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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.

Network45.0.0.0/9
Usable hosts8,388,606
Subnet mask255.128.0.0
Addresses8,388,608
Network address
45.0.0.0
Broadcast address
45.127.255.255
First usable
45.0.0.1
Last usable
45.127.255.254
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 2D000000 · Integer 754974720 to 763363327
Reverse DNS zones
0.45.in-addr.arpa
1.45.in-addr.arpa
2.45.in-addr.arpa
3.45.in-addr.arpa
4.45.in-addr.arpa
5.45.in-addr.arpa
6.45.in-addr.arpa
7.45.in-addr.arpa
8.45.in-addr.arpa
9.45.in-addr.arpa
10.45.in-addr.arpa
11.45.in-addr.arpa
12.45.in-addr.arpa
13.45.in-addr.arpa
14.45.in-addr.arpa
15.45.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
Address00101101.00000000.00000000.0000000045.0.0.0
Subnet mask11111111.10000000.00000000.00000000255.128.0.0
Network00101101.00000000.00000000.0000000045.0.0.0
Broadcast00101101.01111111.11111111.1111111145.127.255.255
Split into smaller subnets/17
/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)

45.0.0.0/9 makes 256 subnets of /17.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
145.0.0.0/1745.0.0.1 to 45.0.127.25445.0.127.25532,766
245.0.128.0/1745.0.128.1 to 45.0.255.25445.0.255.25532,766
345.1.0.0/1745.1.0.1 to 45.1.127.25445.1.127.25532,766
445.1.128.0/1745.1.128.1 to 45.1.255.25445.1.255.25532,766
545.2.0.0/1745.2.0.1 to 45.2.127.25445.2.127.25532,766
645.2.128.0/1745.2.128.1 to 45.2.255.25445.2.255.25532,766
745.3.0.0/1745.3.0.1 to 45.3.127.25445.3.127.25532,766
845.3.128.0/1745.3.128.1 to 45.3.255.25445.3.255.25532,766
945.4.0.0/1745.4.0.1 to 45.4.127.25445.4.127.25532,766
1045.4.128.0/1745.4.128.1 to 45.4.255.25445.4.255.25532,766
1145.5.0.0/1745.5.0.1 to 45.5.127.25445.5.127.25532,766
1245.5.128.0/1745.5.128.1 to 45.5.255.25445.5.255.25532,766
1345.6.0.0/1745.6.0.1 to 45.6.127.25445.6.127.25532,766
1445.6.128.0/1745.6.128.1 to 45.6.255.25445.6.255.25532,766
1545.7.0.0/1745.7.0.1 to 45.7.127.25445.7.127.25532,766
1645.7.128.0/1745.7.128.1 to 45.7.255.25445.7.255.25532,766
1745.8.0.0/1745.8.0.1 to 45.8.127.25445.8.127.25532,766
1845.8.128.0/1745.8.128.1 to 45.8.255.25445.8.255.25532,766
1945.9.0.0/1745.9.0.1 to 45.9.127.25445.9.127.25532,766
2045.9.128.0/1745.9.128.1 to 45.9.255.25445.9.255.25532,766
2145.10.0.0/1745.10.0.1 to 45.10.127.25445.10.127.25532,766
2245.10.128.0/1745.10.128.1 to 45.10.255.25445.10.255.25532,766
2345.11.0.0/1745.11.0.1 to 45.11.127.25445.11.127.25532,766
2445.11.128.0/1745.11.128.1 to 45.11.255.25445.11.255.25532,766
2545.12.0.0/1745.12.0.1 to 45.12.127.25445.12.127.25532,766
2645.12.128.0/1745.12.128.1 to 45.12.255.25445.12.255.25532,766
2745.13.0.0/1745.13.0.1 to 45.13.127.25445.13.127.25532,766
2845.13.128.0/1745.13.128.1 to 45.13.255.25445.13.255.25532,766
2945.14.0.0/1745.14.0.1 to 45.14.127.25445.14.127.25532,766
3045.14.128.0/1745.14.128.1 to 45.14.255.25445.14.255.25532,766
