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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.

Network252.41.0.0/17
Usable hosts32,766
Subnet mask255.255.128.0
Addresses32,768
Network address
252.41.0.0
Broadcast address
252.41.127.255
First usable
252.41.0.1
Last usable
252.41.127.254
Usable hosts
32,766 (32,768 less the network and broadcast addresses)
Subnet mask
255.255.128.0
Wildcard mask
0.0.127.255 (Cisco ACLs, OSPF)
Prefix length
/17
Type
Reserved 240.0.0.0/4
Future use; not usable on most systems
Old class
E (reserved)
As numbers
Hex FC290000 · Integer 4230545408 to 4230578175
Reverse DNS zones
0.41.252.in-addr.arpa
1.41.252.in-addr.arpa
2.41.252.in-addr.arpa
3.41.252.in-addr.arpa
4.41.252.in-addr.arpa
5.41.252.in-addr.arpa
6.41.252.in-addr.arpa
7.41.252.in-addr.arpa
8.41.252.in-addr.arpa
9.41.252.in-addr.arpa
10.41.252.in-addr.arpa
11.41.252.in-addr.arpa
12.41.252.in-addr.arpa
13.41.252.in-addr.arpa
14.41.252.in-addr.arpa
15.41.252.in-addr.arpa
and 112 more
/17 is not on a 8-bit boundary, so it takes 128 /24 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address11111100.00101001.00000000.00000000252.41.0.0
Subnet mask11111111.11111111.10000000.00000000255.255.128.0
Network11111100.00101001.00000000.00000000252.41.0.0
Broadcast11111100.00101001.01111111.11111111252.41.127.255
Split into smaller subnets/29
/18 (2)/19 (4)/20 (8)/21 (16)/22 (32)/23 (64)/24 (128)/25 (256)/26 (512)/27 (1,024)/28 (2,048)/29 (4,096)

252.41.0.0/17 makes 4,096 subnets of /29; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1252.41.0.0/29252.41.0.1 to 252.41.0.6252.41.0.76
2252.41.0.8/29252.41.0.9 to 252.41.0.14252.41.0.156
3252.41.0.16/29252.41.0.17 to 252.41.0.22252.41.0.236
4252.41.0.24/29252.41.0.25 to 252.41.0.30252.41.0.316
5252.41.0.32/29252.41.0.33 to 252.41.0.38252.41.0.396
6252.41.0.40/29252.41.0.41 to 252.41.0.46252.41.0.476
7252.41.0.48/29252.41.0.49 to 252.41.0.54252.41.0.556
8252.41.0.56/29252.41.0.57 to 252.41.0.62252.41.0.636
9252.41.0.64/29252.41.0.65 to 252.41.0.70252.41.0.716
10252.41.0.72/29252.41.0.73 to 252.41.0.78252.41.0.796
11252.41.0.80/29252.41.0.81 to 252.41.0.86252.41.0.876
12252.41.0.88/29252.41.0.89 to 252.41.0.94252.41.0.956
13252.41.0.96/29252.41.0.97 to 252.41.0.102252.41.0.1036
14252.41.0.104/29252.41.0.105 to 252.41.0.110252.41.0.1116
15252.41.0.112/29252.41.0.113 to 252.41.0.118252.41.0.1196
16252.41.0.120/29252.41.0.121 to 252.41.0.126252.41.0.1276
17252.41.0.128/29252.41.0.129 to 252.41.0.134252.41.0.1356
18252.41.0.136/29252.41.0.137 to 252.41.0.142252.41.0.1436
19252.41.0.144/29252.41.0.145 to 252.41.0.150252.41.0.1516
20252.41.0.152/29252.41.0.153 to 252.41.0.158252.41.0.1596
21252.41.0.160/29252.41.0.161 to 252.41.0.166252.41.0.1676
