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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.

Network136.0.0.0/6
Usable hosts67,108,862
Subnet mask252.0.0.0
Addresses67,108,864
Network address
136.0.0.0
Broadcast address
139.255.255.255
First usable
136.0.0.1
Last usable
139.255.255.254
Usable hosts
67,108,862 (67,108,864 less the network and broadcast addresses)
Subnet mask
252.0.0.0
Wildcard mask
3.255.255.255 (Cisco ACLs, OSPF)
Prefix length
/6
Type
Public public
Old class
B (default /16)
As numbers
Hex 88000000 · Integer 2281701376 to 2348810239
Reverse DNS zones
136.in-addr.arpa
137.in-addr.arpa
138.in-addr.arpa
139.in-addr.arpa
/6 is not on a 8-bit boundary, so it takes 4 /8 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address10001000.00000000.00000000.00000000136.0.0.0
Subnet mask11111100.00000000.00000000.00000000252.0.0.0
Network10001000.00000000.00000000.00000000136.0.0.0
Broadcast10001011.11111111.11111111.11111111139.255.255.255
Split into smaller subnets/17
/7 (2)/8 (4)/9 (8)/10 (16)/11 (32)/12 (64)/13 (128)/14 (256)/15 (512)/16 (1,024)/17 (2,048)/18 (4,096)

136.0.0.0/6 makes 2,048 subnets of /17; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1136.0.0.0/17136.0.0.1 to 136.0.127.254136.0.127.25532,766
2136.0.128.0/17136.0.128.1 to 136.0.255.254136.0.255.25532,766
3136.1.0.0/17136.1.0.1 to 136.1.127.254136.1.127.25532,766
4136.1.128.0/17136.1.128.1 to 136.1.255.254136.1.255.25532,766
5136.2.0.0/17136.2.0.1 to 136.2.127.254136.2.127.25532,766
6136.2.128.0/17136.2.128.1 to 136.2.255.254136.2.255.25532,766
7136.3.0.0/17136.3.0.1 to 136.3.127.254136.3.127.25532,766
8136.3.128.0/17136.3.128.1 to 136.3.255.254136.3.255.25532,766
9136.4.0.0/17136.4.0.1 to 136.4.127.254136.4.127.25532,766
10136.4.128.0/17136.4.128.1 to 136.4.255.254136.4.255.25532,766
11136.5.0.0/17136.5.0.1 to 136.5.127.254136.5.127.25532,766
12136.5.128.0/17136.5.128.1 to 136.5.255.254136.5.255.25532,766
13136.6.0.0/17136.6.0.1 to 136.6.127.254136.6.127.25532,766
14136.6.128.0/17136.6.128.1 to 136.6.255.254136.6.255.25532,766
15136.7.0.0/17136.7.0.1 to 136.7.127.254136.7.127.25532,766
16136.7.128.0/17136.7.128.1 to 136.7.255.254136.7.255.25532,766
17136.8.0.0/17136.8.0.1 to 136.8.127.254136.8.127.25532,766
18136.8.128.0/17136.8.128.1 to 136.8.255.254136.8.255.25532,766
19136.9.0.0/17136.9.0.1 to 136.9.127.254136.9.127.25532,766
20136.9.128.0/17136.9.128.1 to 136.9.255.254136.9.255.25532,766
21136.10.0.0/17136.10.0.1 to 136.10.127.254136.10.127.25532,766
22136.10.128.0/17136.10.128.1 to 136.10.255.254136.10.255.25532,766
23136.11.0.0/17136.11.0.1 to 136.11.127.254136.11.127.25532,766
24136.11.128.0/17136.11.128.1 to 136.11.255.254136.11.255.25532,766
25136.12.0.0/17136.12.0.1 to 136.12.127.254136.12.127.25532,766
26136.12.128.0/17136.12.128.1 to 136.12.255.254136.12.255.25532,766
27136.13.0.0/17136.13.0.1 to 136.13.127.254136.13.127.25532,766
28136.13.128.0/17136.13.128.1 to 136.13.255.254136.13.255.25532,766
29136.14.0.0/17136.14.0.1 to 136.14.127.254136.14.127.25532,766
30136.14.128.0/17136.14.128.1 to 136.14.255.254136.14.255.25532,766