3145.15.0.0/1745.15.0.1 to 45.15.127.25445.15.127.25532,766
3245.15.128.0/1745.15.128.1 to 45.15.255.25445.15.255.25532,766
3345.16.0.0/1745.16.0.1 to 45.16.127.25445.16.127.25532,766
3445.16.128.0/1745.16.128.1 to 45.16.255.25445.16.255.25532,766
3545.17.0.0/1745.17.0.1 to 45.17.127.25445.17.127.25532,766
3645.17.128.0/1745.17.128.1 to 45.17.255.25445.17.255.25532,766
3745.18.0.0/1745.18.0.1 to 45.18.127.25445.18.127.25532,766
3845.18.128.0/1745.18.128.1 to 45.18.255.25445.18.255.25532,766
3945.19.0.0/1745.19.0.1 to 45.19.127.25445.19.127.25532,766
4045.19.128.0/1745.19.128.1 to 45.19.255.25445.19.255.25532,766
4145.20.0.0/1745.20.0.1 to 45.20.127.25445.20.127.25532,766
4245.20.128.0/1745.20.128.1 to 45.20.255.25445.20.255.25532,766
4345.21.0.0/1745.21.0.1 to 45.21.127.25445.21.127.25532,766
4445.21.128.0/1745.21.128.1 to 45.21.255.25445.21.255.25532,766
4545.22.0.0/1745.22.0.1 to 45.22.127.25445.22.127.25532,766
4645.22.128.0/1745.22.128.1 to 45.22.255.25445.22.255.25532,766
4745.23.0.0/1745.23.0.1 to 45.23.127.25445.23.127.25532,766
4845.23.128.0/1745.23.128.1 to 45.23.255.25445.23.255.25532,766
4945.24.0.0/1745.24.0.1 to 45.24.127.25445.24.127.25532,766
5045.24.128.0/1745.24.128.1 to 45.24.255.25445.24.255.25532,766
5145.25.0.0/1745.25.0.1 to 45.25.127.25445.25.127.25532,766
5245.25.128.0/1745.25.128.1 to 45.25.255.25445.25.255.25532,766
5345.26.0.0/1745.26.0.1 to 45.26.127.25445.26.127.25532,766
5445.26.128.0/1745.26.128.1 to 45.26.255.25445.26.255.25532,766
5545.27.0.0/1745.27.0.1 to 45.27.127.25445.27.127.25532,766
5645.27.128.0/1745.27.128.1 to 45.27.255.25445.27.255.25532,766
5745.28.0.0/1745.28.0.1 to 45.28.127.25445.28.127.25532,766
5845.28.128.0/1745.28.128.1 to 45.28.255.25445.28.255.25532,766
5945.29.0.0/1745.29.0.1 to 45.29.127.25445.29.127.25532,766
6045.29.128.0/1745.29.128.1 to 45.29.255.25445.29.255.25532,766
6145.30.0.0/1745.30.0.1 to 45.30.127.25445.30.127.25532,766
6245.30.128.0/1745.30.128.1 to 45.30.255.25445.30.255.25532,766
6345.31.0.0/1745.31.0.1 to 45.31.127.25445.31.127.25532,766
6445.31.128.0/1745.31.128.1 to 45.31.255.25445.31.255.25532,766
6545.32.0.0/1745.32.0.1 to 45.32.127.25445.32.127.25532,766
6645.32.128.0/1745.32.128.1 to 45.32.255.25445.32.255.25532,766
6745.33.0.0/1745.33.0.1 to 45.33.127.25445.33.127.25532,766
6845.33.128.0/1745.33.128.1 to 45.33.255.25445.33.255.25532,766
6945.34.0.0/1745.34.0.1 to 45.34.127.25445.34.127.25532,766
7045.34.128.0/1745.34.128.1 to 45.34.255.25445.34.255.25532,766
7145.35.0.0/1745.35.0.1 to 45.35.127.25445.35.127.25532,766
7245.35.128.0/1745.35.128.1 to 45.35.255.25445.35.255.25532,766
7345.36.0.0/1745.36.0.1 to 45.36.127.25445.36.127.25532,766
7445.36.128.0/1745.36.128.1 to 45.36.255.25445.36.255.25532,766
7545.37.0.0/1745.37.0.1 to 45.37.127.25445.37.127.25532,766
7645.37.128.0/1745.37.128.1 to 45.37.255.25445.37.255.25532,766