22252.41.0.168/29252.41.0.169 to 252.41.0.174252.41.0.1756
23252.41.0.176/29252.41.0.177 to 252.41.0.182252.41.0.1836
24252.41.0.184/29252.41.0.185 to 252.41.0.190252.41.0.1916
25252.41.0.192/29252.41.0.193 to 252.41.0.198252.41.0.1996
26252.41.0.200/29252.41.0.201 to 252.41.0.206252.41.0.2076
27252.41.0.208/29252.41.0.209 to 252.41.0.214252.41.0.2156
28252.41.0.216/29252.41.0.217 to 252.41.0.222252.41.0.2236
29252.41.0.224/29252.41.0.225 to 252.41.0.230252.41.0.2316
30252.41.0.232/29252.41.0.233 to 252.41.0.238252.41.0.2396
31252.41.0.240/29252.41.0.241 to 252.41.0.246252.41.0.2476
32252.41.0.248/29252.41.0.249 to 252.41.0.254252.41.0.2556
33252.41.1.0/29252.41.1.1 to 252.41.1.6252.41.1.76
34252.41.1.8/29252.41.1.9 to 252.41.1.14252.41.1.156
35252.41.1.16/29252.41.1.17 to 252.41.1.22252.41.1.236
36252.41.1.24/29252.41.1.25 to 252.41.1.30252.41.1.316
37252.41.1.32/29252.41.1.33 to 252.41.1.38252.41.1.396
38252.41.1.40/29252.41.1.41 to 252.41.1.46252.41.1.476
39252.41.1.48/29252.41.1.49 to 252.41.1.54252.41.1.556
40252.41.1.56/29252.41.1.57 to 252.41.1.62252.41.1.636
41252.41.1.64/29252.41.1.65 to 252.41.1.70252.41.1.716
42252.41.1.72/29252.41.1.73 to 252.41.1.78252.41.1.796
43252.41.1.80/29252.41.1.81 to 252.41.1.86252.41.1.876
44252.41.1.88/29252.41.1.89 to 252.41.1.94252.41.1.956
45252.41.1.96/29252.41.1.97 to 252.41.1.102252.41.1.1036
46252.41.1.104/29252.41.1.105 to 252.41.1.110252.41.1.1116
47252.41.1.112/29252.41.1.113 to 252.41.1.118252.41.1.1196
48252.41.1.120/29252.41.1.121 to 252.41.1.126252.41.1.1276
49252.41.1.128/29252.41.1.129 to 252.41.1.134252.41.1.1356
50252.41.1.136/29252.41.1.137 to 252.41.1.142252.41.1.1436
51252.41.1.144/29252.41.1.145 to 252.41.1.150252.41.1.1516
52252.41.1.152/29252.41.1.153 to 252.41.1.158252.41.1.1596
53252.41.1.160/29252.41.1.161 to 252.41.1.166252.41.1.1676
54252.41.1.168/29252.41.1.169 to 252.41.1.174252.41.1.1756
55252.41.1.176/29252.41.1.177 to 252.41.1.182252.41.1.1836
56252.41.1.184/29252.41.1.185 to 252.41.1.190252.41.1.1916
57252.41.1.192/29252.41.1.193 to 252.41.1.198252.41.1.1996
58252.41.1.200/29252.41.1.201 to 252.41.1.206252.41.1.2076
59252.41.1.208/29252.41.1.209 to 252.41.1.214252.41.1.2156
60252.41.1.216/29252.41.1.217 to 252.41.1.222252.41.1.2236
61252.41.1.224/29252.41.1.225 to 252.41.1.230252.41.1.2316
62252.41.1.232/29252.41.1.233 to 252.41.1.238252.41.1.2396
63252.41.1.240/29252.41.1.241 to 252.41.1.246252.41.1.2476
64252.41.1.248/29252.41.1.249 to 252.41.1.254252.41.1.2556
65252.41.2.0/29252.41.2.1 to 252.41.2.6252.41.2.76
66252.41.2.8/29252.41.2.9 to 252.41.2.14252.41.2.156
67252.41.2.16/29252.41.2.17 to 252.41.2.22252.41.2.236
68252.41.2.24/29252.41.2.25 to 252.41.2.30252.41.2.316
69252.41.2.32/29252.41.2.33 to 252.41.2.38252.41.2.396
