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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.

Network192.0.0.0/7
Usable hosts33,554,430
Subnet mask254.0.0.0
Addresses33,554,432
Network address
192.0.0.0
Broadcast address
193.255.255.255
First usable
192.0.0.1
Last usable
193.255.255.254
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
C (default /24)
As numbers
Hex C0000000 · Integer 3221225472 to 3254779903
Reverse DNS zones
192.in-addr.arpa
193.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
Address11000000.00000000.00000000.00000000192.0.0.0
Subnet mask11111110.00000000.00000000.00000000254.0.0.0
Network11000000.00000000.00000000.00000000192.0.0.0
Broadcast11000001.11111111.11111111.11111111193.255.255.255
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)

192.0.0.0/7 makes 2,048 subnets of /18; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1192.0.0.0/18192.0.0.1 to 192.0.63.254192.0.63.25516,382
2192.0.64.0/18192.0.64.1 to 192.0.127.254192.0.127.25516,382
3192.0.128.0/18192.0.128.1 to 192.0.191.254192.0.191.25516,382
4192.0.192.0/18192.0.192.1 to 192.0.255.254192.0.255.25516,382
5192.1.0.0/18192.1.0.1 to 192.1.63.254192.1.63.25516,382
6192.1.64.0/18192.1.64.1 to 192.1.127.254192.1.127.25516,382
7192.1.128.0/18192.1.128.1 to 192.1.191.254192.1.191.25516,382
8192.1.192.0/18192.1.192.1 to 192.1.255.254192.1.255.25516,382
9192.2.0.0/18192.2.0.1 to 192.2.63.254192.2.63.25516,382
10192.2.64.0/18192.2.64.1 to 192.2.127.254192.2.127.25516,382
11192.2.128.0/18192.2.128.1 to 192.2.191.254192.2.191.25516,382
12192.2.192.0/18192.2.192.1 to 192.2.255.254192.2.255.25516,382
13192.3.0.0/18192.3.0.1 to 192.3.63.254192.3.63.25516,382
14192.3.64.0/18192.3.64.1 to 192.3.127.254192.3.127.25516,382
15192.3.128.0/18192.3.128.1 to 192.3.191.254192.3.191.25516,382
16192.3.192.0/18192.3.192.1 to 192.3.255.254192.3.255.25516,382
17192.4.0.0/18192.4.0.1 to 192.4.63.254192.4.63.25516,382
18192.4.64.0/18192.4.64.1 to 192.4.127.254192.4.127.25516,382
19192.4.128.0/18192.4.128.1 to 192.4.191.254192.4.191.25516,382
20192.4.192.0/18192.4.192.1 to 192.4.255.254192.4.255.25516,382
21192.5.0.0/18192.5.0.1 to 192.5.63.254192.5.63.25516,382
22192.5.64.0/18192.5.64.1 to 192.5.127.254192.5.127.25516,382
23192.5.128.0/18192.5.128.1 to 192.5.191.254192.5.191.25516,382
24192.5.192.0/18192.5.192.1 to 192.5.255.254192.5.255.25516,382
25192.6.0.0/18192.6.0.1 to 192.6.63.254192.6.63.25516,382
26192.6.64.0/18192.6.64.1 to 192.6.127.254192.6.127.25516,382
27192.6.128.0/18192.6.128.1 to 192.6.191.254192.6.191.25516,382
28192.6.192.0/18192.6.192.1 to 192.6.255.254192.6.255.25516,382
29192.7.0.0/18192.7.0.1 to 192.7.63.254192.7.63.25516,382
30192.7.64.0/18192.7.64.1 to 192.7.127.254192.7.127.25516,382
31192.7.128.0/18192.7.128.1 to 192.7.191.254192.7.191.25516,382
32192.7.192.0/18192.7.192.1 to 192.7.255.254192.7.255.25516,382
33192.8.0.0/18192.8.0.1 to 192.8.63.254192.8.63.25516,382
34192.8.64.0/18192.8.64.1 to 192.8.127.254192.8.127.25516,382
