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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.

Network177.78.0.0/17
Usable hosts32,766
Subnet mask255.255.128.0
Addresses32,768
Network address
177.78.0.0
Broadcast address
177.78.127.255
First usable
177.78.0.1
Last usable
177.78.127.254
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 B14E0000 · Integer 2974679040 to 2974711807
Reverse DNS zones
0.78.177.in-addr.arpa
1.78.177.in-addr.arpa
2.78.177.in-addr.arpa
3.78.177.in-addr.arpa
4.78.177.in-addr.arpa
5.78.177.in-addr.arpa
6.78.177.in-addr.arpa
7.78.177.in-addr.arpa
8.78.177.in-addr.arpa
9.78.177.in-addr.arpa
10.78.177.in-addr.arpa
11.78.177.in-addr.arpa
12.78.177.in-addr.arpa
13.78.177.in-addr.arpa
14.78.177.in-addr.arpa
15.78.177.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
Address10110001.01001110.00000000.00000000177.78.0.0
Subnet mask11111111.11111111.10000000.00000000255.255.128.0
Network10110001.01001110.00000000.00000000177.78.0.0
Broadcast10110001.01001110.01111111.11111111177.78.127.255
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)

177.78.0.0/17 makes 256 subnets of /25.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1177.78.0.0/25177.78.0.1 to 177.78.0.126177.78.0.127126
2177.78.0.128/25177.78.0.129 to 177.78.0.254177.78.0.255126
3177.78.1.0/25177.78.1.1 to 177.78.1.126177.78.1.127126
4177.78.1.128/25177.78.1.129 to 177.78.1.254177.78.1.255126
5177.78.2.0/25177.78.2.1 to 177.78.2.126177.78.2.127126
6177.78.2.128/25177.78.2.129 to 177.78.2.254177.78.2.255126
7177.78.3.0/25177.78.3.1 to 177.78.3.126177.78.3.127126
8177.78.3.128/25177.78.3.129 to 177.78.3.254177.78.3.255126
9177.78.4.0/25177.78.4.1 to 177.78.4.126177.78.4.127126
10177.78.4.128/25177.78.4.129 to 177.78.4.254177.78.4.255126
11177.78.5.0/25177.78.5.1 to 177.78.5.126177.78.5.127126
12177.78.5.128/25177.78.5.129 to 177.78.5.254177.78.5.255126
13177.78.6.0/25177.78.6.1 to 177.78.6.126177.78.6.127126
14177.78.6.128/25177.78.6.129 to 177.78.6.254177.78.6.255126
15177.78.7.0/25177.78.7.1 to 177.78.7.126177.78.7.127126
16177.78.7.128/25177.78.7.129 to 177.78.7.254177.78.7.255126
17177.78.8.0/25177.78.8.1 to 177.78.8.126177.78.8.127126
18177.78.8.128/25177.78.8.129 to 177.78.8.254177.78.8.255126
19177.78.9.0/25177.78.9.1 to 177.78.9.126177.78.9.127126
20177.78.9.128/25177.78.9.129 to 177.78.9.254177.78.9.255126
21177.78.10.0/25177.78.10.1 to 177.78.10.126177.78.10.127126
22177.78.10.128/25177.78.10.129 to 177.78.10.254177.78.10.255126
23177.78.11.0/25177.78.11.1 to 177.78.11.126177.78.11.127126
24177.78.11.128/25177.78.11.129 to 177.78.11.254177.78.11.255126
25177.78.12.0/25177.78.12.1 to 177.78.12.126177.78.12.127126
26177.78.12.128/25177.78.12.129 to 177.78.12.254177.78.12.255126
27177.78.13.0/25177.78.13.1 to 177.78.13.126177.78.13.127126
28177.78.13.128/25177.78.13.129 to 177.78.13.254177.78.13.255126
29177.78.14.0/25177.78.14.1 to 177.78.14.126177.78.14.127126
