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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.

Network136.2.0.0/15
Usable hosts131,070
Subnet mask255.254.0.0
Addresses131,072
Network address
136.2.0.0
Broadcast address
136.3.255.255
First usable
136.2.0.1
Last usable
136.3.255.254
Usable hosts
131,070 (131,072 less the network and broadcast addresses)
Subnet mask
255.254.0.0
Wildcard mask
0.1.255.255 (Cisco ACLs, OSPF)
Prefix length
/15
Type
Public public
Old class
B (default /16)
As numbers
Hex 88020000 · Integer 2281832448 to 2281963519
Reverse DNS zones
2.136.in-addr.arpa
3.136.in-addr.arpa
/15 is not on a 8-bit boundary, so it takes 2 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address10001000.00000010.00000000.00000000136.2.0.0
Subnet mask11111111.11111110.00000000.00000000255.254.0.0
Network10001000.00000010.00000000.00000000136.2.0.0
Broadcast10001000.00000011.11111111.11111111136.3.255.255
Split into smaller subnets/26
/16 (2)/17 (4)/18 (8)/19 (16)/20 (32)/21 (64)/22 (128)/23 (256)/24 (512)/25 (1,024)/26 (2,048)/27 (4,096)

136.2.0.0/15 makes 2,048 subnets of /26; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1136.2.0.0/26136.2.0.1 to 136.2.0.62136.2.0.6362
2136.2.0.64/26136.2.0.65 to 136.2.0.126136.2.0.12762
3136.2.0.128/26136.2.0.129 to 136.2.0.190136.2.0.19162
4136.2.0.192/26136.2.0.193 to 136.2.0.254136.2.0.25562
5136.2.1.0/26136.2.1.1 to 136.2.1.62136.2.1.6362
6136.2.1.64/26136.2.1.65 to 136.2.1.126136.2.1.12762
7136.2.1.128/26136.2.1.129 to 136.2.1.190136.2.1.19162
8136.2.1.192/26136.2.1.193 to 136.2.1.254136.2.1.25562
9136.2.2.0/26136.2.2.1 to 136.2.2.62136.2.2.6362
10136.2.2.64/26136.2.2.65 to 136.2.2.126136.2.2.12762
11136.2.2.128/26136.2.2.129 to 136.2.2.190136.2.2.19162
12136.2.2.192/26136.2.2.193 to 136.2.2.254136.2.2.25562
13136.2.3.0/26136.2.3.1 to 136.2.3.62136.2.3.6362
14136.2.3.64/26136.2.3.65 to 136.2.3.126136.2.3.12762
15136.2.3.128/26136.2.3.129 to 136.2.3.190136.2.3.19162
16136.2.3.192/26136.2.3.193 to 136.2.3.254136.2.3.25562
17136.2.4.0/26136.2.4.1 to 136.2.4.62136.2.4.6362
18136.2.4.64/26136.2.4.65 to 136.2.4.126136.2.4.12762
19136.2.4.128/26136.2.4.129 to 136.2.4.190136.2.4.19162
20136.2.4.192/26136.2.4.193 to 136.2.4.254136.2.4.25562
21136.2.5.0/26136.2.5.1 to 136.2.5.62136.2.5.6362
22136.2.5.64/26136.2.5.65 to 136.2.5.126136.2.5.12762
23136.2.5.128/26136.2.5.129 to 136.2.5.190136.2.5.19162
24136.2.5.192/26136.2.5.193 to 136.2.5.254136.2.5.25562
25136.2.6.0/26136.2.6.1 to 136.2.6.62136.2.6.6362
26136.2.6.64/26136.2.6.65 to 136.2.6.126136.2.6.12762
27136.2.6.128/26136.2.6.129 to 136.2.6.190136.2.6.19162
28136.2.6.192/26136.2.6.193 to 136.2.6.254136.2.6.25562
