44.120.25419.44.120.255126
24319.44.121.0/2519.44.121.1 to 19.44.121.12619.44.121.127126
24419.44.121.128/2519.44.121.129 to 19.44.121.25419.44.121.255126
24519.44.122.0/2519.44.122.1 to 19.44.122.12619.44.122.127126
24619.44.122.128/2519.44.122.129 to 19.44.122.25419.44.122.255126
24719.44.123.0/2519.44.123.1 to 19.44.123.12619.44.123.127126
24819.44.123.128/2519.44.123.129 to 19.44.123.25419.44.123.255126
24919.44.124.0/2519.44.124.1 to 19.44.124.12619.44.124.127126
25019.44.124.128/2519.44.124.129 to 19.44.124.25419.44.124.255126
25119.44.125.0/2519.44.125.1 to 19.44.125.12619.44.125.127126
25219.44.125.128/2519.44.125.129 to 19.44.125.25419.44.125.255126
25319.44.126.0/2519.44.126.1 to 19.44.126.12619.44.126.127126
25419.44.126.128/2519.44.126.129 to 19.44.126.25419.44.126.255126
25519.44.127.0/2519.44.127.1 to 19.44.127.12619.44.127.127126
25619.44.127.128/2519.44.127.129 to 19.44.127.25419.44.127.255126

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.