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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.

Network102.0.0.0/7
Usable hosts33,554,430
Subnet mask254.0.0.0
Addresses33,554,432
Network address
102.0.0.0
Broadcast address
103.255.255.255
First usable
102.0.0.1
Last usable
103.255.255.254
Usable hosts
33,554,430 (33,554,432 less the network and broadcast addresses)
Subnet mask
254.0.0.0
Wildcard mask
1.255.255.255 (Cisco ACLs, OSPF)
Prefix length
/7
Type
Public public
Old class
A (default /8)
As numbers
Hex 66000000 · Integer 1711276032 to 1744830463
Reverse DNS zones
102.in-addr.arpa
103.in-addr.arpa
/7 is not on a 8-bit boundary, so it takes 2 /8 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address01100110.00000000.00000000.00000000102.0.0.0
Subnet mask11111110.00000000.00000000.00000000254.0.0.0
Network01100110.00000000.00000000.00000000102.0.0.0
Broadcast01100111.11111111.11111111.11111111103.255.255.255
Split into smaller subnets/18
/8 (2)/9 (4)/10 (8)/11 (16)/12 (32)/13 (64)/14 (128)/15 (256)/16 (512)/17 (1,024)/18 (2,048)/19 (4,096)

102.0.0.0/7 makes 2,048 subnets of /18; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1102.0.0.0/18102.0.0.1 to 102.0.63.254102.0.63.25516,382
2102.0.64.0/18102.0.64.1 to 102.0.127.254102.0.127.25516,382
3102.0.128.0/18102.0.128.1 to 102.0.191.254102.0.191.25516,382
4102.0.192.0/18102.0.192.1 to 102.0.255.254102.0.255.25516,382
5102.1.0.0/18102.1.0.1 to 102.1.63.254102.1.63.25516,382
6102.1.64.0/18102.1.64.1 to 102.1.127.254102.1.127.25516,382
7102.1.128.0/18102.1.128.1 to 102.1.191.254102.1.191.25516,382
8102.1.192.0/18102.1.192.1 to 102.1.255.254102.1.255.25516,382
9102.2.0.0/18102.2.0.1 to 102.2.63.254102.2.63.25516,382
10102.2.64.0/18102.2.64.1 to 102.2.127.254102.2.127.25516,382
11102.2.128.0/18102.2.128.1 to 102.2.191.254102.2.191.25516,382
12102.2.192.0/18102.2.192.1 to 102.2.255.254102.2.255.25516,382
13102.3.0.0/18102.3.0.1 to 102.3.63.254102.3.63.25516,382
14102.3.64.0/18102.3.64.1 to 102.3.127.254102.3.127.25516,382
15102.3.128.0/18102.3.128.1 to 102.3.191.254102.3.191.25516,382
16102.3.192.0/18102.3.192.1 to 102.3.255.254102.3.255.25516,382
17102.4.0.0/18102.4.0.1 to 102.4.63.254102.4.63.25516,382
18102.4.64.0/18102.4.64.1 to 102.4.127.254102.4.127.25516,382
19102.4.128.0/18102.4.128.1 to 102.4.191.254102.4.191.25516,382
20102.4.192.0/18102.4.192.1 to 102.4.255.254102.4.255.25516,382
21102.5.0.0/18102.5.0.1 to 102.5.63.254102.5.63.25516,382
22102.5.64.0/18102.5.64.1 to 102.5.127.254102.5.127.25516,382
23102.5.128.0/18102.5.128.1 to 102.5.191.254102.5.191.25516,382
24102.5.192.0/18102.5.192.1 to 102.5.255.254102.5.255.25516,382
25102.6.0.0/18102.6.0.1 to 102.6.63.254102.6.63.25516,382
26102.6.64.0/18102.6.64.1 to 102.6.127.254102.6.127.25516,382
27102.6.128.0/18102.6.128.1 to 102.6.191.254102.6.191.25516,382
28102.6.192.0/18102.6.192.1 to 102.6.255.254102.6.255.25516,382
29102.7.0.0/18102.7.0.1 to 102.7.63.254102.7.63.25516,382
30102.7.64.0/18102.7.64.1 to 102.7.127.254102.7.127.25516,382
