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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.

Network180.26.0.0/17
Usable hosts32,766
Subnet mask255.255.128.0
Addresses32,768
Network address
180.26.0.0
Broadcast address
180.26.127.255
First usable
180.26.0.1
Last usable
180.26.127.254
Usable hosts
32,766 (32,768 less the network and broadcast addresses)
Subnet mask
255.255.128.0
Wildcard mask
0.0.127.255 (Cisco ACLs, OSPF)
Prefix length
/17
Type
Public public
Old class
B (default /16)
As numbers
Hex B41A0000 · Integer 3021602816 to 3021635583
Reverse DNS zones
0.26.180.in-addr.arpa
1.26.180.in-addr.arpa
2.26.180.in-addr.arpa
3.26.180.in-addr.arpa
4.26.180.in-addr.arpa
5.26.180.in-addr.arpa
6.26.180.in-addr.arpa
7.26.180.in-addr.arpa
8.26.180.in-addr.arpa
9.26.180.in-addr.arpa
10.26.180.in-addr.arpa
11.26.180.in-addr.arpa
12.26.180.in-addr.arpa
13.26.180.in-addr.arpa
14.26.180.in-addr.arpa
15.26.180.in-addr.arpa
and 112 more
/17 is not on a 8-bit boundary, so it takes 128 /24 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address10110100.00011010.00000000.00000000180.26.0.0
Subnet mask11111111.11111111.10000000.00000000255.255.128.0
Network10110100.00011010.00000000.00000000180.26.0.0
Broadcast10110100.00011010.01111111.11111111180.26.127.255
Split into smaller subnets/25
/18 (2)/19 (4)/20 (8)/21 (16)/22 (32)/23 (64)/24 (128)/25 (256)/26 (512)/27 (1,024)/28 (2,048)/29 (4,096)

