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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.

Network75.0.0.0/9
Usable hosts8,388,606
Subnet mask255.128.0.0
Addresses8,388,608
Network address
75.0.0.0
Broadcast address
75.127.255.255
First usable
75.0.0.1
Last usable
75.127.255.254
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 4B000000 · Integer 1258291200 to 1266679807
Reverse DNS zones
0.75.in-addr.arpa
1.75.in-addr.arpa
2.75.in-addr.arpa
3.75.in-addr.arpa
4.75.in-addr.arpa
5.75.in-addr.arpa
6.75.in-addr.arpa
7.75.in-addr.arpa
8.75.in-addr.arpa
9.75.in-addr.arpa
10.75.in-addr.arpa
11.75.in-addr.arpa
12.75.in-addr.arpa
13.75.in-addr.arpa
14.75.in-addr.arpa
15.75.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
Address01001011.00000000.00000000.0000000075.0.0.0
Subnet mask11111111.10000000.00000000.00000000255.128.0.0
Network01001011.00000000.00000000.0000000075.0.0.0
Broadcast01001011.01111111.11111111.1111111175.127.255.255
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)

75.0.0.0/9 makes 256 subnets of /17.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
175.0.0.0/1775.0.0.1 to 75.0.127.25475.0.127.25532,766
275.0.128.0/1775.0.128.1 to 75.0.255.25475.0.255.25532,766
375.1.0.0/1775.1.0.1 to 75.1.127.25475.1.127.25532,766
475.1.128.0/1775.1.128.1 to 75.1.255.25475.1.255.25532,766
575.2.0.0/1775.2.0.1 to 75.2.127.25475.2.127.25532,766
675.2.128.0/1775.2.128.1 to 75.2.255.25475.2.255.25532,766
775.3.0.0/1775.3.0.1 to 75.3.127.25475.3.127.25532,766
875.3.128.0/1775.3.128.1 to 75.3.255.25475.3.255.25532,766
975.4.0.0/1775.4.0.1 to 75.4.127.25475.4.127.25532,766
1075.4.128.0/1775.4.128.1 to 75.4.255.25475.4.255.25532,766
1175.5.0.0/1775.5.0.1 to 75.5.127.25475.5.127.25532,766
1275.5.128.0/1775.5.128.1 to 75.5.255.25475.5.255.25532,766
1375.6.0.0/1775.6.0.1 to 75.6.127.25475.6.127.25532,766
1475.6.128.0/1775.6.128.1 to 75.6.255.25475.6.255.25532,766
1575.7.0.0/1775.7.0.1 to 75.7.127.25475.7.127.25532,766
1675.7.128.0/1775.7.128.1 to 75.7.255.25475.7.255.25532,766
1775.8.0.0/1775.8.0.1 to 75.8.127.25475.8.127.25532,766
1875.8.128.0/1775.8.128.1 to 75.8.255.25475.8.255.25532,766
1975.9.0.0/1775.9.0.1 to 75.9.127.25475.9.127.25532,766
2075.9.128.0/1775.9.128.1 to 75.9.255.25475.9.255.25532,766
2175.10.0.0/1775.10.0.1 to 75.10.127.25475.10.127.25532,766
2275.10.128.0/1775.10.128.1 to 75.10.255.25475.10.255.25532,766
2375.11.0.0/1775.11.0.1 to 75.11.127.25475.11.127.25532,766
2475.11.128.0/1775.11.128.1 to 75.11.255.25475.11.255.25532,766
2575.12.0.0/1775.12.0.1 to 75.12.127.25475.12.127.25532,766
2675.12.128.0/1775.12.128.1 to 75.12.255.25475.12.255.25532,766
2775.13.0.0/1775.13.0.1 to 75.13.127.25475.13.127.25532,766
2875.13.128.0/1775.13.128.1 to 75.13.255.25475.13.255.25532,766
2975.14.0.0/1775.14.0.1 to 75.14.127.25475.14.127.25532,766
3075.14.128.0/1775.14.128.1 to 75.14.255.25475.14.255.25532,766
