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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.

Network61.0.0.0/9
Usable hosts8,388,606
Subnet mask255.128.0.0
Addresses8,388,608
Network address
61.0.0.0
Broadcast address
61.127.255.255
First usable
61.0.0.1
Last usable
61.127.255.254
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 3D000000 · Integer 1023410176 to 1031798783
Reverse DNS zones
0.61.in-addr.arpa
1.61.in-addr.arpa
2.61.in-addr.arpa
3.61.in-addr.arpa
4.61.in-addr.arpa
5.61.in-addr.arpa
6.61.in-addr.arpa
7.61.in-addr.arpa
8.61.in-addr.arpa
9.61.in-addr.arpa
10.61.in-addr.arpa
11.61.in-addr.arpa
12.61.in-addr.arpa
13.61.in-addr.arpa
14.61.in-addr.arpa
15.61.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
Address00111101.00000000.00000000.0000000061.0.0.0
Subnet mask11111111.10000000.00000000.00000000255.128.0.0
Network00111101.00000000.00000000.0000000061.0.0.0
Broadcast00111101.01111111.11111111.1111111161.127.255.255
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)

61.0.0.0/9 makes 256 subnets of /17.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
161.0.0.0/1761.0.0.1 to 61.0.127.25461.0.127.25532,766
261.0.128.0/1761.0.128.1 to 61.0.255.25461.0.255.25532,766
361.1.0.0/1761.1.0.1 to 61.1.127.25461.1.127.25532,766
461.1.128.0/1761.1.128.1 to 61.1.255.25461.1.255.25532,766
561.2.0.0/1761.2.0.1 to 61.2.127.25461.2.127.25532,766
661.2.128.0/1761.2.128.1 to 61.2.255.25461.2.255.25532,766
761.3.0.0/1761.3.0.1 to 61.3.127.25461.3.127.25532,766
861.3.128.0/1761.3.128.1 to 61.3.255.25461.3.255.25532,766
961.4.0.0/1761.4.0.1 to 61.4.127.25461.4.127.25532,766
1061.4.128.0/1761.4.128.1 to 61.4.255.25461.4.255.25532,766
1161.5.0.0/1761.5.0.1 to 61.5.127.25461.5.127.25532,766
1261.5.128.0/1761.5.128.1 to 61.5.255.25461.5.255.25532,766
1361.6.0.0/1761.6.0.1 to 61.6.127.25461.6.127.25532,766
1461.6.128.0/1761.6.128.1 to 61.6.255.25461.6.255.25532,766
1561.7.0.0/1761.7.0.1 to 61.7.127.25461.7.127.25532,766
1661.7.128.0/1761.7.128.1 to 61.7.255.25461.7.255.25532,766
1761.8.0.0/1761.8.0.1 to 61.8.127.25461.8.127.25532,766
1861.8.128.0/1761.8.128.1 to 61.8.255.25461.8.255.25532,766
1961.9.0.0/1761.9.0.1 to 61.9.127.25461.9.127.25532,766
2061.9.128.0/1761.9.128.1 to 61.9.255.25461.9.255.25532,766
2161.10.0.0/1761.10.0.1 to 61.10.127.25461.10.127.25532,766
2261.10.128.0/1761.10.128.1 to 61.10.255.25461.10.255.25532,766
2361.11.0.0/1761.11.0.1 to 61.11.127.25461.11.127.25532,766
2461.11.128.0/1761.11.128.1 to 61.11.255.25461.11.255.25532,766
2561.12.0.0/1761.12.0.1 to 61.12.127.25461.12.127.25532,766
2661.12.128.0/1761.12.128.1 to 61.12.255.25461.12.255.25532,766
2761.13.0.0/1761.13.0.1 to 61.13.127.25461.13.127.25532,766
2861.13.128.0/1761.13.128.1 to 61.13.255.25461.13.255.25532,766
2961.14.0.0/1761.14.0.1 to 61.14.127.25461.14.127.25532,766
3061.14.128.0/1761.14.128.1 to 61.14.255.25461.14.255.25532,766
