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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.

Network180.0.0.0/7
Usable hosts33,554,430
Subnet mask254.0.0.0
Addresses33,554,432
Network address
180.0.0.0
Broadcast address
181.255.255.255
First usable
180.0.0.1
Last usable
181.255.255.254
Usable hosts
33,554,430 (33,554,432 less the network and broadcast addresses)
Subnet mask
254.0.0.0
Wildcard mask
1.255.255.255 (Cisco ACLs, OSPF)
Prefix length
/7
Type
Public public
Old class
B (default /16)
As numbers
Hex B4000000 · Integer 3019898880 to 3053453311
Reverse DNS zones
180.in-addr.arpa
181.in-addr.arpa
/7 is not on a 8-bit boundary, so it takes 2 /8 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address10110100.00000000.00000000.00000000180.0.0.0
Subnet mask11111110.00000000.00000000.00000000254.0.0.0
Network10110100.00000000.00000000.00000000180.0.0.0
Broadcast10110101.11111111.11111111.11111111181.255.255.255
Split into smaller subnets/17
/8 (2)/9 (4)/10 (8)/11 (16)/12 (32)/13 (64)/14 (128)/15 (256)/16 (512)/17 (1,024)/18 (2,048)/19 (4,096)

180.0.0.0/7 makes 1,024 subnets of /17; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1180.0.0.0/17180.0.0.1 to 180.0.127.254180.0.127.25532,766
2180.0.128.0/17180.0.128.1 to 180.0.255.254180.0.255.25532,766
3180.1.0.0/17180.1.0.1 to 180.1.127.254180.1.127.25532,766
4180.1.128.0/17180.1.128.1 to 180.1.255.254180.1.255.25532,766
5180.2.0.0/17180.2.0.1 to 180.2.127.254180.2.127.25532,766
6180.2.128.0/17180.2.128.1 to 180.2.255.254180.2.255.25532,766
7180.3.0.0/17180.3.0.1 to 180.3.127.254180.3.127.25532,766
8180.3.128.0/17180.3.128.1 to 180.3.255.254180.3.255.25532,766
9180.4.0.0/17180.4.0.1 to 180.4.127.254180.4.127.25532,766
10180.4.128.0/17180.4.128.1 to 180.4.255.254180.4.255.25532,766
11180.5.0.0/17180.5.0.1 to 180.5.127.254180.5.127.25532,766
12180.5.128.0/17180.5.128.1 to 180.5.255.254180.5.255.25532,766
13180.6.0.0/17180.6.0.1 to 180.6.127.254180.6.127.25532,766
14180.6.128.0/17180.6.128.1 to 180.6.255.254180.6.255.25532,766
15180.7.0.0/17180.7.0.1 to 180.7.127.254180.7.127.25532,766
16180.7.128.0/17180.7.128.1 to 180.7.255.254180.7.255.25532,766
17180.8.0.0/17180.8.0.1 to 180.8.127.254180.8.127.25532,766
18180.8.128.0/17180.8.128.1 to 180.8.255.254180.8.255.25532,766
19180.9.0.0/17180.9.0.1 to 180.9.127.254180.9.127.25532,766
20180.9.128.0/17180.9.128.1 to 180.9.255.254180.9.255.25532,766
21180.10.0.0/17180.10.0.1 to 180.10.127.254180.10.127.25532,766
22180.10.128.0/17180.10.128.1 to 180.10.255.254180.10.255.25532,766
23180.11.0.0/17180.11.0.1 to 180.11.127.254180.11.127.25532,766
24180.11.128.0/17180.11.128.1 to 180.11.255.254180.11.255.25532,766
25180.12.0.0/17180.12.0.1 to 180.12.127.254180.12.127.25532,766
26180.12.128.0/17180.12.128.1 to 180.12.255.254180.12.255.25532,766
27180.13.0.0/17180.13.0.1 to 180.13.127.254180.13.127.25532,766
28180.13.128.0/17180.13.128.1 to 180.13.255.254180.13.255.25532,766
29180.14.0.0/17180.14.0.1 to 180.14.127.254180.14.127.25532,766
30180.14.128.0/17180.14.128.1 to 180.14.255.254180.14.255.25532,766