3175.15.0.0/1775.15.0.1 to 75.15.127.25475.15.127.25532,766
3275.15.128.0/1775.15.128.1 to 75.15.255.25475.15.255.25532,766
3375.16.0.0/1775.16.0.1 to 75.16.127.25475.16.127.25532,766
3475.16.128.0/1775.16.128.1 to 75.16.255.25475.16.255.25532,766
3575.17.0.0/1775.17.0.1 to 75.17.127.25475.17.127.25532,766
3675.17.128.0/1775.17.128.1 to 75.17.255.25475.17.255.25532,766
3775.18.0.0/1775.18.0.1 to 75.18.127.25475.18.127.25532,766
3875.18.128.0/1775.18.128.1 to 75.18.255.25475.18.255.25532,766
3975.19.0.0/1775.19.0.1 to 75.19.127.25475.19.127.25532,766
4075.19.128.0/1775.19.128.1 to 75.19.255.25475.19.255.25532,766
4175.20.0.0/1775.20.0.1 to 75.20.127.25475.20.127.25532,766
4275.20.128.0/1775.20.128.1 to 75.20.255.25475.20.255.25532,766
4375.21.0.0/1775.21.0.1 to 75.21.127.25475.21.127.25532,766
4475.21.128.0/1775.21.128.1 to 75.21.255.25475.21.255.25532,766
4575.22.0.0/1775.22.0.1 to 75.22.127.25475.22.127.25532,766
4675.22.128.0/1775.22.128.1 to 75.22.255.25475.22.255.25532,766
4775.23.0.0/1775.23.0.1 to 75.23.127.25475.23.127.25532,766
4875.23.128.0/1775.23.128.1 to 75.23.255.25475.23.255.25532,766
4975.24.0.0/1775.24.0.1 to 75.24.127.25475.24.127.25532,766
5075.24.128.0/1775.24.128.1 to 75.24.255.25475.24.255.25532,766
5175.25.0.0/1775.25.0.1 to 75.25.127.25475.25.127.25532,766
5275.25.128.0/1775.25.128.1 to 75.25.255.25475.25.255.25532,766
5375.26.0.0/1775.26.0.1 to 75.26.127.25475.26.127.25532,766
5475.26.128.0/1775.26.128.1 to 75.26.255.25475.26.255.25532,766
5575.27.0.0/1775.27.0.1 to 75.27.127.25475.27.127.25532,766
5675.27.128.0/1775.27.128.1 to 75.27.255.25475.27.255.25532,766
5775.28.0.0/1775.28.0.1 to 75.28.127.25475.28.127.25532,766
5875.28.128.0/1775.28.128.1 to 75.28.255.25475.28.255.25532,766
5975.29.0.0/1775.29.0.1 to 75.29.127.25475.29.127.25532,766
6075.29.128.0/1775.29.128.1 to 75.29.255.25475.29.255.25532,766
6175.30.0.0/1775.30.0.1 to 75.30.127.25475.30.127.25532,766
6275.30.128.0/1775.30.128.1 to 75.30.255.25475.30.255.25532,766
6375.31.0.0/1775.31.0.1 to 75.31.127.25475.31.127.25532,766
6475.31.128.0/1775.31.128.1 to 75.31.255.25475.31.255.25532,766
6575.32.0.0/1775.32.0.1 to 75.32.127.25475.32.127.25532,766
6675.32.128.0/1775.32.128.1 to 75.32.255.25475.32.255.25532,766
6775.33.0.0/1775.33.0.1 to 75.33.127.25475.33.127.25532,766
6875.33.128.0/1775.33.128.1 to 75.33.255.25475.33.255.25532,766
6975.34.0.0/1775.34.0.1 to 75.34.127.25475.34.127.25532,766
7075.34.128.0/1775.34.128.1 to 75.34.255.25475.34.255.25532,766
7175.35.0.0/1775.35.0.1 to 75.35.127.25475.35.127.25532,766
7275.35.128.0/1775.35.128.1 to 75.35.255.25475.35.255.25532,766
7375.36.0.0/1775.36.0.1 to 75.36.127.25475.36.127.25532,766
7475.36.128.0/1775.36.128.1 to 75.36.255.25475.36.255.25532,766
7575.37.0.0/1775.37.0.1 to 75.37.127.25475.37.127.25532,766
7675.37.128.0/1775.37.128.1 to 75.37.255.25475.37.255.25532,766
7775.38.0.0/1775.38.0.1 to 75.38.127.25475.38.127.25532,766
