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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.

Network200.0.0.0/10
Usable hosts4,194,302
Subnet mask255.192.0.0
Addresses4,194,304
Network address
200.0.0.0
Broadcast address
200.63.255.255
First usable
200.0.0.1
Last usable
200.63.255.254
Usable hosts
4,194,302 (4,194,304 less the network and broadcast addresses)
Subnet mask
255.192.0.0
Wildcard mask
0.63.255.255 (Cisco ACLs, OSPF)
Prefix length
/10
Type
Public public
Old class
C (default /24)
As numbers
Hex C8000000 · Integer 3355443200 to 3359637503
Reverse DNS zones
0.200.in-addr.arpa
1.200.in-addr.arpa
2.200.in-addr.arpa
3.200.in-addr.arpa
4.200.in-addr.arpa
5.200.in-addr.arpa
6.200.in-addr.arpa
7.200.in-addr.arpa
8.200.in-addr.arpa
9.200.in-addr.arpa
10.200.in-addr.arpa
11.200.in-addr.arpa
12.200.in-addr.arpa
13.200.in-addr.arpa
14.200.in-addr.arpa
15.200.in-addr.arpa
and 48 more
/10 is not on a 8-bit boundary, so it takes 64 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address11001000.00000000.00000000.00000000200.0.0.0
Subnet mask11111111.11000000.00000000.00000000255.192.0.0
Network11001000.00000000.00000000.00000000200.0.0.0
Broadcast11001000.00111111.11111111.11111111200.63.255.255
Split into smaller subnets/21
/11 (2)/12 (4)/13 (8)/14 (16)/15 (32)/16 (64)/17 (128)/18 (256)/19 (512)/20 (1,024)/21 (2,048)/22 (4,096)

200.0.0.0/10 makes 2,048 subnets of /21; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1200.0.0.0/21200.0.0.1 to 200.0.7.254200.0.7.2552,046
2200.0.8.0/21200.0.8.1 to 200.0.15.254200.0.15.2552,046
3200.0.16.0/21200.0.16.1 to 200.0.23.254200.0.23.2552,046
4200.0.24.0/21200.0.24.1 to 200.0.31.254200.0.31.2552,046
5200.0.32.0/21200.0.32.1 to 200.0.39.254200.0.39.2552,046
6200.0.40.0/21200.0.40.1 to 200.0.47.254200.0.47.2552,046
7200.0.48.0/21200.0.48.1 to 200.0.55.254200.0.55.2552,046
8200.0.56.0/21200.0.56.1 to 200.0.63.254200.0.63.2552,046
9200.0.64.0/21200.0.64.1 to 200.0.71.254200.0.71.2552,046
10200.0.72.0/21200.0.72.1 to 200.0.79.254200.0.79.2552,046
11200.0.80.0/21200.0.80.1 to 200.0.87.254200.0.87.2552,046
12200.0.88.0/21200.0.88.1 to 200.0.95.254200.0.95.2552,046
13200.0.96.0/21200.0.96.1 to 200.0.103.254200.0.103.2552,046
14200.0.104.0/21200.0.104.1 to 200.0.111.254200.0.111.2552,046
15200.0.112.0/21200.0.112.1 to 200.0.119.254200.0.119.2552,046
16200.0.120.0/21200.0.120.1 to 200.0.127.254200.0.127.2552,046
17200.0.128.0/21200.0.128.1 to 200.0.135.254200.0.135.2552,046
18200.0.136.0/21200.0.136.1 to 200.0.143.254200.0.143.2552,046
19200.0.144.0/21200.0.144.1 to 200.0.151.254200.0.151.2552,046
20200.0.152.0/21200.0.152.1 to 200.0.159.254200.0.159.2552,046
21200.0.160.0/21200.0.160.1 to 200.0.167.254200.0.167.2552,046
22200.0.168.0/21200.0.168.1 to 200.0.175.254200.0.175.2552,046
23200.0.176.0/21200.0.176.1 to 200.0.183.254200.0.183.2552,046
24200.0.184.0/21200.0.184.1 to 200.0.191.254200.0.191.2552,046