31180.15.0.0/17180.15.0.1 to 180.15.127.254180.15.127.25532,766
32180.15.128.0/17180.15.128.1 to 180.15.255.254180.15.255.25532,766
33180.16.0.0/17180.16.0.1 to 180.16.127.254180.16.127.25532,766
34180.16.128.0/17180.16.128.1 to 180.16.255.254180.16.255.25532,766
35180.17.0.0/17180.17.0.1 to 180.17.127.254180.17.127.25532,766
36180.17.128.0/17180.17.128.1 to 180.17.255.254180.17.255.25532,766
37180.18.0.0/17180.18.0.1 to 180.18.127.254180.18.127.25532,766
38180.18.128.0/17180.18.128.1 to 180.18.255.254180.18.255.25532,766
39180.19.0.0/17180.19.0.1 to 180.19.127.254180.19.127.25532,766
40180.19.128.0/17180.19.128.1 to 180.19.255.254180.19.255.25532,766
41180.20.0.0/17180.20.0.1 to 180.20.127.254180.20.127.25532,766
42180.20.128.0/17180.20.128.1 to 180.20.255.254180.20.255.25532,766
43180.21.0.0/17180.21.0.1 to 180.21.127.254180.21.127.25532,766
44180.21.128.0/17180.21.128.1 to 180.21.255.254180.21.255.25532,766
45180.22.0.0/17180.22.0.1 to 180.22.127.254180.22.127.25532,766
46180.22.128.0/17180.22.128.1 to 180.22.255.254180.22.255.25532,766
47180.23.0.0/17180.23.0.1 to 180.23.127.254180.23.127.25532,766
48180.23.128.0/17180.23.128.1 to 180.23.255.254180.23.255.25532,766
49180.24.0.0/17180.24.0.1 to 180.24.127.254180.24.127.25532,766
50180.24.128.0/17180.24.128.1 to 180.24.255.254180.24.255.25532,766
51180.25.0.0/17180.25.0.1 to 180.25.127.254180.25.127.25532,766
52180.25.128.0/17180.25.128.1 to 180.25.255.254180.25.255.25532,766
53180.26.0.0/17180.26.0.1 to 180.26.127.254180.26.127.25532,766
54180.26.128.0/17180.26.128.1 to 180.26.255.254180.26.255.25532,766
55180.27.0.0/17180.27.0.1 to 180.27.127.254180.27.127.25532,766
56180.27.128.0/17180.27.128.1 to 180.27.255.254180.27.255.25532,766
57180.28.0.0/17180.28.0.1 to 180.28.127.254180.28.127.25532,766
58180.28.128.0/17180.28.128.1 to 180.28.255.254180.28.255.25532,766
59180.29.0.0/17180.29.0.1 to 180.29.127.254180.29.127.25532,766
60180.29.128.0/17180.29.128.1 to 180.29.255.254180.29.255.25532,766
61180.30.0.0/17180.30.0.1 to 180.30.127.254180.30.127.25532,766
62180.30.128.0/17180.30.128.1 to 180.30.255.254180.30.255.25532,766
63180.31.0.0/17180.31.0.1 to 180.31.127.254180.31.127.25532,766
64180.31.128.0/17180.31.128.1 to 180.31.255.254180.31.255.25532,766
65180.32.0.0/17180.32.0.1 to 180.32.127.254180.32.127.25532,766
66180.32.128.0/17180.32.128.1 to 180.32.255.254180.32.255.25532,766
67180.33.0.0/17180.33.0.1 to 180.33.127.254180.33.127.25532,766
68180.33.128.0/17180.33.128.1 to 180.33.255.254180.33.255.25532,766
69180.34.0.0/17180.34.0.1 to 180.34.127.254180.34.127.25532,766
70180.34.128.0/17180.34.128.1 to 180.34.255.254180.34.255.25532,766
71180.35.0.0/17180.35.0.1 to 180.35.127.254180.35.127.25532,766
72180.35.128.0/17180.35.128.1 to 180.35.255.254180.35.255.25532,766
73180.36.0.0/17180.36.0.1 to 180.36.127.254180.36.127.25532,766
74180.36.128.0/17180.36.128.1 to 180.36.255.254180.36.255.25532,766
75180.37.0.0/17180.37.0.1 to 180.37.127.254180.37.127.25532,766
76180.37.128.0/17180.37.128.1 to 180.37.255.254180.37.255.25532,766
77180.38.0.0/17180.38.0.1 to 180.38.127.254180.38.127.25532,766