180.26.0.0/17 makes 256 subnets of /25.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1180.26.0.0/25180.26.0.1 to 180.26.0.126180.26.0.127126
2180.26.0.128/25180.26.0.129 to 180.26.0.254180.26.0.255126
3180.26.1.0/25180.26.1.1 to 180.26.1.126180.26.1.127126
4180.26.1.128/25180.26.1.129 to 180.26.1.254180.26.1.255126
5180.26.2.0/25180.26.2.1 to 180.26.2.126180.26.2.127126
6180.26.2.128/25180.26.2.129 to 180.26.2.254180.26.2.255126
7180.26.3.0/25180.26.3.1 to 180.26.3.126180.26.3.127126
8180.26.3.128/25180.26.3.129 to 180.26.3.254180.26.3.255126
9180.26.4.0/25180.26.4.1 to 180.26.4.126180.26.4.127126
10180.26.4.128/25180.26.4.129 to 180.26.4.254180.26.4.255126
11180.26.5.0/25180.26.5.1 to 180.26.5.126180.26.5.127126
12180.26.5.128/25180.26.5.129 to 180.26.5.254180.26.5.255126
13180.26.6.0/25180.26.6.1 to 180.26.6.126180.26.6.127126
14180.26.6.128/25180.26.6.129 to 180.26.6.254180.26.6.255126
15180.26.7.0/25180.26.7.1 to 180.26.7.126180.26.7.127126
16180.26.7.128/25180.26.7.129 to 180.26.7.254180.26.7.255126
17180.26.8.0/25180.26.8.1 to 180.26.8.126180.26.8.127126
18180.26.8.128/25180.26.8.129 to 180.26.8.254180.26.8.255126
19180.26.9.0/25180.26.9.1 to 180.26.9.126180.26.9.127126
20180.26.9.128/25180.26.9.129 to 180.26.9.254180.26.9.255126
21180.26.10.0/25180.26.10.1 to 180.26.10.126180.26.10.127126
22180.26.10.128/25180.26.10.129 to 180.26.10.254180.26.10.255126
23180.26.11.0/25180.26.11.1 to 180.26.11.126180.26.11.127126
24180.26.11.128/25180.26.11.129 to 180.26.11.254180.26.11.255126
25180.26.12.0/25180.26.12.1 to 180.26.12.126180.26.12.127126
26180.26.12.128/25180.26.12.129 to 180.26.12.254180.26.12.255126
27180.26.13.0/25180.26.13.1 to 180.26.13.126180.26.13.127126
28180.26.13.128/25180.26.13.129 to 180.26.13.254180.26.13.255126
29180.26.14.0/25180.26.14.1 to 180.26.14.126180.26.14.127126
30180.26.14.128/25180.26.14.129 to 180.26.14.254180.26.14.255126
31180.26.15.0/25180.26.15.1 to 180.26.15.126180.26.15.127126
32180.26.15.128/25180.26.15.129 to 180.26.15.254180.26.15.255126
33180.26.16.0/25180.26.16.1 to 180.26.16.126180.26.16.127126
34180.26.16.128/25180.26.16.129 to 180.26.16.254180.26.16.255126
35180.26.17.0/25180.26.17.1 to 180.26.17.126180.26.17.127126
36180.26.17.128/25180.26.17.129 to 180.26.17.254180.26.17.255126
37180.26.18.0/25180.26.18.1 to 180.26.18.126180.26.18.127126
38180.26.18.128/25180.26.18.129 to 180.26.18.254180.26.18.255126
39180.26.19.0/25180.26.19.1 to 180.26.19.126180.26.19.127126
40180.26.19.128/25180.26.19.129 to 180.26.19.254180.26.19.255126
41180.26.20.0/25180.26.20.1 to 180.26.20.126180.26.20.127126
42180.26.20.128/25180.26.20.129 to 180.26.20.254180.26.20.255126
43180.26.21.0/25180.26.21.1 to 180.26.21.126180.26.21.127126
44180.26.21.128/25180.26.21.129 to 180.26.21.254180.26.21.255126
45180.26.22.0/25180.26.22.1 to 180.26.22.126180.26.22.127126
46180.26.22.128/25180.26.22.129 to 180.26.22.254180.26.22.255126
47180.26.23.0/25180.26.23.1 to 180.26.23.126180.26.23.127126
48180.26.23.128/25180.26.23.129 to 180.26.23.254180.26.23.255126
49180.26.24.0/25180.26.24.1 to 180.26.24.126180.26.24.127126
50180.26.24.128/25180.26.24.129 to 180.26.24.254180.26.24.255126
51180.26.25.0/25180.26.25.1 to 180.26.25.126180.26.25.127126
52180.26.25.128/25180.26.25.129 to 180.26.25.254180.26.25.255126
53180.26.26.0/25180.26.26.1 to 180.26.26.126180.26.26.127126
54180.26.26.128/25180.26.26.129 to 180.26.26.254180.26.26.255126
55180.26.27.0/25180.26.27.1 to 180.26.27.126180.26.27.127126
56180.26.27.128/25180.26.27.129 to 180.26.27.254180.26.27.255126
57180.26.28.0/25180.26.28.1 to 180.26.28.126180.26.28.127126
58180.26.28.128/25180.26.28.129 to 180.26.28.254180.26.28.255126
59180.26.29.0/25180.26.29.1 to 180.26.29.126180.26.29.127126
60180.26.29.128/25180.26.29.129 to 180.26.29.254180.26.29.255126
61180.26.30.0/25180.26.30.1 to 180.26.30.126180.26.30.127126
62180.26.30.128/25180.26.30.129 to 180.26.30.254180.26.30.255126
63180.26.31.0/25180.26.31.1 to 180.26.31.126180.26.31.127126
64180.26.31.128/25180.26.31.129 to 180.26.31.254180.26.31.255126
65180.26.32.0/25180.26.32.1 to 180.26.32.126180.26.32.127126
