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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.

Network192.0.0.0/8
Usable hosts16,777,214
Subnet mask255.0.0.0
Addresses16,777,216
Network address
192.0.0.0
Broadcast address
192.255.255.255
First usable
192.0.0.1
Last usable
192.255.255.254
Usable hosts
16,777,214 (16,777,216 less the network and broadcast addresses)
Subnet mask
255.0.0.0
Wildcard mask
0.255.255.255 (Cisco ACLs, OSPF)
Prefix length
/8
Type
Public public
Old class
C (default /24)
As numbers
Hex C0000000 · Integer 3221225472 to 3238002687
Reverse DNS zone
192.in-addr.arpa
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address11000000..00000000.00000000.00000000192.0.0.0
Subnet mask11111111..00000000.00000000.00000000255.0.0.0
Network11000000..00000000.00000000.00000000192.0.0.0
Broadcast11000000..11111111.11111111.11111111192.255.255.255
Split into smaller subnets/20
/9 (2)/10 (4)/11 (8)/12 (16)/13 (32)/14 (64)/15 (128)/16 (256)/17 (512)/18 (1,024)/19 (2,048)/20 (4,096)

192.0.0.0/8 makes 4,096 subnets of /20; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1192.0.0.0/20192.0.0.1 to 192.0.15.254192.0.15.2554,094
2192.0.16.0/20192.0.16.1 to 192.0.31.254192.0.31.2554,094
3192.0.32.0/20192.0.32.1 to 192.0.47.254192.0.47.2554,094
4192.0.48.0/20192.0.48.1 to 192.0.63.254192.0.63.2554,094
5192.0.64.0/20192.0.64.1 to 192.0.79.254192.0.79.2554,094
6192.0.80.0/20192.0.80.1 to 192.0.95.254192.0.95.2554,094
7192.0.96.0/20192.0.96.1 to 192.0.111.254192.0.111.2554,094
8192.0.112.0/20192.0.112.1 to 192.0.127.254192.0.127.2554,094
9192.0.128.0/20192.0.128.1 to 192.0.143.254192.0.143.2554,094
10192.0.144.0/20192.0.144.1 to 192.0.159.254192.0.159.2554,094
11192.0.160.0/20192.0.160.1 to 192.0.175.254192.0.175.2554,094
12192.0.176.0/20192.0.176.1 to 192.0.191.254192.0.191.2554,094
13192.0.192.0/20192.0.192.1 to 192.0.207.254192.0.207.2554,094
14192.0.208.0/20192.0.208.1 to 192.0.223.254192.0.223.2554,094
15192.0.224.0/20192.0.224.1 to 192.0.239.254192.0.239.2554,094
16192.0.240.0/20192.0.240.1 to 192.0.255.254192.0.255.2554,094
17192.1.0.0/20192.1.0.1 to 192.1.15.254192.1.15.2554,094
18192.1.16.0/20192.1.16.1 to 192.1.31.254192.1.31.2554,094
19192.1.32.0/20192.1.32.1 to 192.1.47.254192.1.47.2554,094
20192.1.48.0/20192.1.48.1 to 192.1.63.254192.1.63.2554,094
21192.1.64.0/20192.1.64.1 to 192.1.79.254192.1.79.2554,094
22192.1.80.0/20192.1.80.1 to 192.1.95.254192.1.95.2554,094
23192.1.96.0/20192.1.96.1 to 192.1.111.254192.1.111.2554,094
24192.1.112.0/20192.1.112.1 to 192.1.127.254192.1.127.2554,094
25192.1.128.0/20192.1.128.1 to 192.1.143.254192.1.143.2554,094
26192.1.144.0/20192.1.144.1 to 192.1.159.254192.1.159.2554,094
27192.1.160.0/20192.1.160.1 to 192.1.175.254192.1.175.2554,094
28192.1.176.0/20192.1.176.1 to 192.1.191.254192.1.191.2554,094
29192.1.192.0/20192.1.192.1 to 192.1.207.254192.1.207.2554,094