31102.7.128.0/18102.7.128.1 to 102.7.191.254102.7.191.25516,382
32102.7.192.0/18102.7.192.1 to 102.7.255.254102.7.255.25516,382
33102.8.0.0/18102.8.0.1 to 102.8.63.254102.8.63.25516,382
34102.8.64.0/18102.8.64.1 to 102.8.127.254102.8.127.25516,382
35102.8.128.0/18102.8.128.1 to 102.8.191.254102.8.191.25516,382
36102.8.192.0/18102.8.192.1 to 102.8.255.254102.8.255.25516,382
37102.9.0.0/18102.9.0.1 to 102.9.63.254102.9.63.25516,382
38102.9.64.0/18102.9.64.1 to 102.9.127.254102.9.127.25516,382
39102.9.128.0/18102.9.128.1 to 102.9.191.254102.9.191.25516,382
40102.9.192.0/18102.9.192.1 to 102.9.255.254102.9.255.25516,382
41102.10.0.0/18102.10.0.1 to 102.10.63.254102.10.63.25516,382
42102.10.64.0/18102.10.64.1 to 102.10.127.254102.10.127.25516,382
43102.10.128.0/18102.10.128.1 to 102.10.191.254102.10.191.25516,382
44102.10.192.0/18102.10.192.1 to 102.10.255.254102.10.255.25516,382
45102.11.0.0/18102.11.0.1 to 102.11.63.254102.11.63.25516,382
46102.11.64.0/18102.11.64.1 to 102.11.127.254102.11.127.25516,382
47102.11.128.0/18102.11.128.1 to 102.11.191.254102.11.191.25516,382
48102.11.192.0/18102.11.192.1 to 102.11.255.254102.11.255.25516,382
49102.12.0.0/18102.12.0.1 to 102.12.63.254102.12.63.25516,382
50102.12.64.0/18102.12.64.1 to 102.12.127.254102.12.127.25516,382
51102.12.128.0/18102.12.128.1 to 102.12.191.254102.12.191.25516,382
52102.12.192.0/18102.12.192.1 to 102.12.255.254102.12.255.25516,382
53102.13.0.0/18102.13.0.1 to 102.13.63.254102.13.63.25516,382
54102.13.64.0/18102.13.64.1 to 102.13.127.254102.13.127.25516,382
55102.13.128.0/18102.13.128.1 to 102.13.191.254102.13.191.25516,382
56102.13.192.0/18102.13.192.1 to 102.13.255.254102.13.255.25516,382
57102.14.0.0/18102.14.0.1 to 102.14.63.254102.14.63.25516,382
58102.14.64.0/18102.14.64.1 to 102.14.127.254102.14.127.25516,382
59102.14.128.0/18102.14.128.1 to 102.14.191.254102.14.191.25516,382
60102.14.192.0/18102.14.192.1 to 102.14.255.254102.14.255.25516,382
61102.15.0.0/18102.15.0.1 to 102.15.63.254102.15.63.25516,382
62102.15.64.0/18102.15.64.1 to 102.15.127.254102.15.127.25516,382
63102.15.128.0/18102.15.128.1 to 102.15.191.254102.15.191.25516,382
64102.15.192.0/18102.15.192.1 to 102.15.255.254102.15.255.25516,382
65102.16.0.0/18102.16.0.1 to 102.16.63.254102.16.63.25516,382
66102.16.64.0/18102.16.64.1 to 102.16.127.254102.16.127.25516,382
67102.16.128.0/18102.16.128.1 to 102.16.191.254102.16.191.25516,382
68102.16.192.0/18102.16.192.1 to 102.16.255.254102.16.255.25516,382
69102.17.0.0/18102.17.0.1 to 102.17.63.254102.17.63.25516,382
70102.17.64.0/18102.17.64.1 to 102.17.127.254102.17.127.25516,382
71102.17.128.0/18102.17.128.1 to 102.17.191.254102.17.191.25516,382
72102.17.192.0/18102.17.192.1 to 102.17.255.254102.17.255.25516,382
73102.18.0.0/18102.18.0.1 to 102.18.63.254102.18.63.25516,382
74102.18.64.0/18102.18.64.1 to 102.18.127.254102.18.127.25516,382
75102.18.128.0/18102.18.128.1 to 102.18.191.254102.18.191.25516,382
76102.18.192.0/18102.18.192.1 to 102.18.255.254102.18.255.25516,382