78180.38.128.0/17180.38.128.1 to 180.38.255.254180.38.255.25532,766
79180.39.0.0/17180.39.0.1 to 180.39.127.254180.39.127.25532,766
80180.39.128.0/17180.39.128.1 to 180.39.255.254180.39.255.25532,766
81180.40.0.0/17180.40.0.1 to 180.40.127.254180.40.127.25532,766
82180.40.128.0/17180.40.128.1 to 180.40.255.254180.40.255.25532,766
83180.41.0.0/17180.41.0.1 to 180.41.127.254180.41.127.25532,766
84180.41.128.0/17180.41.128.1 to 180.41.255.254180.41.255.25532,766
85180.42.0.0/17180.42.0.1 to 180.42.127.254180.42.127.25532,766
86180.42.128.0/17180.42.128.1 to 180.42.255.254180.42.255.25532,766
87180.43.0.0/17180.43.0.1 to 180.43.127.254180.43.127.25532,766
88180.43.128.0/17180.43.128.1 to 180.43.255.254180.43.255.25532,766
89180.44.0.0/17180.44.0.1 to 180.44.127.254180.44.127.25532,766
90180.44.128.0/17180.44.128.1 to 180.44.255.254180.44.255.25532,766
91180.45.0.0/17180.45.0.1 to 180.45.127.254180.45.127.25532,766
92180.45.128.0/17180.45.128.1 to 180.45.255.254180.45.255.25532,766
93180.46.0.0/17180.46.0.1 to 180.46.127.254180.46.127.25532,766
94180.46.128.0/17180.46.128.1 to 180.46.255.254180.46.255.25532,766
95180.47.0.0/17180.47.0.1 to 180.47.127.254180.47.127.25532,766
96180.47.128.0/17180.47.128.1 to 180.47.255.254180.47.255.25532,766
97180.48.0.0/17180.48.0.1 to 180.48.127.254180.48.127.25532,766
98180.48.128.0/17180.48.128.1 to 180.48.255.254180.48.255.25532,766
99180.49.0.0/17180.49.0.1 to 180.49.127.254180.49.127.25532,766
100180.49.128.0/17180.49.128.1 to 180.49.255.254180.49.255.25532,766
101180.50.0.0/17180.50.0.1 to 180.50.127.254180.50.127.25532,766
102180.50.128.0/17180.50.128.1 to 180.50.255.254180.50.255.25532,766
103180.51.0.0/17180.51.0.1 to 180.51.127.254180.51.127.25532,766
104180.51.128.0/17180.51.128.1 to 180.51.255.254180.51.255.25532,766
105180.52.0.0/17180.52.0.1 to 180.52.127.254180.52.127.25532,766
106180.52.128.0/17180.52.128.1 to 180.52.255.254180.52.255.25532,766
107180.53.0.0/17180.53.0.1 to 180.53.127.254180.53.127.25532,766
108180.53.128.0/17180.53.128.1 to 180.53.255.254180.53.255.25532,766
109180.54.0.0/17180.54.0.1 to 180.54.127.254180.54.127.25532,766
110180.54.128.0/17180.54.128.1 to 180.54.255.254180.54.255.25532,766
111180.55.0.0/17180.55.0.1 to 180.55.127.254180.55.127.25532,766
112180.55.128.0/17180.55.128.1 to 180.55.255.254180.55.255.25532,766
113180.56.0.0/17180.56.0.1 to 180.56.127.254180.56.127.25532,766
114180.56.128.0/17180.56.128.1 to 180.56.255.254180.56.255.25532,766
115180.57.0.0/17180.57.0.1 to 180.57.127.254180.57.127.25532,766
116180.57.128.0/17180.57.128.1 to 180.57.255.254180.57.255.25532,766
117180.58.0.0/17180.58.0.1 to 180.58.127.254180.58.127.25532,766
118180.58.128.0/17180.58.128.1 to 180.58.255.254180.58.255.25532,766
119180.59.0.0/17180.59.0.1 to 180.59.127.254180.59.127.25532,766
120180.59.128.0/17180.59.128.1 to 180.59.255.254180.59.255.25532,766
121180.60.0.0/17180.60.0.1 to 180.60.127.254180.60.127.25532,766
122180.60.128.0/17180.60.128.1 to 180.60.255.254180.60.255.25532,766
123180.61.0.0/17180.61.0.1 to 180.61.127.254180.61.127.25532,766
