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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.

Network128.6.64.0/19
Usable hosts8,190
Subnet mask255.255.224.0
Addresses8,192
Network address
128.6.64.0
Broadcast address
128.6.95.255
First usable
128.6.64.1
Last usable
128.6.95.254
Usable hosts
8,190 (8,192 less the network and broadcast addresses)
Subnet mask
255.255.224.0
Wildcard mask
0.0.31.255 (Cisco ACLs, OSPF)
Prefix length
/19
Type
Public public
Old class
B (default /16)
As numbers
Hex 80064000 · Integer 2147893248 to 2147901439
Reverse DNS zones
64.6.128.in-addr.arpa
65.6.128.in-addr.arpa
66.6.128.in-addr.arpa
67.6.128.in-addr.arpa
68.6.128.in-addr.arpa
69.6.128.in-addr.arpa
70.6.128.in-addr.arpa
71.6.128.in-addr.arpa
72.6.128.in-addr.arpa
73.6.128.in-addr.arpa
74.6.128.in-addr.arpa
75.6.128.in-addr.arpa
76.6.128.in-addr.arpa
77.6.128.in-addr.arpa
78.6.128.in-addr.arpa
79.6.128.in-addr.arpa
and 16 more
/19 is not on a 8-bit boundary, so it takes 32 /24 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address10000000.00000110.01000000.00000000128.6.64.0
Subnet mask11111111.11111111.11100000.00000000255.255.224.0
Network10000000.00000110.01000000.00000000128.6.64.0
Broadcast10000000.00000110.01011111.11111111128.6.95.255
Split into smaller subnets/29
/20 (2)/21 (4)/22 (8)/23 (16)/24 (32)/25 (64)/26 (128)/27 (256)/28 (512)/29 (1,024)/30 (2,048)/31 (4,096)

128.6.64.0/19 makes 1,024 subnets of /29; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1128.6.64.0/29128.6.64.1 to 128.6.64.6128.6.64.76
2128.6.64.8/29128.6.64.9 to 128.6.64.14128.6.64.156
3128.6.64.16/29128.6.64.17 to 128.6.64.22128.6.64.236
4128.6.64.24/29128.6.64.25 to 128.6.64.30128.6.64.316
5128.6.64.32/29128.6.64.33 to 128.6.64.38128.6.64.396
6128.6.64.40/29128.6.64.41 to 128.6.64.46128.6.64.476
7128.6.64.48/29128.6.64.49 to 128.6.64.54128.6.64.556
8128.6.64.56/29128.6.64.57 to 128.6.64.62128.6.64.636
9128.6.64.64/29128.6.64.65 to 128.6.64.70128.6.64.716
10128.6.64.72/29128.6.64.73 to 128.6.64.78128.6.64.796
11128.6.64.80/29128.6.64.81 to 128.6.64.86128.6.64.876
12128.6.64.88/29128.6.64.89 to 128.6.64.94128.6.64.956
13128.6.64.96/29128.6.64.97 to 128.6.64.102128.6.64.1036
14128.6.64.104/29128.6.64.105 to 128.6.64.110128.6.64.1116
15128.6.64.112/29128.6.64.113 to 128.6.64.118128.6.64.1196
16128.6.64.120/29128.6.64.121 to 128.6.64.126128.6.64.1276
17128.6.64.128/29128.6.64.129 to 128.6.64.134128.6.64.1356
18128.6.64.136/29128.6.64.137 to 128.6.64.142128.6.64.1436
19128.6.64.144/29128.6.64.145 to 128.6.64.150128.6.64.1516
20128.6.64.152/29128.6.64.153 to 128.6.64.158128.6.64.1596
21128.6.64.160/29128.6.64.161 to 128.6.64.166128.6.64.1676
22128.6.64.168/29128.6.64.169 to 128.6.64.174128.6.64.1756