66180.26.32.128/25180.26.32.129 to 180.26.32.254180.26.32.255126
67180.26.33.0/25180.26.33.1 to 180.26.33.126180.26.33.127126
68180.26.33.128/25180.26.33.129 to 180.26.33.254180.26.33.255126
69180.26.34.0/25180.26.34.1 to 180.26.34.126180.26.34.127126
70180.26.34.128/25180.26.34.129 to 180.26.34.254180.26.34.255126
71180.26.35.0/25180.26.35.1 to 180.26.35.126180.26.35.127126
72180.26.35.128/25180.26.35.129 to 180.26.35.254180.26.35.255126
73180.26.36.0/25180.26.36.1 to 180.26.36.126180.26.36.127126
74180.26.36.128/25180.26.36.129 to 180.26.36.254180.26.36.255126
75180.26.37.0/25180.26.37.1 to 180.26.37.126180.26.37.127126
76180.26.37.128/25180.26.37.129 to 180.26.37.254180.26.37.255126
77180.26.38.0/25180.26.38.1 to 180.26.38.126180.26.38.127126
78180.26.38.128/25180.26.38.129 to 180.26.38.254180.26.38.255126
79180.26.39.0/25180.26.39.1 to 180.26.39.126180.26.39.127126
80180.26.39.128/25180.26.39.129 to 180.26.39.254180.26.39.255126
81180.26.40.0/25180.26.40.1 to 180.26.40.126180.26.40.127126
82180.26.40.128/25180.26.40.129 to 180.26.40.254180.26.40.255126
83180.26.41.0/25180.26.41.1 to 180.26.41.126180.26.41.127126
84180.26.41.128/25180.26.41.129 to 180.26.41.254180.26.41.255126
85180.26.42.0/25180.26.42.1 to 180.26.42.126180.26.42.127126
86180.26.42.128/25180.26.42.129 to 180.26.42.254180.26.42.255126
87180.26.43.0/25180.26.43.1 to 180.26.43.126180.26.43.127126
88180.26.43.128/25180.26.43.129 to 180.26.43.254180.26.43.255126
89180.26.44.0/25180.26.44.1 to 180.26.44.126180.26.44.127126
90180.26.44.128/25180.26.44.129 to 180.26.44.254180.26.44.255126
91180.26.45.0/25180.26.45.1 to 180.26.45.126180.26.45.127126
92180.26.45.128/25180.26.45.129 to 180.26.45.254180.26.45.255126
93180.26.46.0/25180.26.46.1 to 180.26.46.126180.26.46.127126
94180.26.46.128/25180.26.46.129 to 180.26.46.254180.26.46.255126
95180.26.47.0/25180.26.47.1 to 180.26.47.126180.26.47.127126
96180.26.47.128/25180.26.47.129 to 180.26.47.254180.26.47.255126
97180.26.48.0/25180.26.48.1 to 180.26.48.126180.26.48.127126
98180.26.48.128/25180.26.48.129 to 180.26.48.254180.26.48.255126
99180.26.49.0/25180.26.49.1 to 180.26.49.126180.26.49.127126
100180.26.49.128/25180.26.49.129 to 180.26.49.254180.26.49.255126
101180.26.50.0/25180.26.50.1 to 180.26.50.126180.26.50.127126
102180.26.50.128/25180.26.50.129 to 180.26.50.254180.26.50.255126
103180.26.51.0/25180.26.51.1 to 180.26.51.126180.26.51.127126
104180.26.51.128/25180.26.51.129 to 180.26.51.254180.26.51.255126
105180.26.52.0/25180.26.52.1 to 180.26.52.126180.26.52.127126
106180.26.52.128/25180.26.52.129 to 180.26.52.254180.26.52.255126
107180.26.53.0/25180.26.53.1 to 180.26.53.126180.26.53.127126
108180.26.53.128/25180.26.53.129 to 180.26.53.254180.26.53.255126
109180.26.54.0/25180.26.54.1 to 180.26.54.126180.26.54.127126
110180.26.54.128/25180.26.54.129 to 180.26.54.254180.26.54.255126
111180.26.55.0/25180.26.55.1 to 180.26.55.126180.26.55.127126
112180.26.55.128/25180.26.55.129 to 180.26.55.254180.26.55.255126
113180.26.56.0/25180.26.56.1 to 180.26.56.126180.26.56.127126
114180.26.56.128/25180.26.56.129 to 180.26.56.254180.26.56.255126
115180.26.57.0/25180.26.57.1 to 180.26.57.126180.26.57.127126
116180.26.57.128/25180.26.57.129 to 180.26.57.254180.26.57.255126
117180.26.58.0/25180.26.58.1 to 180.26.58.126180.26.58.127126
118180.26.58.128/25180.26.58.129 to 180.26.58.254180.26.58.255126
119180.26.59.0/25180.26.59.1 to 180.26.59.126180.26.59.127126
120180.26.59.128/25180.26.59.129 to 180.26.59.254180.26.59.255126
121180.26.60.0/25180.26.60.1 to 180.26.60.126180.26.60.127126
122180.26.60.128/25180.26.60.129 to 180.26.60.254180.26.60.255126
123180.26.61.0/25180.26.61.1 to 180.26.61.126180.26.61.127126
124180.26.61.128/25180.26.61.129 to 180.26.61.254180.26.61.255126
125180.26.62.0/25180.26.62.1 to 180.26.62.126180.26.62.127126
126180.26.62.128/25180.26.62.129 to 180.26.62.254180.26.62.255126
127180.26.63.0/25180.26.63.1 to 180.26.63.126180.26.63.127126
128180.26.63.128/25180.26.63.129 to 180.26.63.254180.26.63.255126
129180.26.64.0/25180.26.64.1 to 180.26.64.126180.26.64.127126
130180.26.64.128/25180.26.64.129 to 180.26.64.254180.26.64.255126
131180.26.65.0/25180.26.65.1 to 180.26.65.126180.26.65.127126