3161.15.0.0/1761.15.0.1 to 61.15.127.25461.15.127.25532,766
3261.15.128.0/1761.15.128.1 to 61.15.255.25461.15.255.25532,766
3361.16.0.0/1761.16.0.1 to 61.16.127.25461.16.127.25532,766
3461.16.128.0/1761.16.128.1 to 61.16.255.25461.16.255.25532,766
3561.17.0.0/1761.17.0.1 to 61.17.127.25461.17.127.25532,766
3661.17.128.0/1761.17.128.1 to 61.17.255.25461.17.255.25532,766
3761.18.0.0/1761.18.0.1 to 61.18.127.25461.18.127.25532,766
3861.18.128.0/1761.18.128.1 to 61.18.255.25461.18.255.25532,766
3961.19.0.0/1761.19.0.1 to 61.19.127.25461.19.127.25532,766
4061.19.128.0/1761.19.128.1 to 61.19.255.25461.19.255.25532,766
4161.20.0.0/1761.20.0.1 to 61.20.127.25461.20.127.25532,766
4261.20.128.0/1761.20.128.1 to 61.20.255.25461.20.255.25532,766
4361.21.0.0/1761.21.0.1 to 61.21.127.25461.21.127.25532,766
4461.21.128.0/1761.21.128.1 to 61.21.255.25461.21.255.25532,766
4561.22.0.0/1761.22.0.1 to 61.22.127.25461.22.127.25532,766
4661.22.128.0/1761.22.128.1 to 61.22.255.25461.22.255.25532,766
4761.23.0.0/1761.23.0.1 to 61.23.127.25461.23.127.25532,766
4861.23.128.0/1761.23.128.1 to 61.23.255.25461.23.255.25532,766
4961.24.0.0/1761.24.0.1 to 61.24.127.25461.24.127.25532,766
5061.24.128.0/1761.24.128.1 to 61.24.255.25461.24.255.25532,766
5161.25.0.0/1761.25.0.1 to 61.25.127.25461.25.127.25532,766
5261.25.128.0/1761.25.128.1 to 61.25.255.25461.25.255.25532,766
5361.26.0.0/1761.26.0.1 to 61.26.127.25461.26.127.25532,766
5461.26.128.0/1761.26.128.1 to 61.26.255.25461.26.255.25532,766
5561.27.0.0/1761.27.0.1 to 61.27.127.25461.27.127.25532,766
5661.27.128.0/1761.27.128.1 to 61.27.255.25461.27.255.25532,766
5761.28.0.0/1761.28.0.1 to 61.28.127.25461.28.127.25532,766
5861.28.128.0/1761.28.128.1 to 61.28.255.25461.28.255.25532,766
5961.29.0.0/1761.29.0.1 to 61.29.127.25461.29.127.25532,766
6061.29.128.0/1761.29.128.1 to 61.29.255.25461.29.255.25532,766
6161.30.0.0/1761.30.0.1 to 61.30.127.25461.30.127.25532,766
6261.30.128.0/1761.30.128.1 to 61.30.255.25461.30.255.25532,766
6361.31.0.0/1761.31.0.1 to 61.31.127.25461.31.127.25532,766
6461.31.128.0/1761.31.128.1 to 61.31.255.25461.31.255.25532,766
6561.32.0.0/1761.32.0.1 to 61.32.127.25461.32.127.25532,766
6661.32.128.0/1761.32.128.1 to 61.32.255.25461.32.255.25532,766
6761.33.0.0/1761.33.0.1 to 61.33.127.25461.33.127.25532,766
6861.33.128.0/1761.33.128.1 to 61.33.255.25461.33.255.25532,766
6961.34.0.0/1761.34.0.1 to 61.34.127.25461.34.127.25532,766
7061.34.128.0/1761.34.128.1 to 61.34.255.25461.34.255.25532,766
7161.35.0.0/1761.35.0.1 to 61.35.127.25461.35.127.25532,766
7261.35.128.0/1761.35.128.1 to 61.35.255.25461.35.255.25532,766
7361.36.0.0/1761.36.0.1 to 61.36.127.25461.36.127.25532,766
7461.36.128.0/1761.36.128.1 to 61.36.255.25461.36.255.25532,766
7561.37.0.0/1761.37.0.1 to 61.37.127.25461.37.127.25532,766
7661.37.128.0/1761.37.128.1 to 61.37.255.25461.37.255.25532,766
7761.38.0.0/1761.38.0.1 to 61.38.127.25461.38.127.25532,766