70252.41.2.40/29252.41.2.41 to 252.41.2.46252.41.2.476
71252.41.2.48/29252.41.2.49 to 252.41.2.54252.41.2.556
72252.41.2.56/29252.41.2.57 to 252.41.2.62252.41.2.636
73252.41.2.64/29252.41.2.65 to 252.41.2.70252.41.2.716
74252.41.2.72/29252.41.2.73 to 252.41.2.78252.41.2.796
75252.41.2.80/29252.41.2.81 to 252.41.2.86252.41.2.876
76252.41.2.88/29252.41.2.89 to 252.41.2.94252.41.2.956
77252.41.2.96/29252.41.2.97 to 252.41.2.102252.41.2.1036
78252.41.2.104/29252.41.2.105 to 252.41.2.110252.41.2.1116
79252.41.2.112/29252.41.2.113 to 252.41.2.118252.41.2.1196
80252.41.2.120/29252.41.2.121 to 252.41.2.126252.41.2.1276
81252.41.2.128/29252.41.2.129 to 252.41.2.134252.41.2.1356
82252.41.2.136/29252.41.2.137 to 252.41.2.142252.41.2.1436
83252.41.2.144/29252.41.2.145 to 252.41.2.150252.41.2.1516
84252.41.2.152/29252.41.2.153 to 252.41.2.158252.41.2.1596
85252.41.2.160/29252.41.2.161 to 252.41.2.166252.41.2.1676
86252.41.2.168/29252.41.2.169 to 252.41.2.174252.41.2.1756
87252.41.2.176/29252.41.2.177 to 252.41.2.182252.41.2.1836
88252.41.2.184/29252.41.2.185 to 252.41.2.190252.41.2.1916
89252.41.2.192/29252.41.2.193 to 252.41.2.198252.41.2.1996
90252.41.2.200/29252.41.2.201 to 252.41.2.206252.41.2.2076
91252.41.2.208/29252.41.2.209 to 252.41.2.214252.41.2.2156
92252.41.2.216/29252.41.2.217 to 252.41.2.222252.41.2.2236
93252.41.2.224/29252.41.2.225 to 252.41.2.230252.41.2.2316
94252.41.2.232/29252.41.2.233 to 252.41.2.238252.41.2.2396
95252.41.2.240/29252.41.2.241 to 252.41.2.246252.41.2.2476
96252.41.2.248/29252.41.2.249 to 252.41.2.254252.41.2.2556
97252.41.3.0/29252.41.3.1 to 252.41.3.6252.41.3.76
98252.41.3.8/29252.41.3.9 to 252.41.3.14252.41.3.156
99252.41.3.16/29252.41.3.17 to 252.41.3.22252.41.3.236
100252.41.3.24/29252.41.3.25 to 252.41.3.30252.41.3.316
101252.41.3.32/29252.41.3.33 to 252.41.3.38252.41.3.396
102252.41.3.40/29252.41.3.41 to 252.41.3.46252.41.3.476
103252.41.3.48/29252.41.3.49 to 252.41.3.54252.41.3.556
104252.41.3.56/29252.41.3.57 to 252.41.3.62252.41.3.636
105252.41.3.64/29252.41.3.65 to 252.41.3.70252.41.3.716
106252.41.3.72/29252.41.3.73 to 252.41.3.78252.41.3.796
107252.41.3.80/29252.41.3.81 to 252.41.3.86252.41.3.876
108252.41.3.88/29252.41.3.89 to 252.41.3.94252.41.3.956
109252.41.3.96/29252.41.3.97 to 252.41.3.102252.41.3.1036
110252.41.3.104/29252.41.3.105 to 252.41.3.110252.41.3.1116
111252.41.3.112/29252.41.3.113 to 252.41.3.118252.41.3.1196
112252.41.3.120/29252.41.3.121 to 252.41.3.126252.41.3.1276
113252.41.3.128/29252.41.3.129 to 252.41.3.134252.41.3.1356
114252.41.3.136/29252.41.3.137 to 252.41.3.142252.41.3.1436
115252.41.3.144/29252.41.3.145 to 252.41.3.150252.41.3.1516
116252.41.3.152/29252.41.3.153 to 252.41.3.158252.41.3.1596