25200.0.192.0/21200.0.192.1 to 200.0.199.254200.0.199.2552,046
26200.0.200.0/21200.0.200.1 to 200.0.207.254200.0.207.2552,046
27200.0.208.0/21200.0.208.1 to 200.0.215.254200.0.215.2552,046
28200.0.216.0/21200.0.216.1 to 200.0.223.254200.0.223.2552,046
29200.0.224.0/21200.0.224.1 to 200.0.231.254200.0.231.2552,046
30200.0.232.0/21200.0.232.1 to 200.0.239.254200.0.239.2552,046
31200.0.240.0/21200.0.240.1 to 200.0.247.254200.0.247.2552,046
32200.0.248.0/21200.0.248.1 to 200.0.255.254200.0.255.2552,046
33200.1.0.0/21200.1.0.1 to 200.1.7.254200.1.7.2552,046
34200.1.8.0/21200.1.8.1 to 200.1.15.254200.1.15.2552,046
35200.1.16.0/21200.1.16.1 to 200.1.23.254200.1.23.2552,046
36200.1.24.0/21200.1.24.1 to 200.1.31.254200.1.31.2552,046
37200.1.32.0/21200.1.32.1 to 200.1.39.254200.1.39.2552,046
38200.1.40.0/21200.1.40.1 to 200.1.47.254200.1.47.2552,046
39200.1.48.0/21200.1.48.1 to 200.1.55.254200.1.55.2552,046
40200.1.56.0/21200.1.56.1 to 200.1.63.254200.1.63.2552,046
41200.1.64.0/21200.1.64.1 to 200.1.71.254200.1.71.2552,046
42200.1.72.0/21200.1.72.1 to 200.1.79.254200.1.79.2552,046
43200.1.80.0/21200.1.80.1 to 200.1.87.254200.1.87.2552,046
44200.1.88.0/21200.1.88.1 to 200.1.95.254200.1.95.2552,046
45200.1.96.0/21200.1.96.1 to 200.1.103.254200.1.103.2552,046
46200.1.104.0/21200.1.104.1 to 200.1.111.254200.1.111.2552,046
47200.1.112.0/21200.1.112.1 to 200.1.119.254200.1.119.2552,046
48200.1.120.0/21200.1.120.1 to 200.1.127.254200.1.127.2552,046
49200.1.128.0/21200.1.128.1 to 200.1.135.254200.1.135.2552,046
50200.1.136.0/21200.1.136.1 to 200.1.143.254200.1.143.2552,046
51200.1.144.0/21200.1.144.1 to 200.1.151.254200.1.151.2552,046
52200.1.152.0/21200.1.152.1 to 200.1.159.254200.1.159.2552,046
53200.1.160.0/21200.1.160.1 to 200.1.167.254200.1.167.2552,046
54200.1.168.0/21200.1.168.1 to 200.1.175.254200.1.175.2552,046
55200.1.176.0/21200.1.176.1 to 200.1.183.254200.1.183.2552,046
56200.1.184.0/21200.1.184.1 to 200.1.191.254200.1.191.2552,046
57200.1.192.0/21200.1.192.1 to 200.1.199.254200.1.199.2552,046
58200.1.200.0/21200.1.200.1 to 200.1.207.254200.1.207.2552,046
59200.1.208.0/21200.1.208.1 to 200.1.215.254200.1.215.2552,046
60200.1.216.0/21200.1.216.1 to 200.1.223.254200.1.223.2552,046
61200.1.224.0/21200.1.224.1 to 200.1.231.254200.1.231.2552,046
62200.1.232.0/21200.1.232.1 to 200.1.239.254200.1.239.2552,046
63200.1.240.0/21200.1.240.1 to 200.1.247.254200.1.247.2552,046
64200.1.248.0/21200.1.248.1 to 200.1.255.254200.1.255.2552,046
65200.2.0.0/21200.2.0.1 to 200.2.7.254200.2.7.2552,046
66200.2.8.0/21200.2.8.1 to 200.2.15.254200.2.15.2552,046
67200.2.16.0/21200.2.16.1 to 200.2.23.254200.2.23.2552,046
68200.2.24.0/21200.2.24.1 to 200.2.31.254200.2.31.2552,046
69200.2.32.0/21200.2.32.1 to 200.2.39.254200.2.39.2552,046
70200.2.40.0/21200.2.40.1 to 200.2.47.254200.2.47.2552,046
71200.2.48.0/21200.2.48.1 to 200.2.55.254200.2.55.2552,046