7861.38.128.0/1761.38.128.1 to 61.38.255.25461.38.255.25532,766
7961.39.0.0/1761.39.0.1 to 61.39.127.25461.39.127.25532,766
8061.39.128.0/1761.39.128.1 to 61.39.255.25461.39.255.25532,766
8161.40.0.0/1761.40.0.1 to 61.40.127.25461.40.127.25532,766
8261.40.128.0/1761.40.128.1 to 61.40.255.25461.40.255.25532,766
8361.41.0.0/1761.41.0.1 to 61.41.127.25461.41.127.25532,766
8461.41.128.0/1761.41.128.1 to 61.41.255.25461.41.255.25532,766
8561.42.0.0/1761.42.0.1 to 61.42.127.25461.42.127.25532,766
8661.42.128.0/1761.42.128.1 to 61.42.255.25461.42.255.25532,766
8761.43.0.0/1761.43.0.1 to 61.43.127.25461.43.127.25532,766
8861.43.128.0/1761.43.128.1 to 61.43.255.25461.43.255.25532,766
8961.44.0.0/1761.44.0.1 to 61.44.127.25461.44.127.25532,766
9061.44.128.0/1761.44.128.1 to 61.44.255.25461.44.255.25532,766
9161.45.0.0/1761.45.0.1 to 61.45.127.25461.45.127.25532,766
9261.45.128.0/1761.45.128.1 to 61.45.255.25461.45.255.25532,766
9361.46.0.0/1761.46.0.1 to 61.46.127.25461.46.127.25532,766
9461.46.128.0/1761.46.128.1 to 61.46.255.25461.46.255.25532,766
9561.47.0.0/1761.47.0.1 to 61.47.127.25461.47.127.25532,766
9661.47.128.0/1761.47.128.1 to 61.47.255.25461.47.255.25532,766
9761.48.0.0/1761.48.0.1 to 61.48.127.25461.48.127.25532,766
9861.48.128.0/1761.48.128.1 to 61.48.255.25461.48.255.25532,766
9961.49.0.0/1761.49.0.1 to 61.49.127.25461.49.127.25532,766
10061.49.128.0/1761.49.128.1 to 61.49.255.25461.49.255.25532,766
10161.50.0.0/1761.50.0.1 to 61.50.127.25461.50.127.25532,766
10261.50.128.0/1761.50.128.1 to 61.50.255.25461.50.255.25532,766
10361.51.0.0/1761.51.0.1 to 61.51.127.25461.51.127.25532,766
10461.51.128.0/1761.51.128.1 to 61.51.255.25461.51.255.25532,766
10561.52.0.0/1761.52.0.1 to 61.52.127.25461.52.127.25532,766
10661.52.128.0/1761.52.128.1 to 61.52.255.25461.52.255.25532,766
10761.53.0.0/1761.53.0.1 to 61.53.127.25461.53.127.25532,766
10861.53.128.0/1761.53.128.1 to 61.53.255.25461.53.255.25532,766
10961.54.0.0/1761.54.0.1 to 61.54.127.25461.54.127.25532,766
11061.54.128.0/1761.54.128.1 to 61.54.255.25461.54.255.25532,766
11161.55.0.0/1761.55.0.1 to 61.55.127.25461.55.127.25532,766
11261.55.128.0/1761.55.128.1 to 61.55.255.25461.55.255.25532,766
11361.56.0.0/1761.56.0.1 to 61.56.127.25461.56.127.25532,766
11461.56.128.0/1761.56.128.1 to 61.56.255.25461.56.255.25532,766
11561.57.0.0/1761.57.0.1 to 61.57.127.25461.57.127.25532,766
11661.57.128.0/1761.57.128.1 to 61.57.255.25461.57.255.25532,766
11761.58.0.0/1761.58.0.1 to 61.58.127.25461.58.127.25532,766
11861.58.128.0/1761.58.128.1 to 61.58.255.25461.58.255.25532,766
11961.59.0.0/1761.59.0.1 to 61.59.127.25461.59.127.25532,766
12061.59.128.0/1761.59.128.1 to 61.59.255.25461.59.255.25532,766
12161.60.0.0/1761.60.0.1 to 61.60.127.25461.60.127.25532,766
12261.60.128.0/1761.60.128.1 to 61.60.255.25461.60.255.25532,766
12361.61.0.0/1761.61.0.1 to 61.61.127.25461.61.127.25532,766