29136.2.7.0/26136.2.7.1 to 136.2.7.62136.2.7.6362
30136.2.7.64/26136.2.7.65 to 136.2.7.126136.2.7.12762
31136.2.7.128/26136.2.7.129 to 136.2.7.190136.2.7.19162
32136.2.7.192/26136.2.7.193 to 136.2.7.254136.2.7.25562
33136.2.8.0/26136.2.8.1 to 136.2.8.62136.2.8.6362
34136.2.8.64/26136.2.8.65 to 136.2.8.126136.2.8.12762
35136.2.8.128/26136.2.8.129 to 136.2.8.190136.2.8.19162
36136.2.8.192/26136.2.8.193 to 136.2.8.254136.2.8.25562
37136.2.9.0/26136.2.9.1 to 136.2.9.62136.2.9.6362
38136.2.9.64/26136.2.9.65 to 136.2.9.126136.2.9.12762
39136.2.9.128/26136.2.9.129 to 136.2.9.190136.2.9.19162
40136.2.9.192/26136.2.9.193 to 136.2.9.254136.2.9.25562
41136.2.10.0/26136.2.10.1 to 136.2.10.62136.2.10.6362
42136.2.10.64/26136.2.10.65 to 136.2.10.126136.2.10.12762
43136.2.10.128/26136.2.10.129 to 136.2.10.190136.2.10.19162
44136.2.10.192/26136.2.10.193 to 136.2.10.254136.2.10.25562
45136.2.11.0/26136.2.11.1 to 136.2.11.62136.2.11.6362
46136.2.11.64/26136.2.11.65 to 136.2.11.126136.2.11.12762
47136.2.11.128/26136.2.11.129 to 136.2.11.190136.2.11.19162
48136.2.11.192/26136.2.11.193 to 136.2.11.254136.2.11.25562
49136.2.12.0/26136.2.12.1 to 136.2.12.62136.2.12.6362
50136.2.12.64/26136.2.12.65 to 136.2.12.126136.2.12.12762
51136.2.12.128/26136.2.12.129 to 136.2.12.190136.2.12.19162
52136.2.12.192/26136.2.12.193 to 136.2.12.254136.2.12.25562
53136.2.13.0/26136.2.13.1 to 136.2.13.62136.2.13.6362
54136.2.13.64/26136.2.13.65 to 136.2.13.126136.2.13.12762
55136.2.13.128/26136.2.13.129 to 136.2.13.190136.2.13.19162
56136.2.13.192/26136.2.13.193 to 136.2.13.254136.2.13.25562
57136.2.14.0/26136.2.14.1 to 136.2.14.62136.2.14.6362
58136.2.14.64/26136.2.14.65 to 136.2.14.126136.2.14.12762
59136.2.14.128/26136.2.14.129 to 136.2.14.190136.2.14.19162
60136.2.14.192/26136.2.14.193 to 136.2.14.254136.2.14.25562
61136.2.15.0/26136.2.15.1 to 136.2.15.62136.2.15.6362
62136.2.15.64/26136.2.15.65 to 136.2.15.126136.2.15.12762
63136.2.15.128/26136.2.15.129 to 136.2.15.190136.2.15.19162
64136.2.15.192/26136.2.15.193 to 136.2.15.254136.2.15.25562
65136.2.16.0/26136.2.16.1 to 136.2.16.62136.2.16.6362
66136.2.16.64/26136.2.16.65 to 136.2.16.126136.2.16.12762
67136.2.16.128/26136.2.16.129 to 136.2.16.190136.2.16.19162
68136.2.16.192/26136.2.16.193 to 136.2.16.254136.2.16.25562
69136.2.17.0/26136.2.17.1 to 136.2.17.62136.2.17.6362
70136.2.17.64/26136.2.17.65 to 136.2.17.126136.2.17.12762
71136.2.17.128/26136.2.17.129 to 136.2.17.190136.2.17.19162
72136.2.17.192/26136.2.17.193 to 136.2.17.254136.2.17.25562
73136.2.18.0/26136.2.18.1 to 136.2.18.62136.2.18.6362
74136.2.18.64/26136.2.18.65 to 136.2.18.126136.2.18.12762
75136.2.18.128/26136.2.18.129 to 136.2.18.190136.2.18.19162