124180.61.128.0/17180.61.128.1 to 180.61.255.254180.61.255.25532,766
125180.62.0.0/17180.62.0.1 to 180.62.127.254180.62.127.25532,766
126180.62.128.0/17180.62.128.1 to 180.62.255.254180.62.255.25532,766
127180.63.0.0/17180.63.0.1 to 180.63.127.254180.63.127.25532,766
128180.63.128.0/17180.63.128.1 to 180.63.255.254180.63.255.25532,766
129180.64.0.0/17180.64.0.1 to 180.64.127.254180.64.127.25532,766
130180.64.128.0/17180.64.128.1 to 180.64.255.254180.64.255.25532,766
131180.65.0.0/17180.65.0.1 to 180.65.127.254180.65.127.25532,766
132180.65.128.0/17180.65.128.1 to 180.65.255.254180.65.255.25532,766
133180.66.0.0/17180.66.0.1 to 180.66.127.254180.66.127.25532,766
134180.66.128.0/17180.66.128.1 to 180.66.255.254180.66.255.25532,766
135180.67.0.0/17180.67.0.1 to 180.67.127.254180.67.127.25532,766
136180.67.128.0/17180.67.128.1 to 180.67.255.254180.67.255.25532,766
137180.68.0.0/17180.68.0.1 to 180.68.127.254180.68.127.25532,766
138180.68.128.0/17180.68.128.1 to 180.68.255.254180.68.255.25532,766
139180.69.0.0/17180.69.0.1 to 180.69.127.254180.69.127.25532,766
140180.69.128.0/17180.69.128.1 to 180.69.255.254180.69.255.25532,766
141180.70.0.0/17180.70.0.1 to 180.70.127.254180.70.127.25532,766
142180.70.128.0/17180.70.128.1 to 180.70.255.254180.70.255.25532,766
143180.71.0.0/17180.71.0.1 to 180.71.127.254180.71.127.25532,766
144180.71.128.0/17180.71.128.1 to 180.71.255.254180.71.255.25532,766
145180.72.0.0/17180.72.0.1 to 180.72.127.254180.72.127.25532,766
146180.72.128.0/17180.72.128.1 to 180.72.255.254180.72.255.25532,766
147180.73.0.0/17180.73.0.1 to 180.73.127.254180.73.127.25532,766
148180.73.128.0/17180.73.128.1 to 180.73.255.254180.73.255.25532,766
149180.74.0.0/17180.74.0.1 to 180.74.127.254180.74.127.25532,766
150180.74.128.0/17180.74.128.1 to 180.74.255.254180.74.255.25532,766
151180.75.0.0/17180.75.0.1 to 180.75.127.254180.75.127.25532,766
152180.75.128.0/17180.75.128.1 to 180.75.255.254180.75.255.25532,766
153180.76.0.0/17180.76.0.1 to 180.76.127.254180.76.127.25532,766
154180.76.128.0/17180.76.128.1 to 180.76.255.254180.76.255.25532,766
155180.77.0.0/17180.77.0.1 to 180.77.127.254180.77.127.25532,766
156180.77.128.0/17180.77.128.1 to 180.77.255.254180.77.255.25532,766
157180.78.0.0/17180.78.0.1 to 180.78.127.254180.78.127.25532,766
158180.78.128.0/17180.78.128.1 to 180.78.255.254180.78.255.25532,766
159180.79.0.0/17180.79.0.1 to 180.79.127.254180.79.127.25532,766
160180.79.128.0/17180.79.128.1 to 180.79.255.254180.79.255.25532,766
161180.80.0.0/17180.80.0.1 to 180.80.127.254180.80.127.25532,766
162180.80.128.0/17180.80.128.1 to 180.80.255.254180.80.255.25532,766
163180.81.0.0/17180.81.0.1 to 180.81.127.254180.81.127.25532,766
164180.81.128.0/17180.81.128.1 to 180.81.255.254180.81.255.25532,766
165180.82.0.0/17180.82.0.1 to 180.82.127.254180.82.127.25532,766
166180.82.128.0/17180.82.128.1 to 180.82.255.254180.82.255.25532,766
167180.83.0.0/17180.83.0.1 to 180.83.127.254180.83.127.25532,766
168180.83.128.0/17180.83.128.1 to 180.83.255.254180.83.255.25532,766
169180.84.0.0/17180.84.0.1 to 180.84.127.254180.84.127.25532,766