132180.26.65.128/25180.26.65.129 to 180.26.65.254180.26.65.255126
133180.26.66.0/25180.26.66.1 to 180.26.66.126180.26.66.127126
134180.26.66.128/25180.26.66.129 to 180.26.66.254180.26.66.255126
135180.26.67.0/25180.26.67.1 to 180.26.67.126180.26.67.127126
136180.26.67.128/25180.26.67.129 to 180.26.67.254180.26.67.255126
137180.26.68.0/25180.26.68.1 to 180.26.68.126180.26.68.127126
138180.26.68.128/25180.26.68.129 to 180.26.68.254180.26.68.255126
139180.26.69.0/25180.26.69.1 to 180.26.69.126180.26.69.127126
140180.26.69.128/25180.26.69.129 to 180.26.69.254180.26.69.255126
141180.26.70.0/25180.26.70.1 to 180.26.70.126180.26.70.127126
142180.26.70.128/25180.26.70.129 to 180.26.70.254180.26.70.255126
143180.26.71.0/25180.26.71.1 to 180.26.71.126180.26.71.127126
144180.26.71.128/25180.26.71.129 to 180.26.71.254180.26.71.255126
145180.26.72.0/25180.26.72.1 to 180.26.72.126180.26.72.127126
146180.26.72.128/25180.26.72.129 to 180.26.72.254180.26.72.255126
147180.26.73.0/25180.26.73.1 to 180.26.73.126180.26.73.127126
148180.26.73.128/25180.26.73.129 to 180.26.73.254180.26.73.255126
149180.26.74.0/25180.26.74.1 to 180.26.74.126180.26.74.127126
150180.26.74.128/25180.26.74.129 to 180.26.74.254180.26.74.255126
151180.26.75.0/25180.26.75.1 to 180.26.75.126180.26.75.127126
152180.26.75.128/25180.26.75.129 to 180.26.75.254180.26.75.255126
153180.26.76.0/25180.26.76.1 to 180.26.76.126180.26.76.127126
154180.26.76.128/25180.26.76.129 to 180.26.76.254180.26.76.255126
155180.26.77.0/25180.26.77.1 to 180.26.77.126180.26.77.127126
156180.26.77.128/25180.26.77.129 to 180.26.77.254180.26.77.255126
157180.26.78.0/25180.26.78.1 to 180.26.78.126180.26.78.127126
158180.26.78.128/25180.26.78.129 to 180.26.78.254180.26.78.255126
159180.26.79.0/25180.26.79.1 to 180.26.79.126180.26.79.127126
160180.26.79.128/25180.26.79.129 to 180.26.79.254180.26.79.255126
161180.26.80.0/25180.26.80.1 to 180.26.80.126180.26.80.127126
162180.26.80.128/25180.26.80.129 to 180.26.80.254180.26.80.255126
163180.26.81.0/25180.26.81.1 to 180.26.81.126180.26.81.127126
164180.26.81.128/25180.26.81.129 to 180.26.81.254180.26.81.255126
165180.26.82.0/25180.26.82.1 to 180.26.82.126180.26.82.127126
166180.26.82.128/25180.26.82.129 to 180.26.82.254180.26.82.255126
167180.26.83.0/25180.26.83.1 to 180.26.83.126180.26.83.127126
168180.26.83.128/25180.26.83.129 to 180.26.83.254180.26.83.255126
169180.26.84.0/25180.26.84.1 to 180.26.84.126180.26.84.127126
170180.26.84.128/25180.26.84.129 to 180.26.84.254180.26.84.255126
171180.26.85.0/25180.26.85.1 to 180.26.85.126180.26.85.127126
172180.26.85.128/25180.26.85.129 to 180.26.85.254180.26.85.255126
173180.26.86.0/25180.26.86.1 to 180.26.86.126180.26.86.127126
174180.26.86.128/25180.26.86.129 to 180.26.86.254180.26.86.255126
175180.26.87.0/25180.26.87.1 to 180.26.87.126180.26.87.127126
176180.26.87.128/25180.26.87.129 to 180.26.87.254180.26.87.255126
177180.26.88.0/25180.26.88.1 to 180.26.88.126180.26.88.127126
178180.26.88.128/25180.26.88.129 to 180.26.88.254180.26.88.255126
179180.26.89.0/25180.26.89.1 to 180.26.89.126180.26.89.127126
180180.26.89.128/25180.26.89.129 to 180.26.89.254180.26.89.255126
181180.26.90.0/25180.26.90.1 to 180.26.90.126180.26.90.127126
182180.26.90.128/25180.26.90.129 to 180.26.90.254180.26.90.255126
183180.26.91.0/25180.26.91.1 to 180.26.91.126180.26.91.127126
184180.26.91.128/25180.26.91.129 to 180.26.91.254180.26.91.255126
185180.26.92.0/25180.26.92.1 to 180.26.92.126180.26.92.127126
186180.26.92.128/25180.26.92.129 to 180.26.92.254180.26.92.255126
187180.26.93.0/25180.26.93.1 to 180.26.93.126180.26.93.127126
188180.26.93.128/25180.26.93.129 to 180.26.93.254180.26.93.255126
189180.26.94.0/25180.26.94.1 to 180.26.94.126180.26.94.127126
190180.26.94.128/25180.26.94.129 to 180.26.94.254180.26.94.255126
191180.26.95.0/25180.26.95.1 to 180.26.95.126180.26.95.127126
192180.26.95.128/25180.26.95.129 to 180.26.95.254180.26.95.255126
193180.26.96.0/25180.26.96.1 to 180.26.96.126180.26.96.127126
194180.26.96.128/25180.26.96.129 to 180.26.96.254180.26.96.255126
195180.26.97.0/25180.26.97.1 to 180.26.97.126180.26.97.127126