35192.8.128.0/18192.8.128.1 to 192.8.191.254192.8.191.25516,382
36192.8.192.0/18192.8.192.1 to 192.8.255.254192.8.255.25516,382
37192.9.0.0/18192.9.0.1 to 192.9.63.254192.9.63.25516,382
38192.9.64.0/18192.9.64.1 to 192.9.127.254192.9.127.25516,382
39192.9.128.0/18192.9.128.1 to 192.9.191.254192.9.191.25516,382
40192.9.192.0/18192.9.192.1 to 192.9.255.254192.9.255.25516,382
41192.10.0.0/18192.10.0.1 to 192.10.63.254192.10.63.25516,382
42192.10.64.0/18192.10.64.1 to 192.10.127.254192.10.127.25516,382
43192.10.128.0/18192.10.128.1 to 192.10.191.254192.10.191.25516,382
44192.10.192.0/18192.10.192.1 to 192.10.255.254192.10.255.25516,382
45192.11.0.0/18192.11.0.1 to 192.11.63.254192.11.63.25516,382
46192.11.64.0/18192.11.64.1 to 192.11.127.254192.11.127.25516,382
47192.11.128.0/18192.11.128.1 to 192.11.191.254192.11.191.25516,382
48192.11.192.0/18192.11.192.1 to 192.11.255.254192.11.255.25516,382
49192.12.0.0/18192.12.0.1 to 192.12.63.254192.12.63.25516,382
50192.12.64.0/18192.12.64.1 to 192.12.127.254192.12.127.25516,382
51192.12.128.0/18192.12.128.1 to 192.12.191.254192.12.191.25516,382
52192.12.192.0/18192.12.192.1 to 192.12.255.254192.12.255.25516,382
53192.13.0.0/18192.13.0.1 to 192.13.63.254192.13.63.25516,382
54192.13.64.0/18192.13.64.1 to 192.13.127.254192.13.127.25516,382
55192.13.128.0/18192.13.128.1 to 192.13.191.254192.13.191.25516,382
56192.13.192.0/18192.13.192.1 to 192.13.255.254192.13.255.25516,382
57192.14.0.0/18192.14.0.1 to 192.14.63.254192.14.63.25516,382
58192.14.64.0/18192.14.64.1 to 192.14.127.254192.14.127.25516,382
59192.14.128.0/18192.14.128.1 to 192.14.191.254192.14.191.25516,382
60192.14.192.0/18192.14.192.1 to 192.14.255.254192.14.255.25516,382
61192.15.0.0/18192.15.0.1 to 192.15.63.254192.15.63.25516,382
62192.15.64.0/18192.15.64.1 to 192.15.127.254192.15.127.25516,382
63192.15.128.0/18192.15.128.1 to 192.15.191.254192.15.191.25516,382
64192.15.192.0/18192.15.192.1 to 192.15.255.254192.15.255.25516,382
65192.16.0.0/18192.16.0.1 to 192.16.63.254192.16.63.25516,382
66192.16.64.0/18192.16.64.1 to 192.16.127.254192.16.127.25516,382
67192.16.128.0/18192.16.128.1 to 192.16.191.254192.16.191.25516,382
68192.16.192.0/18192.16.192.1 to 192.16.255.254192.16.255.25516,382
69192.17.0.0/18192.17.0.1 to 192.17.63.254192.17.63.25516,382
70192.17.64.0/18192.17.64.1 to 192.17.127.254192.17.127.25516,382
71192.17.128.0/18192.17.128.1 to 192.17.191.254192.17.191.25516,382
72192.17.192.0/18192.17.192.1 to 192.17.255.254192.17.255.25516,382
73192.18.0.0/18192.18.0.1 to 192.18.63.254192.18.63.25516,382
74192.18.64.0/18192.18.64.1 to 192.18.127.254192.18.127.25516,382
75192.18.128.0/18192.18.128.1 to 192.18.191.254192.18.191.25516,382
76192.18.192.0/18192.18.192.1 to 192.18.255.254192.18.255.25516,382
77192.19.0.0/18192.19.0.1 to 192.19.63.254192.19.63.25516,382
78192.19.64.0/18192.19.64.1 to 192.19.127.254192.19.127.25516,382
79192.19.128.0/18192.19.128.1 to 192.19.191.254192.19.191.25516,382
