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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.

Network199.0.0.0/8
Usable hosts16,777,214
Subnet mask255.0.0.0
Addresses16,777,216
Network address
199.0.0.0
Broadcast address
199.255.255.255
First usable
199.0.0.1
Last usable
199.255.255.254
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 C7000000 · Integer 3338665984 to 3355443199
Reverse DNS zone
199.in-addr.arpa
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address11000111..00000000.00000000.00000000199.0.0.0
Subnet mask11111111..00000000.00000000.00000000255.0.0.0
Network11000111..00000000.00000000.00000000199.0.0.0
Broadcast11000111..11111111.11111111.11111111199.255.255.255
Split into smaller subnets/19
/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)

199.0.0.0/8 makes 2,048 subnets of /19; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1199.0.0.0/19199.0.0.1 to 199.0.31.254199.0.31.2558,190
2199.0.32.0/19199.0.32.1 to 199.0.63.254199.0.63.2558,190
3199.0.64.0/19199.0.64.1 to 199.0.95.254199.0.95.2558,190
4199.0.96.0/19199.0.96.1 to 199.0.127.254199.0.127.2558,190
5199.0.128.0/19199.0.128.1 to 199.0.159.254199.0.159.2558,190
6199.0.160.0/19199.0.160.1 to 199.0.191.254199.0.191.2558,190
7199.0.192.0/19199.0.192.1 to 199.0.223.254199.0.223.2558,190
8199.0.224.0/19199.0.224.1 to 199.0.255.254199.0.255.2558,190
9199.1.0.0/19199.1.0.1 to 199.1.31.254199.1.31.2558,190
10199.1.32.0/19199.1.32.1 to 199.1.63.254199.1.63.2558,190
11199.1.64.0/19199.1.64.1 to 199.1.95.254199.1.95.2558,190
12199.1.96.0/19199.1.96.1 to 199.1.127.254199.1.127.2558,190
13199.1.128.0/19199.1.128.1 to 199.1.159.254199.1.159.2558,190
14199.1.160.0/19199.1.160.1 to 199.1.191.254199.1.191.2558,190
15199.1.192.0/19199.1.192.1 to 199.1.223.254199.1.223.2558,190
16199.1.224.0/19199.1.224.1 to 199.1.255.254199.1.255.2558,190
17199.2.0.0/19199.2.0.1 to 199.2.31.254199.2.31.2558,190
18199.2.32.0/19199.2.32.1 to 199.2.63.254199.2.63.2558,190
19199.2.64.0/19199.2.64.1 to 199.2.95.254199.2.95.2558,190
20199.2.96.0/19199.2.96.1 to 199.2.127.254199.2.127.2558,190
21199.2.128.0/19199.2.128.1 to 199.2.159.254199.2.159.2558,190
22199.2.160.0/19199.2.160.1 to 199.2.191.254199.2.191.2558,190
23199.2.192.0/19199.2.192.1 to 199.2.223.254199.2.223.2558,190
24199.2.224.0/19199.2.224.1 to 199.2.255.254199.2.255.2558,190
25199.3.0.0/19199.3.0.1 to 199.3.31.254199.3.31.2558,190
26199.3.32.0/19199.3.32.1 to 199.3.63.254199.3.63.2558,190
27199.3.64.0/19199.3.64.1 to 199.3.95.254199.3.95.2558,190
28199.3.96.0/19199.3.96.1 to 199.3.127.254199.3.127.2558,190
29199.3.128.0/19199.3.128.1 to 199.3.159.254199.3.159.2558,190
30199.3.160.0/19199.3.160.1 to 199.3.191.254199.3.191.2558,190
31199.3.192.0/19199.3.192.1 to 199.3.223.254199.3.223.2558,190
32199.3.224.0/19199.3.224.1 to 199.3.255.254199.3.255.2558,190
33199.4.0.0/19199.4.0.1 to 199.4.31.254199.4.31.2558,190