30192.1.208.0/20192.1.208.1 to 192.1.223.254192.1.223.2554,094
31192.1.224.0/20192.1.224.1 to 192.1.239.254192.1.239.2554,094
32192.1.240.0/20192.1.240.1 to 192.1.255.254192.1.255.2554,094
33192.2.0.0/20192.2.0.1 to 192.2.15.254192.2.15.2554,094
34192.2.16.0/20192.2.16.1 to 192.2.31.254192.2.31.2554,094
35192.2.32.0/20192.2.32.1 to 192.2.47.254192.2.47.2554,094
36192.2.48.0/20192.2.48.1 to 192.2.63.254192.2.63.2554,094
37192.2.64.0/20192.2.64.1 to 192.2.79.254192.2.79.2554,094
38192.2.80.0/20192.2.80.1 to 192.2.95.254192.2.95.2554,094
39192.2.96.0/20192.2.96.1 to 192.2.111.254192.2.111.2554,094
40192.2.112.0/20192.2.112.1 to 192.2.127.254192.2.127.2554,094
41192.2.128.0/20192.2.128.1 to 192.2.143.254192.2.143.2554,094
42192.2.144.0/20192.2.144.1 to 192.2.159.254192.2.159.2554,094
43192.2.160.0/20192.2.160.1 to 192.2.175.254192.2.175.2554,094
44192.2.176.0/20192.2.176.1 to 192.2.191.254192.2.191.2554,094
45192.2.192.0/20192.2.192.1 to 192.2.207.254192.2.207.2554,094
46192.2.208.0/20192.2.208.1 to 192.2.223.254192.2.223.2554,094
47192.2.224.0/20192.2.224.1 to 192.2.239.254192.2.239.2554,094
48192.2.240.0/20192.2.240.1 to 192.2.255.254192.2.255.2554,094
49192.3.0.0/20192.3.0.1 to 192.3.15.254192.3.15.2554,094
50192.3.16.0/20192.3.16.1 to 192.3.31.254192.3.31.2554,094
51192.3.32.0/20192.3.32.1 to 192.3.47.254192.3.47.2554,094
52192.3.48.0/20192.3.48.1 to 192.3.63.254192.3.63.2554,094
53192.3.64.0/20192.3.64.1 to 192.3.79.254192.3.79.2554,094
54192.3.80.0/20192.3.80.1 to 192.3.95.254192.3.95.2554,094
55192.3.96.0/20192.3.96.1 to 192.3.111.254192.3.111.2554,094
56192.3.112.0/20192.3.112.1 to 192.3.127.254192.3.127.2554,094
57192.3.128.0/20192.3.128.1 to 192.3.143.254192.3.143.2554,094
58192.3.144.0/20192.3.144.1 to 192.3.159.254192.3.159.2554,094
59192.3.160.0/20192.3.160.1 to 192.3.175.254192.3.175.2554,094
60192.3.176.0/20192.3.176.1 to 192.3.191.254192.3.191.2554,094
61192.3.192.0/20192.3.192.1 to 192.3.207.254192.3.207.2554,094
62192.3.208.0/20192.3.208.1 to 192.3.223.254192.3.223.2554,094
63192.3.224.0/20192.3.224.1 to 192.3.239.254192.3.239.2554,094
64192.3.240.0/20192.3.240.1 to 192.3.255.254192.3.255.2554,094
65192.4.0.0/20192.4.0.1 to 192.4.15.254192.4.15.2554,094
66192.4.16.0/20192.4.16.1 to 192.4.31.254192.4.31.2554,094
67192.4.32.0/20192.4.32.1 to 192.4.47.254192.4.47.2554,094
68192.4.48.0/20192.4.48.1 to 192.4.63.254192.4.63.2554,094
69192.4.64.0/20192.4.64.1 to 192.4.79.254192.4.79.2554,094
70192.4.80.0/20192.4.80.1 to 192.4.95.254192.4.95.2554,094
71192.4.96.0/20192.4.96.1 to 192.4.111.254192.4.111.2554,094
72192.4.112.0/20192.4.112.1 to 192.4.127.254192.4.127.2554,094
73192.4.128.0/20192.4.128.1 to 192.4.143.254192.4.143.2554,094
74192.4.144.0/20192.4.144.1 to 192.4.159.254192.4.159.2554,094
75192.4.160.0/20192.4.160.1 to 192.4.175.254192.4.175.2554,094
76192.4.176.0/20192.4.176.1 to 192.4.191.254192.4.191.2554,094
77192.4.192.0/20192.4.192.1 to 192.4.207.254192.4.207.2554,094