23128.6.64.176/29128.6.64.177 to 128.6.64.182128.6.64.1836
24128.6.64.184/29128.6.64.185 to 128.6.64.190128.6.64.1916
25128.6.64.192/29128.6.64.193 to 128.6.64.198128.6.64.1996
26128.6.64.200/29128.6.64.201 to 128.6.64.206128.6.64.2076
27128.6.64.208/29128.6.64.209 to 128.6.64.214128.6.64.2156
28128.6.64.216/29128.6.64.217 to 128.6.64.222128.6.64.2236
29128.6.64.224/29128.6.64.225 to 128.6.64.230128.6.64.2316
30128.6.64.232/29128.6.64.233 to 128.6.64.238128.6.64.2396
31128.6.64.240/29128.6.64.241 to 128.6.64.246128.6.64.2476
32128.6.64.248/29128.6.64.249 to 128.6.64.254128.6.64.2556
33128.6.65.0/29128.6.65.1 to 128.6.65.6128.6.65.76
34128.6.65.8/29128.6.65.9 to 128.6.65.14128.6.65.156
35128.6.65.16/29128.6.65.17 to 128.6.65.22128.6.65.236
36128.6.65.24/29128.6.65.25 to 128.6.65.30128.6.65.316
37128.6.65.32/29128.6.65.33 to 128.6.65.38128.6.65.396
38128.6.65.40/29128.6.65.41 to 128.6.65.46128.6.65.476
39128.6.65.48/29128.6.65.49 to 128.6.65.54128.6.65.556
40128.6.65.56/29128.6.65.57 to 128.6.65.62128.6.65.636
41128.6.65.64/29128.6.65.65 to 128.6.65.70128.6.65.716
42128.6.65.72/29128.6.65.73 to 128.6.65.78128.6.65.796
43128.6.65.80/29128.6.65.81 to 128.6.65.86128.6.65.876
44128.6.65.88/29128.6.65.89 to 128.6.65.94128.6.65.956
45128.6.65.96/29128.6.65.97 to 128.6.65.102128.6.65.1036
46128.6.65.104/29128.6.65.105 to 128.6.65.110128.6.65.1116
47128.6.65.112/29128.6.65.113 to 128.6.65.118128.6.65.1196
48128.6.65.120/29128.6.65.121 to 128.6.65.126128.6.65.1276
49128.6.65.128/29128.6.65.129 to 128.6.65.134128.6.65.1356
50128.6.65.136/29128.6.65.137 to 128.6.65.142128.6.65.1436
51128.6.65.144/29128.6.65.145 to 128.6.65.150128.6.65.1516
52128.6.65.152/29128.6.65.153 to 128.6.65.158128.6.65.1596
53128.6.65.160/29128.6.65.161 to 128.6.65.166128.6.65.1676
54128.6.65.168/29128.6.65.169 to 128.6.65.174128.6.65.1756
55128.6.65.176/29128.6.65.177 to 128.6.65.182128.6.65.1836
56128.6.65.184/29128.6.65.185 to 128.6.65.190128.6.65.1916
57128.6.65.192/29128.6.65.193 to 128.6.65.198128.6.65.1996
58128.6.65.200/29128.6.65.201 to 128.6.65.206128.6.65.2076
59128.6.65.208/29128.6.65.209 to 128.6.65.214128.6.65.2156
60128.6.65.216/29128.6.65.217 to 128.6.65.222128.6.65.2236
61128.6.65.224/29128.6.65.225 to 128.6.65.230128.6.65.2316
62128.6.65.232/29128.6.65.233 to 128.6.65.238128.6.65.2396
63128.6.65.240/29128.6.65.241 to 128.6.65.246128.6.65.2476
64128.6.65.248/29128.6.65.249 to 128.6.65.254128.6.65.2556
65128.6.66.0/29128.6.66.1 to 128.6.66.6128.6.66.76
66128.6.66.8/29128.6.66.9 to 128.6.66.14128.6.66.156
67128.6.66.16/29128.6.66.17 to 128.6.66.22128.6.66.236
68128.6.66.24/29128.6.66.25 to 128.6.66.30128.6.66.316
69128.6.66.32/29128.6.66.33 to 128.6.66.38128.6.66.396
70128.6.66.40/29128.6.66.41 to 128.6.66.46128.6.66.476
