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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.

Network71.58.0.0/17
Usable hosts32,766
Subnet mask255.255.128.0
Addresses32,768
Network address
71.58.0.0
Broadcast address
71.58.127.255
First usable
71.58.0.1
Last usable
71.58.127.254
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 473A0000 · Integer 1194983424 to 1195016191
Reverse DNS zones
0.58.71.in-addr.arpa
1.58.71.in-addr.arpa
2.58.71.in-addr.arpa
3.58.71.in-addr.arpa
4.58.71.in-addr.arpa
5.58.71.in-addr.arpa
6.58.71.in-addr.arpa
7.58.71.in-addr.arpa
8.58.71.in-addr.arpa
9.58.71.in-addr.arpa
10.58.71.in-addr.arpa
11.58.71.in-addr.arpa
12.58.71.in-addr.arpa
13.58.71.in-addr.arpa
14.58.71.in-addr.arpa
15.58.71.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
Address01000111.00111010.00000000.0000000071.58.0.0
Subnet mask11111111.11111111.10000000.00000000255.255.128.0
Network01000111.00111010.00000000.0000000071.58.0.0
Broadcast01000111.00111010.01111111.1111111171.58.127.255
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)

71.58.0.0/17 makes 256 subnets of /25.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
171.58.0.0/2571.58.0.1 to 71.58.0.12671.58.0.127126
271.58.0.128/2571.58.0.129 to 71.58.0.25471.58.0.255126
371.58.1.0/2571.58.1.1 to 71.58.1.12671.58.1.127126
471.58.1.128/2571.58.1.129 to 71.58.1.25471.58.1.255126
571.58.2.0/2571.58.2.1 to 71.58.2.12671.58.2.127126
671.58.2.128/2571.58.2.129 to 71.58.2.25471.58.2.255126
771.58.3.0/2571.58.3.1 to 71.58.3.12671.58.3.127126
871.58.3.128/2571.58.3.129 to 71.58.3.25471.58.3.255126
971.58.4.0/2571.58.4.1 to 71.58.4.12671.58.4.127126
1071.58.4.128/2571.58.4.129 to 71.58.4.25471.58.4.255126
1171.58.5.0/2571.58.5.1 to 71.58.5.12671.58.5.127126
1271.58.5.128/2571.58.5.129 to 71.58.5.25471.58.5.255126
1371.58.6.0/2571.58.6.1 to 71.58.6.12671.58.6.127126
1471.58.6.128/2571.58.6.129 to 71.58.6.25471.58.6.255126
1571.58.7.0/2571.58.7.1 to 71.58.7.12671.58.7.127126
1671.58.7.128/2571.58.7.129 to 71.58.7.25471.58.7.255126
1771.58.8.0/2571.58.8.1 to 71.58.8.12671.58.8.127126
1871.58.8.128/2571.58.8.129 to 71.58.8.25471.58.8.255126
1971.58.9.0/2571.58.9.1 to 71.58.9.12671.58.9.127126
2071.58.9.128/2571.58.9.129 to 71.58.9.25471.58.9.255126
2171.58.10.0/2571.58.10.1 to 71.58.10.12671.58.10.127126
2271.58.10.128/2571.58.10.129 to 71.58.10.25471.58.10.255126
2371.58.11.0/2571.58.11.1 to 71.58.11.12671.58.11.127126
2471.58.11.128/2571.58.11.129 to 71.58.11.25471.58.11.255126
2571.58.12.0/2571.58.12.1 to 71.58.12.12671.58.12.127126
2671.58.12.128/2571.58.12.129 to 71.58.12.25471.58.12.255126
2771.58.13.0/2571.58.13.1 to 71.58.13.12671.58.13.127126
2871.58.13.128/2571.58.13.129 to 71.58.13.25471.58.13.255126
2971.58.14.0/2571.58.14.1 to 71.58.14.12671.58.14.127126