30177.78.14.128/25177.78.14.129 to 177.78.14.254177.78.14.255126
31177.78.15.0/25177.78.15.1 to 177.78.15.126177.78.15.127126
32177.78.15.128/25177.78.15.129 to 177.78.15.254177.78.15.255126
33177.78.16.0/25177.78.16.1 to 177.78.16.126177.78.16.127126
34177.78.16.128/25177.78.16.129 to 177.78.16.254177.78.16.255126
35177.78.17.0/25177.78.17.1 to 177.78.17.126177.78.17.127126
36177.78.17.128/25177.78.17.129 to 177.78.17.254177.78.17.255126
37177.78.18.0/25177.78.18.1 to 177.78.18.126177.78.18.127126
38177.78.18.128/25177.78.18.129 to 177.78.18.254177.78.18.255126
39177.78.19.0/25177.78.19.1 to 177.78.19.126177.78.19.127126
40177.78.19.128/25177.78.19.129 to 177.78.19.254177.78.19.255126
41177.78.20.0/25177.78.20.1 to 177.78.20.126177.78.20.127126
42177.78.20.128/25177.78.20.129 to 177.78.20.254177.78.20.255126
43177.78.21.0/25177.78.21.1 to 177.78.21.126177.78.21.127126
44177.78.21.128/25177.78.21.129 to 177.78.21.254177.78.21.255126
45177.78.22.0/25177.78.22.1 to 177.78.22.126177.78.22.127126
46177.78.22.128/25177.78.22.129 to 177.78.22.254177.78.22.255126
47177.78.23.0/25177.78.23.1 to 177.78.23.126177.78.23.127126
48177.78.23.128/25177.78.23.129 to 177.78.23.254177.78.23.255126
49177.78.24.0/25177.78.24.1 to 177.78.24.126177.78.24.127126
50177.78.24.128/25177.78.24.129 to 177.78.24.254177.78.24.255126
51177.78.25.0/25177.78.25.1 to 177.78.25.126177.78.25.127126
52177.78.25.128/25177.78.25.129 to 177.78.25.254177.78.25.255126
53177.78.26.0/25177.78.26.1 to 177.78.26.126177.78.26.127126
54177.78.26.128/25177.78.26.129 to 177.78.26.254177.78.26.255126
55177.78.27.0/25177.78.27.1 to 177.78.27.126177.78.27.127126
56177.78.27.128/25177.78.27.129 to 177.78.27.254177.78.27.255126
57177.78.28.0/25177.78.28.1 to 177.78.28.126177.78.28.127126
58177.78.28.128/25177.78.28.129 to 177.78.28.254177.78.28.255126
59177.78.29.0/25177.78.29.1 to 177.78.29.126177.78.29.127126
60177.78.29.128/25177.78.29.129 to 177.78.29.254177.78.29.255126
61177.78.30.0/25177.78.30.1 to 177.78.30.126177.78.30.127126
62177.78.30.128/25177.78.30.129 to 177.78.30.254177.78.30.255126
63177.78.31.0/25177.78.31.1 to 177.78.31.126177.78.31.127126
64177.78.31.128/25177.78.31.129 to 177.78.31.254177.78.31.255126
65177.78.32.0/25177.78.32.1 to 177.78.32.126177.78.32.127126
66177.78.32.128/25177.78.32.129 to 177.78.32.254177.78.32.255126
67177.78.33.0/25177.78.33.1 to 177.78.33.126177.78.33.127126
68177.78.33.128/25177.78.33.129 to 177.78.33.254177.78.33.255126
69177.78.34.0/25177.78.34.1 to 177.78.34.126177.78.34.127126
70177.78.34.128/25177.78.34.129 to 177.78.34.254177.78.34.255126
71177.78.35.0/25177.78.35.1 to 177.78.35.126177.78.35.127126
72177.78.35.128/25177.78.35.129 to 177.78.35.254177.78.35.255126
73177.78.36.0/25177.78.36.1 to 177.78.36.126177.78.36.127126
74177.78.36.128/25177.78.36.129 to 177.78.36.254177.78.36.255126
75177.78.37.0/25177.78.37.1 to 177.78.37.126177.78.37.127126
76177.78.37.128/25177.78.37.129 to 177.78.37.254177.78.37.255126
