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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.

Network136.34.0.0/17
Usable hosts32,766
Subnet mask255.255.128.0
Addresses32,768
Network address
136.34.0.0
Broadcast address
136.34.127.255
First usable
136.34.0.1
Last usable
136.34.127.254
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 88220000 · Integer 2283929600 to 2283962367
Reverse DNS zones
0.34.136.in-addr.arpa
1.34.136.in-addr.arpa
2.34.136.in-addr.arpa
3.34.136.in-addr.arpa
4.34.136.in-addr.arpa
5.34.136.in-addr.arpa
6.34.136.in-addr.arpa
7.34.136.in-addr.arpa
8.34.136.in-addr.arpa
9.34.136.in-addr.arpa
10.34.136.in-addr.arpa
11.34.136.in-addr.arpa
12.34.136.in-addr.arpa
13.34.136.in-addr.arpa
14.34.136.in-addr.arpa
15.34.136.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
Address10001000.00100010.00000000.00000000136.34.0.0
Subnet mask11111111.11111111.10000000.00000000255.255.128.0
Network10001000.00100010.00000000.00000000136.34.0.0
Broadcast10001000.00100010.01111111.11111111136.34.127.255
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)

136.34.0.0/17 makes 256 subnets of /25.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1136.34.0.0/25136.34.0.1 to 136.34.0.126136.34.0.127126
2136.34.0.128/25136.34.0.129 to 136.34.0.254136.34.0.255126
3136.34.1.0/25136.34.1.1 to 136.34.1.126136.34.1.127126
4136.34.1.128/25136.34.1.129 to 136.34.1.254136.34.1.255126
5136.34.2.0/25136.34.2.1 to 136.34.2.126136.34.2.127126
6136.34.2.128/25136.34.2.129 to 136.34.2.254136.34.2.255126
7136.34.3.0/25136.34.3.1 to 136.34.3.126136.34.3.127126
8136.34.3.128/25136.34.3.129 to 136.34.3.254136.34.3.255126
9136.34.4.0/25136.34.4.1 to 136.34.4.126136.34.4.127126
10136.34.4.128/25136.34.4.129 to 136.34.4.254136.34.4.255126
11136.34.5.0/25136.34.5.1 to 136.34.5.126136.34.5.127126
12136.34.5.128/25136.34.5.129 to 136.34.5.254136.34.5.255126
13136.34.6.0/25136.34.6.1 to 136.34.6.126136.34.6.127126
14136.34.6.128/25136.34.6.129 to 136.34.6.254136.34.6.255126
15136.34.7.0/25136.34.7.1 to 136.34.7.126136.34.7.127126
16136.34.7.128/25136.34.7.129 to 136.34.7.254136.34.7.255126
17136.34.8.0/25136.34.8.1 to 136.34.8.126136.34.8.127126
18136.34.8.128/25136.34.8.129 to 136.34.8.254136.34.8.255126
19136.34.9.0/25136.34.9.1 to 136.34.9.126136.34.9.127126
20136.34.9.128/25136.34.9.129 to 136.34.9.254136.34.9.255126
21136.34.10.0/25136.34.10.1 to 136.34.10.126136.34.10.127126
22136.34.10.128/25136.34.10.129 to 136.34.10.254136.34.10.255126
23136.34.11.0/25136.34.11.1 to 136.34.11.126136.34.11.127126
24136.34.11.128/25136.34.11.129 to 136.34.11.254136.34.11.255126
25136.34.12.0/25136.34.12.1 to 136.34.12.126136.34.12.127126
26136.34.12.128/25136.34.12.129 to 136.34.12.254136.34.12.255126
27136.34.13.0/25136.34.13.1 to 136.34.13.126136.34.13.127126
28136.34.13.128/25136.34.13.129 to 136.34.13.254136.34.13.255126
29136.34.14.0/25136.34.14.1 to 136.34.14.126136.34.14.127126
