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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.

Network202.78.0.0/17
Usable hosts32,766
Subnet mask255.255.128.0
Addresses32,768
Network address
202.78.0.0
Broadcast address
202.78.127.255
First usable
202.78.0.1
Last usable
202.78.127.254
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
Public public
Old class
C (default /24)
As numbers
Hex CA4E0000 · Integer 3394109440 to 3394142207
Reverse DNS zones
0.78.202.in-addr.arpa
1.78.202.in-addr.arpa
2.78.202.in-addr.arpa
3.78.202.in-addr.arpa
4.78.202.in-addr.arpa
5.78.202.in-addr.arpa
6.78.202.in-addr.arpa
7.78.202.in-addr.arpa
8.78.202.in-addr.arpa
9.78.202.in-addr.arpa
10.78.202.in-addr.arpa
11.78.202.in-addr.arpa
12.78.202.in-addr.arpa
13.78.202.in-addr.arpa
14.78.202.in-addr.arpa
15.78.202.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
Address11001010.01001110.00000000.00000000202.78.0.0
Subnet mask11111111.11111111.10000000.00000000255.255.128.0
Network11001010.01001110.00000000.00000000202.78.0.0
Broadcast11001010.01001110.01111111.11111111202.78.127.255
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)

202.78.0.0/17 makes 4,096 subnets of /29; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1202.78.0.0/29202.78.0.1 to 202.78.0.6202.78.0.76
2202.78.0.8/29202.78.0.9 to 202.78.0.14202.78.0.156
3202.78.0.16/29202.78.0.17 to 202.78.0.22202.78.0.236
4202.78.0.24/29202.78.0.25 to 202.78.0.30202.78.0.316
5202.78.0.32/29202.78.0.33 to 202.78.0.38202.78.0.396
6202.78.0.40/29202.78.0.41 to 202.78.0.46202.78.0.476
7202.78.0.48/29202.78.0.49 to 202.78.0.54202.78.0.556
8202.78.0.56/29202.78.0.57 to 202.78.0.62202.78.0.636
9202.78.0.64/29202.78.0.65 to 202.78.0.70202.78.0.716
10202.78.0.72/29202.78.0.73 to 202.78.0.78202.78.0.796
11202.78.0.80/29202.78.0.81 to 202.78.0.86202.78.0.876
12202.78.0.88/29202.78.0.89 to 202.78.0.94202.78.0.956
13202.78.0.96/29202.78.0.97 to 202.78.0.102202.78.0.1036
14202.78.0.104/29202.78.0.105 to 202.78.0.110202.78.0.1116
15202.78.0.112/29202.78.0.113 to 202.78.0.118202.78.0.1196
16202.78.0.120/29202.78.0.121 to 202.78.0.126202.78.0.1276
17202.78.0.128/29202.78.0.129 to 202.78.0.134202.78.0.1356
18202.78.0.136/29202.78.0.137 to 202.78.0.142202.78.0.1436
19202.78.0.144/29202.78.0.145 to 202.78.0.150202.78.0.1516
20202.78.0.152/29202.78.0.153 to 202.78.0.158202.78.0.1596
21202.78.0.160/29202.78.0.161 to 202.78.0.166202.78.0.1676
22202.78.0.168/29202.78.0.169 to 202.78.0.174202.78.0.1756
23202.78.0.176/29202.78.0.177 to 202.78.0.182202.78.0.1836
24202.78.0.184/29202.78.0.185 to 202.78.0.190202.78.0.1916
25202.78.0.192/29202.78.0.193 to 202.78.0.198202.78.0.1996
26202.78.0.200/29202.78.0.201 to 202.78.0.206202.78.0.2076
27202.78.0.208/29202.78.0.209 to 202.78.0.214202.78.0.2156
28202.78.0.216/29202.78.0.217 to 202.78.0.222202.78.0.2236
29202.78.0.224/29202.78.0.225 to 202.78.0.230202.78.0.2316
30202.78.0.232/29202.78.0.233 to 202.78.0.238202.78.0.2396
31202.78.0.240/29202.78.0.241 to 202.78.0.246202.78.0.2476
32202.78.0.248/29202.78.0.249 to 202.78.0.254202.78.0.2556
33202.78.1.0/29202.78.1.1 to 202.78.1.6202.78.1.76
34202.78.1.8/29202.78.1.9 to 202.78.1.14202.78.1.156
35202.78.1.16/29202.78.1.17 to 202.78.1.22202.78.1.236
36202.78.1.24/29202.78.1.25 to 202.78.1.30202.78.1.316
37202.78.1.32/29202.78.1.33 to 202.78.1.38202.78.1.396
38202.78.1.40/29202.78.1.41 to 202.78.1.46202.78.1.476
39202.78.1.48/29202.78.1.49 to 202.78.1.54202.78.1.556
40202.78.1.56/29202.78.1.57 to 202.78.1.62202.78.1.636
41202.78.1.64/29202.78.1.65 to 202.78.1.70202.78.1.716
42202.78.1.72/29202.78.1.73 to 202.78.1.78202.78.1.796
43202.78.1.80/29202.78.1.81 to 202.78.1.86202.78.1.876