7875.38.128.0/1775.38.128.1 to 75.38.255.25475.38.255.25532,766
7975.39.0.0/1775.39.0.1 to 75.39.127.25475.39.127.25532,766
8075.39.128.0/1775.39.128.1 to 75.39.255.25475.39.255.25532,766
8175.40.0.0/1775.40.0.1 to 75.40.127.25475.40.127.25532,766
8275.40.128.0/1775.40.128.1 to 75.40.255.25475.40.255.25532,766
8375.41.0.0/1775.41.0.1 to 75.41.127.25475.41.127.25532,766
8475.41.128.0/1775.41.128.1 to 75.41.255.25475.41.255.25532,766
8575.42.0.0/1775.42.0.1 to 75.42.127.25475.42.127.25532,766
8675.42.128.0/1775.42.128.1 to 75.42.255.25475.42.255.25532,766
8775.43.0.0/1775.43.0.1 to 75.43.127.25475.43.127.25532,766
8875.43.128.0/1775.43.128.1 to 75.43.255.25475.43.255.25532,766
8975.44.0.0/1775.44.0.1 to 75.44.127.25475.44.127.25532,766
9075.44.128.0/1775.44.128.1 to 75.44.255.25475.44.255.25532,766
9175.45.0.0/1775.45.0.1 to 75.45.127.25475.45.127.25532,766
9275.45.128.0/1775.45.128.1 to 75.45.255.25475.45.255.25532,766
9375.46.0.0/1775.46.0.1 to 75.46.127.25475.46.127.25532,766
9475.46.128.0/1775.46.128.1 to 75.46.255.25475.46.255.25532,766
9575.47.0.0/1775.47.0.1 to 75.47.127.25475.47.127.25532,766
9675.47.128.0/1775.47.128.1 to 75.47.255.25475.47.255.25532,766
9775.48.0.0/1775.48.0.1 to 75.48.127.25475.48.127.25532,766
9875.48.128.0/1775.48.128.1 to 75.48.255.25475.48.255.25532,766
9975.49.0.0/1775.49.0.1 to 75.49.127.25475.49.127.25532,766
10075.49.128.0/1775.49.128.1 to 75.49.255.25475.49.255.25532,766
10175.50.0.0/1775.50.0.1 to 75.50.127.25475.50.127.25532,766
10275.50.128.0/1775.50.128.1 to 75.50.255.25475.50.255.25532,766
10375.51.0.0/1775.51.0.1 to 75.51.127.25475.51.127.25532,766
10475.51.128.0/1775.51.128.1 to 75.51.255.25475.51.255.25532,766
10575.52.0.0/1775.52.0.1 to 75.52.127.25475.52.127.25532,766
10675.52.128.0/1775.52.128.1 to 75.52.255.25475.52.255.25532,766
10775.53.0.0/1775.53.0.1 to 75.53.127.25475.53.127.25532,766
10875.53.128.0/1775.53.128.1 to 75.53.255.25475.53.255.25532,766
10975.54.0.0/1775.54.0.1 to 75.54.127.25475.54.127.25532,766
11075.54.128.0/1775.54.128.1 to 75.54.255.25475.54.255.25532,766
11175.55.0.0/1775.55.0.1 to 75.55.127.25475.55.127.25532,766
11275.55.128.0/1775.55.128.1 to 75.55.255.25475.55.255.25532,766
11375.56.0.0/1775.56.0.1 to 75.56.127.25475.56.127.25532,766
11475.56.128.0/1775.56.128.1 to 75.56.255.25475.56.255.25532,766
11575.57.0.0/1775.57.0.1 to 75.57.127.25475.57.127.25532,766
11675.57.128.0/1775.57.128.1 to 75.57.255.25475.57.255.25532,766
11775.58.0.0/1775.58.0.1 to 75.58.127.25475.58.127.25532,766
11875.58.128.0/1775.58.128.1 to 75.58.255.25475.58.255.25532,766
11975.59.0.0/1775.59.0.1 to 75.59.127.25475.59.127.25532,766
12075.59.128.0/1775.59.128.1 to 75.59.255.25475.59.255.25532,766
12175.60.0.0/1775.60.0.1 to 75.60.127.25475.60.127.25532,766
12275.60.128.0/1775.60.128.1 to 75.60.255.25475.60.255.25532,766
12375.61.0.0/1775.61.0.1 to 75.61.127.25475.61.127.25532,766