34199.4.32.0/19199.4.32.1 to 199.4.63.254199.4.63.2558,190
35199.4.64.0/19199.4.64.1 to 199.4.95.254199.4.95.2558,190
36199.4.96.0/19199.4.96.1 to 199.4.127.254199.4.127.2558,190
37199.4.128.0/19199.4.128.1 to 199.4.159.254199.4.159.2558,190
38199.4.160.0/19199.4.160.1 to 199.4.191.254199.4.191.2558,190
39199.4.192.0/19199.4.192.1 to 199.4.223.254199.4.223.2558,190
40199.4.224.0/19199.4.224.1 to 199.4.255.254199.4.255.2558,190
41199.5.0.0/19199.5.0.1 to 199.5.31.254199.5.31.2558,190
42199.5.32.0/19199.5.32.1 to 199.5.63.254199.5.63.2558,190
43199.5.64.0/19199.5.64.1 to 199.5.95.254199.5.95.2558,190
44199.5.96.0/19199.5.96.1 to 199.5.127.254199.5.127.2558,190
45199.5.128.0/19199.5.128.1 to 199.5.159.254199.5.159.2558,190
46199.5.160.0/19199.5.160.1 to 199.5.191.254199.5.191.2558,190
47199.5.192.0/19199.5.192.1 to 199.5.223.254199.5.223.2558,190
48199.5.224.0/19199.5.224.1 to 199.5.255.254199.5.255.2558,190
49199.6.0.0/19199.6.0.1 to 199.6.31.254199.6.31.2558,190
50199.6.32.0/19199.6.32.1 to 199.6.63.254199.6.63.2558,190
51199.6.64.0/19199.6.64.1 to 199.6.95.254199.6.95.2558,190
52199.6.96.0/19199.6.96.1 to 199.6.127.254199.6.127.2558,190
53199.6.128.0/19199.6.128.1 to 199.6.159.254199.6.159.2558,190
54199.6.160.0/19199.6.160.1 to 199.6.191.254199.6.191.2558,190
55199.6.192.0/19199.6.192.1 to 199.6.223.254199.6.223.2558,190
56199.6.224.0/19199.6.224.1 to 199.6.255.254199.6.255.2558,190
57199.7.0.0/19199.7.0.1 to 199.7.31.254199.7.31.2558,190
58199.7.32.0/19199.7.32.1 to 199.7.63.254199.7.63.2558,190
59199.7.64.0/19199.7.64.1 to 199.7.95.254199.7.95.2558,190
60199.7.96.0/19199.7.96.1 to 199.7.127.254199.7.127.2558,190
61199.7.128.0/19199.7.128.1 to 199.7.159.254199.7.159.2558,190
62199.7.160.0/19199.7.160.1 to 199.7.191.254199.7.191.2558,190
63199.7.192.0/19199.7.192.1 to 199.7.223.254199.7.223.2558,190
64199.7.224.0/19199.7.224.1 to 199.7.255.254199.7.255.2558,190
65199.8.0.0/19199.8.0.1 to 199.8.31.254199.8.31.2558,190
66199.8.32.0/19199.8.32.1 to 199.8.63.254199.8.63.2558,190
67199.8.64.0/19199.8.64.1 to 199.8.95.254199.8.95.2558,190
68199.8.96.0/19199.8.96.1 to 199.8.127.254199.8.127.2558,190
69199.8.128.0/19199.8.128.1 to 199.8.159.254199.8.159.2558,190
70199.8.160.0/19199.8.160.1 to 199.8.191.254199.8.191.2558,190
71199.8.192.0/19199.8.192.1 to 199.8.223.254199.8.223.2558,190
72199.8.224.0/19199.8.224.1 to 199.8.255.254199.8.255.2558,190
73199.9.0.0/19199.9.0.1 to 199.9.31.254199.9.31.2558,190
74199.9.32.0/19199.9.32.1 to 199.9.63.254199.9.63.2558,190
75199.9.64.0/19199.9.64.1 to 199.9.95.254199.9.95.2558,190
76199.9.96.0/19199.9.96.1 to 199.9.127.254199.9.127.2558,190
77199.9.128.0/19199.9.128.1 to 199.9.159.254199.9.159.2558,190
78199.9.160.0/19199.9.160.1 to 199.9.191.254199.9.191.2558,190
79199.9.192.0/19199.9.192.1 to 199.9.223.254199.9.223.2558,190
80199.9.224.0/19199.9.224.1 to 199.9.255.254199.9.255.2558,190
81199.10.0.0/19199.10.0.1 to 199.10.31.254199.10.31.2558,190