77102.19.0.0/18102.19.0.1 to 102.19.63.254102.19.63.25516,382
78102.19.64.0/18102.19.64.1 to 102.19.127.254102.19.127.25516,382
79102.19.128.0/18102.19.128.1 to 102.19.191.254102.19.191.25516,382
80102.19.192.0/18102.19.192.1 to 102.19.255.254102.19.255.25516,382
81102.20.0.0/18102.20.0.1 to 102.20.63.254102.20.63.25516,382
82102.20.64.0/18102.20.64.1 to 102.20.127.254102.20.127.25516,382
83102.20.128.0/18102.20.128.1 to 102.20.191.254102.20.191.25516,382
84102.20.192.0/18102.20.192.1 to 102.20.255.254102.20.255.25516,382
85102.21.0.0/18102.21.0.1 to 102.21.63.254102.21.63.25516,382
86102.21.64.0/18102.21.64.1 to 102.21.127.254102.21.127.25516,382
87102.21.128.0/18102.21.128.1 to 102.21.191.254102.21.191.25516,382
88102.21.192.0/18102.21.192.1 to 102.21.255.254102.21.255.25516,382
89102.22.0.0/18102.22.0.1 to 102.22.63.254102.22.63.25516,382
90102.22.64.0/18102.22.64.1 to 102.22.127.254102.22.127.25516,382
91102.22.128.0/18102.22.128.1 to 102.22.191.254102.22.191.25516,382
92102.22.192.0/18102.22.192.1 to 102.22.255.254102.22.255.25516,382
93102.23.0.0/18102.23.0.1 to 102.23.63.254102.23.63.25516,382
94102.23.64.0/18102.23.64.1 to 102.23.127.254102.23.127.25516,382
95102.23.128.0/18102.23.128.1 to 102.23.191.254102.23.191.25516,382
96102.23.192.0/18102.23.192.1 to 102.23.255.254102.23.255.25516,382
97102.24.0.0/18102.24.0.1 to 102.24.63.254102.24.63.25516,382
98102.24.64.0/18102.24.64.1 to 102.24.127.254102.24.127.25516,382
99102.24.128.0/18102.24.128.1 to 102.24.191.254102.24.191.25516,382
100102.24.192.0/18102.24.192.1 to 102.24.255.254102.24.255.25516,382
101102.25.0.0/18102.25.0.1 to 102.25.63.254102.25.63.25516,382
102102.25.64.0/18102.25.64.1 to 102.25.127.254102.25.127.25516,382
103102.25.128.0/18102.25.128.1 to 102.25.191.254102.25.191.25516,382
104102.25.192.0/18102.25.192.1 to 102.25.255.254102.25.255.25516,382
105102.26.0.0/18102.26.0.1 to 102.26.63.254102.26.63.25516,382
106102.26.64.0/18102.26.64.1 to 102.26.127.254102.26.127.25516,382
107102.26.128.0/18102.26.128.1 to 102.26.191.254102.26.191.25516,382
108102.26.192.0/18102.26.192.1 to 102.26.255.254102.26.255.25516,382
109102.27.0.0/18102.27.0.1 to 102.27.63.254102.27.63.25516,382
110102.27.64.0/18102.27.64.1 to 102.27.127.254102.27.127.25516,382
111102.27.128.0/18102.27.128.1 to 102.27.191.254102.27.191.25516,382
112102.27.192.0/18102.27.192.1 to 102.27.255.254102.27.255.25516,382
113102.28.0.0/18102.28.0.1 to 102.28.63.254102.28.63.25516,382
114102.28.64.0/18102.28.64.1 to 102.28.127.254102.28.127.25516,382
115102.28.128.0/18102.28.128.1 to 102.28.191.254102.28.191.25516,382
116102.28.192.0/18102.28.192.1 to 102.28.255.254102.28.255.25516,382
117102.29.0.0/18102.29.0.1 to 102.29.63.254102.29.63.25516,382
118102.29.64.0/18102.29.64.1 to 102.29.127.254102.29.127.25516,382
119102.29.128.0/18102.29.128.1 to 102.29.191.254102.29.191.25516,382
120102.29.192.0/18102.29.192.1 to 102.29.255.254102.29.255.25516,382
121102.30.0.0/18102.30.0.1 to 102.30.63.254102.30.63.25516,382
122102.30.64.0/18102.30.64.1 to 102.30.127.254102.30.127.25516,382