31136.15.0.0/17136.15.0.1 to 136.15.127.254136.15.127.25532,766
32136.15.128.0/17136.15.128.1 to 136.15.255.254136.15.255.25532,766
33136.16.0.0/17136.16.0.1 to 136.16.127.254136.16.127.25532,766
34136.16.128.0/17136.16.128.1 to 136.16.255.254136.16.255.25532,766
35136.17.0.0/17136.17.0.1 to 136.17.127.254136.17.127.25532,766
36136.17.128.0/17136.17.128.1 to 136.17.255.254136.17.255.25532,766
37136.18.0.0/17136.18.0.1 to 136.18.127.254136.18.127.25532,766
38136.18.128.0/17136.18.128.1 to 136.18.255.254136.18.255.25532,766
39136.19.0.0/17136.19.0.1 to 136.19.127.254136.19.127.25532,766
40136.19.128.0/17136.19.128.1 to 136.19.255.254136.19.255.25532,766
41136.20.0.0/17136.20.0.1 to 136.20.127.254136.20.127.25532,766
42136.20.128.0/17136.20.128.1 to 136.20.255.254136.20.255.25532,766
43136.21.0.0/17136.21.0.1 to 136.21.127.254136.21.127.25532,766
44136.21.128.0/17136.21.128.1 to 136.21.255.254136.21.255.25532,766
45136.22.0.0/17136.22.0.1 to 136.22.127.254136.22.127.25532,766
46136.22.128.0/17136.22.128.1 to 136.22.255.254136.22.255.25532,766
47136.23.0.0/17136.23.0.1 to 136.23.127.254136.23.127.25532,766
48136.23.128.0/17136.23.128.1 to 136.23.255.254136.23.255.25532,766
49136.24.0.0/17136.24.0.1 to 136.24.127.254136.24.127.25532,766
50136.24.128.0/17136.24.128.1 to 136.24.255.254136.24.255.25532,766
51136.25.0.0/17136.25.0.1 to 136.25.127.254136.25.127.25532,766
52136.25.128.0/17136.25.128.1 to 136.25.255.254136.25.255.25532,766
53136.26.0.0/17136.26.0.1 to 136.26.127.254136.26.127.25532,766
54136.26.128.0/17136.26.128.1 to 136.26.255.254136.26.255.25532,766
55136.27.0.0/17136.27.0.1 to 136.27.127.254136.27.127.25532,766
56136.27.128.0/17136.27.128.1 to 136.27.255.254136.27.255.25532,766
57136.28.0.0/17136.28.0.1 to 136.28.127.254136.28.127.25532,766
58136.28.128.0/17136.28.128.1 to 136.28.255.254136.28.255.25532,766
59136.29.0.0/17136.29.0.1 to 136.29.127.254136.29.127.25532,766
60136.29.128.0/17136.29.128.1 to 136.29.255.254136.29.255.25532,766
61136.30.0.0/17136.30.0.1 to 136.30.127.254136.30.127.25532,766
62136.30.128.0/17136.30.128.1 to 136.30.255.254136.30.255.25532,766
63136.31.0.0/17136.31.0.1 to 136.31.127.254136.31.127.25532,766
64136.31.128.0/17136.31.128.1 to 136.31.255.254136.31.255.25532,766
65136.32.0.0/17136.32.0.1 to 136.32.127.254136.32.127.25532,766
66136.32.128.0/17136.32.128.1 to 136.32.255.254136.32.255.25532,766
67136.33.0.0/17136.33.0.1 to 136.33.127.254136.33.127.25532,766
68136.33.128.0/17136.33.128.1 to 136.33.255.254136.33.255.25532,766
69136.34.0.0/17136.34.0.1 to 136.34.127.254136.34.127.25532,766
70136.34.128.0/17136.34.128.1 to 136.34.255.254136.34.255.25532,766
71136.35.0.0/17136.35.0.1 to 136.35.127.254136.35.127.25532,766
72136.35.128.0/17136.35.128.1 to 136.35.255.254136.35.255.25532,766
73136.36.0.0/17136.36.0.1 to 136.36.127.254136.36.127.25532,766
74136.36.128.0/17136.36.128.1 to 136.36.255.254136.36.255.25532,766
75136.37.0.0/17136.37.0.1 to 136.37.127.254136.37.127.25532,766
76136.37.128.0/17136.37.128.1 to 136.37.255.254136.37.255.25532,766