12461.61.128.0/1761.61.128.1 to 61.61.255.25461.61.255.25532,766
12561.62.0.0/1761.62.0.1 to 61.62.127.25461.62.127.25532,766
12661.62.128.0/1761.62.128.1 to 61.62.255.25461.62.255.25532,766
12761.63.0.0/1761.63.0.1 to 61.63.127.25461.63.127.25532,766
12861.63.128.0/1761.63.128.1 to 61.63.255.25461.63.255.25532,766
12961.64.0.0/1761.64.0.1 to 61.64.127.25461.64.127.25532,766
13061.64.128.0/1761.64.128.1 to 61.64.255.25461.64.255.25532,766
13161.65.0.0/1761.65.0.1 to 61.65.127.25461.65.127.25532,766
13261.65.128.0/1761.65.128.1 to 61.65.255.25461.65.255.25532,766
13361.66.0.0/1761.66.0.1 to 61.66.127.25461.66.127.25532,766
13461.66.128.0/1761.66.128.1 to 61.66.255.25461.66.255.25532,766
13561.67.0.0/1761.67.0.1 to 61.67.127.25461.67.127.25532,766
13661.67.128.0/1761.67.128.1 to 61.67.255.25461.67.255.25532,766
13761.68.0.0/1761.68.0.1 to 61.68.127.25461.68.127.25532,766
13861.68.128.0/1761.68.128.1 to 61.68.255.25461.68.255.25532,766
13961.69.0.0/1761.69.0.1 to 61.69.127.25461.69.127.25532,766
14061.69.128.0/1761.69.128.1 to 61.69.255.25461.69.255.25532,766
14161.70.0.0/1761.70.0.1 to 61.70.127.25461.70.127.25532,766
14261.70.128.0/1761.70.128.1 to 61.70.255.25461.70.255.25532,766
14361.71.0.0/1761.71.0.1 to 61.71.127.25461.71.127.25532,766
14461.71.128.0/1761.71.128.1 to 61.71.255.25461.71.255.25532,766
14561.72.0.0/1761.72.0.1 to 61.72.127.25461.72.127.25532,766
14661.72.128.0/1761.72.128.1 to 61.72.255.25461.72.255.25532,766
14761.73.0.0/1761.73.0.1 to 61.73.127.25461.73.127.25532,766
14861.73.128.0/1761.73.128.1 to 61.73.255.25461.73.255.25532,766
14961.74.0.0/1761.74.0.1 to 61.74.127.25461.74.127.25532,766
15061.74.128.0/1761.74.128.1 to 61.74.255.25461.74.255.25532,766
15161.75.0.0/1761.75.0.1 to 61.75.127.25461.75.127.25532,766
15261.75.128.0/1761.75.128.1 to 61.75.255.25461.75.255.25532,766
15361.76.0.0/1761.76.0.1 to 61.76.127.25461.76.127.25532,766
15461.76.128.0/1761.76.128.1 to 61.76.255.25461.76.255.25532,766
15561.77.0.0/1761.77.0.1 to 61.77.127.25461.77.127.25532,766
15661.77.128.0/1761.77.128.1 to 61.77.255.25461.77.255.25532,766
15761.78.0.0/1761.78.0.1 to 61.78.127.25461.78.127.25532,766
15861.78.128.0/1761.78.128.1 to 61.78.255.25461.78.255.25532,766
15961.79.0.0/1761.79.0.1 to 61.79.127.25461.79.127.25532,766
16061.79.128.0/1761.79.128.1 to 61.79.255.25461.79.255.25532,766
16161.80.0.0/1761.80.0.1 to 61.80.127.25461.80.127.25532,766
16261.80.128.0/1761.80.128.1 to 61.80.255.25461.80.255.25532,766
16361.81.0.0/1761.81.0.1 to 61.81.127.25461.81.127.25532,766
16461.81.128.0/1761.81.128.1 to 61.81.255.25461.81.255.25532,766
16561.82.0.0/1761.82.0.1 to 61.82.127.25461.82.127.25532,766
16661.82.128.0/1761.82.128.1 to 61.82.255.25461.82.255.25532,766
16761.83.0.0/1761.83.0.1 to 61.83.127.25461.83.127.25532,766
16861.83.128.0/1761.83.128.1 to 61.83.255.25461.83.255.25532,766
16961.84.0.0/1761.84.0.1 to 61.84.127.25461.84.127.25532,766