76136.2.18.192/26136.2.18.193 to 136.2.18.254136.2.18.25562
77136.2.19.0/26136.2.19.1 to 136.2.19.62136.2.19.6362
78136.2.19.64/26136.2.19.65 to 136.2.19.126136.2.19.12762
79136.2.19.128/26136.2.19.129 to 136.2.19.190136.2.19.19162
80136.2.19.192/26136.2.19.193 to 136.2.19.254136.2.19.25562
81136.2.20.0/26136.2.20.1 to 136.2.20.62136.2.20.6362
82136.2.20.64/26136.2.20.65 to 136.2.20.126136.2.20.12762
83136.2.20.128/26136.2.20.129 to 136.2.20.190136.2.20.19162
84136.2.20.192/26136.2.20.193 to 136.2.20.254136.2.20.25562
85136.2.21.0/26136.2.21.1 to 136.2.21.62136.2.21.6362
86136.2.21.64/26136.2.21.65 to 136.2.21.126136.2.21.12762
87136.2.21.128/26136.2.21.129 to 136.2.21.190136.2.21.19162
88136.2.21.192/26136.2.21.193 to 136.2.21.254136.2.21.25562
89136.2.22.0/26136.2.22.1 to 136.2.22.62136.2.22.6362
90136.2.22.64/26136.2.22.65 to 136.2.22.126136.2.22.12762
91136.2.22.128/26136.2.22.129 to 136.2.22.190136.2.22.19162
92136.2.22.192/26136.2.22.193 to 136.2.22.254136.2.22.25562
93136.2.23.0/26136.2.23.1 to 136.2.23.62136.2.23.6362
94136.2.23.64/26136.2.23.65 to 136.2.23.126136.2.23.12762
95136.2.23.128/26136.2.23.129 to 136.2.23.190136.2.23.19162
96136.2.23.192/26136.2.23.193 to 136.2.23.254136.2.23.25562
97136.2.24.0/26136.2.24.1 to 136.2.24.62136.2.24.6362
98136.2.24.64/26136.2.24.65 to 136.2.24.126136.2.24.12762
99136.2.24.128/26136.2.24.129 to 136.2.24.190136.2.24.19162
100136.2.24.192/26136.2.24.193 to 136.2.24.254136.2.24.25562
101136.2.25.0/26136.2.25.1 to 136.2.25.62136.2.25.6362
102136.2.25.64/26136.2.25.65 to 136.2.25.126136.2.25.12762
103136.2.25.128/26136.2.25.129 to 136.2.25.190136.2.25.19162
104136.2.25.192/26136.2.25.193 to 136.2.25.254136.2.25.25562
105136.2.26.0/26136.2.26.1 to 136.2.26.62136.2.26.6362
106136.2.26.64/26136.2.26.65 to 136.2.26.126136.2.26.12762
107136.2.26.128/26136.2.26.129 to 136.2.26.190136.2.26.19162
108136.2.26.192/26136.2.26.193 to 136.2.26.254136.2.26.25562
109136.2.27.0/26136.2.27.1 to 136.2.27.62136.2.27.6362
110136.2.27.64/26136.2.27.65 to 136.2.27.126136.2.27.12762
111136.2.27.128/26136.2.27.129 to 136.2.27.190136.2.27.19162
112136.2.27.192/26136.2.27.193 to 136.2.27.254136.2.27.25562
113136.2.28.0/26136.2.28.1 to 136.2.28.62136.2.28.6362
114136.2.28.64/26136.2.28.65 to 136.2.28.126136.2.28.12762
115136.2.28.128/26136.2.28.129 to 136.2.28.190136.2.28.19162
116136.2.28.192/26136.2.28.193 to 136.2.28.254136.2.28.25562
117136.2.29.0/26136.2.29.1 to 136.2.29.62136.2.29.6362
118136.2.29.64/26136.2.29.65 to 136.2.29.126136.2.29.12762
119136.2.29.128/26136.2.29.129 to 136.2.29.190136.2.29.19162
120136.2.29.192/26136.2.29.193 to 136.2.29.254136.2.29.25562
121136.2.30.0/26136.2.30.1 to 136.2.30.62136.2.30.6362