196180.26.97.128/25180.26.97.129 to 180.26.97.254180.26.97.255126
197180.26.98.0/25180.26.98.1 to 180.26.98.126180.26.98.127126
198180.26.98.128/25180.26.98.129 to 180.26.98.254180.26.98.255126
199180.26.99.0/25180.26.99.1 to 180.26.99.126180.26.99.127126
200180.26.99.128/25180.26.99.129 to 180.26.99.254180.26.99.255126
201180.26.100.0/25180.26.100.1 to 180.26.100.126180.26.100.127126
202180.26.100.128/25180.26.100.129 to 180.26.100.254180.26.100.255126
203180.26.101.0/25180.26.101.1 to 180.26.101.126180.26.101.127126
204180.26.101.128/25180.26.101.129 to 180.26.101.254180.26.101.255126
205180.26.102.0/25180.26.102.1 to 180.26.102.126180.26.102.127126
206180.26.102.128/25180.26.102.129 to 180.26.102.254180.26.102.255126
207180.26.103.0/25180.26.103.1 to 180.26.103.126180.26.103.127126
208180.26.103.128/25180.26.103.129 to 180.26.103.254180.26.103.255126
209180.26.104.0/25180.26.104.1 to 180.26.104.126180.26.104.127126
210180.26.104.128/25180.26.104.129 to 180.26.104.254180.26.104.255126
211180.26.105.0/25180.26.105.1 to 180.26.105.126180.26.105.127126
212180.26.105.128/25180.26.105.129 to 180.26.105.254180.26.105.255126
213180.26.106.0/25180.26.106.1 to 180.26.106.126180.26.106.127126
214180.26.106.128/25180.26.106.129 to 180.26.106.254180.26.106.255126
215180.26.107.0/25180.26.107.1 to 180.26.107.126180.26.107.127126
216180.26.107.128/25180.26.107.129 to 180.26.107.254180.26.107.255126
217180.26.108.0/25180.26.108.1 to 180.26.108.126180.26.108.127126
218180.26.108.128/25180.26.108.129 to 180.26.108.254180.26.108.255126
219180.26.109.0/25180.26.109.1 to 180.26.109.126180.26.109.127126
220180.26.109.128/25180.26.109.129 to 180.26.109.254180.26.109.255126
221180.26.110.0/25180.26.110.1 to 180.26.110.126180.26.110.127126
222180.26.110.128/25180.26.110.129 to 180.26.110.254180.26.110.255126
223180.26.111.0/25180.26.111.1 to 180.26.111.126180.26.111.127126
224180.26.111.128/25180.26.111.129 to 180.26.111.254180.26.111.255126
225180.26.112.0/25180.26.112.1 to 180.26.112.126180.26.112.127126
226180.26.112.128/25180.26.112.129 to 180.26.112.254180.26.112.255126
227180.26.113.0/25180.26.113.1 to 180.26.113.126180.26.113.127126
228180.26.113.128/25180.26.113.129 to 180.26.113.254180.26.113.255126
229180.26.114.0/25180.26.114.1 to 180.26.114.126180.26.114.127126
230180.26.114.128/25180.26.114.129 to 180.26.114.254180.26.114.255126
231180.26.115.0/25180.26.115.1 to 180.26.115.126180.26.115.127126
232180.26.115.128/25180.26.115.129 to 180.26.115.254180.26.115.255126
233180.26.116.0/25180.26.116.1 to 180.26.116.126180.26.116.127126
234180.26.116.128/25180.26.116.129 to 180.26.116.254180.26.116.255126
235180.26.117.0/25180.26.117.1 to 180.26.117.126180.26.117.127126
236180.26.117.128/25180.26.117.129 to 180.26.117.254180.26.117.255126
237180.26.118.0/25180.26.118.1 to 180.26.118.126180.26.118.127126
238180.26.118.128/25180.26.118.129 to 180.26.118.254180.26.118.255126
239180.26.119.0/25180.26.119.1 to 180.26.119.126180.26.119.127126
240180.26.119.128/25180.26.119.129 to 180.26.119.254180.26.119.255126
241180.26.120.0/25180.26.120.1 to 180.26.120.126180.26.120.127126
242180.26.120.128/25180.26.120.129 to 180.26.120.254180.26.120.255126
243180.26.121.0/25180.26.121.1 to 180.26.121.126180.26.121.127126
244180.26.121.128/25180.26.121.129 to 180.26.121.254180.26.121.255126
245180.26.122.0/25180.26.122.1 to 180.26.122.126180.26.122.127126
246180.26.122.128/25180.26.122.129 to 180.26.122.254180.26.122.255126
247180.26.123.0/25180.26.123.1 to 180.26.123.126180.26.123.127126
248180.26.123.128/25180.26.123.129 to 180.26.123.254180.26.123.255126
249180.26.124.0/25180.26.124.1 to 180.26.124.126180.26.124.127126
250180.26.124.128/25180.26.124.129 to 180.26.124.254180.26.124.255126
251180.26.125.0/25180.26.125.1 to 180.26.125.126180.26.125.127126
252180.26.125.128/25180.26.125.129 to 180.26.125.254180.26.125.255126
253180.26.126.0/25180.26.126.1 to 180.26.126.126180.26.126.127126
254180.26.126.128/25180.26.126.129 to 180.26.126.254180.26.126.255126
255180.26.127.0/25180.26.127.1 to 180.26.127.126180.26.127.127126
256180.26.127.128/25180.26.127.129 to 180.26.127.254180.26.127.255126