170180.84.128.0/17180.84.128.1 to 180.84.255.254180.84.255.25532,766
171180.85.0.0/17180.85.0.1 to 180.85.127.254180.85.127.25532,766
172180.85.128.0/17180.85.128.1 to 180.85.255.254180.85.255.25532,766
173180.86.0.0/17180.86.0.1 to 180.86.127.254180.86.127.25532,766
174180.86.128.0/17180.86.128.1 to 180.86.255.254180.86.255.25532,766
175180.87.0.0/17180.87.0.1 to 180.87.127.254180.87.127.25532,766
176180.87.128.0/17180.87.128.1 to 180.87.255.254180.87.255.25532,766
177180.88.0.0/17180.88.0.1 to 180.88.127.254180.88.127.25532,766
178180.88.128.0/17180.88.128.1 to 180.88.255.254180.88.255.25532,766
179180.89.0.0/17180.89.0.1 to 180.89.127.254180.89.127.25532,766
180180.89.128.0/17180.89.128.1 to 180.89.255.254180.89.255.25532,766
181180.90.0.0/17180.90.0.1 to 180.90.127.254180.90.127.25532,766
182180.90.128.0/17180.90.128.1 to 180.90.255.254180.90.255.25532,766
183180.91.0.0/17180.91.0.1 to 180.91.127.254180.91.127.25532,766
184180.91.128.0/17180.91.128.1 to 180.91.255.254180.91.255.25532,766
185180.92.0.0/17180.92.0.1 to 180.92.127.254180.92.127.25532,766
186180.92.128.0/17180.92.128.1 to 180.92.255.254180.92.255.25532,766
187180.93.0.0/17180.93.0.1 to 180.93.127.254180.93.127.25532,766
188180.93.128.0/17180.93.128.1 to 180.93.255.254180.93.255.25532,766
189180.94.0.0/17180.94.0.1 to 180.94.127.254180.94.127.25532,766
190180.94.128.0/17180.94.128.1 to 180.94.255.254180.94.255.25532,766
191180.95.0.0/17180.95.0.1 to 180.95.127.254180.95.127.25532,766
192180.95.128.0/17180.95.128.1 to 180.95.255.254180.95.255.25532,766
193180.96.0.0/17180.96.0.1 to 180.96.127.254180.96.127.25532,766
194180.96.128.0/17180.96.128.1 to 180.96.255.254180.96.255.25532,766
195180.97.0.0/17180.97.0.1 to 180.97.127.254180.97.127.25532,766
196180.97.128.0/17180.97.128.1 to 180.97.255.254180.97.255.25532,766
197180.98.0.0/17180.98.0.1 to 180.98.127.254180.98.127.25532,766
198180.98.128.0/17180.98.128.1 to 180.98.255.254180.98.255.25532,766
199180.99.0.0/17180.99.0.1 to 180.99.127.254180.99.127.25532,766
200180.99.128.0/17180.99.128.1 to 180.99.255.254180.99.255.25532,766
201180.100.0.0/17180.100.0.1 to 180.100.127.254180.100.127.25532,766
202180.100.128.0/17180.100.128.1 to 180.100.255.254180.100.255.25532,766
203180.101.0.0/17180.101.0.1 to 180.101.127.254180.101.127.25532,766
204180.101.128.0/17180.101.128.1 to 180.101.255.254180.101.255.25532,766
205180.102.0.0/17180.102.0.1 to 180.102.127.254180.102.127.25532,766
206180.102.128.0/17180.102.128.1 to 180.102.255.254180.102.255.25532,766
207180.103.0.0/17180.103.0.1 to 180.103.127.254180.103.127.25532,766
208180.103.128.0/17180.103.128.1 to 180.103.255.254180.103.255.25532,766
209180.104.0.0/17180.104.0.1 to 180.104.127.254180.104.127.25532,766
210180.104.128.0/17180.104.128.1 to 180.104.255.254180.104.255.25532,766
211180.105.0.0/17180.105.0.1 to 180.105.127.254180.105.127.25532,766
212180.105.128.0/17180.105.128.1 to 180.105.255.254180.105.255.25532,766
213180.106.0.0/17180.106.0.1 to 180.106.127.254180.106.127.25532,766
214180.106.128.0/17180.106.128.1 to 180.106.255.254180.106.255.25532,766