80192.19.192.0/18192.19.192.1 to 192.19.255.254192.19.255.25516,382
81192.20.0.0/18192.20.0.1 to 192.20.63.254192.20.63.25516,382
82192.20.64.0/18192.20.64.1 to 192.20.127.254192.20.127.25516,382
83192.20.128.0/18192.20.128.1 to 192.20.191.254192.20.191.25516,382
84192.20.192.0/18192.20.192.1 to 192.20.255.254192.20.255.25516,382
85192.21.0.0/18192.21.0.1 to 192.21.63.254192.21.63.25516,382
86192.21.64.0/18192.21.64.1 to 192.21.127.254192.21.127.25516,382
87192.21.128.0/18192.21.128.1 to 192.21.191.254192.21.191.25516,382
88192.21.192.0/18192.21.192.1 to 192.21.255.254192.21.255.25516,382
89192.22.0.0/18192.22.0.1 to 192.22.63.254192.22.63.25516,382
90192.22.64.0/18192.22.64.1 to 192.22.127.254192.22.127.25516,382
91192.22.128.0/18192.22.128.1 to 192.22.191.254192.22.191.25516,382
92192.22.192.0/18192.22.192.1 to 192.22.255.254192.22.255.25516,382
93192.23.0.0/18192.23.0.1 to 192.23.63.254192.23.63.25516,382
94192.23.64.0/18192.23.64.1 to 192.23.127.254192.23.127.25516,382
95192.23.128.0/18192.23.128.1 to 192.23.191.254192.23.191.25516,382
96192.23.192.0/18192.23.192.1 to 192.23.255.254192.23.255.25516,382
97192.24.0.0/18192.24.0.1 to 192.24.63.254192.24.63.25516,382
98192.24.64.0/18192.24.64.1 to 192.24.127.254192.24.127.25516,382
99192.24.128.0/18192.24.128.1 to 192.24.191.254192.24.191.25516,382
100192.24.192.0/18192.24.192.1 to 192.24.255.254192.24.255.25516,382
101192.25.0.0/18192.25.0.1 to 192.25.63.254192.25.63.25516,382
102192.25.64.0/18192.25.64.1 to 192.25.127.254192.25.127.25516,382
103192.25.128.0/18192.25.128.1 to 192.25.191.254192.25.191.25516,382
104192.25.192.0/18192.25.192.1 to 192.25.255.254192.25.255.25516,382
105192.26.0.0/18192.26.0.1 to 192.26.63.254192.26.63.25516,382
106192.26.64.0/18192.26.64.1 to 192.26.127.254192.26.127.25516,382
107192.26.128.0/18192.26.128.1 to 192.26.191.254192.26.191.25516,382
108192.26.192.0/18192.26.192.1 to 192.26.255.254192.26.255.25516,382
109192.27.0.0/18192.27.0.1 to 192.27.63.254192.27.63.25516,382
110192.27.64.0/18192.27.64.1 to 192.27.127.254192.27.127.25516,382
111192.27.128.0/18192.27.128.1 to 192.27.191.254192.27.191.25516,382
112192.27.192.0/18192.27.192.1 to 192.27.255.254192.27.255.25516,382
113192.28.0.0/18192.28.0.1 to 192.28.63.254192.28.63.25516,382
114192.28.64.0/18192.28.64.1 to 192.28.127.254192.28.127.25516,382
115192.28.128.0/18192.28.128.1 to 192.28.191.254192.28.191.25516,382
116192.28.192.0/18192.28.192.1 to 192.28.255.254192.28.255.25516,382
117192.29.0.0/18192.29.0.1 to 192.29.63.254192.29.63.25516,382
118192.29.64.0/18192.29.64.1 to 192.29.127.254192.29.127.25516,382
119192.29.128.0/18192.29.128.1 to 192.29.191.254192.29.191.25516,382
120192.29.192.0/18192.29.192.1 to 192.29.255.254192.29.255.25516,382
121192.30.0.0/18192.30.0.1 to 192.30.63.254192.30.63.25516,382
122192.30.64.0/18192.30.64.1 to 192.30.127.254192.30.127.25516,382
123192.30.128.0/18192.30.128.1 to 192.30.191.254192.30.191.25516,382
124192.30.192.0/18192.30.192.1 to 192.30.255.254192.30.255.25516,382