3071.58.14.128/2571.58.14.129 to 71.58.14.25471.58.14.255126
3171.58.15.0/2571.58.15.1 to 71.58.15.12671.58.15.127126
3271.58.15.128/2571.58.15.129 to 71.58.15.25471.58.15.255126
3371.58.16.0/2571.58.16.1 to 71.58.16.12671.58.16.127126
3471.58.16.128/2571.58.16.129 to 71.58.16.25471.58.16.255126
3571.58.17.0/2571.58.17.1 to 71.58.17.12671.58.17.127126
3671.58.17.128/2571.58.17.129 to 71.58.17.25471.58.17.255126
3771.58.18.0/2571.58.18.1 to 71.58.18.12671.58.18.127126
3871.58.18.128/2571.58.18.129 to 71.58.18.25471.58.18.255126
3971.58.19.0/2571.58.19.1 to 71.58.19.12671.58.19.127126
4071.58.19.128/2571.58.19.129 to 71.58.19.25471.58.19.255126
4171.58.20.0/2571.58.20.1 to 71.58.20.12671.58.20.127126
4271.58.20.128/2571.58.20.129 to 71.58.20.25471.58.20.255126
4371.58.21.0/2571.58.21.1 to 71.58.21.12671.58.21.127126
4471.58.21.128/2571.58.21.129 to 71.58.21.25471.58.21.255126
4571.58.22.0/2571.58.22.1 to 71.58.22.12671.58.22.127126
4671.58.22.128/2571.58.22.129 to 71.58.22.25471.58.22.255126
4771.58.23.0/2571.58.23.1 to 71.58.23.12671.58.23.127126
4871.58.23.128/2571.58.23.129 to 71.58.23.25471.58.23.255126
4971.58.24.0/2571.58.24.1 to 71.58.24.12671.58.24.127126
5071.58.24.128/2571.58.24.129 to 71.58.24.25471.58.24.255126
5171.58.25.0/2571.58.25.1 to 71.58.25.12671.58.25.127126
5271.58.25.128/2571.58.25.129 to 71.58.25.25471.58.25.255126
5371.58.26.0/2571.58.26.1 to 71.58.26.12671.58.26.127126
5471.58.26.128/2571.58.26.129 to 71.58.26.25471.58.26.255126
5571.58.27.0/2571.58.27.1 to 71.58.27.12671.58.27.127126
5671.58.27.128/2571.58.27.129 to 71.58.27.25471.58.27.255126
5771.58.28.0/2571.58.28.1 to 71.58.28.12671.58.28.127126
5871.58.28.128/2571.58.28.129 to 71.58.28.25471.58.28.255126
5971.58.29.0/2571.58.29.1 to 71.58.29.12671.58.29.127126
6071.58.29.128/2571.58.29.129 to 71.58.29.25471.58.29.255126
6171.58.30.0/2571.58.30.1 to 71.58.30.12671.58.30.127126
6271.58.30.128/2571.58.30.129 to 71.58.30.25471.58.30.255126
6371.58.31.0/2571.58.31.1 to 71.58.31.12671.58.31.127126
6471.58.31.128/2571.58.31.129 to 71.58.31.25471.58.31.255126
6571.58.32.0/2571.58.32.1 to 71.58.32.12671.58.32.127126
6671.58.32.128/2571.58.32.129 to 71.58.32.25471.58.32.255126
6771.58.33.0/2571.58.33.1 to 71.58.33.12671.58.33.127126
6871.58.33.128/2571.58.33.129 to 71.58.33.25471.58.33.255126
6971.58.34.0/2571.58.34.1 to 71.58.34.12671.58.34.127126
7071.58.34.128/2571.58.34.129 to 71.58.34.25471.58.34.255126
7171.58.35.0/2571.58.35.1 to 71.58.35.12671.58.35.127126
7271.58.35.128/2571.58.35.129 to 71.58.35.25471.58.35.255126
7371.58.36.0/2571.58.36.1 to 71.58.36.12671.58.36.127126
7471.58.36.128/2571.58.36.129 to 71.58.36.25471.58.36.255126
7571.58.37.0/2571.58.37.1 to 71.58.37.12671.58.37.127126
7671.58.37.128/2571.58.37.129 to 71.58.37.25471.58.37.255126