77136.38.0.0/17136.38.0.1 to 136.38.127.254136.38.127.25532,766
78136.38.128.0/17136.38.128.1 to 136.38.255.254136.38.255.25532,766
79136.39.0.0/17136.39.0.1 to 136.39.127.254136.39.127.25532,766
80136.39.128.0/17136.39.128.1 to 136.39.255.254136.39.255.25532,766
81136.40.0.0/17136.40.0.1 to 136.40.127.254136.40.127.25532,766
82136.40.128.0/17136.40.128.1 to 136.40.255.254136.40.255.25532,766
83136.41.0.0/17136.41.0.1 to 136.41.127.254136.41.127.25532,766
84136.41.128.0/17136.41.128.1 to 136.41.255.254136.41.255.25532,766
85136.42.0.0/17136.42.0.1 to 136.42.127.254136.42.127.25532,766
86136.42.128.0/17136.42.128.1 to 136.42.255.254136.42.255.25532,766
87136.43.0.0/17136.43.0.1 to 136.43.127.254136.43.127.25532,766
88136.43.128.0/17136.43.128.1 to 136.43.255.254136.43.255.25532,766
89136.44.0.0/17136.44.0.1 to 136.44.127.254136.44.127.25532,766
90136.44.128.0/17136.44.128.1 to 136.44.255.254136.44.255.25532,766
91136.45.0.0/17136.45.0.1 to 136.45.127.254136.45.127.25532,766
92136.45.128.0/17136.45.128.1 to 136.45.255.254136.45.255.25532,766
93136.46.0.0/17136.46.0.1 to 136.46.127.254136.46.127.25532,766
94136.46.128.0/17136.46.128.1 to 136.46.255.254136.46.255.25532,766
95136.47.0.0/17136.47.0.1 to 136.47.127.254136.47.127.25532,766
96136.47.128.0/17136.47.128.1 to 136.47.255.254136.47.255.25532,766
97136.48.0.0/17136.48.0.1 to 136.48.127.254136.48.127.25532,766
98136.48.128.0/17136.48.128.1 to 136.48.255.254136.48.255.25532,766
99136.49.0.0/17136.49.0.1 to 136.49.127.254136.49.127.25532,766
100136.49.128.0/17136.49.128.1 to 136.49.255.254136.49.255.25532,766
101136.50.0.0/17136.50.0.1 to 136.50.127.254136.50.127.25532,766
102136.50.128.0/17136.50.128.1 to 136.50.255.254136.50.255.25532,766
103136.51.0.0/17136.51.0.1 to 136.51.127.254136.51.127.25532,766
104136.51.128.0/17136.51.128.1 to 136.51.255.254136.51.255.25532,766
105136.52.0.0/17136.52.0.1 to 136.52.127.254136.52.127.25532,766
106136.52.128.0/17136.52.128.1 to 136.52.255.254136.52.255.25532,766
107136.53.0.0/17136.53.0.1 to 136.53.127.254136.53.127.25532,766
108136.53.128.0/17136.53.128.1 to 136.53.255.254136.53.255.25532,766
109136.54.0.0/17136.54.0.1 to 136.54.127.254136.54.127.25532,766
110136.54.128.0/17136.54.128.1 to 136.54.255.254136.54.255.25532,766
111136.55.0.0/17136.55.0.1 to 136.55.127.254136.55.127.25532,766
112136.55.128.0/17136.55.128.1 to 136.55.255.254136.55.255.25532,766
113136.56.0.0/17136.56.0.1 to 136.56.127.254136.56.127.25532,766
114136.56.128.0/17136.56.128.1 to 136.56.255.254136.56.255.25532,766
115136.57.0.0/17136.57.0.1 to 136.57.127.254136.57.127.25532,766
116136.57.128.0/17136.57.128.1 to 136.57.255.254136.57.255.25532,766
117136.58.0.0/17136.58.0.1 to 136.58.127.254136.58.127.25532,766
118136.58.128.0/17136.58.128.1 to 136.58.255.254136.58.255.25532,766
119136.59.0.0/17136.59.0.1 to 136.59.127.254136.59.127.25532,766
120136.59.128.0/17136.59.128.1 to 136.59.255.254136.59.255.25532,766
121136.60.0.0/17136.60.0.1 to 136.60.127.254136.60.127.25532,766
122136.60.128.0/17136.60.128.1 to 136.60.255.254136.60.255.25532,766
123136.61.0.0/17136.61.0.1 to 136.61.127.254136.61.127.25532,766