72200.2.56.0/21200.2.56.1 to 200.2.63.254200.2.63.2552,046
73200.2.64.0/21200.2.64.1 to 200.2.71.254200.2.71.2552,046
74200.2.72.0/21200.2.72.1 to 200.2.79.254200.2.79.2552,046
75200.2.80.0/21200.2.80.1 to 200.2.87.254200.2.87.2552,046
76200.2.88.0/21200.2.88.1 to 200.2.95.254200.2.95.2552,046
77200.2.96.0/21200.2.96.1 to 200.2.103.254200.2.103.2552,046
78200.2.104.0/21200.2.104.1 to 200.2.111.254200.2.111.2552,046
79200.2.112.0/21200.2.112.1 to 200.2.119.254200.2.119.2552,046
80200.2.120.0/21200.2.120.1 to 200.2.127.254200.2.127.2552,046
81200.2.128.0/21200.2.128.1 to 200.2.135.254200.2.135.2552,046
82200.2.136.0/21200.2.136.1 to 200.2.143.254200.2.143.2552,046
83200.2.144.0/21200.2.144.1 to 200.2.151.254200.2.151.2552,046
84200.2.152.0/21200.2.152.1 to 200.2.159.254200.2.159.2552,046
85200.2.160.0/21200.2.160.1 to 200.2.167.254200.2.167.2552,046
86200.2.168.0/21200.2.168.1 to 200.2.175.254200.2.175.2552,046
87200.2.176.0/21200.2.176.1 to 200.2.183.254200.2.183.2552,046
88200.2.184.0/21200.2.184.1 to 200.2.191.254200.2.191.2552,046
89200.2.192.0/21200.2.192.1 to 200.2.199.254200.2.199.2552,046
90200.2.200.0/21200.2.200.1 to 200.2.207.254200.2.207.2552,046
91200.2.208.0/21200.2.208.1 to 200.2.215.254200.2.215.2552,046
92200.2.216.0/21200.2.216.1 to 200.2.223.254200.2.223.2552,046
93200.2.224.0/21200.2.224.1 to 200.2.231.254200.2.231.2552,046
94200.2.232.0/21200.2.232.1 to 200.2.239.254200.2.239.2552,046
95200.2.240.0/21200.2.240.1 to 200.2.247.254200.2.247.2552,046
96200.2.248.0/21200.2.248.1 to 200.2.255.254200.2.255.2552,046
97200.3.0.0/21200.3.0.1 to 200.3.7.254200.3.7.2552,046
98200.3.8.0/21200.3.8.1 to 200.3.15.254200.3.15.2552,046
99200.3.16.0/21200.3.16.1 to 200.3.23.254200.3.23.2552,046
100200.3.24.0/21200.3.24.1 to 200.3.31.254200.3.31.2552,046
101200.3.32.0/21200.3.32.1 to 200.3.39.254200.3.39.2552,046
102200.3.40.0/21200.3.40.1 to 200.3.47.254200.3.47.2552,046
103200.3.48.0/21200.3.48.1 to 200.3.55.254200.3.55.2552,046
104200.3.56.0/21200.3.56.1 to 200.3.63.254200.3.63.2552,046
105200.3.64.0/21200.3.64.1 to 200.3.71.254200.3.71.2552,046
106200.3.72.0/21200.3.72.1 to 200.3.79.254200.3.79.2552,046
107200.3.80.0/21200.3.80.1 to 200.3.87.254200.3.87.2552,046
108200.3.88.0/21200.3.88.1 to 200.3.95.254200.3.95.2552,046
109200.3.96.0/21200.3.96.1 to 200.3.103.254200.3.103.2552,046
110200.3.104.0/21200.3.104.1 to 200.3.111.254200.3.111.2552,046
111200.3.112.0/21200.3.112.1 to 200.3.119.254200.3.119.2552,046
112200.3.120.0/21200.3.120.1 to 200.3.127.254200.3.127.2552,046
113200.3.128.0/21200.3.128.1 to 200.3.135.254200.3.135.2552,046
114200.3.136.0/21200.3.136.1 to 200.3.143.254200.3.143.2552,046
115200.3.144.0/21200.3.144.1 to 200.3.151.254200.3.151.2552,046
116200.3.152.0/21200.3.152.1 to 200.3.159.254200.3.159.2552,046
117200.3.160.0/21200.3.160.1 to 200.3.167.254200.3.167.2552,046
118200.3.168.0/21200.3.168.1 to 200.3.175.254200.3.175.2552,046