78192.4.208.0/20192.4.208.1 to 192.4.223.254192.4.223.2554,094
79192.4.224.0/20192.4.224.1 to 192.4.239.254192.4.239.2554,094
80192.4.240.0/20192.4.240.1 to 192.4.255.254192.4.255.2554,094
81192.5.0.0/20192.5.0.1 to 192.5.15.254192.5.15.2554,094
82192.5.16.0/20192.5.16.1 to 192.5.31.254192.5.31.2554,094
83192.5.32.0/20192.5.32.1 to 192.5.47.254192.5.47.2554,094
84192.5.48.0/20192.5.48.1 to 192.5.63.254192.5.63.2554,094
85192.5.64.0/20192.5.64.1 to 192.5.79.254192.5.79.2554,094
86192.5.80.0/20192.5.80.1 to 192.5.95.254192.5.95.2554,094
87192.5.96.0/20192.5.96.1 to 192.5.111.254192.5.111.2554,094
88192.5.112.0/20192.5.112.1 to 192.5.127.254192.5.127.2554,094
89192.5.128.0/20192.5.128.1 to 192.5.143.254192.5.143.2554,094
90192.5.144.0/20192.5.144.1 to 192.5.159.254192.5.159.2554,094
91192.5.160.0/20192.5.160.1 to 192.5.175.254192.5.175.2554,094
92192.5.176.0/20192.5.176.1 to 192.5.191.254192.5.191.2554,094
93192.5.192.0/20192.5.192.1 to 192.5.207.254192.5.207.2554,094
94192.5.208.0/20192.5.208.1 to 192.5.223.254192.5.223.2554,094
95192.5.224.0/20192.5.224.1 to 192.5.239.254192.5.239.2554,094
96192.5.240.0/20192.5.240.1 to 192.5.255.254192.5.255.2554,094
97192.6.0.0/20192.6.0.1 to 192.6.15.254192.6.15.2554,094
98192.6.16.0/20192.6.16.1 to 192.6.31.254192.6.31.2554,094
99192.6.32.0/20192.6.32.1 to 192.6.47.254192.6.47.2554,094
100192.6.48.0/20192.6.48.1 to 192.6.63.254192.6.63.2554,094
101192.6.64.0/20192.6.64.1 to 192.6.79.254192.6.79.2554,094
102192.6.80.0/20192.6.80.1 to 192.6.95.254192.6.95.2554,094
103192.6.96.0/20192.6.96.1 to 192.6.111.254192.6.111.2554,094
104192.6.112.0/20192.6.112.1 to 192.6.127.254192.6.127.2554,094
105192.6.128.0/20192.6.128.1 to 192.6.143.254192.6.143.2554,094
106192.6.144.0/20192.6.144.1 to 192.6.159.254192.6.159.2554,094
107192.6.160.0/20192.6.160.1 to 192.6.175.254192.6.175.2554,094
108192.6.176.0/20192.6.176.1 to 192.6.191.254192.6.191.2554,094
109192.6.192.0/20192.6.192.1 to 192.6.207.254192.6.207.2554,094
110192.6.208.0/20192.6.208.1 to 192.6.223.254192.6.223.2554,094
111192.6.224.0/20192.6.224.1 to 192.6.239.254192.6.239.2554,094
112192.6.240.0/20192.6.240.1 to 192.6.255.254192.6.255.2554,094
113192.7.0.0/20192.7.0.1 to 192.7.15.254192.7.15.2554,094
114192.7.16.0/20192.7.16.1 to 192.7.31.254192.7.31.2554,094
115192.7.32.0/20192.7.32.1 to 192.7.47.254192.7.47.2554,094
116192.7.48.0/20192.7.48.1 to 192.7.63.254192.7.63.2554,094
117192.7.64.0/20192.7.64.1 to 192.7.79.254192.7.79.2554,094
118192.7.80.0/20192.7.80.1 to 192.7.95.254192.7.95.2554,094
119192.7.96.0/20192.7.96.1 to 192.7.111.254192.7.111.2554,094
120192.7.112.0/20192.7.112.1 to 192.7.127.254192.7.127.2554,094
121192.7.128.0/20192.7.128.1 to 192.7.143.254192.7.143.2554,094
122192.7.144.0/20192.7.144.1 to 192.7.159.254192.7.159.2554,094
123192.7.160.0/20192.7.160.1 to 192.7.175.254192.7.175.2554,094
124192.7.176.0/20192.7.176.1 to 192.7.191.254192.7.191.2554,094