12475.61.128.0/1775.61.128.1 to 75.61.255.25475.61.255.25532,766
12575.62.0.0/1775.62.0.1 to 75.62.127.25475.62.127.25532,766
12675.62.128.0/1775.62.128.1 to 75.62.255.25475.62.255.25532,766
12775.63.0.0/1775.63.0.1 to 75.63.127.25475.63.127.25532,766
12875.63.128.0/1775.63.128.1 to 75.63.255.25475.63.255.25532,766
12975.64.0.0/1775.64.0.1 to 75.64.127.25475.64.127.25532,766
13075.64.128.0/1775.64.128.1 to 75.64.255.25475.64.255.25532,766
13175.65.0.0/1775.65.0.1 to 75.65.127.25475.65.127.25532,766
13275.65.128.0/1775.65.128.1 to 75.65.255.25475.65.255.25532,766
13375.66.0.0/1775.66.0.1 to 75.66.127.25475.66.127.25532,766
13475.66.128.0/1775.66.128.1 to 75.66.255.25475.66.255.25532,766
13575.67.0.0/1775.67.0.1 to 75.67.127.25475.67.127.25532,766
13675.67.128.0/1775.67.128.1 to 75.67.255.25475.67.255.25532,766
13775.68.0.0/1775.68.0.1 to 75.68.127.25475.68.127.25532,766
13875.68.128.0/1775.68.128.1 to 75.68.255.25475.68.255.25532,766
13975.69.0.0/1775.69.0.1 to 75.69.127.25475.69.127.25532,766
14075.69.128.0/1775.69.128.1 to 75.69.255.25475.69.255.25532,766
14175.70.0.0/1775.70.0.1 to 75.70.127.25475.70.127.25532,766
14275.70.128.0/1775.70.128.1 to 75.70.255.25475.70.255.25532,766
14375.71.0.0/1775.71.0.1 to 75.71.127.25475.71.127.25532,766
14475.71.128.0/1775.71.128.1 to 75.71.255.25475.71.255.25532,766
14575.72.0.0/1775.72.0.1 to 75.72.127.25475.72.127.25532,766
14675.72.128.0/1775.72.128.1 to 75.72.255.25475.72.255.25532,766
14775.73.0.0/1775.73.0.1 to 75.73.127.25475.73.127.25532,766
14875.73.128.0/1775.73.128.1 to 75.73.255.25475.73.255.25532,766
14975.74.0.0/1775.74.0.1 to 75.74.127.25475.74.127.25532,766
15075.74.128.0/1775.74.128.1 to 75.74.255.25475.74.255.25532,766
15175.75.0.0/1775.75.0.1 to 75.75.127.25475.75.127.25532,766
15275.75.128.0/1775.75.128.1 to 75.75.255.25475.75.255.25532,766
15375.76.0.0/1775.76.0.1 to 75.76.127.25475.76.127.25532,766
15475.76.128.0/1775.76.128.1 to 75.76.255.25475.76.255.25532,766
15575.77.0.0/1775.77.0.1 to 75.77.127.25475.77.127.25532,766
15675.77.128.0/1775.77.128.1 to 75.77.255.25475.77.255.25532,766
15775.78.0.0/1775.78.0.1 to 75.78.127.25475.78.127.25532,766
15875.78.128.0/1775.78.128.1 to 75.78.255.25475.78.255.25532,766
15975.79.0.0/1775.79.0.1 to 75.79.127.25475.79.127.25532,766
16075.79.128.0/1775.79.128.1 to 75.79.255.25475.79.255.25532,766
16175.80.0.0/1775.80.0.1 to 75.80.127.25475.80.127.25532,766
16275.80.128.0/1775.80.128.1 to 75.80.255.25475.80.255.25532,766
16375.81.0.0/1775.81.0.1 to 75.81.127.25475.81.127.25532,766
16475.81.128.0/1775.81.128.1 to 75.81.255.25475.81.255.25532,766
16575.82.0.0/1775.82.0.1 to 75.82.127.25475.82.127.25532,766
16675.82.128.0/1775.82.128.1 to 75.82.255.25475.82.255.25532,766
16775.83.0.0/1775.83.0.1 to 75.83.127.25475.83.127.25532,766
16875.83.128.0/1775.83.128.1 to 75.83.255.25475.83.255.25532,766
16975.84.0.0/1775.84.0.1 to 75.84.127.25475.84.127.25532,766