119200.3.176.0/21200.3.176.1 to 200.3.183.254200.3.183.2552,046
120200.3.184.0/21200.3.184.1 to 200.3.191.254200.3.191.2552,046
121200.3.192.0/21200.3.192.1 to 200.3.199.254200.3.199.2552,046
122200.3.200.0/21200.3.200.1 to 200.3.207.254200.3.207.2552,046
123200.3.208.0/21200.3.208.1 to 200.3.215.254200.3.215.2552,046
124200.3.216.0/21200.3.216.1 to 200.3.223.254200.3.223.2552,046
125200.3.224.0/21200.3.224.1 to 200.3.231.254200.3.231.2552,046
126200.3.232.0/21200.3.232.1 to 200.3.239.254200.3.239.2552,046
127200.3.240.0/21200.3.240.1 to 200.3.247.254200.3.247.2552,046
128200.3.248.0/21200.3.248.1 to 200.3.255.254200.3.255.2552,046
129200.4.0.0/21200.4.0.1 to 200.4.7.254200.4.7.2552,046
130200.4.8.0/21200.4.8.1 to 200.4.15.254200.4.15.2552,046
131200.4.16.0/21200.4.16.1 to 200.4.23.254200.4.23.2552,046
132200.4.24.0/21200.4.24.1 to 200.4.31.254200.4.31.2552,046
133200.4.32.0/21200.4.32.1 to 200.4.39.254200.4.39.2552,046
134200.4.40.0/21200.4.40.1 to 200.4.47.254200.4.47.2552,046
135200.4.48.0/21200.4.48.1 to 200.4.55.254200.4.55.2552,046
136200.4.56.0/21200.4.56.1 to 200.4.63.254200.4.63.2552,046
137200.4.64.0/21200.4.64.1 to 200.4.71.254200.4.71.2552,046
138200.4.72.0/21200.4.72.1 to 200.4.79.254200.4.79.2552,046
139200.4.80.0/21200.4.80.1 to 200.4.87.254200.4.87.2552,046
140200.4.88.0/21200.4.88.1 to 200.4.95.254200.4.95.2552,046
141200.4.96.0/21200.4.96.1 to 200.4.103.254200.4.103.2552,046
142200.4.104.0/21200.4.104.1 to 200.4.111.254200.4.111.2552,046
143200.4.112.0/21200.4.112.1 to 200.4.119.254200.4.119.2552,046
144200.4.120.0/21200.4.120.1 to 200.4.127.254200.4.127.2552,046
145200.4.128.0/21200.4.128.1 to 200.4.135.254200.4.135.2552,046
146200.4.136.0/21200.4.136.1 to 200.4.143.254200.4.143.2552,046
147200.4.144.0/21200.4.144.1 to 200.4.151.254200.4.151.2552,046
148200.4.152.0/21200.4.152.1 to 200.4.159.254200.4.159.2552,046
149200.4.160.0/21200.4.160.1 to 200.4.167.254200.4.167.2552,046
150200.4.168.0/21200.4.168.1 to 200.4.175.254200.4.175.2552,046
151200.4.176.0/21200.4.176.1 to 200.4.183.254200.4.183.2552,046
152200.4.184.0/21200.4.184.1 to 200.4.191.254200.4.191.2552,046
153200.4.192.0/21200.4.192.1 to 200.4.199.254200.4.199.2552,046
154200.4.200.0/21200.4.200.1 to 200.4.207.254200.4.207.2552,046
155200.4.208.0/21200.4.208.1 to 200.4.215.254200.4.215.2552,046
156200.4.216.0/21200.4.216.1 to 200.4.223.254200.4.223.2552,046
157200.4.224.0/21200.4.224.1 to 200.4.231.254200.4.231.2552,046
158200.4.232.0/21200.4.232.1 to 200.4.239.254200.4.239.2552,046
159200.4.240.0/21200.4.240.1 to 200.4.247.254200.4.247.2552,046
160200.4.248.0/21200.4.248.1 to 200.4.255.254200.4.255.2552,046
161200.5.0.0/21200.5.0.1 to 200.5.7.254200.5.7.2552,046
162200.5.8.0/21200.5.8.1 to 200.5.15.254200.5.15.2552,046
163200.5.16.0/21200.5.16.1 to 200.5.23.254200.5.23.2552,046
164200.5.24.0/21200.5.24.1 to 200.5.31.254200.5.31.2552,046