123102.30.128.0/18102.30.128.1 to 102.30.191.254102.30.191.25516,382
124102.30.192.0/18102.30.192.1 to 102.30.255.254102.30.255.25516,382
125102.31.0.0/18102.31.0.1 to 102.31.63.254102.31.63.25516,382
126102.31.64.0/18102.31.64.1 to 102.31.127.254102.31.127.25516,382
127102.31.128.0/18102.31.128.1 to 102.31.191.254102.31.191.25516,382
128102.31.192.0/18102.31.192.1 to 102.31.255.254102.31.255.25516,382
129102.32.0.0/18102.32.0.1 to 102.32.63.254102.32.63.25516,382
130102.32.64.0/18102.32.64.1 to 102.32.127.254102.32.127.25516,382
131102.32.128.0/18102.32.128.1 to 102.32.191.254102.32.191.25516,382
132102.32.192.0/18102.32.192.1 to 102.32.255.254102.32.255.25516,382
133102.33.0.0/18102.33.0.1 to 102.33.63.254102.33.63.25516,382
134102.33.64.0/18102.33.64.1 to 102.33.127.254102.33.127.25516,382
135102.33.128.0/18102.33.128.1 to 102.33.191.254102.33.191.25516,382
136102.33.192.0/18102.33.192.1 to 102.33.255.254102.33.255.25516,382
137102.34.0.0/18102.34.0.1 to 102.34.63.254102.34.63.25516,382
138102.34.64.0/18102.34.64.1 to 102.34.127.254102.34.127.25516,382
139102.34.128.0/18102.34.128.1 to 102.34.191.254102.34.191.25516,382
140102.34.192.0/18102.34.192.1 to 102.34.255.254102.34.255.25516,382
141102.35.0.0/18102.35.0.1 to 102.35.63.254102.35.63.25516,382
142102.35.64.0/18102.35.64.1 to 102.35.127.254102.35.127.25516,382
143102.35.128.0/18102.35.128.1 to 102.35.191.254102.35.191.25516,382
144102.35.192.0/18102.35.192.1 to 102.35.255.254102.35.255.25516,382
145102.36.0.0/18102.36.0.1 to 102.36.63.254102.36.63.25516,382
146102.36.64.0/18102.36.64.1 to 102.36.127.254102.36.127.25516,382
147102.36.128.0/18102.36.128.1 to 102.36.191.254102.36.191.25516,382
148102.36.192.0/18102.36.192.1 to 102.36.255.254102.36.255.25516,382
149102.37.0.0/18102.37.0.1 to 102.37.63.254102.37.63.25516,382
150102.37.64.0/18102.37.64.1 to 102.37.127.254102.37.127.25516,382
151102.37.128.0/18102.37.128.1 to 102.37.191.254102.37.191.25516,382
152102.37.192.0/18102.37.192.1 to 102.37.255.254102.37.255.25516,382
153102.38.0.0/18102.38.0.1 to 102.38.63.254102.38.63.25516,382
154102.38.64.0/18102.38.64.1 to 102.38.127.254102.38.127.25516,382
155102.38.128.0/18102.38.128.1 to 102.38.191.254102.38.191.25516,382
156102.38.192.0/18102.38.192.1 to 102.38.255.254102.38.255.25516,382
157102.39.0.0/18102.39.0.1 to 102.39.63.254102.39.63.25516,382
158102.39.64.0/18102.39.64.1 to 102.39.127.254102.39.127.25516,382
159102.39.128.0/18102.39.128.1 to 102.39.191.254102.39.191.25516,382
160102.39.192.0/18102.39.192.1 to 102.39.255.254102.39.255.25516,382
161102.40.0.0/18102.40.0.1 to 102.40.63.254102.40.63.25516,382
162102.40.64.0/18102.40.64.1 to 102.40.127.254102.40.127.25516,382
163102.40.128.0/18102.40.128.1 to 102.40.191.254102.40.191.25516,382
164102.40.192.0/18102.40.192.1 to 102.40.255.254102.40.255.25516,382
165102.41.0.0/18102.41.0.1 to 102.41.63.254102.41.63.25516,382
166102.41.64.0/18102.41.64.1 to 102.41.127.254102.41.127.25516,382
167102.41.128.0/18102.41.128.1 to 102.41.191.254102.41.191.25516,382