125192.31.0.0/18192.31.0.1 to 192.31.63.254192.31.63.25516,382
126192.31.64.0/18192.31.64.1 to 192.31.127.254192.31.127.25516,382
127192.31.128.0/18192.31.128.1 to 192.31.191.254192.31.191.25516,382
128192.31.192.0/18192.31.192.1 to 192.31.255.254192.31.255.25516,382
129192.32.0.0/18192.32.0.1 to 192.32.63.254192.32.63.25516,382
130192.32.64.0/18192.32.64.1 to 192.32.127.254192.32.127.25516,382
131192.32.128.0/18192.32.128.1 to 192.32.191.254192.32.191.25516,382
132192.32.192.0/18192.32.192.1 to 192.32.255.254192.32.255.25516,382
133192.33.0.0/18192.33.0.1 to 192.33.63.254192.33.63.25516,382
134192.33.64.0/18192.33.64.1 to 192.33.127.254192.33.127.25516,382
135192.33.128.0/18192.33.128.1 to 192.33.191.254192.33.191.25516,382
136192.33.192.0/18192.33.192.1 to 192.33.255.254192.33.255.25516,382
137192.34.0.0/18192.34.0.1 to 192.34.63.254192.34.63.25516,382
138192.34.64.0/18192.34.64.1 to 192.34.127.254192.34.127.25516,382
139192.34.128.0/18192.34.128.1 to 192.34.191.254192.34.191.25516,382
140192.34.192.0/18192.34.192.1 to 192.34.255.254192.34.255.25516,382
141192.35.0.0/18192.35.0.1 to 192.35.63.254192.35.63.25516,382
142192.35.64.0/18192.35.64.1 to 192.35.127.254192.35.127.25516,382
143192.35.128.0/18192.35.128.1 to 192.35.191.254192.35.191.25516,382
144192.35.192.0/18192.35.192.1 to 192.35.255.254192.35.255.25516,382
145192.36.0.0/18192.36.0.1 to 192.36.63.254192.36.63.25516,382
146192.36.64.0/18192.36.64.1 to 192.36.127.254192.36.127.25516,382
147192.36.128.0/18192.36.128.1 to 192.36.191.254192.36.191.25516,382
148192.36.192.0/18192.36.192.1 to 192.36.255.254192.36.255.25516,382
149192.37.0.0/18192.37.0.1 to 192.37.63.254192.37.63.25516,382
150192.37.64.0/18192.37.64.1 to 192.37.127.254192.37.127.25516,382
151192.37.128.0/18192.37.128.1 to 192.37.191.254192.37.191.25516,382
152192.37.192.0/18192.37.192.1 to 192.37.255.254192.37.255.25516,382
153192.38.0.0/18192.38.0.1 to 192.38.63.254192.38.63.25516,382
154192.38.64.0/18192.38.64.1 to 192.38.127.254192.38.127.25516,382
155192.38.128.0/18192.38.128.1 to 192.38.191.254192.38.191.25516,382
156192.38.192.0/18192.38.192.1 to 192.38.255.254192.38.255.25516,382
157192.39.0.0/18192.39.0.1 to 192.39.63.254192.39.63.25516,382
158192.39.64.0/18192.39.64.1 to 192.39.127.254192.39.127.25516,382
159192.39.128.0/18192.39.128.1 to 192.39.191.254192.39.191.25516,382
160192.39.192.0/18192.39.192.1 to 192.39.255.254192.39.255.25516,382
161192.40.0.0/18192.40.0.1 to 192.40.63.254192.40.63.25516,382
162192.40.64.0/18192.40.64.1 to 192.40.127.254192.40.127.25516,382
163192.40.128.0/18192.40.128.1 to 192.40.191.254192.40.191.25516,382
164192.40.192.0/18192.40.192.1 to 192.40.255.254192.40.255.25516,382
165192.41.0.0/18192.41.0.1 to 192.41.63.254192.41.63.25516,382
166192.41.64.0/18192.41.64.1 to 192.41.127.254192.41.127.25516,382
167192.41.128.0/18192.41.128.1 to 192.41.191.254192.41.191.25516,382
168192.41.192.0/18192.41.192.1 to 192.41.255.254192.41.255.25516,382