117252.41.3.160/29252.41.3.161 to 252.41.3.166252.41.3.1676
118252.41.3.168/29252.41.3.169 to 252.41.3.174252.41.3.1756
119252.41.3.176/29252.41.3.177 to 252.41.3.182252.41.3.1836
120252.41.3.184/29252.41.3.185 to 252.41.3.190252.41.3.1916
121252.41.3.192/29252.41.3.193 to 252.41.3.198252.41.3.1996
122252.41.3.200/29252.41.3.201 to 252.41.3.206252.41.3.2076
123252.41.3.208/29252.41.3.209 to 252.41.3.214252.41.3.2156
124252.41.3.216/29252.41.3.217 to 252.41.3.222252.41.3.2236
125252.41.3.224/29252.41.3.225 to 252.41.3.230252.41.3.2316
126252.41.3.232/29252.41.3.233 to 252.41.3.238252.41.3.2396
127252.41.3.240/29252.41.3.241 to 252.41.3.246252.41.3.2476
128252.41.3.248/29252.41.3.249 to 252.41.3.254252.41.3.2556
129252.41.4.0/29252.41.4.1 to 252.41.4.6252.41.4.76
130252.41.4.8/29252.41.4.9 to 252.41.4.14252.41.4.156
131252.41.4.16/29252.41.4.17 to 252.41.4.22252.41.4.236
132252.41.4.24/29252.41.4.25 to 252.41.4.30252.41.4.316
133252.41.4.32/29252.41.4.33 to 252.41.4.38252.41.4.396
134252.41.4.40/29252.41.4.41 to 252.41.4.46252.41.4.476
135252.41.4.48/29252.41.4.49 to 252.41.4.54252.41.4.556
136252.41.4.56/29252.41.4.57 to 252.41.4.62252.41.4.636
137252.41.4.64/29252.41.4.65 to 252.41.4.70252.41.4.716
138252.41.4.72/29252.41.4.73 to 252.41.4.78252.41.4.796
139252.41.4.80/29252.41.4.81 to 252.41.4.86252.41.4.876
140252.41.4.88/29252.41.4.89 to 252.41.4.94252.41.4.956
141252.41.4.96/29252.41.4.97 to 252.41.4.102252.41.4.1036
142252.41.4.104/29252.41.4.105 to 252.41.4.110252.41.4.1116
143252.41.4.112/29252.41.4.113 to 252.41.4.118252.41.4.1196
144252.41.4.120/29252.41.4.121 to 252.41.4.126252.41.4.1276
145252.41.4.128/29252.41.4.129 to 252.41.4.134252.41.4.1356
146252.41.4.136/29252.41.4.137 to 252.41.4.142252.41.4.1436
147252.41.4.144/29252.41.4.145 to 252.41.4.150252.41.4.1516
148252.41.4.152/29252.41.4.153 to 252.41.4.158252.41.4.1596
149252.41.4.160/29252.41.4.161 to 252.41.4.166252.41.4.1676
150252.41.4.168/29252.41.4.169 to 252.41.4.174252.41.4.1756
151252.41.4.176/29252.41.4.177 to 252.41.4.182252.41.4.1836
152252.41.4.184/29252.41.4.185 to 252.41.4.190252.41.4.1916
153252.41.4.192/29252.41.4.193 to 252.41.4.198252.41.4.1996
154252.41.4.200/29252.41.4.201 to 252.41.4.206252.41.4.2076
155252.41.4.208/29252.41.4.209 to 252.41.4.214252.41.4.2156
156252.41.4.216/29252.41.4.217 to 252.41.4.222252.41.4.2236
157252.41.4.224/29252.41.4.225 to 252.41.4.230252.41.4.2316
158252.41.4.232/29252.41.4.233 to 252.41.4.238252.41.4.2396
159252.41.4.240/29252.41.4.241 to 252.41.4.246252.41.4.2476
160252.41.4.248/29252.41.4.249 to 252.41.4.254252.41.4.2556
161252.41.5.0/29252.41.5.1 to 252.41.5.6252.41.5.76
162252.41.5.8/29252.41.5.9 to 252.41.5.14252.41.5.156
163252.41.5.16/29252.41.5.17 to 252.41.5.22252.41.5.236