17075.84.128.0/1775.84.128.1 to 75.84.255.25475.84.255.25532,766
17175.85.0.0/1775.85.0.1 to 75.85.127.25475.85.127.25532,766
17275.85.128.0/1775.85.128.1 to 75.85.255.25475.85.255.25532,766
17375.86.0.0/1775.86.0.1 to 75.86.127.25475.86.127.25532,766
17475.86.128.0/1775.86.128.1 to 75.86.255.25475.86.255.25532,766
17575.87.0.0/1775.87.0.1 to 75.87.127.25475.87.127.25532,766
17675.87.128.0/1775.87.128.1 to 75.87.255.25475.87.255.25532,766
17775.88.0.0/1775.88.0.1 to 75.88.127.25475.88.127.25532,766
17875.88.128.0/1775.88.128.1 to 75.88.255.25475.88.255.25532,766
17975.89.0.0/1775.89.0.1 to 75.89.127.25475.89.127.25532,766
18075.89.128.0/1775.89.128.1 to 75.89.255.25475.89.255.25532,766
18175.90.0.0/1775.90.0.1 to 75.90.127.25475.90.127.25532,766
18275.90.128.0/1775.90.128.1 to 75.90.255.25475.90.255.25532,766
18375.91.0.0/1775.91.0.1 to 75.91.127.25475.91.127.25532,766
18475.91.128.0/1775.91.128.1 to 75.91.255.25475.91.255.25532,766
18575.92.0.0/1775.92.0.1 to 75.92.127.25475.92.127.25532,766
18675.92.128.0/1775.92.128.1 to 75.92.255.25475.92.255.25532,766
18775.93.0.0/1775.93.0.1 to 75.93.127.25475.93.127.25532,766
18875.93.128.0/1775.93.128.1 to 75.93.255.25475.93.255.25532,766
18975.94.0.0/1775.94.0.1 to 75.94.127.25475.94.127.25532,766
19075.94.128.0/1775.94.128.1 to 75.94.255.25475.94.255.25532,766
19175.95.0.0/1775.95.0.1 to 75.95.127.25475.95.127.25532,766
19275.95.128.0/1775.95.128.1 to 75.95.255.25475.95.255.25532,766
19375.96.0.0/1775.96.0.1 to 75.96.127.25475.96.127.25532,766
19475.96.128.0/1775.96.128.1 to 75.96.255.25475.96.255.25532,766
19575.97.0.0/1775.97.0.1 to 75.97.127.25475.97.127.25532,766
19675.97.128.0/1775.97.128.1 to 75.97.255.25475.97.255.25532,766
19775.98.0.0/1775.98.0.1 to 75.98.127.25475.98.127.25532,766
19875.98.128.0/1775.98.128.1 to 75.98.255.25475.98.255.25532,766
19975.99.0.0/1775.99.0.1 to 75.99.127.25475.99.127.25532,766
20075.99.128.0/1775.99.128.1 to 75.99.255.25475.99.255.25532,766
20175.100.0.0/1775.100.0.1 to 75.100.127.25475.100.127.25532,766
20275.100.128.0/1775.100.128.1 to 75.100.255.25475.100.255.25532,766
20375.101.0.0/1775.101.0.1 to 75.101.127.25475.101.127.25532,766
20475.101.128.0/1775.101.128.1 to 75.101.255.25475.101.255.25532,766
20575.102.0.0/1775.102.0.1 to 75.102.127.25475.102.127.25532,766
20675.102.128.0/1775.102.128.1 to 75.102.255.25475.102.255.25532,766
20775.103.0.0/1775.103.0.1 to 75.103.127.25475.103.127.25532,766
20875.103.128.0/1775.103.128.1 to 75.103.255.25475.103.255.25532,766
20975.104.0.0/1775.104.0.1 to 75.104.127.25475.104.127.25532,766
21075.104.128.0/1775.104.128.1 to 75.104.255.25475.104.255.25532,766
21175.105.0.0/1775.105.0.1 to 75.105.127.25475.105.127.25532,766
21275.105.128.0/1775.105.128.1 to 75.105.255.25475.105.255.25532,766
21375.106.0.0/1775.106.0.1 to 75.106.127.25475.106.127.25532,766
21475.106.128.0/1775.106.128.1 to 75.106.255.25475.106.255.25532,766