82199.10.32.0/19199.10.32.1 to 199.10.63.254199.10.63.2558,190
83199.10.64.0/19199.10.64.1 to 199.10.95.254199.10.95.2558,190
84199.10.96.0/19199.10.96.1 to 199.10.127.254199.10.127.2558,190
85199.10.128.0/19199.10.128.1 to 199.10.159.254199.10.159.2558,190
86199.10.160.0/19199.10.160.1 to 199.10.191.254199.10.191.2558,190
87199.10.192.0/19199.10.192.1 to 199.10.223.254199.10.223.2558,190
88199.10.224.0/19199.10.224.1 to 199.10.255.254199.10.255.2558,190
89199.11.0.0/19199.11.0.1 to 199.11.31.254199.11.31.2558,190
90199.11.32.0/19199.11.32.1 to 199.11.63.254199.11.63.2558,190
91199.11.64.0/19199.11.64.1 to 199.11.95.254199.11.95.2558,190
92199.11.96.0/19199.11.96.1 to 199.11.127.254199.11.127.2558,190
93199.11.128.0/19199.11.128.1 to 199.11.159.254199.11.159.2558,190
94199.11.160.0/19199.11.160.1 to 199.11.191.254199.11.191.2558,190
95199.11.192.0/19199.11.192.1 to 199.11.223.254199.11.223.2558,190
96199.11.224.0/19199.11.224.1 to 199.11.255.254199.11.255.2558,190
97199.12.0.0/19199.12.0.1 to 199.12.31.254199.12.31.2558,190
98199.12.32.0/19199.12.32.1 to 199.12.63.254199.12.63.2558,190
99199.12.64.0/19199.12.64.1 to 199.12.95.254199.12.95.2558,190
100199.12.96.0/19199.12.96.1 to 199.12.127.254199.12.127.2558,190
101199.12.128.0/19199.12.128.1 to 199.12.159.254199.12.159.2558,190
102199.12.160.0/19199.12.160.1 to 199.12.191.254199.12.191.2558,190
103199.12.192.0/19199.12.192.1 to 199.12.223.254199.12.223.2558,190
104199.12.224.0/19199.12.224.1 to 199.12.255.254199.12.255.2558,190
105199.13.0.0/19199.13.0.1 to 199.13.31.254199.13.31.2558,190
106199.13.32.0/19199.13.32.1 to 199.13.63.254199.13.63.2558,190
107199.13.64.0/19199.13.64.1 to 199.13.95.254199.13.95.2558,190
108199.13.96.0/19199.13.96.1 to 199.13.127.254199.13.127.2558,190
109199.13.128.0/19199.13.128.1 to 199.13.159.254199.13.159.2558,190
110199.13.160.0/19199.13.160.1 to 199.13.191.254199.13.191.2558,190
111199.13.192.0/19199.13.192.1 to 199.13.223.254199.13.223.2558,190
112199.13.224.0/19199.13.224.1 to 199.13.255.254199.13.255.2558,190
113199.14.0.0/19199.14.0.1 to 199.14.31.254199.14.31.2558,190
114199.14.32.0/19199.14.32.1 to 199.14.63.254199.14.63.2558,190
115199.14.64.0/19199.14.64.1 to 199.14.95.254199.14.95.2558,190
116199.14.96.0/19199.14.96.1 to 199.14.127.254199.14.127.2558,190
117199.14.128.0/19199.14.128.1 to 199.14.159.254199.14.159.2558,190
118199.14.160.0/19199.14.160.1 to 199.14.191.254199.14.191.2558,190
119199.14.192.0/19199.14.192.1 to 199.14.223.254199.14.223.2558,190
120199.14.224.0/19199.14.224.1 to 199.14.255.254199.14.255.2558,190
121199.15.0.0/19199.15.0.1 to 199.15.31.254199.15.31.2558,190
122199.15.32.0/19199.15.32.1 to 199.15.63.254199.15.63.2558,190
123199.15.64.0/19199.15.64.1 to 199.15.95.254199.15.95.2558,190
124199.15.96.0/19199.15.96.1 to 199.15.127.254199.15.127.2558,190
125199.15.128.0/19199.15.128.1 to 199.15.159.254199.15.159.2558,190