122136.2.30.64/26136.2.30.65 to 136.2.30.126136.2.30.12762
123136.2.30.128/26136.2.30.129 to 136.2.30.190136.2.30.19162
124136.2.30.192/26136.2.30.193 to 136.2.30.254136.2.30.25562
125136.2.31.0/26136.2.31.1 to 136.2.31.62136.2.31.6362
126136.2.31.64/26136.2.31.65 to 136.2.31.126136.2.31.12762
127136.2.31.128/26136.2.31.129 to 136.2.31.190136.2.31.19162
128136.2.31.192/26136.2.31.193 to 136.2.31.254136.2.31.25562
129136.2.32.0/26136.2.32.1 to 136.2.32.62136.2.32.6362
130136.2.32.64/26136.2.32.65 to 136.2.32.126136.2.32.12762
131136.2.32.128/26136.2.32.129 to 136.2.32.190136.2.32.19162
132136.2.32.192/26136.2.32.193 to 136.2.32.254136.2.32.25562
133136.2.33.0/26136.2.33.1 to 136.2.33.62136.2.33.6362
134136.2.33.64/26136.2.33.65 to 136.2.33.126136.2.33.12762
135136.2.33.128/26136.2.33.129 to 136.2.33.190136.2.33.19162
136136.2.33.192/26136.2.33.193 to 136.2.33.254136.2.33.25562
137136.2.34.0/26136.2.34.1 to 136.2.34.62136.2.34.6362
138136.2.34.64/26136.2.34.65 to 136.2.34.126136.2.34.12762
139136.2.34.128/26136.2.34.129 to 136.2.34.190136.2.34.19162
140136.2.34.192/26136.2.34.193 to 136.2.34.254136.2.34.25562
141136.2.35.0/26136.2.35.1 to 136.2.35.62136.2.35.6362
142136.2.35.64/26136.2.35.65 to 136.2.35.126136.2.35.12762
143136.2.35.128/26136.2.35.129 to 136.2.35.190136.2.35.19162
144136.2.35.192/26136.2.35.193 to 136.2.35.254136.2.35.25562
145136.2.36.0/26136.2.36.1 to 136.2.36.62136.2.36.6362
146136.2.36.64/26136.2.36.65 to 136.2.36.126136.2.36.12762
147136.2.36.128/26136.2.36.129 to 136.2.36.190136.2.36.19162
148136.2.36.192/26136.2.36.193 to 136.2.36.254136.2.36.25562
149136.2.37.0/26136.2.37.1 to 136.2.37.62136.2.37.6362
150136.2.37.64/26136.2.37.65 to 136.2.37.126136.2.37.12762
151136.2.37.128/26136.2.37.129 to 136.2.37.190136.2.37.19162
152136.2.37.192/26136.2.37.193 to 136.2.37.254136.2.37.25562
153136.2.38.0/26136.2.38.1 to 136.2.38.62136.2.38.6362
154136.2.38.64/26136.2.38.65 to 136.2.38.126136.2.38.12762
155136.2.38.128/26136.2.38.129 to 136.2.38.190136.2.38.19162
156136.2.38.192/26136.2.38.193 to 136.2.38.254136.2.38.25562
157136.2.39.0/26136.2.39.1 to 136.2.39.62136.2.39.6362
158136.2.39.64/26136.2.39.65 to 136.2.39.126136.2.39.12762
159136.2.39.128/26136.2.39.129 to 136.2.39.190136.2.39.19162
160136.2.39.192/26136.2.39.193 to 136.2.39.254136.2.39.25562
161136.2.40.0/26136.2.40.1 to 136.2.40.62136.2.40.6362
162136.2.40.64/26136.2.40.65 to 136.2.40.126136.2.40.12762
163136.2.40.128/26136.2.40.129 to 136.2.40.190136.2.40.19162
164136.2.40.192/26136.2.40.193 to 136.2.40.254136.2.40.25562
165136.2.41.0/26136.2.41.1 to 136.2.41.62136.2.41.6362
166136.2.41.64/26136.2.41.65 to 136.2.41.126136.2.41.12762