7745.38.0.0/1745.38.0.1 to 45.38.127.25445.38.127.25532,766
7845.38.128.0/1745.38.128.1 to 45.38.255.25445.38.255.25532,766
7945.39.0.0/1745.39.0.1 to 45.39.127.25445.39.127.25532,766
8045.39.128.0/1745.39.128.1 to 45.39.255.25445.39.255.25532,766
8145.40.0.0/1745.40.0.1 to 45.40.127.25445.40.127.25532,766
8245.40.128.0/1745.40.128.1 to 45.40.255.25445.40.255.25532,766
8345.41.0.0/1745.41.0.1 to 45.41.127.25445.41.127.25532,766
8445.41.128.0/1745.41.128.1 to 45.41.255.25445.41.255.25532,766
8545.42.0.0/1745.42.0.1 to 45.42.127.25445.42.127.25532,766
8645.42.128.0/1745.42.128.1 to 45.42.255.25445.42.255.25532,766
8745.43.0.0/1745.43.0.1 to 45.43.127.25445.43.127.25532,766
8845.43.128.0/1745.43.128.1 to 45.43.255.25445.43.255.25532,766
8945.44.0.0/1745.44.0.1 to 45.44.127.25445.44.127.25532,766
9045.44.128.0/1745.44.128.1 to 45.44.255.25445.44.255.25532,766
9145.45.0.0/1745.45.0.1 to 45.45.127.25445.45.127.25532,766
9245.45.128.0/1745.45.128.1 to 45.45.255.25445.45.255.25532,766
9345.46.0.0/1745.46.0.1 to 45.46.127.25445.46.127.25532,766
9445.46.128.0/1745.46.128.1 to 45.46.255.25445.46.255.25532,766
9545.47.0.0/1745.47.0.1 to 45.47.127.25445.47.127.25532,766
9645.47.128.0/1745.47.128.1 to 45.47.255.25445.47.255.25532,766
9745.48.0.0/1745.48.0.1 to 45.48.127.25445.48.127.25532,766
9845.48.128.0/1745.48.128.1 to 45.48.255.25445.48.255.25532,766
9945.49.0.0/1745.49.0.1 to 45.49.127.25445.49.127.25532,766
10045.49.128.0/1745.49.128.1 to 45.49.255.25445.49.255.25532,766
10145.50.0.0/1745.50.0.1 to 45.50.127.25445.50.127.25532,766
10245.50.128.0/1745.50.128.1 to 45.50.255.25445.50.255.25532,766
10345.51.0.0/1745.51.0.1 to 45.51.127.25445.51.127.25532,766
10445.51.128.0/1745.51.128.1 to 45.51.255.25445.51.255.25532,766
10545.52.0.0/1745.52.0.1 to 45.52.127.25445.52.127.25532,766
10645.52.128.0/1745.52.128.1 to 45.52.255.25445.52.255.25532,766
10745.53.0.0/1745.53.0.1 to 45.53.127.25445.53.127.25532,766
10845.53.128.0/1745.53.128.1 to 45.53.255.25445.53.255.25532,766
10945.54.0.0/1745.54.0.1 to 45.54.127.25445.54.127.25532,766
11045.54.128.0/1745.54.128.1 to 45.54.255.25445.54.255.25532,766
11145.55.0.0/1745.55.0.1 to 45.55.127.25445.55.127.25532,766
11245.55.128.0/1745.55.128.1 to 45.55.255.25445.55.255.25532,766
11345.56.0.0/1745.56.0.1 to 45.56.127.25445.56.127.25532,766
11445.56.128.0/1745.56.128.1 to 45.56.255.25445.56.255.25532,766
11545.57.0.0/1745.57.0.1 to 45.57.127.25445.57.127.25532,766
11645.57.128.0/1745.57.128.1 to 45.57.255.25445.57.255.25532,766
11745.58.0.0/1745.58.0.1 to 45.58.127.25445.58.127.25532,766
11845.58.128.0/1745.58.128.1 to 45.58.255.25445.58.255.25532,766
11945.59.0.0/1745.59.0.1 to 45.59.127.25445.59.127.25532,766
12045.59.128.0/1745.59.128.1 to 45.59.255.25445.59.255.25532,766
12145.60.0.0/1745.60.0.1 to 45.60.127.25445.60.127.25532,766
12245.60.128.0/1745.60.128.1 to 45.60.255.25445.60.255.25532,766
12345.61.0.0/1745.61.0.1 to 45.61.127.25445.61.127.25532,766