124136.61.128.0/17136.61.128.1 to 136.61.255.254136.61.255.25532,766
125136.62.0.0/17136.62.0.1 to 136.62.127.254136.62.127.25532,766
126136.62.128.0/17136.62.128.1 to 136.62.255.254136.62.255.25532,766
127136.63.0.0/17136.63.0.1 to 136.63.127.254136.63.127.25532,766
128136.63.128.0/17136.63.128.1 to 136.63.255.254136.63.255.25532,766
129136.64.0.0/17136.64.0.1 to 136.64.127.254136.64.127.25532,766
130136.64.128.0/17136.64.128.1 to 136.64.255.254136.64.255.25532,766
131136.65.0.0/17136.65.0.1 to 136.65.127.254136.65.127.25532,766
132136.65.128.0/17136.65.128.1 to 136.65.255.254136.65.255.25532,766
133136.66.0.0/17136.66.0.1 to 136.66.127.254136.66.127.25532,766
134136.66.128.0/17136.66.128.1 to 136.66.255.254136.66.255.25532,766
135136.67.0.0/17136.67.0.1 to 136.67.127.254136.67.127.25532,766
136136.67.128.0/17136.67.128.1 to 136.67.255.254136.67.255.25532,766
137136.68.0.0/17136.68.0.1 to 136.68.127.254136.68.127.25532,766
138136.68.128.0/17136.68.128.1 to 136.68.255.254136.68.255.25532,766
139136.69.0.0/17136.69.0.1 to 136.69.127.254136.69.127.25532,766
140136.69.128.0/17136.69.128.1 to 136.69.255.254136.69.255.25532,766
141136.70.0.0/17136.70.0.1 to 136.70.127.254136.70.127.25532,766
142136.70.128.0/17136.70.128.1 to 136.70.255.254136.70.255.25532,766
143136.71.0.0/17136.71.0.1 to 136.71.127.254136.71.127.25532,766
144136.71.128.0/17136.71.128.1 to 136.71.255.254136.71.255.25532,766
145136.72.0.0/17136.72.0.1 to 136.72.127.254136.72.127.25532,766
146136.72.128.0/17136.72.128.1 to 136.72.255.254136.72.255.25532,766
147136.73.0.0/17136.73.0.1 to 136.73.127.254136.73.127.25532,766
148136.73.128.0/17136.73.128.1 to 136.73.255.254136.73.255.25532,766
149136.74.0.0/17136.74.0.1 to 136.74.127.254136.74.127.25532,766
150136.74.128.0/17136.74.128.1 to 136.74.255.254136.74.255.25532,766
151136.75.0.0/17136.75.0.1 to 136.75.127.254136.75.127.25532,766
152136.75.128.0/17136.75.128.1 to 136.75.255.254136.75.255.25532,766
153136.76.0.0/17136.76.0.1 to 136.76.127.254136.76.127.25532,766
154136.76.128.0/17136.76.128.1 to 136.76.255.254136.76.255.25532,766
155136.77.0.0/17136.77.0.1 to 136.77.127.254136.77.127.25532,766
156136.77.128.0/17136.77.128.1 to 136.77.255.254136.77.255.25532,766
157136.78.0.0/17136.78.0.1 to 136.78.127.254136.78.127.25532,766
158136.78.128.0/17136.78.128.1 to 136.78.255.254136.78.255.25532,766
159136.79.0.0/17136.79.0.1 to 136.79.127.254136.79.127.25532,766
160136.79.128.0/17136.79.128.1 to 136.79.255.254136.79.255.25532,766
161136.80.0.0/17136.80.0.1 to 136.80.127.254136.80.127.25532,766
162136.80.128.0/17136.80.128.1 to 136.80.255.254136.80.255.25532,766
163136.81.0.0/17136.81.0.1 to 136.81.127.254136.81.127.25532,766
164136.81.128.0/17136.81.128.1 to 136.81.255.254136.81.255.25532,766
165136.82.0.0/17136.82.0.1 to 136.82.127.254136.82.127.25532,766
166136.82.128.0/17136.82.128.1 to 136.82.255.254136.82.255.25532,766
167136.83.0.0/17136.83.0.1 to 136.83.127.254136.83.127.25532,766
168136.83.128.0/17136.83.128.1 to 136.83.255.254136.83.255.25532,766