77177.78.38.0/25177.78.38.1 to 177.78.38.126177.78.38.127126
78177.78.38.128/25177.78.38.129 to 177.78.38.254177.78.38.255126
79177.78.39.0/25177.78.39.1 to 177.78.39.126177.78.39.127126
80177.78.39.128/25177.78.39.129 to 177.78.39.254177.78.39.255126
81177.78.40.0/25177.78.40.1 to 177.78.40.126177.78.40.127126
82177.78.40.128/25177.78.40.129 to 177.78.40.254177.78.40.255126
83177.78.41.0/25177.78.41.1 to 177.78.41.126177.78.41.127126
84177.78.41.128/25177.78.41.129 to 177.78.41.254177.78.41.255126
85177.78.42.0/25177.78.42.1 to 177.78.42.126177.78.42.127126
86177.78.42.128/25177.78.42.129 to 177.78.42.254177.78.42.255126
87177.78.43.0/25177.78.43.1 to 177.78.43.126177.78.43.127126
88177.78.43.128/25177.78.43.129 to 177.78.43.254177.78.43.255126
89177.78.44.0/25177.78.44.1 to 177.78.44.126177.78.44.127126
90177.78.44.128/25177.78.44.129 to 177.78.44.254177.78.44.255126
91177.78.45.0/25177.78.45.1 to 177.78.45.126177.78.45.127126
92177.78.45.128/25177.78.45.129 to 177.78.45.254177.78.45.255126
93177.78.46.0/25177.78.46.1 to 177.78.46.126177.78.46.127126
94177.78.46.128/25177.78.46.129 to 177.78.46.254177.78.46.255126
95177.78.47.0/25177.78.47.1 to 177.78.47.126177.78.47.127126
96177.78.47.128/25177.78.47.129 to 177.78.47.254177.78.47.255126
97177.78.48.0/25177.78.48.1 to 177.78.48.126177.78.48.127126
98177.78.48.128/25177.78.48.129 to 177.78.48.254177.78.48.255126
99177.78.49.0/25177.78.49.1 to 177.78.49.126177.78.49.127126
100177.78.49.128/25177.78.49.129 to 177.78.49.254177.78.49.255126
101177.78.50.0/25177.78.50.1 to 177.78.50.126177.78.50.127126
102177.78.50.128/25177.78.50.129 to 177.78.50.254177.78.50.255126
103177.78.51.0/25177.78.51.1 to 177.78.51.126177.78.51.127126
104177.78.51.128/25177.78.51.129 to 177.78.51.254177.78.51.255126
105177.78.52.0/25177.78.52.1 to 177.78.52.126177.78.52.127126
106177.78.52.128/25177.78.52.129 to 177.78.52.254177.78.52.255126
107177.78.53.0/25177.78.53.1 to 177.78.53.126177.78.53.127126
108177.78.53.128/25177.78.53.129 to 177.78.53.254177.78.53.255126
109177.78.54.0/25177.78.54.1 to 177.78.54.126177.78.54.127126
110177.78.54.128/25177.78.54.129 to 177.78.54.254177.78.54.255126
111177.78.55.0/25177.78.55.1 to 177.78.55.126177.78.55.127126
112177.78.55.128/25177.78.55.129 to 177.78.55.254177.78.55.255126
113177.78.56.0/25177.78.56.1 to 177.78.56.126177.78.56.127126
114177.78.56.128/25177.78.56.129 to 177.78.56.254177.78.56.255126
115177.78.57.0/25177.78.57.1 to 177.78.57.126177.78.57.127126
116177.78.57.128/25177.78.57.129 to 177.78.57.254177.78.57.255126
117177.78.58.0/25177.78.58.1 to 177.78.58.126177.78.58.127126
118177.78.58.128/25177.78.58.129 to 177.78.58.254177.78.58.255126
119177.78.59.0/25177.78.59.1 to 177.78.59.126177.78.59.127126
120177.78.59.128/25177.78.59.129 to 177.78.59.254177.78.59.255126
121177.78.60.0/25177.78.60.1 to 177.78.60.126177.78.60.127126
122177.78.60.128/25177.78.60.129 to 177.78.60.254177.78.60.255126