12445.61.128.0/1745.61.128.1 to 45.61.255.25445.61.255.25532,766
12545.62.0.0/1745.62.0.1 to 45.62.127.25445.62.127.25532,766
12645.62.128.0/1745.62.128.1 to 45.62.255.25445.62.255.25532,766
12745.63.0.0/1745.63.0.1 to 45.63.127.25445.63.127.25532,766
12845.63.128.0/1745.63.128.1 to 45.63.255.25445.63.255.25532,766
12945.64.0.0/1745.64.0.1 to 45.64.127.25445.64.127.25532,766
13045.64.128.0/1745.64.128.1 to 45.64.255.25445.64.255.25532,766
13145.65.0.0/1745.65.0.1 to 45.65.127.25445.65.127.25532,766
13245.65.128.0/1745.65.128.1 to 45.65.255.25445.65.255.25532,766
13345.66.0.0/1745.66.0.1 to 45.66.127.25445.66.127.25532,766
13445.66.128.0/1745.66.128.1 to 45.66.255.25445.66.255.25532,766
13545.67.0.0/1745.67.0.1 to 45.67.127.25445.67.127.25532,766
13645.67.128.0/1745.67.128.1 to 45.67.255.25445.67.255.25532,766
13745.68.0.0/1745.68.0.1 to 45.68.127.25445.68.127.25532,766
13845.68.128.0/1745.68.128.1 to 45.68.255.25445.68.255.25532,766
13945.69.0.0/1745.69.0.1 to 45.69.127.25445.69.127.25532,766
14045.69.128.0/1745.69.128.1 to 45.69.255.25445.69.255.25532,766
14145.70.0.0/1745.70.0.1 to 45.70.127.25445.70.127.25532,766
14245.70.128.0/1745.70.128.1 to 45.70.255.25445.70.255.25532,766
14345.71.0.0/1745.71.0.1 to 45.71.127.25445.71.127.25532,766
14445.71.128.0/1745.71.128.1 to 45.71.255.25445.71.255.25532,766
14545.72.0.0/1745.72.0.1 to 45.72.127.25445.72.127.25532,766
14645.72.128.0/1745.72.128.1 to 45.72.255.25445.72.255.25532,766
14745.73.0.0/1745.73.0.1 to 45.73.127.25445.73.127.25532,766
14845.73.128.0/1745.73.128.1 to 45.73.255.25445.73.255.25532,766
14945.74.0.0/1745.74.0.1 to 45.74.127.25445.74.127.25532,766
15045.74.128.0/1745.74.128.1 to 45.74.255.25445.74.255.25532,766
15145.75.0.0/1745.75.0.1 to 45.75.127.25445.75.127.25532,766
15245.75.128.0/1745.75.128.1 to 45.75.255.25445.75.255.25532,766
15345.76.0.0/1745.76.0.1 to 45.76.127.25445.76.127.25532,766
15445.76.128.0/1745.76.128.1 to 45.76.255.25445.76.255.25532,766
15545.77.0.0/1745.77.0.1 to 45.77.127.25445.77.127.25532,766
15645.77.128.0/1745.77.128.1 to 45.77.255.25445.77.255.25532,766
15745.78.0.0/1745.78.0.1 to 45.78.127.25445.78.127.25532,766
15845.78.128.0/1745.78.128.1 to 45.78.255.25445.78.255.25532,766
15945.79.0.0/1745.79.0.1 to 45.79.127.25445.79.127.25532,766
16045.79.128.0/1745.79.128.1 to 45.79.255.25445.79.255.25532,766
16145.80.0.0/1745.80.0.1 to 45.80.127.25445.80.127.25532,766
16245.80.128.0/1745.80.128.1 to 45.80.255.25445.80.255.25532,766
16345.81.0.0/1745.81.0.1 to 45.81.127.25445.81.127.25532,766
16445.81.128.0/1745.81.128.1 to 45.81.255.25445.81.255.25532,766
16545.82.0.0/1745.82.0.1 to 45.82.127.25445.82.127.25532,766
16645.82.128.0/1745.82.128.1 to 45.82.255.25445.82.255.25532,766
16745.83.0.0/1745.83.0.1 to 45.83.127.25445.83.127.25532,766
16845.83.128.0/1745.83.128.1 to 45.83.255.25445.83.255.25532,766
16945.84.0.0/1745.84.0.1 to 45.84.127.25445.84.127.25532,766