71128.6.66.48/29128.6.66.49 to 128.6.66.54128.6.66.556
72128.6.66.56/29128.6.66.57 to 128.6.66.62128.6.66.636
73128.6.66.64/29128.6.66.65 to 128.6.66.70128.6.66.716
74128.6.66.72/29128.6.66.73 to 128.6.66.78128.6.66.796
75128.6.66.80/29128.6.66.81 to 128.6.66.86128.6.66.876
76128.6.66.88/29128.6.66.89 to 128.6.66.94128.6.66.956
77128.6.66.96/29128.6.66.97 to 128.6.66.102128.6.66.1036
78128.6.66.104/29128.6.66.105 to 128.6.66.110128.6.66.1116
79128.6.66.112/29128.6.66.113 to 128.6.66.118128.6.66.1196
80128.6.66.120/29128.6.66.121 to 128.6.66.126128.6.66.1276
81128.6.66.128/29128.6.66.129 to 128.6.66.134128.6.66.1356
82128.6.66.136/29128.6.66.137 to 128.6.66.142128.6.66.1436
83128.6.66.144/29128.6.66.145 to 128.6.66.150128.6.66.1516
84128.6.66.152/29128.6.66.153 to 128.6.66.158128.6.66.1596
85128.6.66.160/29128.6.66.161 to 128.6.66.166128.6.66.1676
86128.6.66.168/29128.6.66.169 to 128.6.66.174128.6.66.1756
87128.6.66.176/29128.6.66.177 to 128.6.66.182128.6.66.1836
88128.6.66.184/29128.6.66.185 to 128.6.66.190128.6.66.1916
89128.6.66.192/29128.6.66.193 to 128.6.66.198128.6.66.1996
90128.6.66.200/29128.6.66.201 to 128.6.66.206128.6.66.2076
91128.6.66.208/29128.6.66.209 to 128.6.66.214128.6.66.2156
92128.6.66.216/29128.6.66.217 to 128.6.66.222128.6.66.2236
93128.6.66.224/29128.6.66.225 to 128.6.66.230128.6.66.2316
94128.6.66.232/29128.6.66.233 to 128.6.66.238128.6.66.2396
95128.6.66.240/29128.6.66.241 to 128.6.66.246128.6.66.2476
96128.6.66.248/29128.6.66.249 to 128.6.66.254128.6.66.2556
97128.6.67.0/29128.6.67.1 to 128.6.67.6128.6.67.76
98128.6.67.8/29128.6.67.9 to 128.6.67.14128.6.67.156
99128.6.67.16/29128.6.67.17 to 128.6.67.22128.6.67.236
100128.6.67.24/29128.6.67.25 to 128.6.67.30128.6.67.316
101128.6.67.32/29128.6.67.33 to 128.6.67.38128.6.67.396
102128.6.67.40/29128.6.67.41 to 128.6.67.46128.6.67.476
103128.6.67.48/29128.6.67.49 to 128.6.67.54128.6.67.556
104128.6.67.56/29128.6.67.57 to 128.6.67.62128.6.67.636
105128.6.67.64/29128.6.67.65 to 128.6.67.70128.6.67.716
106128.6.67.72/29128.6.67.73 to 128.6.67.78128.6.67.796
107128.6.67.80/29128.6.67.81 to 128.6.67.86128.6.67.876
108128.6.67.88/29128.6.67.89 to 128.6.67.94128.6.67.956
109128.6.67.96/29128.6.67.97 to 128.6.67.102128.6.67.1036
110128.6.67.104/29128.6.67.105 to 128.6.67.110128.6.67.1116
111128.6.67.112/29128.6.67.113 to 128.6.67.118128.6.67.1196
112128.6.67.120/29128.6.67.121 to 128.6.67.126128.6.67.1276
113128.6.67.128/29128.6.67.129 to 128.6.67.134128.6.67.1356
114128.6.67.136/29128.6.67.137 to 128.6.67.142128.6.67.1436
115128.6.67.144/29128.6.67.145 to 128.6.67.150128.6.67.1516
116128.6.67.152/29128.6.67.153 to 128.6.67.158128.6.67.1596
117128.6.67.160/29128.6.67.161 to 128.6.67.166128.6.67.1676