126199.15.160.0/19199.15.160.1 to 199.15.191.254199.15.191.2558,190
127199.15.192.0/19199.15.192.1 to 199.15.223.254199.15.223.2558,190
128199.15.224.0/19199.15.224.1 to 199.15.255.254199.15.255.2558,190
129199.16.0.0/19199.16.0.1 to 199.16.31.254199.16.31.2558,190
130199.16.32.0/19199.16.32.1 to 199.16.63.254199.16.63.2558,190
131199.16.64.0/19199.16.64.1 to 199.16.95.254199.16.95.2558,190
132199.16.96.0/19199.16.96.1 to 199.16.127.254199.16.127.2558,190
133199.16.128.0/19199.16.128.1 to 199.16.159.254199.16.159.2558,190
134199.16.160.0/19199.16.160.1 to 199.16.191.254199.16.191.2558,190
135199.16.192.0/19199.16.192.1 to 199.16.223.254199.16.223.2558,190
136199.16.224.0/19199.16.224.1 to 199.16.255.254199.16.255.2558,190
137199.17.0.0/19199.17.0.1 to 199.17.31.254199.17.31.2558,190
138199.17.32.0/19199.17.32.1 to 199.17.63.254199.17.63.2558,190
139199.17.64.0/19199.17.64.1 to 199.17.95.254199.17.95.2558,190
140199.17.96.0/19199.17.96.1 to 199.17.127.254199.17.127.2558,190
141199.17.128.0/19199.17.128.1 to 199.17.159.254199.17.159.2558,190
142199.17.160.0/19199.17.160.1 to 199.17.191.254199.17.191.2558,190
143199.17.192.0/19199.17.192.1 to 199.17.223.254199.17.223.2558,190
144199.17.224.0/19199.17.224.1 to 199.17.255.254199.17.255.2558,190
145199.18.0.0/19199.18.0.1 to 199.18.31.254199.18.31.2558,190
146199.18.32.0/19199.18.32.1 to 199.18.63.254199.18.63.2558,190
147199.18.64.0/19199.18.64.1 to 199.18.95.254199.18.95.2558,190
148199.18.96.0/19199.18.96.1 to 199.18.127.254199.18.127.2558,190
149199.18.128.0/19199.18.128.1 to 199.18.159.254199.18.159.2558,190
150199.18.160.0/19199.18.160.1 to 199.18.191.254199.18.191.2558,190
151199.18.192.0/19199.18.192.1 to 199.18.223.254199.18.223.2558,190
152199.18.224.0/19199.18.224.1 to 199.18.255.254199.18.255.2558,190
153199.19.0.0/19199.19.0.1 to 199.19.31.254199.19.31.2558,190
154199.19.32.0/19199.19.32.1 to 199.19.63.254199.19.63.2558,190
155199.19.64.0/19199.19.64.1 to 199.19.95.254199.19.95.2558,190
156199.19.96.0/19199.19.96.1 to 199.19.127.254199.19.127.2558,190
157199.19.128.0/19199.19.128.1 to 199.19.159.254199.19.159.2558,190
158199.19.160.0/19199.19.160.1 to 199.19.191.254199.19.191.2558,190
159199.19.192.0/19199.19.192.1 to 199.19.223.254199.19.223.2558,190
160199.19.224.0/19199.19.224.1 to 199.19.255.254199.19.255.2558,190
161199.20.0.0/19199.20.0.1 to 199.20.31.254199.20.31.2558,190
162199.20.32.0/19199.20.32.1 to 199.20.63.254199.20.63.2558,190
163199.20.64.0/19199.20.64.1 to 199.20.95.254199.20.95.2558,190
164199.20.96.0/19199.20.96.1 to 199.20.127.254199.20.127.2558,190
165199.20.128.0/19199.20.128.1 to 199.20.159.254199.20.159.2558,190
166199.20.160.0/19199.20.160.1 to 199.20.191.254199.20.191.2558,190
167199.20.192.0/19199.20.192.1 to 199.20.223.254199.20.223.2558,190
168199.20.224.0/19199.20.224.1 to 199.20.255.254199.20.255.2558,190
169199.21.0.0/19199.21.0.1 to 199.21.31.254199.21.31.2558,190