17045.84.128.0/1745.84.128.1 to 45.84.255.25445.84.255.25532,766
17145.85.0.0/1745.85.0.1 to 45.85.127.25445.85.127.25532,766
17245.85.128.0/1745.85.128.1 to 45.85.255.25445.85.255.25532,766
17345.86.0.0/1745.86.0.1 to 45.86.127.25445.86.127.25532,766
17445.86.128.0/1745.86.128.1 to 45.86.255.25445.86.255.25532,766
17545.87.0.0/1745.87.0.1 to 45.87.127.25445.87.127.25532,766
17645.87.128.0/1745.87.128.1 to 45.87.255.25445.87.255.25532,766
17745.88.0.0/1745.88.0.1 to 45.88.127.25445.88.127.25532,766
17845.88.128.0/1745.88.128.1 to 45.88.255.25445.88.255.25532,766
17945.89.0.0/1745.89.0.1 to 45.89.127.25445.89.127.25532,766
18045.89.128.0/1745.89.128.1 to 45.89.255.25445.89.255.25532,766
18145.90.0.0/1745.90.0.1 to 45.90.127.25445.90.127.25532,766
18245.90.128.0/1745.90.128.1 to 45.90.255.25445.90.255.25532,766
18345.91.0.0/1745.91.0.1 to 45.91.127.25445.91.127.25532,766
18445.91.128.0/1745.91.128.1 to 45.91.255.25445.91.255.25532,766
18545.92.0.0/1745.92.0.1 to 45.92.127.25445.92.127.25532,766
18645.92.128.0/1745.92.128.1 to 45.92.255.25445.92.255.25532,766
18745.93.0.0/1745.93.0.1 to 45.93.127.25445.93.127.25532,766
18845.93.128.0/1745.93.128.1 to 45.93.255.25445.93.255.25532,766
18945.94.0.0/1745.94.0.1 to 45.94.127.25445.94.127.25532,766
19045.94.128.0/1745.94.128.1 to 45.94.255.25445.94.255.25532,766
19145.95.0.0/1745.95.0.1 to 45.95.127.25445.95.127.25532,766
19245.95.128.0/1745.95.128.1 to 45.95.255.25445.95.255.25532,766
19345.96.0.0/1745.96.0.1 to 45.96.127.25445.96.127.25532,766
19445.96.128.0/1745.96.128.1 to 45.96.255.25445.96.255.25532,766
19545.97.0.0/1745.97.0.1 to 45.97.127.25445.97.127.25532,766
19645.97.128.0/1745.97.128.1 to 45.97.255.25445.97.255.25532,766
19745.98.0.0/1745.98.0.1 to 45.98.127.25445.98.127.25532,766
19845.98.128.0/1745.98.128.1 to 45.98.255.25445.98.255.25532,766
19945.99.0.0/1745.99.0.1 to 45.99.127.25445.99.127.25532,766
20045.99.128.0/1745.99.128.1 to 45.99.255.25445.99.255.25532,766
20145.100.0.0/1745.100.0.1 to 45.100.127.25445.100.127.25532,766
20245.100.128.0/1745.100.128.1 to 45.100.255.25445.100.255.25532,766
20345.101.0.0/1745.101.0.1 to 45.101.127.25445.101.127.25532,766
20445.101.128.0/1745.101.128.1 to 45.101.255.25445.101.255.25532,766
20545.102.0.0/1745.102.0.1 to 45.102.127.25445.102.127.25532,766
20645.102.128.0/1745.102.128.1 to 45.102.255.25445.102.255.25532,766
20745.103.0.0/1745.103.0.1 to 45.103.127.25445.103.127.25532,766
20845.103.128.0/1745.103.128.1 to 45.103.255.25445.103.255.25532,766
20945.104.0.0/1745.104.0.1 to 45.104.127.25445.104.127.25532,766
21045.104.128.0/1745.104.128.1 to 45.104.255.25445.104.255.25532,766
21145.105.0.0/1745.105.0.1 to 45.105.127.25445.105.127.25532,766
21245.105.128.0/1745.105.128.1 to 45.105.255.25445.105.255.25532,766
21345.106.0.0/1745.106.0.1 to 45.106.127.25445.106.127.25532,766
21445.106.128.0/1745.106.128.1 to 45.106.255.25445.106.255.25532,766