164252.41.5.24/29252.41.5.25 to 252.41.5.30252.41.5.316
165252.41.5.32/29252.41.5.33 to 252.41.5.38252.41.5.396
166252.41.5.40/29252.41.5.41 to 252.41.5.46252.41.5.476
167252.41.5.48/29252.41.5.49 to 252.41.5.54252.41.5.556
168252.41.5.56/29252.41.5.57 to 252.41.5.62252.41.5.636
169252.41.5.64/29252.41.5.65 to 252.41.5.70252.41.5.716
170252.41.5.72/29252.41.5.73 to 252.41.5.78252.41.5.796
171252.41.5.80/29252.41.5.81 to 252.41.5.86252.41.5.876
172252.41.5.88/29252.41.5.89 to 252.41.5.94252.41.5.956
173252.41.5.96/29252.41.5.97 to 252.41.5.102252.41.5.1036
174252.41.5.104/29252.41.5.105 to 252.41.5.110252.41.5.1116
175252.41.5.112/29252.41.5.113 to 252.41.5.118252.41.5.1196
176252.41.5.120/29252.41.5.121 to 252.41.5.126252.41.5.1276
177252.41.5.128/29252.41.5.129 to 252.41.5.134252.41.5.1356
178252.41.5.136/29252.41.5.137 to 252.41.5.142252.41.5.1436
179252.41.5.144/29252.41.5.145 to 252.41.5.150252.41.5.1516
180252.41.5.152/29252.41.5.153 to 252.41.5.158252.41.5.1596
181252.41.5.160/29252.41.5.161 to 252.41.5.166252.41.5.1676
182252.41.5.168/29252.41.5.169 to 252.41.5.174252.41.5.1756
183252.41.5.176/29252.41.5.177 to 252.41.5.182252.41.5.1836
184252.41.5.184/29252.41.5.185 to 252.41.5.190252.41.5.1916
185252.41.5.192/29252.41.5.193 to 252.41.5.198252.41.5.1996
186252.41.5.200/29252.41.5.201 to 252.41.5.206252.41.5.2076
187252.41.5.208/29252.41.5.209 to 252.41.5.214252.41.5.2156
188252.41.5.216/29252.41.5.217 to 252.41.5.222252.41.5.2236
189252.41.5.224/29252.41.5.225 to 252.41.5.230252.41.5.2316
190252.41.5.232/29252.41.5.233 to 252.41.5.238252.41.5.2396
191252.41.5.240/29252.41.5.241 to 252.41.5.246252.41.5.2476
192252.41.5.248/29252.41.5.249 to 252.41.5.254252.41.5.2556
193252.41.6.0/29252.41.6.1 to 252.41.6.6252.41.6.76
194252.41.6.8/29252.41.6.9 to 252.41.6.14252.41.6.156
195252.41.6.16/29252.41.6.17 to 252.41.6.22252.41.6.236
196252.41.6.24/29252.41.6.25 to 252.41.6.30252.41.6.316
197252.41.6.32/29252.41.6.33 to 252.41.6.38252.41.6.396
198252.41.6.40/29252.41.6.41 to 252.41.6.46252.41.6.476
199252.41.6.48/29252.41.6.49 to 252.41.6.54252.41.6.556
200252.41.6.56/29252.41.6.57 to 252.41.6.62252.41.6.636
201252.41.6.64/29252.41.6.65 to 252.41.6.70252.41.6.716
202252.41.6.72/29252.41.6.73 to 252.41.6.78252.41.6.796
203252.41.6.80/29252.41.6.81 to 252.41.6.86252.41.6.876
204252.41.6.88/29252.41.6.89 to 252.41.6.94252.41.6.956
205252.41.6.96/29252.41.6.97 to 252.41.6.102252.41.6.1036
206252.41.6.104/29252.41.6.105 to 252.41.6.110252.41.6.1116
207252.41.6.112/29252.41.6.113 to 252.41.6.118252.41.6.1196
208252.41.6.120/29252.41.6.121 to 252.41.6.126252.41.6.1276
209252.41.6.128/29252.41.6.129 to 252.41.6.134252.41.6.1356
210252.41.6.136/29252.41.6.137 to 252.41.6.142252.41.6.1436