30136.34.14.128/25136.34.14.129 to 136.34.14.254136.34.14.255126
31136.34.15.0/25136.34.15.1 to 136.34.15.126136.34.15.127126
32136.34.15.128/25136.34.15.129 to 136.34.15.254136.34.15.255126
33136.34.16.0/25136.34.16.1 to 136.34.16.126136.34.16.127126
34136.34.16.128/25136.34.16.129 to 136.34.16.254136.34.16.255126
35136.34.17.0/25136.34.17.1 to 136.34.17.126136.34.17.127126
36136.34.17.128/25136.34.17.129 to 136.34.17.254136.34.17.255126
37136.34.18.0/25136.34.18.1 to 136.34.18.126136.34.18.127126
38136.34.18.128/25136.34.18.129 to 136.34.18.254136.34.18.255126
39136.34.19.0/25136.34.19.1 to 136.34.19.126136.34.19.127126
40136.34.19.128/25136.34.19.129 to 136.34.19.254136.34.19.255126
41136.34.20.0/25136.34.20.1 to 136.34.20.126136.34.20.127126
42136.34.20.128/25136.34.20.129 to 136.34.20.254136.34.20.255126
43136.34.21.0/25136.34.21.1 to 136.34.21.126136.34.21.127126
44136.34.21.128/25136.34.21.129 to 136.34.21.254136.34.21.255126
45136.34.22.0/25136.34.22.1 to 136.34.22.126136.34.22.127126
46136.34.22.128/25136.34.22.129 to 136.34.22.254136.34.22.255126
47136.34.23.0/25136.34.23.1 to 136.34.23.126136.34.23.127126
48136.34.23.128/25136.34.23.129 to 136.34.23.254136.34.23.255126
49136.34.24.0/25136.34.24.1 to 136.34.24.126136.34.24.127126
50136.34.24.128/25136.34.24.129 to 136.34.24.254136.34.24.255126
51136.34.25.0/25136.34.25.1 to 136.34.25.126136.34.25.127126
52136.34.25.128/25136.34.25.129 to 136.34.25.254136.34.25.255126
53136.34.26.0/25136.34.26.1 to 136.34.26.126136.34.26.127126
54136.34.26.128/25136.34.26.129 to 136.34.26.254136.34.26.255126
55136.34.27.0/25136.34.27.1 to 136.34.27.126136.34.27.127126
56136.34.27.128/25136.34.27.129 to 136.34.27.254136.34.27.255126
57136.34.28.0/25136.34.28.1 to 136.34.28.126136.34.28.127126
58136.34.28.128/25136.34.28.129 to 136.34.28.254136.34.28.255126
59136.34.29.0/25136.34.29.1 to 136.34.29.126136.34.29.127126
60136.34.29.128/25136.34.29.129 to 136.34.29.254136.34.29.255126
61136.34.30.0/25136.34.30.1 to 136.34.30.126136.34.30.127126
62136.34.30.128/25136.34.30.129 to 136.34.30.254136.34.30.255126
63136.34.31.0/25136.34.31.1 to 136.34.31.126136.34.31.127126
64136.34.31.128/25136.34.31.129 to 136.34.31.254136.34.31.255126
65136.34.32.0/25136.34.32.1 to 136.34.32.126136.34.32.127126
66136.34.32.128/25136.34.32.129 to 136.34.32.254136.34.32.255126
67136.34.33.0/25136.34.33.1 to 136.34.33.126136.34.33.127126
68136.34.33.128/25136.34.33.129 to 136.34.33.254136.34.33.255126
69136.34.34.0/25136.34.34.1 to 136.34.34.126136.34.34.127126
70136.34.34.128/25136.34.34.129 to 136.34.34.254136.34.34.255126
71136.34.35.0/25136.34.35.1 to 136.34.35.126136.34.35.127126
72136.34.35.128/25136.34.35.129 to 136.34.35.254136.34.35.255126
73136.34.36.0/25136.34.36.1 to 136.34.36.126136.34.36.127126
74136.34.36.128/25136.34.36.129 to 136.34.36.254136.34.36.255126
75136.34.37.0/25136.34.37.1 to 136.34.37.126136.34.37.127126
76136.34.37.128/25136.34.37.129 to 136.34.37.254136.34.37.255126