168102.41.192.0/18102.41.192.1 to 102.41.255.254102.41.255.25516,382
169102.42.0.0/18102.42.0.1 to 102.42.63.254102.42.63.25516,382
170102.42.64.0/18102.42.64.1 to 102.42.127.254102.42.127.25516,382
171102.42.128.0/18102.42.128.1 to 102.42.191.254102.42.191.25516,382
172102.42.192.0/18102.42.192.1 to 102.42.255.254102.42.255.25516,382
173102.43.0.0/18102.43.0.1 to 102.43.63.254102.43.63.25516,382
174102.43.64.0/18102.43.64.1 to 102.43.127.254102.43.127.25516,382
175102.43.128.0/18102.43.128.1 to 102.43.191.254102.43.191.25516,382
176102.43.192.0/18102.43.192.1 to 102.43.255.254102.43.255.25516,382
177102.44.0.0/18102.44.0.1 to 102.44.63.254102.44.63.25516,382
178102.44.64.0/18102.44.64.1 to 102.44.127.254102.44.127.25516,382
179102.44.128.0/18102.44.128.1 to 102.44.191.254102.44.191.25516,382
180102.44.192.0/18102.44.192.1 to 102.44.255.254102.44.255.25516,382
181102.45.0.0/18102.45.0.1 to 102.45.63.254102.45.63.25516,382
182102.45.64.0/18102.45.64.1 to 102.45.127.254102.45.127.25516,382
183102.45.128.0/18102.45.128.1 to 102.45.191.254102.45.191.25516,382
184102.45.192.0/18102.45.192.1 to 102.45.255.254102.45.255.25516,382
185102.46.0.0/18102.46.0.1 to 102.46.63.254102.46.63.25516,382
186102.46.64.0/18102.46.64.1 to 102.46.127.254102.46.127.25516,382
187102.46.128.0/18102.46.128.1 to 102.46.191.254102.46.191.25516,382
188102.46.192.0/18102.46.192.1 to 102.46.255.254102.46.255.25516,382
189102.47.0.0/18102.47.0.1 to 102.47.63.254102.47.63.25516,382
190102.47.64.0/18102.47.64.1 to 102.47.127.254102.47.127.25516,382
191102.47.128.0/18102.47.128.1 to 102.47.191.254102.47.191.25516,382
192102.47.192.0/18102.47.192.1 to 102.47.255.254102.47.255.25516,382
193102.48.0.0/18102.48.0.1 to 102.48.63.254102.48.63.25516,382
194102.48.64.0/18102.48.64.1 to 102.48.127.254102.48.127.25516,382
195102.48.128.0/18102.48.128.1 to 102.48.191.254102.48.191.25516,382
196102.48.192.0/18102.48.192.1 to 102.48.255.254102.48.255.25516,382
197102.49.0.0/18102.49.0.1 to 102.49.63.254102.49.63.25516,382
198102.49.64.0/18102.49.64.1 to 102.49.127.254102.49.127.25516,382
199102.49.128.0/18102.49.128.1 to 102.49.191.254102.49.191.25516,382
200102.49.192.0/18102.49.192.1 to 102.49.255.254102.49.255.25516,382
201102.50.0.0/18102.50.0.1 to 102.50.63.254102.50.63.25516,382
202102.50.64.0/18102.50.64.1 to 102.50.127.254102.50.127.25516,382
203102.50.128.0/18102.50.128.1 to 102.50.191.254102.50.191.25516,382
204102.50.192.0/18102.50.192.1 to 102.50.255.254102.50.255.25516,382
205102.51.0.0/18102.51.0.1 to 102.51.63.254102.51.63.25516,382
206102.51.64.0/18102.51.64.1 to 102.51.127.254102.51.127.25516,382
207102.51.128.0/18102.51.128.1 to 102.51.191.254102.51.191.25516,382
208102.51.192.0/18102.51.192.1 to 102.51.255.254102.51.255.25516,382
209102.52.0.0/18102.52.0.1 to 102.52.63.254102.52.63.25516,382
210102.52.64.0/18102.52.64.1 to 102.52.127.254102.52.127.25516,382
211102.52.128.0/18102.52.128.1 to 102.52.191.254102.52.191.25516,382
212102.52.192.0/18102.52.192.1 to 102.52.255.254102.52.255.25516,382