118128.6.67.168/29128.6.67.169 to 128.6.67.174128.6.67.1756
119128.6.67.176/29128.6.67.177 to 128.6.67.182128.6.67.1836
120128.6.67.184/29128.6.67.185 to 128.6.67.190128.6.67.1916
121128.6.67.192/29128.6.67.193 to 128.6.67.198128.6.67.1996
122128.6.67.200/29128.6.67.201 to 128.6.67.206128.6.67.2076
123128.6.67.208/29128.6.67.209 to 128.6.67.214128.6.67.2156
124128.6.67.216/29128.6.67.217 to 128.6.67.222128.6.67.2236
125128.6.67.224/29128.6.67.225 to 128.6.67.230128.6.67.2316
126128.6.67.232/29128.6.67.233 to 128.6.67.238128.6.67.2396
127128.6.67.240/29128.6.67.241 to 128.6.67.246128.6.67.2476
128128.6.67.248/29128.6.67.249 to 128.6.67.254128.6.67.2556
129128.6.68.0/29128.6.68.1 to 128.6.68.6128.6.68.76
130128.6.68.8/29128.6.68.9 to 128.6.68.14128.6.68.156
131128.6.68.16/29128.6.68.17 to 128.6.68.22128.6.68.236
132128.6.68.24/29128.6.68.25 to 128.6.68.30128.6.68.316
133128.6.68.32/29128.6.68.33 to 128.6.68.38128.6.68.396
134128.6.68.40/29128.6.68.41 to 128.6.68.46128.6.68.476
135128.6.68.48/29128.6.68.49 to 128.6.68.54128.6.68.556
136128.6.68.56/29128.6.68.57 to 128.6.68.62128.6.68.636
137128.6.68.64/29128.6.68.65 to 128.6.68.70128.6.68.716
138128.6.68.72/29128.6.68.73 to 128.6.68.78128.6.68.796
139128.6.68.80/29128.6.68.81 to 128.6.68.86128.6.68.876
140128.6.68.88/29128.6.68.89 to 128.6.68.94128.6.68.956
141128.6.68.96/29128.6.68.97 to 128.6.68.102128.6.68.1036
142128.6.68.104/29128.6.68.105 to 128.6.68.110128.6.68.1116
143128.6.68.112/29128.6.68.113 to 128.6.68.118128.6.68.1196
144128.6.68.120/29128.6.68.121 to 128.6.68.126128.6.68.1276
145128.6.68.128/29128.6.68.129 to 128.6.68.134128.6.68.1356
146128.6.68.136/29128.6.68.137 to 128.6.68.142128.6.68.1436
147128.6.68.144/29128.6.68.145 to 128.6.68.150128.6.68.1516
148128.6.68.152/29128.6.68.153 to 128.6.68.158128.6.68.1596
149128.6.68.160/29128.6.68.161 to 128.6.68.166128.6.68.1676
150128.6.68.168/29128.6.68.169 to 128.6.68.174128.6.68.1756
151128.6.68.176/29128.6.68.177 to 128.6.68.182128.6.68.1836
152128.6.68.184/29128.6.68.185 to 128.6.68.190128.6.68.1916
153128.6.68.192/29128.6.68.193 to 128.6.68.198128.6.68.1996
154128.6.68.200/29128.6.68.201 to 128.6.68.206128.6.68.2076
155128.6.68.208/29128.6.68.209 to 128.6.68.214128.6.68.2156
156128.6.68.216/29128.6.68.217 to 128.6.68.222128.6.68.2236
157128.6.68.224/29128.6.68.225 to 128.6.68.230128.6.68.2316
158128.6.68.232/29128.6.68.233 to 128.6.68.238128.6.68.2396
159128.6.68.240/29128.6.68.241 to 128.6.68.246128.6.68.2476
160128.6.68.248/29128.6.68.249 to 128.6.68.254128.6.68.2556
161128.6.69.0/29128.6.69.1 to 128.6.69.6128.6.69.76
162128.6.69.8/29128.6.69.9 to 128.6.69.14128.6.69.156
163128.6.69.16/29128.6.69.17 to 128.6.69.22128.6.69.236
164128.6.69.24/29128.6.69.25 to 128.6.69.30128.6.69.316