21545.107.0.0/1745.107.0.1 to 45.107.127.25445.107.127.25532,766
21645.107.128.0/1745.107.128.1 to 45.107.255.25445.107.255.25532,766
21745.108.0.0/1745.108.0.1 to 45.108.127.25445.108.127.25532,766
21845.108.128.0/1745.108.128.1 to 45.108.255.25445.108.255.25532,766
21945.109.0.0/1745.109.0.1 to 45.109.127.25445.109.127.25532,766
22045.109.128.0/1745.109.128.1 to 45.109.255.25445.109.255.25532,766
22145.110.0.0/1745.110.0.1 to 45.110.127.25445.110.127.25532,766
22245.110.128.0/1745.110.128.1 to 45.110.255.25445.110.255.25532,766
22345.111.0.0/1745.111.0.1 to 45.111.127.25445.111.127.25532,766
22445.111.128.0/1745.111.128.1 to 45.111.255.25445.111.255.25532,766
22545.112.0.0/1745.112.0.1 to 45.112.127.25445.112.127.25532,766
22645.112.128.0/1745.112.128.1 to 45.112.255.25445.112.255.25532,766
22745.113.0.0/1745.113.0.1 to 45.113.127.25445.113.127.25532,766
22845.113.128.0/1745.113.128.1 to 45.113.255.25445.113.255.25532,766
22945.114.0.0/1745.114.0.1 to 45.114.127.25445.114.127.25532,766
23045.114.128.0/1745.114.128.1 to 45.114.255.25445.114.255.25532,766
23145.115.0.0/1745.115.0.1 to 45.115.127.25445.115.127.25532,766
23245.115.128.0/1745.115.128.1 to 45.115.255.25445.115.255.25532,766
23345.116.0.0/1745.116.0.1 to 45.116.127.25445.116.127.25532,766
23445.116.128.0/1745.116.128.1 to 45.116.255.25445.116.255.25532,766
23545.117.0.0/1745.117.0.1 to 45.117.127.25445.117.127.25532,766
23645.117.128.0/1745.117.128.1 to 45.117.255.25445.117.255.25532,766
23745.118.0.0/1745.118.0.1 to 45.118.127.25445.118.127.25532,766
23845.118.128.0/1745.118.128.1 to 45.118.255.25445.118.255.25532,766
23945.119.0.0/1745.119.0.1 to 45.119.127.25445.119.127.25532,766
24045.119.128.0/1745.119.128.1 to 45.119.255.25445.119.255.25532,766
24145.120.0.0/1745.120.0.1 to 45.120.127.25445.120.127.25532,766
24245.120.128.0/1745.120.128.1 to 45.120.255.25445.120.255.25532,766
24345.121.0.0/1745.121.0.1 to 45.121.127.25445.121.127.25532,766
24445.121.128.0/1745.121.128.1 to 45.121.255.25445.121.255.25532,766
24545.122.0.0/1745.122.0.1 to 45.122.127.25445.122.127.25532,766
24645.122.128.0/1745.122.128.1 to 45.122.255.25445.122.255.25532,766
24745.123.0.0/1745.123.0.1 to 45.123.127.25445.123.127.25532,766
24845.123.128.0/1745.123.128.1 to 45.123.255.25445.123.255.25532,766
24945.124.0.0/1745.124.0.1 to 45.124.127.25445.124.127.25532,766
25045.124.128.0/1745.124.128.1 to 45.124.255.25445.124.255.25532,766
25145.125.0.0/1745.125.0.1 to 45.125.127.25445.125.127.25532,766
25245.125.128.0/1745.125.128.1 to 45.125.255.25445.125.255.25532,766
25345.126.0.0/1745.126.0.1 to 45.126.127.25445.126.127.25532,766
25445.126.128.0/1745.126.128.1 to 45.126.255.25445.126.255.25532,766
25545.127.0.0/1745.127.0.1 to 45.127.127.25445.127.127.25532,766
25645.127.128.0/1745.127.128.1 to 45.127.255.25445.127.255.25532,766

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.