169136.84.0.0/17136.84.0.1 to 136.84.127.254136.84.127.25532,766
170136.84.128.0/17136.84.128.1 to 136.84.255.254136.84.255.25532,766
171136.85.0.0/17136.85.0.1 to 136.85.127.254136.85.127.25532,766
172136.85.128.0/17136.85.128.1 to 136.85.255.254136.85.255.25532,766
173136.86.0.0/17136.86.0.1 to 136.86.127.254136.86.127.25532,766
174136.86.128.0/17136.86.128.1 to 136.86.255.254136.86.255.25532,766
175136.87.0.0/17136.87.0.1 to 136.87.127.254136.87.127.25532,766
176136.87.128.0/17136.87.128.1 to 136.87.255.254136.87.255.25532,766
177136.88.0.0/17136.88.0.1 to 136.88.127.254136.88.127.25532,766
178136.88.128.0/17136.88.128.1 to 136.88.255.254136.88.255.25532,766
179136.89.0.0/17136.89.0.1 to 136.89.127.254136.89.127.25532,766
180136.89.128.0/17136.89.128.1 to 136.89.255.254136.89.255.25532,766
181136.90.0.0/17136.90.0.1 to 136.90.127.254136.90.127.25532,766
182136.90.128.0/17136.90.128.1 to 136.90.255.254136.90.255.25532,766
183136.91.0.0/17136.91.0.1 to 136.91.127.254136.91.127.25532,766
184136.91.128.0/17136.91.128.1 to 136.91.255.254136.91.255.25532,766
185136.92.0.0/17136.92.0.1 to 136.92.127.254136.92.127.25532,766
186136.92.128.0/17136.92.128.1 to 136.92.255.254136.92.255.25532,766
187136.93.0.0/17136.93.0.1 to 136.93.127.254136.93.127.25532,766
188136.93.128.0/17136.93.128.1 to 136.93.255.254136.93.255.25532,766
189136.94.0.0/17136.94.0.1 to 136.94.127.254136.94.127.25532,766
190136.94.128.0/17136.94.128.1 to 136.94.255.254136.94.255.25532,766
191136.95.0.0/17136.95.0.1 to 136.95.127.254136.95.127.25532,766
192136.95.128.0/17136.95.128.1 to 136.95.255.254136.95.255.25532,766
193136.96.0.0/17136.96.0.1 to 136.96.127.254136.96.127.25532,766
194136.96.128.0/17136.96.128.1 to 136.96.255.254136.96.255.25532,766
195136.97.0.0/17136.97.0.1 to 136.97.127.254136.97.127.25532,766
196136.97.128.0/17136.97.128.1 to 136.97.255.254136.97.255.25532,766
197136.98.0.0/17136.98.0.1 to 136.98.127.254136.98.127.25532,766
198136.98.128.0/17136.98.128.1 to 136.98.255.254136.98.255.25532,766
199136.99.0.0/17136.99.0.1 to 136.99.127.254136.99.127.25532,766
200136.99.128.0/17136.99.128.1 to 136.99.255.254136.99.255.25532,766
201136.100.0.0/17136.100.0.1 to 136.100.127.254136.100.127.25532,766
202136.100.128.0/17136.100.128.1 to 136.100.255.254136.100.255.25532,766
203136.101.0.0/17136.101.0.1 to 136.101.127.254136.101.127.25532,766
204136.101.128.0/17136.101.128.1 to 136.101.255.254136.101.255.25532,766
205136.102.0.0/17136.102.0.1 to 136.102.127.254136.102.127.25532,766
206136.102.128.0/17136.102.128.1 to 136.102.255.254136.102.255.25532,766
207136.103.0.0/17136.103.0.1 to 136.103.127.254136.103.127.25532,766
208136.103.128.0/17136.103.128.1 to 136.103.255.254136.103.255.25532,766
209136.104.0.0/17136.104.0.1 to 136.104.127.254136.104.127.25532,766
210136.104.128.0/17136.104.128.1 to 136.104.255.254136.104.255.25532,766
211136.105.0.0/17136.105.0.1 to 136.105.127.254136.105.127.25532,766
212136.105.128.0/17136.105.128.1 to 136.105.255.254136.105.255.25532,766
213136.106.0.0/17136.106.0.1 to 136.106.127.254136.106.127.25532,766