IPv4 CIDR reference (/0 to /32)

IPv4 prefix lengths
PrefixSubnet maskWildcardAddressesUsable hostsSizeTypical use
/00.0.0.0255.255.255.2554,294,967,2964,294,967,29416,777,216 × /24
/1128.0.0.0127.255.255.2552,147,483,6482,147,483,6468,388,608 × /24
/2192.0.0.063.255.255.2551,073,741,8241,073,741,8224,194,304 × /24
/3224.0.0.031.255.255.255536,870,912536,870,9102,097,152 × /24
/4240.0.0.015.255.255.255268,435,456268,435,4541,048,576 × /24
/5248.0.0.07.255.255.255134,217,728134,217,726524,288 × /24
/6252.0.0.03.255.255.25567,108,86467,108,862262,144 × /24
/7254.0.0.01.255.255.25533,554,43233,554,430131,072 × /24
/8255.0.0.00.255.255.25516,777,21616,777,21465,536 × /24Old class A; 10.0.0.0/8
/9255.128.0.00.127.255.2558,388,6088,388,60632,768 × /24
/10255.192.0.00.63.255.2554,194,3044,194,30216,384 × /24
/11255.224.0.00.31.255.2552,097,1522,097,1508,192 × /24
/12255.240.0.00.15.255.2551,048,5761,048,5744,096 × /24172.16.0.0/12
/13255.248.0.00.7.255.255524,288524,2862,048 × /24
/14255.252.0.00.3.255.255262,144262,1421,024 × /24
/15255.254.0.00.1.255.255131,072131,070512 × /24
/16255.255.0.00.0.255.25565,53665,534256 × /24Old class B; 192.168.0.0/16
/17255.255.128.00.0.127.25532,76832,766128 × /24
/18255.255.192.00.0.63.25516,38416,38264 × /24
/19255.255.224.00.0.31.2558,1928,19032 × /24
/20255.255.240.00.0.15.2554,0964,09416 × /24
/21255.255.248.00.0.7.2552,0482,0468 × /24
/22255.255.252.00.0.3.2551,0241,0224 × /24Large office or guest Wi-Fi (1,022 hosts)
/23255.255.254.00.0.1.2555125102 × /24Larger office LAN (510 hosts)
/24255.255.255.00.0.0.2552562541 × /24Typical office LAN (old class C)
/25255.255.255.1280.0.0.1271281261/2 of a /24Smaller LAN or VLAN
/26255.255.255.1920.0.0.6364621/4 of a /24Smaller LAN or VLAN
/27255.255.255.2240.0.0.3132301/8 of a /24Small VLAN, phones, cameras
/28255.255.255.2400.0.0.1516141/16 of a /24Small VLAN, phones, cameras
/29255.255.255.2480.0.0.7861/32 of a /24Small fixed public block (5 usable)
/30255.255.255.2520.0.0.3421/64 of a /24Point-to-point (old style)
/31255.255.255.2540.0.0.1221/128 of a /24Point-to-point link (RFC 3021)
/32255.255.255.2550.0.0.0111/256 of a /24One host