165128.6.69.32/29128.6.69.33 to 128.6.69.38128.6.69.396
166128.6.69.40/29128.6.69.41 to 128.6.69.46128.6.69.476
167128.6.69.48/29128.6.69.49 to 128.6.69.54128.6.69.556
168128.6.69.56/29128.6.69.57 to 128.6.69.62128.6.69.636
169128.6.69.64/29128.6.69.65 to 128.6.69.70128.6.69.716
170128.6.69.72/29128.6.69.73 to 128.6.69.78128.6.69.796
171128.6.69.80/29128.6.69.81 to 128.6.69.86128.6.69.876
172128.6.69.88/29128.6.69.89 to 128.6.69.94128.6.69.956
173128.6.69.96/29128.6.69.97 to 128.6.69.102128.6.69.1036
174128.6.69.104/29128.6.69.105 to 128.6.69.110128.6.69.1116
175128.6.69.112/29128.6.69.113 to 128.6.69.118128.6.69.1196
176128.6.69.120/29128.6.69.121 to 128.6.69.126128.6.69.1276
177128.6.69.128/29128.6.69.129 to 128.6.69.134128.6.69.1356
178128.6.69.136/29128.6.69.137 to 128.6.69.142128.6.69.1436
179128.6.69.144/29128.6.69.145 to 128.6.69.150128.6.69.1516
180128.6.69.152/29128.6.69.153 to 128.6.69.158128.6.69.1596
181128.6.69.160/29128.6.69.161 to 128.6.69.166128.6.69.1676
182128.6.69.168/29128.6.69.169 to 128.6.69.174128.6.69.1756
183128.6.69.176/29128.6.69.177 to 128.6.69.182128.6.69.1836
184128.6.69.184/29128.6.69.185 to 128.6.69.190128.6.69.1916
185128.6.69.192/29128.6.69.193 to 128.6.69.198128.6.69.1996
186128.6.69.200/29128.6.69.201 to 128.6.69.206128.6.69.2076
187128.6.69.208/29128.6.69.209 to 128.6.69.214128.6.69.2156
188128.6.69.216/29128.6.69.217 to 128.6.69.222128.6.69.2236
189128.6.69.224/29128.6.69.225 to 128.6.69.230128.6.69.2316
190128.6.69.232/29128.6.69.233 to 128.6.69.238128.6.69.2396
191128.6.69.240/29128.6.69.241 to 128.6.69.246128.6.69.2476
192128.6.69.248/29128.6.69.249 to 128.6.69.254128.6.69.2556
193128.6.70.0/29128.6.70.1 to 128.6.70.6128.6.70.76
194128.6.70.8/29128.6.70.9 to 128.6.70.14128.6.70.156
195128.6.70.16/29128.6.70.17 to 128.6.70.22128.6.70.236
196128.6.70.24/29128.6.70.25 to 128.6.70.30128.6.70.316
197128.6.70.32/29128.6.70.33 to 128.6.70.38128.6.70.396
198128.6.70.40/29128.6.70.41 to 128.6.70.46128.6.70.476
199128.6.70.48/29128.6.70.49 to 128.6.70.54128.6.70.556
200128.6.70.56/29128.6.70.57 to 128.6.70.62128.6.70.636
201128.6.70.64/29128.6.70.65 to 128.6.70.70128.6.70.716
202128.6.70.72/29128.6.70.73 to 128.6.70.78128.6.70.796
203128.6.70.80/29128.6.70.81 to 128.6.70.86128.6.70.876
204128.6.70.88/29128.6.70.89 to 128.6.70.94128.6.70.956
205128.6.70.96/29128.6.70.97 to 128.6.70.102128.6.70.1036
206128.6.70.104/29128.6.70.105 to 128.6.70.110128.6.70.1116
207128.6.70.112/29128.6.70.113 to 128.6.70.118128.6.70.1196
208128.6.70.120/29128.6.70.121 to 128.6.70.126128.6.70.1276
209128.6.70.128/29128.6.70.129 to 128.6.70.134128.6.70.1356
210128.6.70.136/29128.6.70.137 to 128.6.70.142128.6.70.1436
211128.6.70.144/29128.6.70.145 to 128.6.70.150128.6.70.1516