123177.78.61.0/25177.78.61.1 to 177.78.61.126177.78.61.127126
124177.78.61.128/25177.78.61.129 to 177.78.61.254177.78.61.255126
125177.78.62.0/25177.78.62.1 to 177.78.62.126177.78.62.127126
126177.78.62.128/25177.78.62.129 to 177.78.62.254177.78.62.255126
127177.78.63.0/25177.78.63.1 to 177.78.63.126177.78.63.127126
128177.78.63.128/25177.78.63.129 to 177.78.63.254177.78.63.255126
129177.78.64.0/25177.78.64.1 to 177.78.64.126177.78.64.127126
130177.78.64.128/25177.78.64.129 to 177.78.64.254177.78.64.255126
131177.78.65.0/25177.78.65.1 to 177.78.65.126177.78.65.127126
132177.78.65.128/25177.78.65.129 to 177.78.65.254177.78.65.255126
133177.78.66.0/25177.78.66.1 to 177.78.66.126177.78.66.127126
134177.78.66.128/25177.78.66.129 to 177.78.66.254177.78.66.255126
135177.78.67.0/25177.78.67.1 to 177.78.67.126177.78.67.127126
136177.78.67.128/25177.78.67.129 to 177.78.67.254177.78.67.255126
137177.78.68.0/25177.78.68.1 to 177.78.68.126177.78.68.127126
138177.78.68.128/25177.78.68.129 to 177.78.68.254177.78.68.255126
139177.78.69.0/25177.78.69.1 to 177.78.69.126177.78.69.127126
140177.78.69.128/25177.78.69.129 to 177.78.69.254177.78.69.255126
141177.78.70.0/25177.78.70.1 to 177.78.70.126177.78.70.127126
142177.78.70.128/25177.78.70.129 to 177.78.70.254177.78.70.255126
143177.78.71.0/25177.78.71.1 to 177.78.71.126177.78.71.127126
144177.78.71.128/25177.78.71.129 to 177.78.71.254177.78.71.255126
145177.78.72.0/25177.78.72.1 to 177.78.72.126177.78.72.127126
146177.78.72.128/25177.78.72.129 to 177.78.72.254177.78.72.255126
147177.78.73.0/25177.78.73.1 to 177.78.73.126177.78.73.127126
148177.78.73.128/25177.78.73.129 to 177.78.73.254177.78.73.255126
149177.78.74.0/25177.78.74.1 to 177.78.74.126177.78.74.127126
150177.78.74.128/25177.78.74.129 to 177.78.74.254177.78.74.255126
151177.78.75.0/25177.78.75.1 to 177.78.75.126177.78.75.127126
152177.78.75.128/25177.78.75.129 to 177.78.75.254177.78.75.255126
153177.78.76.0/25177.78.76.1 to 177.78.76.126177.78.76.127126
154177.78.76.128/25177.78.76.129 to 177.78.76.254177.78.76.255126
155177.78.77.0/25177.78.77.1 to 177.78.77.126177.78.77.127126
156177.78.77.128/25177.78.77.129 to 177.78.77.254177.78.77.255126
157177.78.78.0/25177.78.78.1 to 177.78.78.126177.78.78.127126
158177.78.78.128/25177.78.78.129 to 177.78.78.254177.78.78.255126
159177.78.79.0/25177.78.79.1 to 177.78.79.126177.78.79.127126
160177.78.79.128/25177.78.79.129 to 177.78.79.254177.78.79.255126
161177.78.80.0/25177.78.80.1 to 177.78.80.126177.78.80.127126
162177.78.80.128/25177.78.80.129 to 177.78.80.254177.78.80.255126
163177.78.81.0/25177.78.81.1 to 177.78.81.126177.78.81.127126
164177.78.81.128/25177.78.81.129 to 177.78.81.254177.78.81.255126
165177.78.82.0/25177.78.82.1 to 177.78.82.126177.78.82.127126
166177.78.82.128/25177.78.82.129 to 177.78.82.254177.78.82.255126
167177.78.83.0/25177.78.83.1 to 177.78.83.126177.78.83.127126
168177.78.83.128/25177.78.83.129 to 177.78.83.254177.78.83.255126