170199.21.32.0/19199.21.32.1 to 199.21.63.254199.21.63.2558,190
171199.21.64.0/19199.21.64.1 to 199.21.95.254199.21.95.2558,190
172199.21.96.0/19199.21.96.1 to 199.21.127.254199.21.127.2558,190
173199.21.128.0/19199.21.128.1 to 199.21.159.254199.21.159.2558,190
174199.21.160.0/19199.21.160.1 to 199.21.191.254199.21.191.2558,190
175199.21.192.0/19199.21.192.1 to 199.21.223.254199.21.223.2558,190
176199.21.224.0/19199.21.224.1 to 199.21.255.254199.21.255.2558,190
177199.22.0.0/19199.22.0.1 to 199.22.31.254199.22.31.2558,190
178199.22.32.0/19199.22.32.1 to 199.22.63.254199.22.63.2558,190
179199.22.64.0/19199.22.64.1 to 199.22.95.254199.22.95.2558,190
180199.22.96.0/19199.22.96.1 to 199.22.127.254199.22.127.2558,190
181199.22.128.0/19199.22.128.1 to 199.22.159.254199.22.159.2558,190
182199.22.160.0/19199.22.160.1 to 199.22.191.254199.22.191.2558,190
183199.22.192.0/19199.22.192.1 to 199.22.223.254199.22.223.2558,190
184199.22.224.0/19199.22.224.1 to 199.22.255.254199.22.255.2558,190
185199.23.0.0/19199.23.0.1 to 199.23.31.254199.23.31.2558,190
186199.23.32.0/19199.23.32.1 to 199.23.63.254199.23.63.2558,190
187199.23.64.0/19199.23.64.1 to 199.23.95.254199.23.95.2558,190
188199.23.96.0/19199.23.96.1 to 199.23.127.254199.23.127.2558,190
189199.23.128.0/19199.23.128.1 to 199.23.159.254199.23.159.2558,190
190199.23.160.0/19199.23.160.1 to 199.23.191.254199.23.191.2558,190
191199.23.192.0/19199.23.192.1 to 199.23.223.254199.23.223.2558,190
192199.23.224.0/19199.23.224.1 to 199.23.255.254199.23.255.2558,190
193199.24.0.0/19199.24.0.1 to 199.24.31.254199.24.31.2558,190
194199.24.32.0/19199.24.32.1 to 199.24.63.254199.24.63.2558,190
195199.24.64.0/19199.24.64.1 to 199.24.95.254199.24.95.2558,190
196199.24.96.0/19199.24.96.1 to 199.24.127.254199.24.127.2558,190
197199.24.128.0/19199.24.128.1 to 199.24.159.254199.24.159.2558,190
198199.24.160.0/19199.24.160.1 to 199.24.191.254199.24.191.2558,190
199199.24.192.0/19199.24.192.1 to 199.24.223.254199.24.223.2558,190
200199.24.224.0/19199.24.224.1 to 199.24.255.254199.24.255.2558,190
201199.25.0.0/19199.25.0.1 to 199.25.31.254199.25.31.2558,190
202199.25.32.0/19199.25.32.1 to 199.25.63.254199.25.63.2558,190
203199.25.64.0/19199.25.64.1 to 199.25.95.254199.25.95.2558,190
204199.25.96.0/19199.25.96.1 to 199.25.127.254199.25.127.2558,190
205199.25.128.0/19199.25.128.1 to 199.25.159.254199.25.159.2558,190
206199.25.160.0/19199.25.160.1 to 199.25.191.254199.25.191.2558,190
207199.25.192.0/19199.25.192.1 to 199.25.223.254199.25.223.2558,190
208199.25.224.0/19199.25.224.1 to 199.25.255.254199.25.255.2558,190
209199.26.0.0/19199.26.0.1 to 199.26.31.254199.26.31.2558,190
210199.26.32.0/19199.26.32.1 to 199.26.63.254199.26.63.2558,190
211199.26.64.0/19199.26.64.1 to 199.26.95.254199.26.95.2558,190
212199.26.96.0/19199.26.96.1 to 199.26.127.254199.26.127.2558,190
213199.26.128.0/19199.26.128.1 to 199.26.159.254199.26.159.2558,190