165200.5.32.0/21200.5.32.1 to 200.5.39.254200.5.39.2552,046
166200.5.40.0/21200.5.40.1 to 200.5.47.254200.5.47.2552,046
167200.5.48.0/21200.5.48.1 to 200.5.55.254200.5.55.2552,046
168200.5.56.0/21200.5.56.1 to 200.5.63.254200.5.63.2552,046
169200.5.64.0/21200.5.64.1 to 200.5.71.254200.5.71.2552,046
170200.5.72.0/21200.5.72.1 to 200.5.79.254200.5.79.2552,046
171200.5.80.0/21200.5.80.1 to 200.5.87.254200.5.87.2552,046
172200.5.88.0/21200.5.88.1 to 200.5.95.254200.5.95.2552,046
173200.5.96.0/21200.5.96.1 to 200.5.103.254200.5.103.2552,046
174200.5.104.0/21200.5.104.1 to 200.5.111.254200.5.111.2552,046
175200.5.112.0/21200.5.112.1 to 200.5.119.254200.5.119.2552,046
176200.5.120.0/21200.5.120.1 to 200.5.127.254200.5.127.2552,046
177200.5.128.0/21200.5.128.1 to 200.5.135.254200.5.135.2552,046
178200.5.136.0/21200.5.136.1 to 200.5.143.254200.5.143.2552,046
179200.5.144.0/21200.5.144.1 to 200.5.151.254200.5.151.2552,046
180200.5.152.0/21200.5.152.1 to 200.5.159.254200.5.159.2552,046
181200.5.160.0/21200.5.160.1 to 200.5.167.254200.5.167.2552,046
182200.5.168.0/21200.5.168.1 to 200.5.175.254200.5.175.2552,046
183200.5.176.0/21200.5.176.1 to 200.5.183.254200.5.183.2552,046
184200.5.184.0/21200.5.184.1 to 200.5.191.254200.5.191.2552,046
185200.5.192.0/21200.5.192.1 to 200.5.199.254200.5.199.2552,046
186200.5.200.0/21200.5.200.1 to 200.5.207.254200.5.207.2552,046
187200.5.208.0/21200.5.208.1 to 200.5.215.254200.5.215.2552,046
188200.5.216.0/21200.5.216.1 to 200.5.223.254200.5.223.2552,046
189200.5.224.0/21200.5.224.1 to 200.5.231.254200.5.231.2552,046
190200.5.232.0/21200.5.232.1 to 200.5.239.254200.5.239.2552,046
191200.5.240.0/21200.5.240.1 to 200.5.247.254200.5.247.2552,046
192200.5.248.0/21200.5.248.1 to 200.5.255.254200.5.255.2552,046
193200.6.0.0/21200.6.0.1 to 200.6.7.254200.6.7.2552,046
194200.6.8.0/21200.6.8.1 to 200.6.15.254200.6.15.2552,046
195200.6.16.0/21200.6.16.1 to 200.6.23.254200.6.23.2552,046
196200.6.24.0/21200.6.24.1 to 200.6.31.254200.6.31.2552,046
197200.6.32.0/21200.6.32.1 to 200.6.39.254200.6.39.2552,046
198200.6.40.0/21200.6.40.1 to 200.6.47.254200.6.47.2552,046
199200.6.48.0/21200.6.48.1 to 200.6.55.254200.6.55.2552,046
200200.6.56.0/21200.6.56.1 to 200.6.63.254200.6.63.2552,046
201200.6.64.0/21200.6.64.1 to 200.6.71.254200.6.71.2552,046
202200.6.72.0/21200.6.72.1 to 200.6.79.254200.6.79.2552,046
203200.6.80.0/21200.6.80.1 to 200.6.87.254200.6.87.2552,046
204200.6.88.0/21200.6.88.1 to 200.6.95.254200.6.95.2552,046
205200.6.96.0/21200.6.96.1 to 200.6.103.254200.6.103.2552,046
206200.6.104.0/21200.6.104.1 to 200.6.111.254200.6.111.2552,046
207200.6.112.0/21200.6.112.1 to 200.6.119.254200.6.119.2552,046
208200.6.120.0/21200.6.120.1 to 200.6.127.254200.6.127.2552,046
209200.6.128.0/21200.6.128.1 to 200.6.135.254200.6.135.2552,046
210200.6.136.0/21200.6.136.1 to 200.6.143.254200.6.143.2552,046
211200.6.144.0/21200.6.144.1 to 200.6.151.254200.6.151.2552,046