167136.2.41.128/26136.2.41.129 to 136.2.41.190136.2.41.19162
168136.2.41.192/26136.2.41.193 to 136.2.41.254136.2.41.25562
169136.2.42.0/26136.2.42.1 to 136.2.42.62136.2.42.6362
170136.2.42.64/26136.2.42.65 to 136.2.42.126136.2.42.12762
171136.2.42.128/26136.2.42.129 to 136.2.42.190136.2.42.19162
172136.2.42.192/26136.2.42.193 to 136.2.42.254136.2.42.25562
173136.2.43.0/26136.2.43.1 to 136.2.43.62136.2.43.6362
174136.2.43.64/26136.2.43.65 to 136.2.43.126136.2.43.12762
175136.2.43.128/26136.2.43.129 to 136.2.43.190136.2.43.19162
176136.2.43.192/26136.2.43.193 to 136.2.43.254136.2.43.25562
177136.2.44.0/26136.2.44.1 to 136.2.44.62136.2.44.6362
178136.2.44.64/26136.2.44.65 to 136.2.44.126136.2.44.12762
179136.2.44.128/26136.2.44.129 to 136.2.44.190136.2.44.19162
180136.2.44.192/26136.2.44.193 to 136.2.44.254136.2.44.25562
181136.2.45.0/26136.2.45.1 to 136.2.45.62136.2.45.6362
182136.2.45.64/26136.2.45.65 to 136.2.45.126136.2.45.12762
183136.2.45.128/26136.2.45.129 to 136.2.45.190136.2.45.19162
184136.2.45.192/26136.2.45.193 to 136.2.45.254136.2.45.25562
185136.2.46.0/26136.2.46.1 to 136.2.46.62136.2.46.6362
186136.2.46.64/26136.2.46.65 to 136.2.46.126136.2.46.12762
187136.2.46.128/26136.2.46.129 to 136.2.46.190136.2.46.19162
188136.2.46.192/26136.2.46.193 to 136.2.46.254136.2.46.25562
189136.2.47.0/26136.2.47.1 to 136.2.47.62136.2.47.6362
190136.2.47.64/26136.2.47.65 to 136.2.47.126136.2.47.12762
191136.2.47.128/26136.2.47.129 to 136.2.47.190136.2.47.19162
192136.2.47.192/26136.2.47.193 to 136.2.47.254136.2.47.25562
193136.2.48.0/26136.2.48.1 to 136.2.48.62136.2.48.6362
194136.2.48.64/26136.2.48.65 to 136.2.48.126136.2.48.12762
195136.2.48.128/26136.2.48.129 to 136.2.48.190136.2.48.19162
196136.2.48.192/26136.2.48.193 to 136.2.48.254136.2.48.25562
197136.2.49.0/26136.2.49.1 to 136.2.49.62136.2.49.6362
198136.2.49.64/26136.2.49.65 to 136.2.49.126136.2.49.12762
199136.2.49.128/26136.2.49.129 to 136.2.49.190136.2.49.19162
200136.2.49.192/26136.2.49.193 to 136.2.49.254136.2.49.25562
201136.2.50.0/26136.2.50.1 to 136.2.50.62136.2.50.6362
202136.2.50.64/26136.2.50.65 to 136.2.50.126136.2.50.12762
203136.2.50.128/26136.2.50.129 to 136.2.50.190136.2.50.19162
204136.2.50.192/26136.2.50.193 to 136.2.50.254136.2.50.25562
205136.2.51.0/26136.2.51.1 to 136.2.51.62136.2.51.6362
206136.2.51.64/26136.2.51.65 to 136.2.51.126136.2.51.12762
207136.2.51.128/26136.2.51.129 to 136.2.51.190136.2.51.19162
208136.2.51.192/26136.2.51.193 to 136.2.51.254136.2.51.25562
209136.2.52.0/26136.2.52.1 to 136.2.52.62136.2.52.6362
210136.2.52.64/26136.2.52.65 to 136.2.52.126136.2.52.12762
211136.2.52.128/26136.2.52.129 to 136.2.52.190136.2.52.19162
212136.2.52.192/26136.2.52.193 to 136.2.52.254136.2.52.25562