215180.107.0.0/17180.107.0.1 to 180.107.127.254180.107.127.25532,766
216180.107.128.0/17180.107.128.1 to 180.107.255.254180.107.255.25532,766
217180.108.0.0/17180.108.0.1 to 180.108.127.254180.108.127.25532,766
218180.108.128.0/17180.108.128.1 to 180.108.255.254180.108.255.25532,766
219180.109.0.0/17180.109.0.1 to 180.109.127.254180.109.127.25532,766
220180.109.128.0/17180.109.128.1 to 180.109.255.254180.109.255.25532,766
221180.110.0.0/17180.110.0.1 to 180.110.127.254180.110.127.25532,766
222180.110.128.0/17180.110.128.1 to 180.110.255.254180.110.255.25532,766
223180.111.0.0/17180.111.0.1 to 180.111.127.254180.111.127.25532,766
224180.111.128.0/17180.111.128.1 to 180.111.255.254180.111.255.25532,766
225180.112.0.0/17180.112.0.1 to 180.112.127.254180.112.127.25532,766
226180.112.128.0/17180.112.128.1 to 180.112.255.254180.112.255.25532,766
227180.113.0.0/17180.113.0.1 to 180.113.127.254180.113.127.25532,766
228180.113.128.0/17180.113.128.1 to 180.113.255.254180.113.255.25532,766
229180.114.0.0/17180.114.0.1 to 180.114.127.254180.114.127.25532,766
230180.114.128.0/17180.114.128.1 to 180.114.255.254180.114.255.25532,766
231180.115.0.0/17180.115.0.1 to 180.115.127.254180.115.127.25532,766
232180.115.128.0/17180.115.128.1 to 180.115.255.254180.115.255.25532,766
233180.116.0.0/17180.116.0.1 to 180.116.127.254180.116.127.25532,766
234180.116.128.0/17180.116.128.1 to 180.116.255.254180.116.255.25532,766
235180.117.0.0/17180.117.0.1 to 180.117.127.254180.117.127.25532,766
236180.117.128.0/17180.117.128.1 to 180.117.255.254180.117.255.25532,766
237180.118.0.0/17180.118.0.1 to 180.118.127.254180.118.127.25532,766
238180.118.128.0/17180.118.128.1 to 180.118.255.254180.118.255.25532,766
239180.119.0.0/17180.119.0.1 to 180.119.127.254180.119.127.25532,766
240180.119.128.0/17180.119.128.1 to 180.119.255.254180.119.255.25532,766
241180.120.0.0/17180.120.0.1 to 180.120.127.254180.120.127.25532,766
242180.120.128.0/17180.120.128.1 to 180.120.255.254180.120.255.25532,766
243180.121.0.0/17180.121.0.1 to 180.121.127.254180.121.127.25532,766
244180.121.128.0/17180.121.128.1 to 180.121.255.254180.121.255.25532,766
245180.122.0.0/17180.122.0.1 to 180.122.127.254180.122.127.25532,766
246180.122.128.0/17180.122.128.1 to 180.122.255.254180.122.255.25532,766
247180.123.0.0/17180.123.0.1 to 180.123.127.254180.123.127.25532,766
248180.123.128.0/17180.123.128.1 to 180.123.255.254180.123.255.25532,766
249180.124.0.0/17180.124.0.1 to 180.124.127.254180.124.127.25532,766
250180.124.128.0/17180.124.128.1 to 180.124.255.254180.124.255.25532,766
251180.125.0.0/17180.125.0.1 to 180.125.127.254180.125.127.25532,766
252180.125.128.0/17180.125.128.1 to 180.125.255.254180.125.255.25532,766
253180.126.0.0/17180.126.0.1 to 180.126.127.254180.126.127.25532,766
254180.126.128.0/17180.126.128.1 to 180.126.255.254180.126.255.25532,766
255180.127.0.0/17180.127.0.1 to 180.127.127.254180.127.127.25532,766
256180.127.128.0/17180.127.128.1 to 180.127.255.254180.127.255.25532,766

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.