17061.84.128.0/1761.84.128.1 to 61.84.255.25461.84.255.25532,766
17161.85.0.0/1761.85.0.1 to 61.85.127.25461.85.127.25532,766
17261.85.128.0/1761.85.128.1 to 61.85.255.25461.85.255.25532,766
17361.86.0.0/1761.86.0.1 to 61.86.127.25461.86.127.25532,766
17461.86.128.0/1761.86.128.1 to 61.86.255.25461.86.255.25532,766
17561.87.0.0/1761.87.0.1 to 61.87.127.25461.87.127.25532,766
17661.87.128.0/1761.87.128.1 to 61.87.255.25461.87.255.25532,766
17761.88.0.0/1761.88.0.1 to 61.88.127.25461.88.127.25532,766
17861.88.128.0/1761.88.128.1 to 61.88.255.25461.88.255.25532,766
17961.89.0.0/1761.89.0.1 to 61.89.127.25461.89.127.25532,766
18061.89.128.0/1761.89.128.1 to 61.89.255.25461.89.255.25532,766
18161.90.0.0/1761.90.0.1 to 61.90.127.25461.90.127.25532,766
18261.90.128.0/1761.90.128.1 to 61.90.255.25461.90.255.25532,766
18361.91.0.0/1761.91.0.1 to 61.91.127.25461.91.127.25532,766
18461.91.128.0/1761.91.128.1 to 61.91.255.25461.91.255.25532,766
18561.92.0.0/1761.92.0.1 to 61.92.127.25461.92.127.25532,766
18661.92.128.0/1761.92.128.1 to 61.92.255.25461.92.255.25532,766
18761.93.0.0/1761.93.0.1 to 61.93.127.25461.93.127.25532,766
18861.93.128.0/1761.93.128.1 to 61.93.255.25461.93.255.25532,766
18961.94.0.0/1761.94.0.1 to 61.94.127.25461.94.127.25532,766
19061.94.128.0/1761.94.128.1 to 61.94.255.25461.94.255.25532,766
19161.95.0.0/1761.95.0.1 to 61.95.127.25461.95.127.25532,766
19261.95.128.0/1761.95.128.1 to 61.95.255.25461.95.255.25532,766
19361.96.0.0/1761.96.0.1 to 61.96.127.25461.96.127.25532,766
19461.96.128.0/1761.96.128.1 to 61.96.255.25461.96.255.25532,766
19561.97.0.0/1761.97.0.1 to 61.97.127.25461.97.127.25532,766
19661.97.128.0/1761.97.128.1 to 61.97.255.25461.97.255.25532,766
19761.98.0.0/1761.98.0.1 to 61.98.127.25461.98.127.25532,766
19861.98.128.0/1761.98.128.1 to 61.98.255.25461.98.255.25532,766
19961.99.0.0/1761.99.0.1 to 61.99.127.25461.99.127.25532,766
20061.99.128.0/1761.99.128.1 to 61.99.255.25461.99.255.25532,766
20161.100.0.0/1761.100.0.1 to 61.100.127.25461.100.127.25532,766
20261.100.128.0/1761.100.128.1 to 61.100.255.25461.100.255.25532,766
20361.101.0.0/1761.101.0.1 to 61.101.127.25461.101.127.25532,766
20461.101.128.0/1761.101.128.1 to 61.101.255.25461.101.255.25532,766
20561.102.0.0/1761.102.0.1 to 61.102.127.25461.102.127.25532,766
20661.102.128.0/1761.102.128.1 to 61.102.255.25461.102.255.25532,766
20761.103.0.0/1761.103.0.1 to 61.103.127.25461.103.127.25532,766
20861.103.128.0/1761.103.128.1 to 61.103.255.25461.103.255.25532,766
20961.104.0.0/1761.104.0.1 to 61.104.127.25461.104.127.25532,766
21061.104.128.0/1761.104.128.1 to 61.104.255.25461.104.255.25532,766
21161.105.0.0/1761.105.0.1 to 61.105.127.25461.105.127.25532,766
21261.105.128.0/1761.105.128.1 to 61.105.255.25461.105.255.25532,766
21361.106.0.0/1761.106.0.1 to 61.106.127.25461.106.127.25532,766
21461.106.128.0/1761.106.128.1 to 61.106.255.25461.106.255.25532,766