125192.7.192.0/20192.7.192.1 to 192.7.207.254192.7.207.2554,094
126192.7.208.0/20192.7.208.1 to 192.7.223.254192.7.223.2554,094
127192.7.224.0/20192.7.224.1 to 192.7.239.254192.7.239.2554,094
128192.7.240.0/20192.7.240.1 to 192.7.255.254192.7.255.2554,094
129192.8.0.0/20192.8.0.1 to 192.8.15.254192.8.15.2554,094
130192.8.16.0/20192.8.16.1 to 192.8.31.254192.8.31.2554,094
131192.8.32.0/20192.8.32.1 to 192.8.47.254192.8.47.2554,094
132192.8.48.0/20192.8.48.1 to 192.8.63.254192.8.63.2554,094
133192.8.64.0/20192.8.64.1 to 192.8.79.254192.8.79.2554,094
134192.8.80.0/20192.8.80.1 to 192.8.95.254192.8.95.2554,094
135192.8.96.0/20192.8.96.1 to 192.8.111.254192.8.111.2554,094
136192.8.112.0/20192.8.112.1 to 192.8.127.254192.8.127.2554,094
137192.8.128.0/20192.8.128.1 to 192.8.143.254192.8.143.2554,094
138192.8.144.0/20192.8.144.1 to 192.8.159.254192.8.159.2554,094
139192.8.160.0/20192.8.160.1 to 192.8.175.254192.8.175.2554,094
140192.8.176.0/20192.8.176.1 to 192.8.191.254192.8.191.2554,094
141192.8.192.0/20192.8.192.1 to 192.8.207.254192.8.207.2554,094
142192.8.208.0/20192.8.208.1 to 192.8.223.254192.8.223.2554,094
143192.8.224.0/20192.8.224.1 to 192.8.239.254192.8.239.2554,094
144192.8.240.0/20192.8.240.1 to 192.8.255.254192.8.255.2554,094
145192.9.0.0/20192.9.0.1 to 192.9.15.254192.9.15.2554,094
146192.9.16.0/20192.9.16.1 to 192.9.31.254192.9.31.2554,094
147192.9.32.0/20192.9.32.1 to 192.9.47.254192.9.47.2554,094
148192.9.48.0/20192.9.48.1 to 192.9.63.254192.9.63.2554,094
149192.9.64.0/20192.9.64.1 to 192.9.79.254192.9.79.2554,094
150192.9.80.0/20192.9.80.1 to 192.9.95.254192.9.95.2554,094
151192.9.96.0/20192.9.96.1 to 192.9.111.254192.9.111.2554,094
152192.9.112.0/20192.9.112.1 to 192.9.127.254192.9.127.2554,094
153192.9.128.0/20192.9.128.1 to 192.9.143.254192.9.143.2554,094
154192.9.144.0/20192.9.144.1 to 192.9.159.254192.9.159.2554,094
155192.9.160.0/20192.9.160.1 to 192.9.175.254192.9.175.2554,094
156192.9.176.0/20192.9.176.1 to 192.9.191.254192.9.191.2554,094
157192.9.192.0/20192.9.192.1 to 192.9.207.254192.9.207.2554,094
158192.9.208.0/20192.9.208.1 to 192.9.223.254192.9.223.2554,094
159192.9.224.0/20192.9.224.1 to 192.9.239.254192.9.239.2554,094
160192.9.240.0/20192.9.240.1 to 192.9.255.254192.9.255.2554,094
161192.10.0.0/20192.10.0.1 to 192.10.15.254192.10.15.2554,094
162192.10.16.0/20192.10.16.1 to 192.10.31.254192.10.31.2554,094
163192.10.32.0/20192.10.32.1 to 192.10.47.254192.10.47.2554,094
164192.10.48.0/20192.10.48.1 to 192.10.63.254192.10.63.2554,094
165192.10.64.0/20192.10.64.1 to 192.10.79.254192.10.79.2554,094
166192.10.80.0/20192.10.80.1 to 192.10.95.254192.10.95.2554,094
167192.10.96.0/20192.10.96.1 to 192.10.111.254192.10.111.2554,094
168192.10.112.0/20192.10.112.1 to 192.10.127.254192.10.127.2554,094
169192.10.128.0/20192.10.128.1 to 192.10.143.254192.10.143.2554,094
170192.10.144.0/20192.10.144.1 to 192.10.159.254192.10.159.2554,094