77136.34.38.0/25136.34.38.1 to 136.34.38.126136.34.38.127126
78136.34.38.128/25136.34.38.129 to 136.34.38.254136.34.38.255126
79136.34.39.0/25136.34.39.1 to 136.34.39.126136.34.39.127126
80136.34.39.128/25136.34.39.129 to 136.34.39.254136.34.39.255126
81136.34.40.0/25136.34.40.1 to 136.34.40.126136.34.40.127126
82136.34.40.128/25136.34.40.129 to 136.34.40.254136.34.40.255126
83136.34.41.0/25136.34.41.1 to 136.34.41.126136.34.41.127126
84136.34.41.128/25136.34.41.129 to 136.34.41.254136.34.41.255126
85136.34.42.0/25136.34.42.1 to 136.34.42.126136.34.42.127126
86136.34.42.128/25136.34.42.129 to 136.34.42.254136.34.42.255126
87136.34.43.0/25136.34.43.1 to 136.34.43.126136.34.43.127126
88136.34.43.128/25136.34.43.129 to 136.34.43.254136.34.43.255126
89136.34.44.0/25136.34.44.1 to 136.34.44.126136.34.44.127126
90136.34.44.128/25136.34.44.129 to 136.34.44.254136.34.44.255126
91136.34.45.0/25136.34.45.1 to 136.34.45.126136.34.45.127126
92136.34.45.128/25136.34.45.129 to 136.34.45.254136.34.45.255126
93136.34.46.0/25136.34.46.1 to 136.34.46.126136.34.46.127126
94136.34.46.128/25136.34.46.129 to 136.34.46.254136.34.46.255126
95136.34.47.0/25136.34.47.1 to 136.34.47.126136.34.47.127126
96136.34.47.128/25136.34.47.129 to 136.34.47.254136.34.47.255126
97136.34.48.0/25136.34.48.1 to 136.34.48.126136.34.48.127126
98136.34.48.128/25136.34.48.129 to 136.34.48.254136.34.48.255126
99136.34.49.0/25136.34.49.1 to 136.34.49.126136.34.49.127126
100136.34.49.128/25136.34.49.129 to 136.34.49.254136.34.49.255126
101136.34.50.0/25136.34.50.1 to 136.34.50.126136.34.50.127126
102136.34.50.128/25136.34.50.129 to 136.34.50.254136.34.50.255126
103136.34.51.0/25136.34.51.1 to 136.34.51.126136.34.51.127126
104136.34.51.128/25136.34.51.129 to 136.34.51.254136.34.51.255126
105136.34.52.0/25136.34.52.1 to 136.34.52.126136.34.52.127126
106136.34.52.128/25136.34.52.129 to 136.34.52.254136.34.52.255126
107136.34.53.0/25136.34.53.1 to 136.34.53.126136.34.53.127126
108136.34.53.128/25136.34.53.129 to 136.34.53.254136.34.53.255126
109136.34.54.0/25136.34.54.1 to 136.34.54.126136.34.54.127126
110136.34.54.128/25136.34.54.129 to 136.34.54.254136.34.54.255126
111136.34.55.0/25136.34.55.1 to 136.34.55.126136.34.55.127126
112136.34.55.128/25136.34.55.129 to 136.34.55.254136.34.55.255126
113136.34.56.0/25136.34.56.1 to 136.34.56.126136.34.56.127126
114136.34.56.128/25136.34.56.129 to 136.34.56.254136.34.56.255126
115136.34.57.0/25136.34.57.1 to 136.34.57.126136.34.57.127126
116136.34.57.128/25136.34.57.129 to 136.34.57.254136.34.57.255126
117136.34.58.0/25136.34.58.1 to 136.34.58.126136.34.58.127126
118136.34.58.128/25136.34.58.129 to 136.34.58.254136.34.58.255126
119136.34.59.0/25136.34.59.1 to 136.34.59.126136.34.59.127126
120136.34.59.128/25136.34.59.129 to 136.34.59.254136.34.59.255126
121136.34.60.0/25136.34.60.1 to 136.34.60.126136.34.60.127126
122136.34.60.128/25136.34.60.129 to 136.34.60.254136.34.60.255126