21575.107.0.0/1775.107.0.1 to 75.107.127.25475.107.127.25532,766
21675.107.128.0/1775.107.128.1 to 75.107.255.25475.107.255.25532,766
21775.108.0.0/1775.108.0.1 to 75.108.127.25475.108.127.25532,766
21875.108.128.0/1775.108.128.1 to 75.108.255.25475.108.255.25532,766
21975.109.0.0/1775.109.0.1 to 75.109.127.25475.109.127.25532,766
22075.109.128.0/1775.109.128.1 to 75.109.255.25475.109.255.25532,766
22175.110.0.0/1775.110.0.1 to 75.110.127.25475.110.127.25532,766
22275.110.128.0/1775.110.128.1 to 75.110.255.25475.110.255.25532,766
22375.111.0.0/1775.111.0.1 to 75.111.127.25475.111.127.25532,766
22475.111.128.0/1775.111.128.1 to 75.111.255.25475.111.255.25532,766
22575.112.0.0/1775.112.0.1 to 75.112.127.25475.112.127.25532,766
22675.112.128.0/1775.112.128.1 to 75.112.255.25475.112.255.25532,766
22775.113.0.0/1775.113.0.1 to 75.113.127.25475.113.127.25532,766
22875.113.128.0/1775.113.128.1 to 75.113.255.25475.113.255.25532,766
22975.114.0.0/1775.114.0.1 to 75.114.127.25475.114.127.25532,766
23075.114.128.0/1775.114.128.1 to 75.114.255.25475.114.255.25532,766
23175.115.0.0/1775.115.0.1 to 75.115.127.25475.115.127.25532,766
23275.115.128.0/1775.115.128.1 to 75.115.255.25475.115.255.25532,766
23375.116.0.0/1775.116.0.1 to 75.116.127.25475.116.127.25532,766
23475.116.128.0/1775.116.128.1 to 75.116.255.25475.116.255.25532,766
23575.117.0.0/1775.117.0.1 to 75.117.127.25475.117.127.25532,766
23675.117.128.0/1775.117.128.1 to 75.117.255.25475.117.255.25532,766
23775.118.0.0/1775.118.0.1 to 75.118.127.25475.118.127.25532,766
23875.118.128.0/1775.118.128.1 to 75.118.255.25475.118.255.25532,766
23975.119.0.0/1775.119.0.1 to 75.119.127.25475.119.127.25532,766
24075.119.128.0/1775.119.128.1 to 75.119.255.25475.119.255.25532,766
24175.120.0.0/1775.120.0.1 to 75.120.127.25475.120.127.25532,766
24275.120.128.0/1775.120.128.1 to 75.120.255.25475.120.255.25532,766
24375.121.0.0/1775.121.0.1 to 75.121.127.25475.121.127.25532,766
24475.121.128.0/1775.121.128.1 to 75.121.255.25475.121.255.25532,766
24575.122.0.0/1775.122.0.1 to 75.122.127.25475.122.127.25532,766
24675.122.128.0/1775.122.128.1 to 75.122.255.25475.122.255.25532,766
24775.123.0.0/1775.123.0.1 to 75.123.127.25475.123.127.25532,766
24875.123.128.0/1775.123.128.1 to 75.123.255.25475.123.255.25532,766
24975.124.0.0/1775.124.0.1 to 75.124.127.25475.124.127.25532,766
25075.124.128.0/1775.124.128.1 to 75.124.255.25475.124.255.25532,766
25175.125.0.0/1775.125.0.1 to 75.125.127.25475.125.127.25532,766
25275.125.128.0/1775.125.128.1 to 75.125.255.25475.125.255.25532,766
25375.126.0.0/1775.126.0.1 to 75.126.127.25475.126.127.25532,766
25475.126.128.0/1775.126.128.1 to 75.126.255.25475.126.255.25532,766
25575.127.0.0/1775.127.0.1 to 75.127.127.25475.127.127.25532,766
25675.127.128.0/1775.127.128.1 to 75.127.255.25475.127.255.25532,766

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.