213102.53.0.0/18102.53.0.1 to 102.53.63.254102.53.63.25516,382
214102.53.64.0/18102.53.64.1 to 102.53.127.254102.53.127.25516,382
215102.53.128.0/18102.53.128.1 to 102.53.191.254102.53.191.25516,382
216102.53.192.0/18102.53.192.1 to 102.53.255.254102.53.255.25516,382
217102.54.0.0/18102.54.0.1 to 102.54.63.254102.54.63.25516,382
218102.54.64.0/18102.54.64.1 to 102.54.127.254102.54.127.25516,382
219102.54.128.0/18102.54.128.1 to 102.54.191.254102.54.191.25516,382
220102.54.192.0/18102.54.192.1 to 102.54.255.254102.54.255.25516,382
221102.55.0.0/18102.55.0.1 to 102.55.63.254102.55.63.25516,382
222102.55.64.0/18102.55.64.1 to 102.55.127.254102.55.127.25516,382
223102.55.128.0/18102.55.128.1 to 102.55.191.254102.55.191.25516,382
224102.55.192.0/18102.55.192.1 to 102.55.255.254102.55.255.25516,382
225102.56.0.0/18102.56.0.1 to 102.56.63.254102.56.63.25516,382
226102.56.64.0/18102.56.64.1 to 102.56.127.254102.56.127.25516,382
227102.56.128.0/18102.56.128.1 to 102.56.191.254102.56.191.25516,382
228102.56.192.0/18102.56.192.1 to 102.56.255.254102.56.255.25516,382
229102.57.0.0/18102.57.0.1 to 102.57.63.254102.57.63.25516,382
230102.57.64.0/18102.57.64.1 to 102.57.127.254102.57.127.25516,382
231102.57.128.0/18102.57.128.1 to 102.57.191.254102.57.191.25516,382
232102.57.192.0/18102.57.192.1 to 102.57.255.254102.57.255.25516,382
233102.58.0.0/18102.58.0.1 to 102.58.63.254102.58.63.25516,382
234102.58.64.0/18102.58.64.1 to 102.58.127.254102.58.127.25516,382
235102.58.128.0/18102.58.128.1 to 102.58.191.254102.58.191.25516,382
236102.58.192.0/18102.58.192.1 to 102.58.255.254102.58.255.25516,382
237102.59.0.0/18102.59.0.1 to 102.59.63.254102.59.63.25516,382
238102.59.64.0/18102.59.64.1 to 102.59.127.254102.59.127.25516,382
239102.59.128.0/18102.59.128.1 to 102.59.191.254102.59.191.25516,382
240102.59.192.0/18102.59.192.1 to 102.59.255.254102.59.255.25516,382
241102.60.0.0/18102.60.0.1 to 102.60.63.254102.60.63.25516,382
242102.60.64.0/18102.60.64.1 to 102.60.127.254102.60.127.25516,382
243102.60.128.0/18102.60.128.1 to 102.60.191.254102.60.191.25516,382
244102.60.192.0/18102.60.192.1 to 102.60.255.254102.60.255.25516,382
245102.61.0.0/18102.61.0.1 to 102.61.63.254102.61.63.25516,382
246102.61.64.0/18102.61.64.1 to 102.61.127.254102.61.127.25516,382
247102.61.128.0/18102.61.128.1 to 102.61.191.254102.61.191.25516,382
248102.61.192.0/18102.61.192.1 to 102.61.255.254102.61.255.25516,382
249102.62.0.0/18102.62.0.1 to 102.62.63.254102.62.63.25516,382
250102.62.64.0/18102.62.64.1 to 102.62.127.254102.62.127.25516,382
251102.62.128.0/18102.62.128.1 to 102.62.191.254102.62.191.25516,382
252102.62.192.0/18102.62.192.1 to 102.62.255.254102.62.255.25516,382
253102.63.0.0/18102.63.0.1 to 102.63.63.254102.63.63.25516,382
254102.63.64.0/18102.63.64.1 to 102.63.127.254102.63.127.25516,382
255102.63.128.0/18102.63.128.1 to 102.63.191.254102.63.191.25516,382
256102.63.192.0/18102.63.192.1 to 102.63.255.254102.63.255.25516,382

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.