171192.10.160.0/20192.10.160.1 to 192.10.175.254192.10.175.2554,094
172192.10.176.0/20192.10.176.1 to 192.10.191.254192.10.191.2554,094
173192.10.192.0/20192.10.192.1 to 192.10.207.254192.10.207.2554,094
174192.10.208.0/20192.10.208.1 to 192.10.223.254192.10.223.2554,094
175192.10.224.0/20192.10.224.1 to 192.10.239.254192.10.239.2554,094
176192.10.240.0/20192.10.240.1 to 192.10.255.254192.10.255.2554,094
177192.11.0.0/20192.11.0.1 to 192.11.15.254192.11.15.2554,094
178192.11.16.0/20192.11.16.1 to 192.11.31.254192.11.31.2554,094
179192.11.32.0/20192.11.32.1 to 192.11.47.254192.11.47.2554,094
180192.11.48.0/20192.11.48.1 to 192.11.63.254192.11.63.2554,094
181192.11.64.0/20192.11.64.1 to 192.11.79.254192.11.79.2554,094
182192.11.80.0/20192.11.80.1 to 192.11.95.254192.11.95.2554,094
183192.11.96.0/20192.11.96.1 to 192.11.111.254192.11.111.2554,094
184192.11.112.0/20192.11.112.1 to 192.11.127.254192.11.127.2554,094
185192.11.128.0/20192.11.128.1 to 192.11.143.254192.11.143.2554,094
186192.11.144.0/20192.11.144.1 to 192.11.159.254192.11.159.2554,094
187192.11.160.0/20192.11.160.1 to 192.11.175.254192.11.175.2554,094
188192.11.176.0/20192.11.176.1 to 192.11.191.254192.11.191.2554,094
189192.11.192.0/20192.11.192.1 to 192.11.207.254192.11.207.2554,094
190192.11.208.0/20192.11.208.1 to 192.11.223.254192.11.223.2554,094
191192.11.224.0/20192.11.224.1 to 192.11.239.254192.11.239.2554,094
192192.11.240.0/20192.11.240.1 to 192.11.255.254192.11.255.2554,094
193192.12.0.0/20192.12.0.1 to 192.12.15.254192.12.15.2554,094
194192.12.16.0/20192.12.16.1 to 192.12.31.254192.12.31.2554,094
195192.12.32.0/20192.12.32.1 to 192.12.47.254192.12.47.2554,094
196192.12.48.0/20192.12.48.1 to 192.12.63.254192.12.63.2554,094
197192.12.64.0/20192.12.64.1 to 192.12.79.254192.12.79.2554,094
198192.12.80.0/20192.12.80.1 to 192.12.95.254192.12.95.2554,094
199192.12.96.0/20192.12.96.1 to 192.12.111.254192.12.111.2554,094
200192.12.112.0/20192.12.112.1 to 192.12.127.254192.12.127.2554,094
201192.12.128.0/20192.12.128.1 to 192.12.143.254192.12.143.2554,094
202192.12.144.0/20192.12.144.1 to 192.12.159.254192.12.159.2554,094
203192.12.160.0/20192.12.160.1 to 192.12.175.254192.12.175.2554,094
204192.12.176.0/20192.12.176.1 to 192.12.191.254192.12.191.2554,094
205192.12.192.0/20192.12.192.1 to 192.12.207.254192.12.207.2554,094
206192.12.208.0/20192.12.208.1 to 192.12.223.254192.12.223.2554,094
207192.12.224.0/20192.12.224.1 to 192.12.239.254192.12.239.2554,094
208192.12.240.0/20192.12.240.1 to 192.12.255.254192.12.255.2554,094
209192.13.0.0/20192.13.0.1 to 192.13.15.254192.13.15.2554,094
210192.13.16.0/20192.13.16.1 to 192.13.31.254192.13.31.2554,094
211192.13.32.0/20192.13.32.1 to 192.13.47.254192.13.47.2554,094
212192.13.48.0/20192.13.48.1 to 192.13.63.254192.13.63.2554,094
213192.13.64.0/20192.13.64.1 to 192.13.79.254192.13.79.2554,094