7771.58.38.0/2571.58.38.1 to 71.58.38.12671.58.38.127126
7871.58.38.128/2571.58.38.129 to 71.58.38.25471.58.38.255126
7971.58.39.0/2571.58.39.1 to 71.58.39.12671.58.39.127126
8071.58.39.128/2571.58.39.129 to 71.58.39.25471.58.39.255126
8171.58.40.0/2571.58.40.1 to 71.58.40.12671.58.40.127126
8271.58.40.128/2571.58.40.129 to 71.58.40.25471.58.40.255126
8371.58.41.0/2571.58.41.1 to 71.58.41.12671.58.41.127126
8471.58.41.128/2571.58.41.129 to 71.58.41.25471.58.41.255126
8571.58.42.0/2571.58.42.1 to 71.58.42.12671.58.42.127126
8671.58.42.128/2571.58.42.129 to 71.58.42.25471.58.42.255126
8771.58.43.0/2571.58.43.1 to 71.58.43.12671.58.43.127126
8871.58.43.128/2571.58.43.129 to 71.58.43.25471.58.43.255126
8971.58.44.0/2571.58.44.1 to 71.58.44.12671.58.44.127126
9071.58.44.128/2571.58.44.129 to 71.58.44.25471.58.44.255126
9171.58.45.0/2571.58.45.1 to 71.58.45.12671.58.45.127126
9271.58.45.128/2571.58.45.129 to 71.58.45.25471.58.45.255126
9371.58.46.0/2571.58.46.1 to 71.58.46.12671.58.46.127126
9471.58.46.128/2571.58.46.129 to 71.58.46.25471.58.46.255126
9571.58.47.0/2571.58.47.1 to 71.58.47.12671.58.47.127126
9671.58.47.128/2571.58.47.129 to 71.58.47.25471.58.47.255126
9771.58.48.0/2571.58.48.1 to 71.58.48.12671.58.48.127126
9871.58.48.128/2571.58.48.129 to 71.58.48.25471.58.48.255126
9971.58.49.0/2571.58.49.1 to 71.58.49.12671.58.49.127126
10071.58.49.128/2571.58.49.129 to 71.58.49.25471.58.49.255126
10171.58.50.0/2571.58.50.1 to 71.58.50.12671.58.50.127126
10271.58.50.128/2571.58.50.129 to 71.58.50.25471.58.50.255126
10371.58.51.0/2571.58.51.1 to 71.58.51.12671.58.51.127126
10471.58.51.128/2571.58.51.129 to 71.58.51.25471.58.51.255126
10571.58.52.0/2571.58.52.1 to 71.58.52.12671.58.52.127126
10671.58.52.128/2571.58.52.129 to 71.58.52.25471.58.52.255126
10771.58.53.0/2571.58.53.1 to 71.58.53.12671.58.53.127126
10871.58.53.128/2571.58.53.129 to 71.58.53.25471.58.53.255126
10971.58.54.0/2571.58.54.1 to 71.58.54.12671.58.54.127126
11071.58.54.128/2571.58.54.129 to 71.58.54.25471.58.54.255126
11171.58.55.0/2571.58.55.1 to 71.58.55.12671.58.55.127126
11271.58.55.128/2571.58.55.129 to 71.58.55.25471.58.55.255126
11371.58.56.0/2571.58.56.1 to 71.58.56.12671.58.56.127126
11471.58.56.128/2571.58.56.129 to 71.58.56.25471.58.56.255126
11571.58.57.0/2571.58.57.1 to 71.58.57.12671.58.57.127126
11671.58.57.128/2571.58.57.129 to 71.58.57.25471.58.57.255126
11771.58.58.0/2571.58.58.1 to 71.58.58.12671.58.58.127126
11871.58.58.128/2571.58.58.129 to 71.58.58.25471.58.58.255126
11971.58.59.0/2571.58.59.1 to 71.58.59.12671.58.59.127126
12071.58.59.128/2571.58.59.129 to 71.58.59.25471.58.59.255126
12171.58.60.0/2571.58.60.1 to 71.58.60.12671.58.60.127126
12271.58.60.128/2571.58.60.129 to 71.58.60.25471.58.60.255126