169192.42.0.0/18192.42.0.1 to 192.42.63.254192.42.63.25516,382
170192.42.64.0/18192.42.64.1 to 192.42.127.254192.42.127.25516,382
171192.42.128.0/18192.42.128.1 to 192.42.191.254192.42.191.25516,382
172192.42.192.0/18192.42.192.1 to 192.42.255.254192.42.255.25516,382
173192.43.0.0/18192.43.0.1 to 192.43.63.254192.43.63.25516,382
174192.43.64.0/18192.43.64.1 to 192.43.127.254192.43.127.25516,382
175192.43.128.0/18192.43.128.1 to 192.43.191.254192.43.191.25516,382
176192.43.192.0/18192.43.192.1 to 192.43.255.254192.43.255.25516,382
177192.44.0.0/18192.44.0.1 to 192.44.63.254192.44.63.25516,382
178192.44.64.0/18192.44.64.1 to 192.44.127.254192.44.127.25516,382
179192.44.128.0/18192.44.128.1 to 192.44.191.254192.44.191.25516,382
180192.44.192.0/18192.44.192.1 to 192.44.255.254192.44.255.25516,382
181192.45.0.0/18192.45.0.1 to 192.45.63.254192.45.63.25516,382
182192.45.64.0/18192.45.64.1 to 192.45.127.254192.45.127.25516,382
183192.45.128.0/18192.45.128.1 to 192.45.191.254192.45.191.25516,382
184192.45.192.0/18192.45.192.1 to 192.45.255.254192.45.255.25516,382
185192.46.0.0/18192.46.0.1 to 192.46.63.254192.46.63.25516,382
186192.46.64.0/18192.46.64.1 to 192.46.127.254192.46.127.25516,382
187192.46.128.0/18192.46.128.1 to 192.46.191.254192.46.191.25516,382
188192.46.192.0/18192.46.192.1 to 192.46.255.254192.46.255.25516,382
189192.47.0.0/18192.47.0.1 to 192.47.63.254192.47.63.25516,382
190192.47.64.0/18192.47.64.1 to 192.47.127.254192.47.127.25516,382
191192.47.128.0/18192.47.128.1 to 192.47.191.254192.47.191.25516,382
192192.47.192.0/18192.47.192.1 to 192.47.255.254192.47.255.25516,382
193192.48.0.0/18192.48.0.1 to 192.48.63.254192.48.63.25516,382
194192.48.64.0/18192.48.64.1 to 192.48.127.254192.48.127.25516,382
195192.48.128.0/18192.48.128.1 to 192.48.191.254192.48.191.25516,382
196192.48.192.0/18192.48.192.1 to 192.48.255.254192.48.255.25516,382
197192.49.0.0/18192.49.0.1 to 192.49.63.254192.49.63.25516,382
198192.49.64.0/18192.49.64.1 to 192.49.127.254192.49.127.25516,382
199192.49.128.0/18192.49.128.1 to 192.49.191.254192.49.191.25516,382
200192.49.192.0/18192.49.192.1 to 192.49.255.254192.49.255.25516,382
201192.50.0.0/18192.50.0.1 to 192.50.63.254192.50.63.25516,382
202192.50.64.0/18192.50.64.1 to 192.50.127.254192.50.127.25516,382
203192.50.128.0/18192.50.128.1 to 192.50.191.254192.50.191.25516,382
204192.50.192.0/18192.50.192.1 to 192.50.255.254192.50.255.25516,382
205192.51.0.0/18192.51.0.1 to 192.51.63.254192.51.63.25516,382
206192.51.64.0/18192.51.64.1 to 192.51.127.254192.51.127.25516,382
207192.51.128.0/18192.51.128.1 to 192.51.191.254192.51.191.25516,382
208192.51.192.0/18192.51.192.1 to 192.51.255.254192.51.255.25516,382
209192.52.0.0/18192.52.0.1 to 192.52.63.254192.52.63.25516,382
210192.52.64.0/18192.52.64.1 to 192.52.127.254192.52.127.25516,382
211192.52.128.0/18192.52.128.1 to 192.52.191.254192.52.191.25516,382
212192.52.192.0/18192.52.192.1 to 192.52.255.254192.52.255.25516,382