212200.6.152.0/21200.6.152.1 to 200.6.159.254200.6.159.2552,046
213200.6.160.0/21200.6.160.1 to 200.6.167.254200.6.167.2552,046
214200.6.168.0/21200.6.168.1 to 200.6.175.254200.6.175.2552,046
215200.6.176.0/21200.6.176.1 to 200.6.183.254200.6.183.2552,046
216200.6.184.0/21200.6.184.1 to 200.6.191.254200.6.191.2552,046
217200.6.192.0/21200.6.192.1 to 200.6.199.254200.6.199.2552,046
218200.6.200.0/21200.6.200.1 to 200.6.207.254200.6.207.2552,046
219200.6.208.0/21200.6.208.1 to 200.6.215.254200.6.215.2552,046
220200.6.216.0/21200.6.216.1 to 200.6.223.254200.6.223.2552,046
221200.6.224.0/21200.6.224.1 to 200.6.231.254200.6.231.2552,046
222200.6.232.0/21200.6.232.1 to 200.6.239.254200.6.239.2552,046
223200.6.240.0/21200.6.240.1 to 200.6.247.254200.6.247.2552,046
224200.6.248.0/21200.6.248.1 to 200.6.255.254200.6.255.2552,046
225200.7.0.0/21200.7.0.1 to 200.7.7.254200.7.7.2552,046
226200.7.8.0/21200.7.8.1 to 200.7.15.254200.7.15.2552,046
227200.7.16.0/21200.7.16.1 to 200.7.23.254200.7.23.2552,046
228200.7.24.0/21200.7.24.1 to 200.7.31.254200.7.31.2552,046
229200.7.32.0/21200.7.32.1 to 200.7.39.254200.7.39.2552,046
230200.7.40.0/21200.7.40.1 to 200.7.47.254200.7.47.2552,046
231200.7.48.0/21200.7.48.1 to 200.7.55.254200.7.55.2552,046
232200.7.56.0/21200.7.56.1 to 200.7.63.254200.7.63.2552,046
233200.7.64.0/21200.7.64.1 to 200.7.71.254200.7.71.2552,046
234200.7.72.0/21200.7.72.1 to 200.7.79.254200.7.79.2552,046
235200.7.80.0/21200.7.80.1 to 200.7.87.254200.7.87.2552,046
236200.7.88.0/21200.7.88.1 to 200.7.95.254200.7.95.2552,046
237200.7.96.0/21200.7.96.1 to 200.7.103.254200.7.103.2552,046
238200.7.104.0/21200.7.104.1 to 200.7.111.254200.7.111.2552,046
239200.7.112.0/21200.7.112.1 to 200.7.119.254200.7.119.2552,046
240200.7.120.0/21200.7.120.1 to 200.7.127.254200.7.127.2552,046
241200.7.128.0/21200.7.128.1 to 200.7.135.254200.7.135.2552,046
242200.7.136.0/21200.7.136.1 to 200.7.143.254200.7.143.2552,046
243200.7.144.0/21200.7.144.1 to 200.7.151.254200.7.151.2552,046
244200.7.152.0/21200.7.152.1 to 200.7.159.254200.7.159.2552,046
245200.7.160.0/21200.7.160.1 to 200.7.167.254200.7.167.2552,046
246200.7.168.0/21200.7.168.1 to 200.7.175.254200.7.175.2552,046
247200.7.176.0/21200.7.176.1 to 200.7.183.254200.7.183.2552,046
248200.7.184.0/21200.7.184.1 to 200.7.191.254200.7.191.2552,046
249200.7.192.0/21200.7.192.1 to 200.7.199.254200.7.199.2552,046
250200.7.200.0/21200.7.200.1 to 200.7.207.254200.7.207.2552,046
251200.7.208.0/21200.7.208.1 to 200.7.215.254200.7.215.2552,046
252200.7.216.0/21200.7.216.1 to 200.7.223.254200.7.223.2552,046
253200.7.224.0/21200.7.224.1 to 200.7.231.254200.7.231.2552,046
254200.7.232.0/21200.7.232.1 to 200.7.239.254200.7.239.2552,046
255200.7.240.0/21200.7.240.1 to 200.7.247.254200.7.247.2552,046
256200.7.248.0/21200.7.248.1 to 200.7.255.254200.7.255.2552,046

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.