12371.58.61.0/2571.58.61.1 to 71.58.61.12671.58.61.127126
12471.58.61.128/2571.58.61.129 to 71.58.61.25471.58.61.255126
12571.58.62.0/2571.58.62.1 to 71.58.62.12671.58.62.127126
12671.58.62.128/2571.58.62.129 to 71.58.62.25471.58.62.255126
12771.58.63.0/2571.58.63.1 to 71.58.63.12671.58.63.127126
12871.58.63.128/2571.58.63.129 to 71.58.63.25471.58.63.255126
12971.58.64.0/2571.58.64.1 to 71.58.64.12671.58.64.127126
13071.58.64.128/2571.58.64.129 to 71.58.64.25471.58.64.255126
13171.58.65.0/2571.58.65.1 to 71.58.65.12671.58.65.127126
13271.58.65.128/2571.58.65.129 to 71.58.65.25471.58.65.255126
13371.58.66.0/2571.58.66.1 to 71.58.66.12671.58.66.127126
13471.58.66.128/2571.58.66.129 to 71.58.66.25471.58.66.255126
13571.58.67.0/2571.58.67.1 to 71.58.67.12671.58.67.127126
13671.58.67.128/2571.58.67.129 to 71.58.67.25471.58.67.255126
13771.58.68.0/2571.58.68.1 to 71.58.68.12671.58.68.127126
13871.58.68.128/2571.58.68.129 to 71.58.68.25471.58.68.255126
13971.58.69.0/2571.58.69.1 to 71.58.69.12671.58.69.127126
14071.58.69.128/2571.58.69.129 to 71.58.69.25471.58.69.255126
14171.58.70.0/2571.58.70.1 to 71.58.70.12671.58.70.127126
14271.58.70.128/2571.58.70.129 to 71.58.70.25471.58.70.255126
14371.58.71.0/2571.58.71.1 to 71.58.71.12671.58.71.127126
14471.58.71.128/2571.58.71.129 to 71.58.71.25471.58.71.255126
14571.58.72.0/2571.58.72.1 to 71.58.72.12671.58.72.127126
14671.58.72.128/2571.58.72.129 to 71.58.72.25471.58.72.255126
14771.58.73.0/2571.58.73.1 to 71.58.73.12671.58.73.127126
14871.58.73.128/2571.58.73.129 to 71.58.73.25471.58.73.255126
14971.58.74.0/2571.58.74.1 to 71.58.74.12671.58.74.127126
15071.58.74.128/2571.58.74.129 to 71.58.74.25471.58.74.255126
15171.58.75.0/2571.58.75.1 to 71.58.75.12671.58.75.127126
15271.58.75.128/2571.58.75.129 to 71.58.75.25471.58.75.255126
15371.58.76.0/2571.58.76.1 to 71.58.76.12671.58.76.127126
15471.58.76.128/2571.58.76.129 to 71.58.76.25471.58.76.255126
15571.58.77.0/2571.58.77.1 to 71.58.77.12671.58.77.127126
15671.58.77.128/2571.58.77.129 to 71.58.77.25471.58.77.255126
15771.58.78.0/2571.58.78.1 to 71.58.78.12671.58.78.127126
15871.58.78.128/2571.58.78.129 to 71.58.78.25471.58.78.255126
15971.58.79.0/2571.58.79.1 to 71.58.79.12671.58.79.127126
16071.58.79.128/2571.58.79.129 to 71.58.79.25471.58.79.255126
16171.58.80.0/2571.58.80.1 to 71.58.80.12671.58.80.127126
16271.58.80.128/2571.58.80.129 to 71.58.80.25471.58.80.255126
16371.58.81.0/2571.58.81.1 to 71.58.81.12671.58.81.127126
16471.58.81.128/2571.58.81.129 to 71.58.81.25471.58.81.255126
16571.58.82.0/2571.58.82.1 to 71.58.82.12671.58.82.127126
16671.58.82.128/2571.58.82.129 to 71.58.82.25471.58.82.255126
16771.58.83.0/2571.58.83.1 to 71.58.83.12671.58.83.127126
16871.58.83.128/2571.58.83.129 to 71.58.83.25471.58.83.255126