169177.78.84.0/25177.78.84.1 to 177.78.84.126177.78.84.127126
170177.78.84.128/25177.78.84.129 to 177.78.84.254177.78.84.255126
171177.78.85.0/25177.78.85.1 to 177.78.85.126177.78.85.127126
172177.78.85.128/25177.78.85.129 to 177.78.85.254177.78.85.255126
173177.78.86.0/25177.78.86.1 to 177.78.86.126177.78.86.127126
174177.78.86.128/25177.78.86.129 to 177.78.86.254177.78.86.255126
175177.78.87.0/25177.78.87.1 to 177.78.87.126177.78.87.127126
176177.78.87.128/25177.78.87.129 to 177.78.87.254177.78.87.255126
177177.78.88.0/25177.78.88.1 to 177.78.88.126177.78.88.127126
178177.78.88.128/25177.78.88.129 to 177.78.88.254177.78.88.255126
179177.78.89.0/25177.78.89.1 to 177.78.89.126177.78.89.127126
180177.78.89.128/25177.78.89.129 to 177.78.89.254177.78.89.255126
181177.78.90.0/25177.78.90.1 to 177.78.90.126177.78.90.127126
182177.78.90.128/25177.78.90.129 to 177.78.90.254177.78.90.255126
183177.78.91.0/25177.78.91.1 to 177.78.91.126177.78.91.127126
184177.78.91.128/25177.78.91.129 to 177.78.91.254177.78.91.255126
185177.78.92.0/25177.78.92.1 to 177.78.92.126177.78.92.127126
186177.78.92.128/25177.78.92.129 to 177.78.92.254177.78.92.255126
187177.78.93.0/25177.78.93.1 to 177.78.93.126177.78.93.127126
188177.78.93.128/25177.78.93.129 to 177.78.93.254177.78.93.255126
189177.78.94.0/25177.78.94.1 to 177.78.94.126177.78.94.127126
190177.78.94.128/25177.78.94.129 to 177.78.94.254177.78.94.255126
191177.78.95.0/25177.78.95.1 to 177.78.95.126177.78.95.127126
192177.78.95.128/25177.78.95.129 to 177.78.95.254177.78.95.255126
193177.78.96.0/25177.78.96.1 to 177.78.96.126177.78.96.127126
194177.78.96.128/25177.78.96.129 to 177.78.96.254177.78.96.255126
195177.78.97.0/25177.78.97.1 to 177.78.97.126177.78.97.127126
196177.78.97.128/25177.78.97.129 to 177.78.97.254177.78.97.255126
197177.78.98.0/25177.78.98.1 to 177.78.98.126177.78.98.127126
198177.78.98.128/25177.78.98.129 to 177.78.98.254177.78.98.255126
199177.78.99.0/25177.78.99.1 to 177.78.99.126177.78.99.127126
200177.78.99.128/25177.78.99.129 to 177.78.99.254177.78.99.255126
201177.78.100.0/25177.78.100.1 to 177.78.100.126177.78.100.127126
202177.78.100.128/25177.78.100.129 to 177.78.100.254177.78.100.255126
203177.78.101.0/25177.78.101.1 to 177.78.101.126177.78.101.127126
204177.78.101.128/25177.78.101.129 to 177.78.101.254177.78.101.255126
205177.78.102.0/25177.78.102.1 to 177.78.102.126177.78.102.127126
206177.78.102.128/25177.78.102.129 to 177.78.102.254177.78.102.255126
207177.78.103.0/25177.78.103.1 to 177.78.103.126177.78.103.127126
208177.78.103.128/25177.78.103.129 to 177.78.103.254177.78.103.255126
209177.78.104.0/25177.78.104.1 to 177.78.104.126177.78.104.127126
210177.78.104.128/25177.78.104.129 to 177.78.104.254177.78.104.255126
211177.78.105.0/25177.78.105.1 to 177.78.105.126177.78.105.127126
212177.78.105.128/25177.78.105.129 to 177.78.105.254177.78.105.255126
213177.78.106.0/25177.78.106.1 to 177.78.106.126177.78.106.127126
214177.78.106.128/25177.78.106.129 to 177.78.106.254177.78.106.255126