123136.34.61.0/25136.34.61.1 to 136.34.61.126136.34.61.127126
124136.34.61.128/25136.34.61.129 to 136.34.61.254136.34.61.255126
125136.34.62.0/25136.34.62.1 to 136.34.62.126136.34.62.127126
126136.34.62.128/25136.34.62.129 to 136.34.62.254136.34.62.255126
127136.34.63.0/25136.34.63.1 to 136.34.63.126136.34.63.127126
128136.34.63.128/25136.34.63.129 to 136.34.63.254136.34.63.255126
129136.34.64.0/25136.34.64.1 to 136.34.64.126136.34.64.127126
130136.34.64.128/25136.34.64.129 to 136.34.64.254136.34.64.255126
131136.34.65.0/25136.34.65.1 to 136.34.65.126136.34.65.127126
132136.34.65.128/25136.34.65.129 to 136.34.65.254136.34.65.255126
133136.34.66.0/25136.34.66.1 to 136.34.66.126136.34.66.127126
134136.34.66.128/25136.34.66.129 to 136.34.66.254136.34.66.255126
135136.34.67.0/25136.34.67.1 to 136.34.67.126136.34.67.127126
136136.34.67.128/25136.34.67.129 to 136.34.67.254136.34.67.255126
137136.34.68.0/25136.34.68.1 to 136.34.68.126136.34.68.127126
138136.34.68.128/25136.34.68.129 to 136.34.68.254136.34.68.255126
139136.34.69.0/25136.34.69.1 to 136.34.69.126136.34.69.127126
140136.34.69.128/25136.34.69.129 to 136.34.69.254136.34.69.255126
141136.34.70.0/25136.34.70.1 to 136.34.70.126136.34.70.127126
142136.34.70.128/25136.34.70.129 to 136.34.70.254136.34.70.255126
143136.34.71.0/25136.34.71.1 to 136.34.71.126136.34.71.127126
144136.34.71.128/25136.34.71.129 to 136.34.71.254136.34.71.255126
145136.34.72.0/25136.34.72.1 to 136.34.72.126136.34.72.127126
146136.34.72.128/25136.34.72.129 to 136.34.72.254136.34.72.255126
147136.34.73.0/25136.34.73.1 to 136.34.73.126136.34.73.127126
148136.34.73.128/25136.34.73.129 to 136.34.73.254136.34.73.255126
149136.34.74.0/25136.34.74.1 to 136.34.74.126136.34.74.127126
150136.34.74.128/25136.34.74.129 to 136.34.74.254136.34.74.255126
151136.34.75.0/25136.34.75.1 to 136.34.75.126136.34.75.127126
152136.34.75.128/25136.34.75.129 to 136.34.75.254136.34.75.255126
153136.34.76.0/25136.34.76.1 to 136.34.76.126136.34.76.127126
154136.34.76.128/25136.34.76.129 to 136.34.76.254136.34.76.255126
155136.34.77.0/25136.34.77.1 to 136.34.77.126136.34.77.127126
156136.34.77.128/25136.34.77.129 to 136.34.77.254136.34.77.255126
157136.34.78.0/25136.34.78.1 to 136.34.78.126136.34.78.127126
158136.34.78.128/25136.34.78.129 to 136.34.78.254136.34.78.255126
159136.34.79.0/25136.34.79.1 to 136.34.79.126136.34.79.127126
160136.34.79.128/25136.34.79.129 to 136.34.79.254136.34.79.255126
161136.34.80.0/25136.34.80.1 to 136.34.80.126136.34.80.127126
162136.34.80.128/25136.34.80.129 to 136.34.80.254136.34.80.255126
163136.34.81.0/25136.34.81.1 to 136.34.81.126136.34.81.127126
164136.34.81.128/25136.34.81.129 to 136.34.81.254136.34.81.255126
165136.34.82.0/25136.34.82.1 to 136.34.82.126136.34.82.127126
166136.34.82.128/25136.34.82.129 to 136.34.82.254136.34.82.255126
167136.34.83.0/25136.34.83.1 to 136.34.83.126136.34.83.127126
168136.34.83.128/25136.34.83.129 to 136.34.83.254136.34.83.255126