211252.41.6.144/29252.41.6.145 to 252.41.6.150252.41.6.1516
212252.41.6.152/29252.41.6.153 to 252.41.6.158252.41.6.1596
213252.41.6.160/29252.41.6.161 to 252.41.6.166252.41.6.1676
214252.41.6.168/29252.41.6.169 to 252.41.6.174252.41.6.1756
215252.41.6.176/29252.41.6.177 to 252.41.6.182252.41.6.1836
216252.41.6.184/29252.41.6.185 to 252.41.6.190252.41.6.1916
217252.41.6.192/29252.41.6.193 to 252.41.6.198252.41.6.1996
218252.41.6.200/29252.41.6.201 to 252.41.6.206252.41.6.2076
219252.41.6.208/29252.41.6.209 to 252.41.6.214252.41.6.2156
220252.41.6.216/29252.41.6.217 to 252.41.6.222252.41.6.2236
221252.41.6.224/29252.41.6.225 to 252.41.6.230252.41.6.2316
222252.41.6.232/29252.41.6.233 to 252.41.6.238252.41.6.2396
223252.41.6.240/29252.41.6.241 to 252.41.6.246252.41.6.2476
224252.41.6.248/29252.41.6.249 to 252.41.6.254252.41.6.2556
225252.41.7.0/29252.41.7.1 to 252.41.7.6252.41.7.76
226252.41.7.8/29252.41.7.9 to 252.41.7.14252.41.7.156
227252.41.7.16/29252.41.7.17 to 252.41.7.22252.41.7.236
228252.41.7.24/29252.41.7.25 to 252.41.7.30252.41.7.316
229252.41.7.32/29252.41.7.33 to 252.41.7.38252.41.7.396
230252.41.7.40/29252.41.7.41 to 252.41.7.46252.41.7.476
231252.41.7.48/29252.41.7.49 to 252.41.7.54252.41.7.556
232252.41.7.56/29252.41.7.57 to 252.41.7.62252.41.7.636
233252.41.7.64/29252.41.7.65 to 252.41.7.70252.41.7.716
234252.41.7.72/29252.41.7.73 to 252.41.7.78252.41.7.796
235252.41.7.80/29252.41.7.81 to 252.41.7.86252.41.7.876
236252.41.7.88/29252.41.7.89 to 252.41.7.94252.41.7.956
237252.41.7.96/29252.41.7.97 to 252.41.7.102252.41.7.1036
238252.41.7.104/29252.41.7.105 to 252.41.7.110252.41.7.1116
239252.41.7.112/29252.41.7.113 to 252.41.7.118252.41.7.1196
240252.41.7.120/29252.41.7.121 to 252.41.7.126252.41.7.1276
241252.41.7.128/29252.41.7.129 to 252.41.7.134252.41.7.1356
242252.41.7.136/29252.41.7.137 to 252.41.7.142252.41.7.1436
243252.41.7.144/29252.41.7.145 to 252.41.7.150252.41.7.1516
244252.41.7.152/29252.41.7.153 to 252.41.7.158252.41.7.1596
245252.41.7.160/29252.41.7.161 to 252.41.7.166252.41.7.1676
246252.41.7.168/29252.41.7.169 to 252.41.7.174252.41.7.1756
247252.41.7.176/29252.41.7.177 to 252.41.7.182252.41.7.1836
248252.41.7.184/29252.41.7.185 to 252.41.7.190252.41.7.1916
249252.41.7.192/29252.41.7.193 to 252.41.7.198252.41.7.1996
250252.41.7.200/29252.41.7.201 to 252.41.7.206252.41.7.2076
251252.41.7.208/29252.41.7.209 to 252.41.7.214252.41.7.2156
252252.41.7.216/29252.41.7.217 to 252.41.7.222252.41.7.2236
253252.41.7.224/29252.41.7.225 to 252.41.7.230252.41.7.2316
254252.41.7.232/29252.41.7.233 to 252.41.7.238252.41.7.2396
255252.41.7.240/29252.41.7.241 to 252.41.7.246252.41.7.2476
256252.41.7.248/29252.41.7.249 to 252.41.7.254252.41.7.2556

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.