215177.78.107.0/25177.78.107.1 to 177.78.107.126177.78.107.127126
216177.78.107.128/25177.78.107.129 to 177.78.107.254177.78.107.255126
217177.78.108.0/25177.78.108.1 to 177.78.108.126177.78.108.127126
218177.78.108.128/25177.78.108.129 to 177.78.108.254177.78.108.255126
219177.78.109.0/25177.78.109.1 to 177.78.109.126177.78.109.127126
220177.78.109.128/25177.78.109.129 to 177.78.109.254177.78.109.255126
221177.78.110.0/25177.78.110.1 to 177.78.110.126177.78.110.127126
222177.78.110.128/25177.78.110.129 to 177.78.110.254177.78.110.255126
223177.78.111.0/25177.78.111.1 to 177.78.111.126177.78.111.127126
224177.78.111.128/25177.78.111.129 to 177.78.111.254177.78.111.255126
225177.78.112.0/25177.78.112.1 to 177.78.112.126177.78.112.127126
226177.78.112.128/25177.78.112.129 to 177.78.112.254177.78.112.255126
227177.78.113.0/25177.78.113.1 to 177.78.113.126177.78.113.127126
228177.78.113.128/25177.78.113.129 to 177.78.113.254177.78.113.255126
229177.78.114.0/25177.78.114.1 to 177.78.114.126177.78.114.127126
230177.78.114.128/25177.78.114.129 to 177.78.114.254177.78.114.255126
231177.78.115.0/25177.78.115.1 to 177.78.115.126177.78.115.127126
232177.78.115.128/25177.78.115.129 to 177.78.115.254177.78.115.255126
233177.78.116.0/25177.78.116.1 to 177.78.116.126177.78.116.127126
234177.78.116.128/25177.78.116.129 to 177.78.116.254177.78.116.255126
235177.78.117.0/25177.78.117.1 to 177.78.117.126177.78.117.127126
236177.78.117.128/25177.78.117.129 to 177.78.117.254177.78.117.255126
237177.78.118.0/25177.78.118.1 to 177.78.118.126177.78.118.127126
238177.78.118.128/25177.78.118.129 to 177.78.118.254177.78.118.255126
239177.78.119.0/25177.78.119.1 to 177.78.119.126177.78.119.127126
240177.78.119.128/25177.78.119.129 to 177.78.119.254177.78.119.255126
241177.78.120.0/25177.78.120.1 to 177.78.120.126177.78.120.127126
242177.78.120.128/25177.78.120.129 to 177.78.120.254177.78.120.255126
243177.78.121.0/25177.78.121.1 to 177.78.121.126177.78.121.127126
244177.78.121.128/25177.78.121.129 to 177.78.121.254177.78.121.255126
245177.78.122.0/25177.78.122.1 to 177.78.122.126177.78.122.127126
246177.78.122.128/25177.78.122.129 to 177.78.122.254177.78.122.255126
247177.78.123.0/25177.78.123.1 to 177.78.123.126177.78.123.127126
248177.78.123.128/25177.78.123.129 to 177.78.123.254177.78.123.255126
249177.78.124.0/25177.78.124.1 to 177.78.124.126177.78.124.127126
250177.78.124.128/25177.78.124.129 to 177.78.124.254177.78.124.255126
251177.78.125.0/25177.78.125.1 to 177.78.125.126177.78.125.127126
252177.78.125.128/25177.78.125.129 to 177.78.125.254177.78.125.255126
253177.78.126.0/25177.78.126.1 to 177.78.126.126177.78.126.127126
254177.78.126.128/25177.78.126.129 to 177.78.126.254177.78.126.255126
255177.78.127.0/25177.78.127.1 to 177.78.127.126177.78.127.127126
256177.78.127.128/25177.78.127.129 to 177.78.127.254177.78.127.255126

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.