16971.58.84.0/2571.58.84.1 to 71.58.84.12671.58.84.127126
17071.58.84.128/2571.58.84.129 to 71.58.84.25471.58.84.255126
17171.58.85.0/2571.58.85.1 to 71.58.85.12671.58.85.127126
17271.58.85.128/2571.58.85.129 to 71.58.85.25471.58.85.255126
17371.58.86.0/2571.58.86.1 to 71.58.86.12671.58.86.127126
17471.58.86.128/2571.58.86.129 to 71.58.86.25471.58.86.255126
17571.58.87.0/2571.58.87.1 to 71.58.87.12671.58.87.127126
17671.58.87.128/2571.58.87.129 to 71.58.87.25471.58.87.255126
17771.58.88.0/2571.58.88.1 to 71.58.88.12671.58.88.127126
17871.58.88.128/2571.58.88.129 to 71.58.88.25471.58.88.255126
17971.58.89.0/2571.58.89.1 to 71.58.89.12671.58.89.127126
18071.58.89.128/2571.58.89.129 to 71.58.89.25471.58.89.255126
18171.58.90.0/2571.58.90.1 to 71.58.90.12671.58.90.127126
18271.58.90.128/2571.58.90.129 to 71.58.90.25471.58.90.255126
18371.58.91.0/2571.58.91.1 to 71.58.91.12671.58.91.127126
18471.58.91.128/2571.58.91.129 to 71.58.91.25471.58.91.255126
18571.58.92.0/2571.58.92.1 to 71.58.92.12671.58.92.127126
18671.58.92.128/2571.58.92.129 to 71.58.92.25471.58.92.255126
18771.58.93.0/2571.58.93.1 to 71.58.93.12671.58.93.127126
18871.58.93.128/2571.58.93.129 to 71.58.93.25471.58.93.255126
18971.58.94.0/2571.58.94.1 to 71.58.94.12671.58.94.127126
19071.58.94.128/2571.58.94.129 to 71.58.94.25471.58.94.255126
19171.58.95.0/2571.58.95.1 to 71.58.95.12671.58.95.127126
19271.58.95.128/2571.58.95.129 to 71.58.95.25471.58.95.255126
19371.58.96.0/2571.58.96.1 to 71.58.96.12671.58.96.127126
19471.58.96.128/2571.58.96.129 to 71.58.96.25471.58.96.255126
19571.58.97.0/2571.58.97.1 to 71.58.97.12671.58.97.127126
19671.58.97.128/2571.58.97.129 to 71.58.97.25471.58.97.255126
19771.58.98.0/2571.58.98.1 to 71.58.98.12671.58.98.127126
19871.58.98.128/2571.58.98.129 to 71.58.98.25471.58.98.255126
19971.58.99.0/2571.58.99.1 to 71.58.99.12671.58.99.127126
20071.58.99.128/2571.58.99.129 to 71.58.99.25471.58.99.255126
20171.58.100.0/2571.58.100.1 to 71.58.100.12671.58.100.127126
20271.58.100.128/2571.58.100.129 to 71.58.100.25471.58.100.255126
20371.58.101.0/2571.58.101.1 to 71.58.101.12671.58.101.127126
20471.58.101.128/2571.58.101.129 to 71.58.101.25471.58.101.255126
20571.58.102.0/2571.58.102.1 to 71.58.102.12671.58.102.127126
20671.58.102.128/2571.58.102.129 to 71.58.102.25471.58.102.255126
20771.58.103.0/2571.58.103.1 to 71.58.103.12671.58.103.127126
20871.58.103.128/2571.58.103.129 to 71.58.103.25471.58.103.255126
20971.58.104.0/2571.58.104.1 to 71.58.104.12671.58.104.127126
21071.58.104.128/2571.58.104.129 to 71.58.104.25471.58.104.255126
21171.58.105.0/2571.58.105.1 to 71.58.105.12671.58.105.127126
21271.58.105.128/2571.58.105.129 to 71.58.105.25471.58.105.255126
21371.58.106.0/2571.58.106.1 to 71.58.106.12671.58.106.127126
21471.58.106.128/2571.58.106.129 to 71.58.106.25471.58.106.255126