213136.2.53.0/26136.2.53.1 to 136.2.53.62136.2.53.6362
214136.2.53.64/26136.2.53.65 to 136.2.53.126136.2.53.12762
215136.2.53.128/26136.2.53.129 to 136.2.53.190136.2.53.19162
216136.2.53.192/26136.2.53.193 to 136.2.53.254136.2.53.25562
217136.2.54.0/26136.2.54.1 to 136.2.54.62136.2.54.6362
218136.2.54.64/26136.2.54.65 to 136.2.54.126136.2.54.12762
219136.2.54.128/26136.2.54.129 to 136.2.54.190136.2.54.19162
220136.2.54.192/26136.2.54.193 to 136.2.54.254136.2.54.25562
221136.2.55.0/26136.2.55.1 to 136.2.55.62136.2.55.6362
222136.2.55.64/26136.2.55.65 to 136.2.55.126136.2.55.12762
223136.2.55.128/26136.2.55.129 to 136.2.55.190136.2.55.19162
224136.2.55.192/26136.2.55.193 to 136.2.55.254136.2.55.25562
225136.2.56.0/26136.2.56.1 to 136.2.56.62136.2.56.6362
226136.2.56.64/26136.2.56.65 to 136.2.56.126136.2.56.12762
227136.2.56.128/26136.2.56.129 to 136.2.56.190136.2.56.19162
228136.2.56.192/26136.2.56.193 to 136.2.56.254136.2.56.25562
229136.2.57.0/26136.2.57.1 to 136.2.57.62136.2.57.6362
230136.2.57.64/26136.2.57.65 to 136.2.57.126136.2.57.12762
231136.2.57.128/26136.2.57.129 to 136.2.57.190136.2.57.19162
232136.2.57.192/26136.2.57.193 to 136.2.57.254136.2.57.25562
233136.2.58.0/26136.2.58.1 to 136.2.58.62136.2.58.6362
234136.2.58.64/26136.2.58.65 to 136.2.58.126136.2.58.12762
235136.2.58.128/26136.2.58.129 to 136.2.58.190136.2.58.19162
236136.2.58.192/26136.2.58.193 to 136.2.58.254136.2.58.25562
237136.2.59.0/26136.2.59.1 to 136.2.59.62136.2.59.6362
238136.2.59.64/26136.2.59.65 to 136.2.59.126136.2.59.12762
239136.2.59.128/26136.2.59.129 to 136.2.59.190136.2.59.19162
240136.2.59.192/26136.2.59.193 to 136.2.59.254136.2.59.25562
241136.2.60.0/26136.2.60.1 to 136.2.60.62136.2.60.6362
242136.2.60.64/26136.2.60.65 to 136.2.60.126136.2.60.12762
243136.2.60.128/26136.2.60.129 to 136.2.60.190136.2.60.19162
244136.2.60.192/26136.2.60.193 to 136.2.60.254136.2.60.25562
245136.2.61.0/26136.2.61.1 to 136.2.61.62136.2.61.6362
246136.2.61.64/26136.2.61.65 to 136.2.61.126136.2.61.12762
247136.2.61.128/26136.2.61.129 to 136.2.61.190136.2.61.19162
248136.2.61.192/26136.2.61.193 to 136.2.61.254136.2.61.25562
249136.2.62.0/26136.2.62.1 to 136.2.62.62136.2.62.6362
250136.2.62.64/26136.2.62.65 to 136.2.62.126136.2.62.12762
251136.2.62.128/26136.2.62.129 to 136.2.62.190136.2.62.19162
252136.2.62.192/26136.2.62.193 to 136.2.62.254136.2.62.25562
253136.2.63.0/26136.2.63.1 to 136.2.63.62136.2.63.6362
254136.2.63.64/26136.2.63.65 to 136.2.63.126136.2.63.12762
255136.2.63.128/26136.2.63.129 to 136.2.63.190136.2.63.19162
256136.2.63.192/26136.2.63.193 to 136.2.63.254136.2.63.25562

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.