214136.106.128.0/17136.106.128.1 to 136.106.255.254136.106.255.25532,766
215136.107.0.0/17136.107.0.1 to 136.107.127.254136.107.127.25532,766
216136.107.128.0/17136.107.128.1 to 136.107.255.254136.107.255.25532,766
217136.108.0.0/17136.108.0.1 to 136.108.127.254136.108.127.25532,766
218136.108.128.0/17136.108.128.1 to 136.108.255.254136.108.255.25532,766
219136.109.0.0/17136.109.0.1 to 136.109.127.254136.109.127.25532,766
220136.109.128.0/17136.109.128.1 to 136.109.255.254136.109.255.25532,766
221136.110.0.0/17136.110.0.1 to 136.110.127.254136.110.127.25532,766
222136.110.128.0/17136.110.128.1 to 136.110.255.254136.110.255.25532,766
223136.111.0.0/17136.111.0.1 to 136.111.127.254136.111.127.25532,766
224136.111.128.0/17136.111.128.1 to 136.111.255.254136.111.255.25532,766
225136.112.0.0/17136.112.0.1 to 136.112.127.254136.112.127.25532,766
226136.112.128.0/17136.112.128.1 to 136.112.255.254136.112.255.25532,766
227136.113.0.0/17136.113.0.1 to 136.113.127.254136.113.127.25532,766
228136.113.128.0/17136.113.128.1 to 136.113.255.254136.113.255.25532,766
229136.114.0.0/17136.114.0.1 to 136.114.127.254136.114.127.25532,766
230136.114.128.0/17136.114.128.1 to 136.114.255.254136.114.255.25532,766
231136.115.0.0/17136.115.0.1 to 136.115.127.254136.115.127.25532,766
232136.115.128.0/17136.115.128.1 to 136.115.255.254136.115.255.25532,766
233136.116.0.0/17136.116.0.1 to 136.116.127.254136.116.127.25532,766
234136.116.128.0/17136.116.128.1 to 136.116.255.254136.116.255.25532,766
235136.117.0.0/17136.117.0.1 to 136.117.127.254136.117.127.25532,766
236136.117.128.0/17136.117.128.1 to 136.117.255.254136.117.255.25532,766
237136.118.0.0/17136.118.0.1 to 136.118.127.254136.118.127.25532,766
238136.118.128.0/17136.118.128.1 to 136.118.255.254136.118.255.25532,766
239136.119.0.0/17136.119.0.1 to 136.119.127.254136.119.127.25532,766
240136.119.128.0/17136.119.128.1 to 136.119.255.254136.119.255.25532,766
241136.120.0.0/17136.120.0.1 to 136.120.127.254136.120.127.25532,766
242136.120.128.0/17136.120.128.1 to 136.120.255.254136.120.255.25532,766
243136.121.0.0/17136.121.0.1 to 136.121.127.254136.121.127.25532,766
244136.121.128.0/17136.121.128.1 to 136.121.255.254136.121.255.25532,766
245136.122.0.0/17136.122.0.1 to 136.122.127.254136.122.127.25532,766
246136.122.128.0/17136.122.128.1 to 136.122.255.254136.122.255.25532,766
247136.123.0.0/17136.123.0.1 to 136.123.127.254136.123.127.25532,766
248136.123.128.0/17136.123.128.1 to 136.123.255.254136.123.255.25532,766
249136.124.0.0/17136.124.0.1 to 136.124.127.254136.124.127.25532,766
250136.124.128.0/17136.124.128.1 to 136.124.255.254136.124.255.25532,766
251136.125.0.0/17136.125.0.1 to 136.125.127.254136.125.127.25532,766
252136.125.128.0/17136.125.128.1 to 136.125.255.254136.125.255.25532,766
253136.126.0.0/17136.126.0.1 to 136.126.127.254136.126.127.25532,766
254136.126.128.0/17136.126.128.1 to 136.126.255.254136.126.255.25532,766
255136.127.0.0/17136.127.0.1 to 136.127.127.254136.127.127.25532,766
256136.127.128.0/17136.127.128.1 to 136.127.255.254136.127.255.25532,766

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.