169136.34.84.0/25136.34.84.1 to 136.34.84.126136.34.84.127126
170136.34.84.128/25136.34.84.129 to 136.34.84.254136.34.84.255126
171136.34.85.0/25136.34.85.1 to 136.34.85.126136.34.85.127126
172136.34.85.128/25136.34.85.129 to 136.34.85.254136.34.85.255126
173136.34.86.0/25136.34.86.1 to 136.34.86.126136.34.86.127126
174136.34.86.128/25136.34.86.129 to 136.34.86.254136.34.86.255126
175136.34.87.0/25136.34.87.1 to 136.34.87.126136.34.87.127126
176136.34.87.128/25136.34.87.129 to 136.34.87.254136.34.87.255126
177136.34.88.0/25136.34.88.1 to 136.34.88.126136.34.88.127126
178136.34.88.128/25136.34.88.129 to 136.34.88.254136.34.88.255126
179136.34.89.0/25136.34.89.1 to 136.34.89.126136.34.89.127126
180136.34.89.128/25136.34.89.129 to 136.34.89.254136.34.89.255126
181136.34.90.0/25136.34.90.1 to 136.34.90.126136.34.90.127126
182136.34.90.128/25136.34.90.129 to 136.34.90.254136.34.90.255126
183136.34.91.0/25136.34.91.1 to 136.34.91.126136.34.91.127126
184136.34.91.128/25136.34.91.129 to 136.34.91.254136.34.91.255126
185136.34.92.0/25136.34.92.1 to 136.34.92.126136.34.92.127126
186136.34.92.128/25136.34.92.129 to 136.34.92.254136.34.92.255126
187136.34.93.0/25136.34.93.1 to 136.34.93.126136.34.93.127126
188136.34.93.128/25136.34.93.129 to 136.34.93.254136.34.93.255126
189136.34.94.0/25136.34.94.1 to 136.34.94.126136.34.94.127126
190136.34.94.128/25136.34.94.129 to 136.34.94.254136.34.94.255126
191136.34.95.0/25136.34.95.1 to 136.34.95.126136.34.95.127126
192136.34.95.128/25136.34.95.129 to 136.34.95.254136.34.95.255126
193136.34.96.0/25136.34.96.1 to 136.34.96.126136.34.96.127126
194136.34.96.128/25136.34.96.129 to 136.34.96.254136.34.96.255126
195136.34.97.0/25136.34.97.1 to 136.34.97.126136.34.97.127126
196136.34.97.128/25136.34.97.129 to 136.34.97.254136.34.97.255126
197136.34.98.0/25136.34.98.1 to 136.34.98.126136.34.98.127126
198136.34.98.128/25136.34.98.129 to 136.34.98.254136.34.98.255126
199136.34.99.0/25136.34.99.1 to 136.34.99.126136.34.99.127126
200136.34.99.128/25136.34.99.129 to 136.34.99.254136.34.99.255126
201136.34.100.0/25136.34.100.1 to 136.34.100.126136.34.100.127126
202136.34.100.128/25136.34.100.129 to 136.34.100.254136.34.100.255126
203136.34.101.0/25136.34.101.1 to 136.34.101.126136.34.101.127126
204136.34.101.128/25136.34.101.129 to 136.34.101.254136.34.101.255126
205136.34.102.0/25136.34.102.1 to 136.34.102.126136.34.102.127126
206136.34.102.128/25136.34.102.129 to 136.34.102.254136.34.102.255126
207136.34.103.0/25136.34.103.1 to 136.34.103.126136.34.103.127126
208136.34.103.128/25136.34.103.129 to 136.34.103.254136.34.103.255126
209136.34.104.0/25136.34.104.1 to 136.34.104.126136.34.104.127126
210136.34.104.128/25136.34.104.129 to 136.34.104.254136.34.104.255126
211136.34.105.0/25136.34.105.1 to 136.34.105.126136.34.105.127126
212136.34.105.128/25136.34.105.129 to 136.34.105.254136.34.105.255126
213136.34.106.0/25136.34.106.1 to 136.34.106.126136.34.106.127126
214136.34.106.128/25136.34.106.129 to 136.34.106.254136.34.106.255126