212128.6.70.152/29128.6.70.153 to 128.6.70.158128.6.70.1596
213128.6.70.160/29128.6.70.161 to 128.6.70.166128.6.70.1676
214128.6.70.168/29128.6.70.169 to 128.6.70.174128.6.70.1756
215128.6.70.176/29128.6.70.177 to 128.6.70.182128.6.70.1836
216128.6.70.184/29128.6.70.185 to 128.6.70.190128.6.70.1916
217128.6.70.192/29128.6.70.193 to 128.6.70.198128.6.70.1996
218128.6.70.200/29128.6.70.201 to 128.6.70.206128.6.70.2076
219128.6.70.208/29128.6.70.209 to 128.6.70.214128.6.70.2156
220128.6.70.216/29128.6.70.217 to 128.6.70.222128.6.70.2236
221128.6.70.224/29128.6.70.225 to 128.6.70.230128.6.70.2316
222128.6.70.232/29128.6.70.233 to 128.6.70.238128.6.70.2396
223128.6.70.240/29128.6.70.241 to 128.6.70.246128.6.70.2476
224128.6.70.248/29128.6.70.249 to 128.6.70.254128.6.70.2556
225128.6.71.0/29128.6.71.1 to 128.6.71.6128.6.71.76
226128.6.71.8/29128.6.71.9 to 128.6.71.14128.6.71.156
227128.6.71.16/29128.6.71.17 to 128.6.71.22128.6.71.236
228128.6.71.24/29128.6.71.25 to 128.6.71.30128.6.71.316
229128.6.71.32/29128.6.71.33 to 128.6.71.38128.6.71.396
230128.6.71.40/29128.6.71.41 to 128.6.71.46128.6.71.476
231128.6.71.48/29128.6.71.49 to 128.6.71.54128.6.71.556
232128.6.71.56/29128.6.71.57 to 128.6.71.62128.6.71.636
233128.6.71.64/29128.6.71.65 to 128.6.71.70128.6.71.716
234128.6.71.72/29128.6.71.73 to 128.6.71.78128.6.71.796
235128.6.71.80/29128.6.71.81 to 128.6.71.86128.6.71.876
236128.6.71.88/29128.6.71.89 to 128.6.71.94128.6.71.956
237128.6.71.96/29128.6.71.97 to 128.6.71.102128.6.71.1036
238128.6.71.104/29128.6.71.105 to 128.6.71.110128.6.71.1116
239128.6.71.112/29128.6.71.113 to 128.6.71.118128.6.71.1196
240128.6.71.120/29128.6.71.121 to 128.6.71.126128.6.71.1276
241128.6.71.128/29128.6.71.129 to 128.6.71.134128.6.71.1356
242128.6.71.136/29128.6.71.137 to 128.6.71.142128.6.71.1436
243128.6.71.144/29128.6.71.145 to 128.6.71.150128.6.71.1516
244128.6.71.152/29128.6.71.153 to 128.6.71.158128.6.71.1596
245128.6.71.160/29128.6.71.161 to 128.6.71.166128.6.71.1676
246128.6.71.168/29128.6.71.169 to 128.6.71.174128.6.71.1756
247128.6.71.176/29128.6.71.177 to 128.6.71.182128.6.71.1836
248128.6.71.184/29128.6.71.185 to 128.6.71.190128.6.71.1916
249128.6.71.192/29128.6.71.193 to 128.6.71.198128.6.71.1996
250128.6.71.200/29128.6.71.201 to 128.6.71.206128.6.71.2076
251128.6.71.208/29128.6.71.209 to 128.6.71.214128.6.71.2156
252128.6.71.216/29128.6.71.217 to 128.6.71.222128.6.71.2236
253128.6.71.224/29128.6.71.225 to 128.6.71.230128.6.71.2316
254128.6.71.232/29128.6.71.233 to 128.6.71.238128.6.71.2396
255128.6.71.240/29128.6.71.241 to 128.6.71.246128.6.71.2476
256128.6.71.248/29128.6.71.249 to 128.6.71.254128.6.71.2556

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.