214199.26.160.0/19199.26.160.1 to 199.26.191.254199.26.191.2558,190
215199.26.192.0/19199.26.192.1 to 199.26.223.254199.26.223.2558,190
216199.26.224.0/19199.26.224.1 to 199.26.255.254199.26.255.2558,190
217199.27.0.0/19199.27.0.1 to 199.27.31.254199.27.31.2558,190
218199.27.32.0/19199.27.32.1 to 199.27.63.254199.27.63.2558,190
219199.27.64.0/19199.27.64.1 to 199.27.95.254199.27.95.2558,190
220199.27.96.0/19199.27.96.1 to 199.27.127.254199.27.127.2558,190
221199.27.128.0/19199.27.128.1 to 199.27.159.254199.27.159.2558,190
222199.27.160.0/19199.27.160.1 to 199.27.191.254199.27.191.2558,190
223199.27.192.0/19199.27.192.1 to 199.27.223.254199.27.223.2558,190
224199.27.224.0/19199.27.224.1 to 199.27.255.254199.27.255.2558,190
225199.28.0.0/19199.28.0.1 to 199.28.31.254199.28.31.2558,190
226199.28.32.0/19199.28.32.1 to 199.28.63.254199.28.63.2558,190
227199.28.64.0/19199.28.64.1 to 199.28.95.254199.28.95.2558,190
228199.28.96.0/19199.28.96.1 to 199.28.127.254199.28.127.2558,190
229199.28.128.0/19199.28.128.1 to 199.28.159.254199.28.159.2558,190
230199.28.160.0/19199.28.160.1 to 199.28.191.254199.28.191.2558,190
231199.28.192.0/19199.28.192.1 to 199.28.223.254199.28.223.2558,190
232199.28.224.0/19199.28.224.1 to 199.28.255.254199.28.255.2558,190
233199.29.0.0/19199.29.0.1 to 199.29.31.254199.29.31.2558,190
234199.29.32.0/19199.29.32.1 to 199.29.63.254199.29.63.2558,190
235199.29.64.0/19199.29.64.1 to 199.29.95.254199.29.95.2558,190
236199.29.96.0/19199.29.96.1 to 199.29.127.254199.29.127.2558,190
237199.29.128.0/19199.29.128.1 to 199.29.159.254199.29.159.2558,190
238199.29.160.0/19199.29.160.1 to 199.29.191.254199.29.191.2558,190
239199.29.192.0/19199.29.192.1 to 199.29.223.254199.29.223.2558,190
240199.29.224.0/19199.29.224.1 to 199.29.255.254199.29.255.2558,190
241199.30.0.0/19199.30.0.1 to 199.30.31.254199.30.31.2558,190
242199.30.32.0/19199.30.32.1 to 199.30.63.254199.30.63.2558,190
243199.30.64.0/19199.30.64.1 to 199.30.95.254199.30.95.2558,190
244199.30.96.0/19199.30.96.1 to 199.30.127.254199.30.127.2558,190
245199.30.128.0/19199.30.128.1 to 199.30.159.254199.30.159.2558,190
246199.30.160.0/19199.30.160.1 to 199.30.191.254199.30.191.2558,190
247199.30.192.0/19199.30.192.1 to 199.30.223.254199.30.223.2558,190
248199.30.224.0/19199.30.224.1 to 199.30.255.254199.30.255.2558,190
249199.31.0.0/19199.31.0.1 to 199.31.31.254199.31.31.2558,190
250199.31.32.0/19199.31.32.1 to 199.31.63.254199.31.63.2558,190
251199.31.64.0/19199.31.64.1 to 199.31.95.254199.31.95.2558,190
252199.31.96.0/19199.31.96.1 to 199.31.127.254199.31.127.2558,190
253199.31.128.0/19199.31.128.1 to 199.31.159.254199.31.159.2558,190
254199.31.160.0/19199.31.160.1 to 199.31.191.254199.31.191.2558,190
255199.31.192.0/19199.31.192.1 to 199.31.223.254199.31.223.2558,190
256199.31.224.0/19199.31.224.1 to 199.31.255.254199.31.255.2558,190

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.