21561.107.0.0/1761.107.0.1 to 61.107.127.25461.107.127.25532,766
21661.107.128.0/1761.107.128.1 to 61.107.255.25461.107.255.25532,766
21761.108.0.0/1761.108.0.1 to 61.108.127.25461.108.127.25532,766
21861.108.128.0/1761.108.128.1 to 61.108.255.25461.108.255.25532,766
21961.109.0.0/1761.109.0.1 to 61.109.127.25461.109.127.25532,766
22061.109.128.0/1761.109.128.1 to 61.109.255.25461.109.255.25532,766
22161.110.0.0/1761.110.0.1 to 61.110.127.25461.110.127.25532,766
22261.110.128.0/1761.110.128.1 to 61.110.255.25461.110.255.25532,766
22361.111.0.0/1761.111.0.1 to 61.111.127.25461.111.127.25532,766
22461.111.128.0/1761.111.128.1 to 61.111.255.25461.111.255.25532,766
22561.112.0.0/1761.112.0.1 to 61.112.127.25461.112.127.25532,766
22661.112.128.0/1761.112.128.1 to 61.112.255.25461.112.255.25532,766
22761.113.0.0/1761.113.0.1 to 61.113.127.25461.113.127.25532,766
22861.113.128.0/1761.113.128.1 to 61.113.255.25461.113.255.25532,766
22961.114.0.0/1761.114.0.1 to 61.114.127.25461.114.127.25532,766
23061.114.128.0/1761.114.128.1 to 61.114.255.25461.114.255.25532,766
23161.115.0.0/1761.115.0.1 to 61.115.127.25461.115.127.25532,766
23261.115.128.0/1761.115.128.1 to 61.115.255.25461.115.255.25532,766
23361.116.0.0/1761.116.0.1 to 61.116.127.25461.116.127.25532,766
23461.116.128.0/1761.116.128.1 to 61.116.255.25461.116.255.25532,766
23561.117.0.0/1761.117.0.1 to 61.117.127.25461.117.127.25532,766
23661.117.128.0/1761.117.128.1 to 61.117.255.25461.117.255.25532,766
23761.118.0.0/1761.118.0.1 to 61.118.127.25461.118.127.25532,766
23861.118.128.0/1761.118.128.1 to 61.118.255.25461.118.255.25532,766
23961.119.0.0/1761.119.0.1 to 61.119.127.25461.119.127.25532,766
24061.119.128.0/1761.119.128.1 to 61.119.255.25461.119.255.25532,766
24161.120.0.0/1761.120.0.1 to 61.120.127.25461.120.127.25532,766
24261.120.128.0/1761.120.128.1 to 61.120.255.25461.120.255.25532,766
24361.121.0.0/1761.121.0.1 to 61.121.127.25461.121.127.25532,766
24461.121.128.0/1761.121.128.1 to 61.121.255.25461.121.255.25532,766
24561.122.0.0/1761.122.0.1 to 61.122.127.25461.122.127.25532,766
24661.122.128.0/1761.122.128.1 to 61.122.255.25461.122.255.25532,766
24761.123.0.0/1761.123.0.1 to 61.123.127.25461.123.127.25532,766
24861.123.128.0/1761.123.128.1 to 61.123.255.25461.123.255.25532,766
24961.124.0.0/1761.124.0.1 to 61.124.127.25461.124.127.25532,766
25061.124.128.0/1761.124.128.1 to 61.124.255.25461.124.255.25532,766
25161.125.0.0/1761.125.0.1 to 61.125.127.25461.125.127.25532,766
25261.125.128.0/1761.125.128.1 to 61.125.255.25461.125.255.25532,766
25361.126.0.0/1761.126.0.1 to 61.126.127.25461.126.127.25532,766
25461.126.128.0/1761.126.128.1 to 61.126.255.25461.126.255.25532,766
25561.127.0.0/1761.127.0.1 to 61.127.127.25461.127.127.25532,766
25661.127.128.0/1761.127.128.1 to 61.127.255.25461.127.255.25532,766

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.