IPv6 prefix reference

IPv6 prefix lengths
PrefixAddresses/64 LANs/48 sitesNibbleTypical use
/342,535,295,865,117,307,932,921,825,928,971,026,432 (2^125)2,305,843,009,213,693,95235,184,372,088,832NoAll global unicast (2000::/3)
/165,192,296,858,534,827,628,530,496,329,220,096 (2^112)281,474,976,710,6564,294,967,296Yes
/20324,518,553,658,426,726,783,156,020,576,256 (2^108)17,592,186,044,416268,435,456YesLarge provider allocation (RIPE minimum for some)
/29633,825,300,114,114,700,748,351,602,688 (2^99)34,359,738,368524,288NoRIPE allocation to a provider (often)
/3279,228,162,514,264,337,593,543,950,336 (2^96)4,294,967,29665,536YesProvider allocation (RIPE default)
/364,951,760,157,141,521,099,596,496,896 (2^92)268,435,4564,096Yes
/40309,485,009,821,345,068,724,781,056 (2^88)16,777,216256Yes
/4419,342,813,113,834,066,795,298,816 (2^84)1,048,57616Yes
/481,208,925,819,614,629,174,706,176 (2^80)65,5361YesOne site or organisation (RIPE PI / assignment)
/5275,557,863,725,914,323,419,136 (2^76)4,096Yes
/564,722,366,482,869,645,213,696 (2^72)256YesSmall site or home (common provider assignment)
/60295,147,905,179,352,825,856 (2^68)16YesSome home broadband (16 LANs)
/6418,446,744,073,709,551,616 (2^64)1YesOne LAN or VLAN (needed for SLAAC)
/7272,057,594,037,927,936 (2^56)1/256 of a /64Yes
/80281,474,976,710,656 (2^48)1/65,536 of a /64Yes
/964,294,967,2961/4,294,967,296 of a /64YesEmbeds an IPv4 address (NAT64)
/11265,5361/281,474,976,710,656 of a /64Yes
/1202561/72,057,594,037,927,936 of a /64Yes
/124161/1,152,921,504,606,846,976 of a /64Yes
/12641/4,611,686,018,427,387,904 of a /64No
/12721/9,223,372,036,854,775,808 of a /64NoPoint-to-point link (RFC 6164)
/12811/18,446,744,073,709,551,616 of a /64YesOne host or loopback