215136.34.107.0/25136.34.107.1 to 136.34.107.126136.34.107.127126
216136.34.107.128/25136.34.107.129 to 136.34.107.254136.34.107.255126
217136.34.108.0/25136.34.108.1 to 136.34.108.126136.34.108.127126
218136.34.108.128/25136.34.108.129 to 136.34.108.254136.34.108.255126
219136.34.109.0/25136.34.109.1 to 136.34.109.126136.34.109.127126
220136.34.109.128/25136.34.109.129 to 136.34.109.254136.34.109.255126
221136.34.110.0/25136.34.110.1 to 136.34.110.126136.34.110.127126
222136.34.110.128/25136.34.110.129 to 136.34.110.254136.34.110.255126
223136.34.111.0/25136.34.111.1 to 136.34.111.126136.34.111.127126
224136.34.111.128/25136.34.111.129 to 136.34.111.254136.34.111.255126
225136.34.112.0/25136.34.112.1 to 136.34.112.126136.34.112.127126
226136.34.112.128/25136.34.112.129 to 136.34.112.254136.34.112.255126
227136.34.113.0/25136.34.113.1 to 136.34.113.126136.34.113.127126
228136.34.113.128/25136.34.113.129 to 136.34.113.254136.34.113.255126
229136.34.114.0/25136.34.114.1 to 136.34.114.126136.34.114.127126
230136.34.114.128/25136.34.114.129 to 136.34.114.254136.34.114.255126
231136.34.115.0/25136.34.115.1 to 136.34.115.126136.34.115.127126
232136.34.115.128/25136.34.115.129 to 136.34.115.254136.34.115.255126
233136.34.116.0/25136.34.116.1 to 136.34.116.126136.34.116.127126
234136.34.116.128/25136.34.116.129 to 136.34.116.254136.34.116.255126
235136.34.117.0/25136.34.117.1 to 136.34.117.126136.34.117.127126
236136.34.117.128/25136.34.117.129 to 136.34.117.254136.34.117.255126
237136.34.118.0/25136.34.118.1 to 136.34.118.126136.34.118.127126
238136.34.118.128/25136.34.118.129 to 136.34.118.254136.34.118.255126
239136.34.119.0/25136.34.119.1 to 136.34.119.126136.34.119.127126
240136.34.119.128/25136.34.119.129 to 136.34.119.254136.34.119.255126
241136.34.120.0/25136.34.120.1 to 136.34.120.126136.34.120.127126
242136.34.120.128/25136.34.120.129 to 136.34.120.254136.34.120.255126
243136.34.121.0/25136.34.121.1 to 136.34.121.126136.34.121.127126
244136.34.121.128/25136.34.121.129 to 136.34.121.254136.34.121.255126
245136.34.122.0/25136.34.122.1 to 136.34.122.126136.34.122.127126
246136.34.122.128/25136.34.122.129 to 136.34.122.254136.34.122.255126
247136.34.123.0/25136.34.123.1 to 136.34.123.126136.34.123.127126
248136.34.123.128/25136.34.123.129 to 136.34.123.254136.34.123.255126
249136.34.124.0/25136.34.124.1 to 136.34.124.126136.34.124.127126
250136.34.124.128/25136.34.124.129 to 136.34.124.254136.34.124.255126
251136.34.125.0/25136.34.125.1 to 136.34.125.126136.34.125.127126
252136.34.125.128/25136.34.125.129 to 136.34.125.254136.34.125.255126
253136.34.126.0/25136.34.126.1 to 136.34.126.126136.34.126.127126
254136.34.126.128/25136.34.126.129 to 136.34.126.254136.34.126.255126
255136.34.127.0/25136.34.127.1 to 136.34.127.126136.34.127.127126
256136.34.127.128/25136.34.127.129 to 136.34.127.254136.34.127.255126

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.