214192.13.80.0/20192.13.80.1 to 192.13.95.254192.13.95.2554,094
215192.13.96.0/20192.13.96.1 to 192.13.111.254192.13.111.2554,094
216192.13.112.0/20192.13.112.1 to 192.13.127.254192.13.127.2554,094
217192.13.128.0/20192.13.128.1 to 192.13.143.254192.13.143.2554,094
218192.13.144.0/20192.13.144.1 to 192.13.159.254192.13.159.2554,094
219192.13.160.0/20192.13.160.1 to 192.13.175.254192.13.175.2554,094
220192.13.176.0/20192.13.176.1 to 192.13.191.254192.13.191.2554,094
221192.13.192.0/20192.13.192.1 to 192.13.207.254192.13.207.2554,094
222192.13.208.0/20192.13.208.1 to 192.13.223.254192.13.223.2554,094
223192.13.224.0/20192.13.224.1 to 192.13.239.254192.13.239.2554,094
224192.13.240.0/20192.13.240.1 to 192.13.255.254192.13.255.2554,094
225192.14.0.0/20192.14.0.1 to 192.14.15.254192.14.15.2554,094
226192.14.16.0/20192.14.16.1 to 192.14.31.254192.14.31.2554,094
227192.14.32.0/20192.14.32.1 to 192.14.47.254192.14.47.2554,094
228192.14.48.0/20192.14.48.1 to 192.14.63.254192.14.63.2554,094
229192.14.64.0/20192.14.64.1 to 192.14.79.254192.14.79.2554,094
230192.14.80.0/20192.14.80.1 to 192.14.95.254192.14.95.2554,094
231192.14.96.0/20192.14.96.1 to 192.14.111.254192.14.111.2554,094
232192.14.112.0/20192.14.112.1 to 192.14.127.254192.14.127.2554,094
233192.14.128.0/20192.14.128.1 to 192.14.143.254192.14.143.2554,094
234192.14.144.0/20192.14.144.1 to 192.14.159.254192.14.159.2554,094
235192.14.160.0/20192.14.160.1 to 192.14.175.254192.14.175.2554,094
236192.14.176.0/20192.14.176.1 to 192.14.191.254192.14.191.2554,094
237192.14.192.0/20192.14.192.1 to 192.14.207.254192.14.207.2554,094
238192.14.208.0/20192.14.208.1 to 192.14.223.254192.14.223.2554,094
239192.14.224.0/20192.14.224.1 to 192.14.239.254192.14.239.2554,094
240192.14.240.0/20192.14.240.1 to 192.14.255.254192.14.255.2554,094
241192.15.0.0/20192.15.0.1 to 192.15.15.254192.15.15.2554,094
242192.15.16.0/20192.15.16.1 to 192.15.31.254192.15.31.2554,094
243192.15.32.0/20192.15.32.1 to 192.15.47.254192.15.47.2554,094
244192.15.48.0/20192.15.48.1 to 192.15.63.254192.15.63.2554,094
245192.15.64.0/20192.15.64.1 to 192.15.79.254192.15.79.2554,094
246192.15.80.0/20192.15.80.1 to 192.15.95.254192.15.95.2554,094
247192.15.96.0/20192.15.96.1 to 192.15.111.254192.15.111.2554,094
248192.15.112.0/20192.15.112.1 to 192.15.127.254192.15.127.2554,094
249192.15.128.0/20192.15.128.1 to 192.15.143.254192.15.143.2554,094
250192.15.144.0/20192.15.144.1 to 192.15.159.254192.15.159.2554,094
251192.15.160.0/20192.15.160.1 to 192.15.175.254192.15.175.2554,094
252192.15.176.0/20192.15.176.1 to 192.15.191.254192.15.191.2554,094
253192.15.192.0/20192.15.192.1 to 192.15.207.254192.15.207.2554,094
254192.15.208.0/20192.15.208.1 to 192.15.223.254192.15.223.2554,094
255192.15.224.0/20192.15.224.1 to 192.15.239.254192.15.239.2554,094
256192.15.240.0/20192.15.240.1 to 192.15.255.254192.15.255.2554,094

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.