Private and special ranges

IPv4

Special-purpose ranges
RangeNameWhat it is
255.255.255.255/32Limited broadcastEvery host on the local network
0.0.0.0/8This networkNot routed; 0.0.0.0 means "any address" in settings
10.0.0.0/8Private (RFC 1918)Office and home networks; not routed on the internet
100.64.0.0/10Shared address space (CGNAT)Used by providers behind carrier-grade NAT (RFC 6598)
127.0.0.0/8LoopbackThis computer
169.254.0.0/16Link-local (APIPA)Self-assigned when no DHCP server answers
172.16.0.0/12Private (RFC 1918)Office and home networks; not routed on the internet
192.0.0.0/24IETF protocol assignmentsSpecial uses such as DS-Lite
192.0.2.0/24Documentation (TEST-NET-1)For examples; never used on a network
192.88.99.0/246to4 relay (deprecated)Formerly anycast for 6to4
192.168.0.0/16Private (RFC 1918)Office and home networks; not routed on the internet
198.18.0.0/15BenchmarkingNetwork equipment testing (RFC 2544)
198.51.100.0/24Documentation (TEST-NET-2)For examples; never used on a network
203.0.113.0/24Documentation (TEST-NET-3)For examples; never used on a network
224.0.0.0/4MulticastOne-to-many traffic, such as IPTV and routing protocols
240.0.0.0/4ReservedFuture use; not usable on most systems

IPv6

Special-purpose ranges
RangeNameWhat it is
::/128UnspecifiedNo address; :: means "any address" in settings
::1/128LoopbackThis computer
::ffff:0:0/96IPv4-mappedAn IPv4 address written as IPv6
64:ff9b::/96NAT64IPv4 addresses reached through a NAT64 gateway
100::/64Discard onlyTraffic sent here is dropped (RFC 6666)
2001:db8::/32DocumentationFor examples; never used on a network
2001::/32TeredoIPv6 tunnelled over IPv4 UDP
2002::/166to4IPv6 tunnelled over IPv4 (largely retired)
3fff::/20DocumentationFor examples (RFC 9637)
fc00::/7Unique local (ULA)Private IPv6, like RFC 1918; usually fd00::/8
fe80::/10Link-localEvery IPv6 interface has one; not routed
ff00::/8MulticastOne-to-many traffic; replaces broadcast
2000::/3Global unicastPublic internet addresses

About this tool

A network is written as an address and a prefix length, such as 192.168.1.0/24: the first 24 bits name the network and the rest number the devices on it. The calculator works out where the network starts and ends, how many devices it holds, its subnet and wildcard masks, and the reverse DNS zone to ask your provider for.

It also splits a network into equal smaller ones (one per VLAN or site), turns a range of addresses into the fewest CIDR blocks for a firewall rule, and lists every IPv4 prefix length and the common IPv6 ones in reference tables.

Common questions

Why are two addresses lost in every IPv4 subnet?

The first address names the network and the last is the broadcast address, so a /24 has 256 addresses but 254 for devices. A /31 (a link between two routers) and a /32 (one host) are the exceptions.

What size of IPv6 network should a LAN use?

Always /64. Devices pick their own address within it (SLAAC), which needs the full 64 bits. A site usually gets a /48 or /56 from its provider, which holds 65,536 or 256 LANs.

What is a wildcard mask?

The subnet mask turned inside out: 255.255.255.0 becomes 0.0.0.255. Cisco access lists and OSPF use it to say which bits must match.

Which ranges can I use inside an office?

IPv4: 10.0.0.0/8, 172.16.0.0/12 and 192.168.0.0/16. IPv6: unique local addresses from fd00::/8, though most networks use the public prefix from their provider.