21571.58.107.0/2571.58.107.1 to 71.58.107.12671.58.107.127126
21671.58.107.128/2571.58.107.129 to 71.58.107.25471.58.107.255126
21771.58.108.0/2571.58.108.1 to 71.58.108.12671.58.108.127126
21871.58.108.128/2571.58.108.129 to 71.58.108.25471.58.108.255126
21971.58.109.0/2571.58.109.1 to 71.58.109.12671.58.109.127126
22071.58.109.128/2571.58.109.129 to 71.58.109.25471.58.109.255126
22171.58.110.0/2571.58.110.1 to 71.58.110.12671.58.110.127126
22271.58.110.128/2571.58.110.129 to 71.58.110.25471.58.110.255126
22371.58.111.0/2571.58.111.1 to 71.58.111.12671.58.111.127126
22471.58.111.128/2571.58.111.129 to 71.58.111.25471.58.111.255126
22571.58.112.0/2571.58.112.1 to 71.58.112.12671.58.112.127126
22671.58.112.128/2571.58.112.129 to 71.58.112.25471.58.112.255126
22771.58.113.0/2571.58.113.1 to 71.58.113.12671.58.113.127126
22871.58.113.128/2571.58.113.129 to 71.58.113.25471.58.113.255126
22971.58.114.0/2571.58.114.1 to 71.58.114.12671.58.114.127126
23071.58.114.128/2571.58.114.129 to 71.58.114.25471.58.114.255126
23171.58.115.0/2571.58.115.1 to 71.58.115.12671.58.115.127126
23271.58.115.128/2571.58.115.129 to 71.58.115.25471.58.115.255126
23371.58.116.0/2571.58.116.1 to 71.58.116.12671.58.116.127126
23471.58.116.128/2571.58.116.129 to 71.58.116.25471.58.116.255126
23571.58.117.0/2571.58.117.1 to 71.58.117.12671.58.117.127126
23671.58.117.128/2571.58.117.129 to 71.58.117.25471.58.117.255126
23771.58.118.0/2571.58.118.1 to 71.58.118.12671.58.118.127126
23871.58.118.128/2571.58.118.129 to 71.58.118.25471.58.118.255126
23971.58.119.0/2571.58.119.1 to 71.58.119.12671.58.119.127126
24071.58.119.128/2571.58.119.129 to 71.58.119.25471.58.119.255126
24171.58.120.0/2571.58.120.1 to 71.58.120.12671.58.120.127126
24271.58.120.128/2571.58.120.129 to 71.58.120.25471.58.120.255126
24371.58.121.0/2571.58.121.1 to 71.58.121.12671.58.121.127126
24471.58.121.128/2571.58.121.129 to 71.58.121.25471.58.121.255126
24571.58.122.0/2571.58.122.1 to 71.58.122.12671.58.122.127126
24671.58.122.128/2571.58.122.129 to 71.58.122.25471.58.122.255126
24771.58.123.0/2571.58.123.1 to 71.58.123.12671.58.123.127126
24871.58.123.128/2571.58.123.129 to 71.58.123.25471.58.123.255126
24971.58.124.0/2571.58.124.1 to 71.58.124.12671.58.124.127126
25071.58.124.128/2571.58.124.129 to 71.58.124.25471.58.124.255126
25171.58.125.0/2571.58.125.1 to 71.58.125.12671.58.125.127126
25271.58.125.128/2571.58.125.129 to 71.58.125.25471.58.125.255126
25371.58.126.0/2571.58.126.1 to 71.58.126.12671.58.126.127126
25471.58.126.128/2571.58.126.129 to 71.58.126.25471.58.126.255126
25571.58.127.0/2571.58.127.1 to 71.58.127.12671.58.127.127126
25671.58.127.128/2571.58.127.129 to 71.58.127.25471.58.127.255126

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.