213192.53.0.0/18192.53.0.1 to 192.53.63.254192.53.63.25516,382
214192.53.64.0/18192.53.64.1 to 192.53.127.254192.53.127.25516,382
215192.53.128.0/18192.53.128.1 to 192.53.191.254192.53.191.25516,382
216192.53.192.0/18192.53.192.1 to 192.53.255.254192.53.255.25516,382
217192.54.0.0/18192.54.0.1 to 192.54.63.254192.54.63.25516,382
218192.54.64.0/18192.54.64.1 to 192.54.127.254192.54.127.25516,382
219192.54.128.0/18192.54.128.1 to 192.54.191.254192.54.191.25516,382
220192.54.192.0/18192.54.192.1 to 192.54.255.254192.54.255.25516,382
221192.55.0.0/18192.55.0.1 to 192.55.63.254192.55.63.25516,382
222192.55.64.0/18192.55.64.1 to 192.55.127.254192.55.127.25516,382
223192.55.128.0/18192.55.128.1 to 192.55.191.254192.55.191.25516,382
224192.55.192.0/18192.55.192.1 to 192.55.255.254192.55.255.25516,382
225192.56.0.0/18192.56.0.1 to 192.56.63.254192.56.63.25516,382
226192.56.64.0/18192.56.64.1 to 192.56.127.254192.56.127.25516,382
227192.56.128.0/18192.56.128.1 to 192.56.191.254192.56.191.25516,382
228192.56.192.0/18192.56.192.1 to 192.56.255.254192.56.255.25516,382
229192.57.0.0/18192.57.0.1 to 192.57.63.254192.57.63.25516,382
230192.57.64.0/18192.57.64.1 to 192.57.127.254192.57.127.25516,382
231192.57.128.0/18192.57.128.1 to 192.57.191.254192.57.191.25516,382
232192.57.192.0/18192.57.192.1 to 192.57.255.254192.57.255.25516,382
233192.58.0.0/18192.58.0.1 to 192.58.63.254192.58.63.25516,382
234192.58.64.0/18192.58.64.1 to 192.58.127.254192.58.127.25516,382
235192.58.128.0/18192.58.128.1 to 192.58.191.254192.58.191.25516,382
236192.58.192.0/18192.58.192.1 to 192.58.255.254192.58.255.25516,382
237192.59.0.0/18192.59.0.1 to 192.59.63.254192.59.63.25516,382
238192.59.64.0/18192.59.64.1 to 192.59.127.254192.59.127.25516,382
239192.59.128.0/18192.59.128.1 to 192.59.191.254192.59.191.25516,382
240192.59.192.0/18192.59.192.1 to 192.59.255.254192.59.255.25516,382
241192.60.0.0/18192.60.0.1 to 192.60.63.254192.60.63.25516,382
242192.60.64.0/18192.60.64.1 to 192.60.127.254192.60.127.25516,382
243192.60.128.0/18192.60.128.1 to 192.60.191.254192.60.191.25516,382
244192.60.192.0/18192.60.192.1 to 192.60.255.254192.60.255.25516,382
245192.61.0.0/18192.61.0.1 to 192.61.63.254192.61.63.25516,382
246192.61.64.0/18192.61.64.1 to 192.61.127.254192.61.127.25516,382
247192.61.128.0/18192.61.128.1 to 192.61.191.254192.61.191.25516,382
248192.61.192.0/18192.61.192.1 to 192.61.255.254192.61.255.25516,382
249192.62.0.0/18192.62.0.1 to 192.62.63.254192.62.63.25516,382
250192.62.64.0/18192.62.64.1 to 192.62.127.254192.62.127.25516,382
251192.62.128.0/18192.62.128.1 to 192.62.191.254192.62.191.25516,382
252192.62.192.0/18192.62.192.1 to 192.62.255.254192.62.255.25516,382
253192.63.0.0/18192.63.0.1 to 192.63.63.254192.63.63.25516,382
254192.63.64.0/18192.63.64.1 to 192.63.127.254192.63.127.25516,382
255192.63.128.0/18192.63.128.1 to 192.63.191.254192.63.191.25516,382
256192.63.192.0/18192.63.192.1 to 192.63.255.254192.63.255.25516,382

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.