44202.78.1.88/29202.78.1.89 to 202.78.1.94202.78.1.956
45202.78.1.96/29202.78.1.97 to 202.78.1.102202.78.1.1036
46202.78.1.104/29202.78.1.105 to 202.78.1.110202.78.1.1116
47202.78.1.112/29202.78.1.113 to 202.78.1.118202.78.1.1196
48202.78.1.120/29202.78.1.121 to 202.78.1.126202.78.1.1276
49202.78.1.128/29202.78.1.129 to 202.78.1.134202.78.1.1356
50202.78.1.136/29202.78.1.137 to 202.78.1.142202.78.1.1436
51202.78.1.144/29202.78.1.145 to 202.78.1.150202.78.1.1516
52202.78.1.152/29202.78.1.153 to 202.78.1.158202.78.1.1596
53202.78.1.160/29202.78.1.161 to 202.78.1.166202.78.1.1676
54202.78.1.168/29202.78.1.169 to 202.78.1.174202.78.1.1756
55202.78.1.176/29202.78.1.177 to 202.78.1.182202.78.1.1836
56202.78.1.184/29202.78.1.185 to 202.78.1.190202.78.1.1916
57202.78.1.192/29202.78.1.193 to 202.78.1.198202.78.1.1996
58202.78.1.200/29202.78.1.201 to 202.78.1.206202.78.1.2076
59202.78.1.208/29202.78.1.209 to 202.78.1.214202.78.1.2156
60202.78.1.216/29202.78.1.217 to 202.78.1.222202.78.1.2236
61202.78.1.224/29202.78.1.225 to 202.78.1.230202.78.1.2316
62202.78.1.232/29202.78.1.233 to 202.78.1.238202.78.1.2396
63202.78.1.240/29202.78.1.241 to 202.78.1.246202.78.1.2476
64202.78.1.248/29202.78.1.249 to 202.78.1.254202.78.1.2556
65202.78.2.0/29202.78.2.1 to 202.78.2.6202.78.2.76
66202.78.2.8/29202.78.2.9 to 202.78.2.14202.78.2.156
67202.78.2.16/29202.78.2.17 to 202.78.2.22202.78.2.236
68202.78.2.24/29202.78.2.25 to 202.78.2.30202.78.2.316
69202.78.2.32/29202.78.2.33 to 202.78.2.38202.78.2.396
70202.78.2.40/29202.78.2.41 to 202.78.2.46202.78.2.476
71202.78.2.48/29202.78.2.49 to 202.78.2.54202.78.2.556
72202.78.2.56/29202.78.2.57 to 202.78.2.62202.78.2.636
73202.78.2.64/29202.78.2.65 to 202.78.2.70202.78.2.716
74202.78.2.72/29202.78.2.73 to 202.78.2.78202.78.2.796
75202.78.2.80/29202.78.2.81 to 202.78.2.86202.78.2.876
76202.78.2.88/29202.78.2.89 to 202.78.2.94202.78.2.956
77202.78.2.96/29202.78.2.97 to 202.78.2.102202.78.2.1036
78202.78.2.104/29202.78.2.105 to 202.78.2.110202.78.2.1116
79202.78.2.112/29202.78.2.113 to 202.78.2.118202.78.2.1196
80202.78.2.120/29202.78.2.121 to 202.78.2.126202.78.2.1276
81202.78.2.128/29202.78.2.129 to 202.78.2.134202.78.2.1356
82202.78.2.136/29202.78.2.137 to 202.78.2.142202.78.2.1436
83202.78.2.144/29202.78.2.145 to 202.78.2.150202.78.2.1516
84202.78.2.152/29202.78.2.153 to 202.78.2.158202.78.2.1596
85202.78.2.160/29202.78.2.161 to 202.78.2.166202.78.2.1676
86202.78.2.168/29202.78.2.169 to 202.78.2.174202.78.2.1756
87202.78.2.176/29202.78.2.177 to 202.78.2.182202.78.2.1836
88202.78.2.184/29202.78.2.185 to 202.78.2.190202.78.2.1916
89202.78.2.192/29202.78.2.193 to 202.78.2.198202.78.2.1996
90202.78.2.200/29202.78.2.201 to 202.78.2.206202.78.2.2076
91202.78.2.208/29202.78.2.209 to 202.78.2.214202.78.2.2156
92202.78.2.216/29202.78.2.217 to 202.78.2.222202.78.2.2236
93202.78.2.224/29202.78.2.225 to 202.78.2.230202.78.2.2316
94202.78.2.232/29202.78.2.233 to 202.78.2.238202.78.2.2396
95202.78.2.240/29202.78.2.241 to 202.78.2.246202.78.2.2476
96202.78.2.248/29202.78.2.249 to 202.78.2.254202.78.2.2556
97202.78.3.0/29202.78.3.1 to 202.78.3.6202.78.3.76
98202.78.3.8/29202.78.3.9 to 202.78.3.14202.78.3.156
99202.78.3.16/29202.78.3.17 to 202.78.3.22202.78.3.236
100202.78.3.24/29202.78.3.25 to 202.78.3.30202.78.3.316
101202.78.3.32/29202.78.3.33 to 202.78.3.38202.78.3.396
102202.78.3.40/29202.78.3.41 to 202.78.3.46202.78.3.476
103202.78.3.48/29202.78.3.49 to 202.78.3.54202.78.3.556
104202.78.3.56/29202.78.3.57 to 202.78.3.62202.78.3.636
105202.78.3.64/29202.78.3.65 to 202.78.3.70202.78.3.716
106202.78.3.72/29202.78.3.73 to 202.78.3.78202.78.3.796
107202.78.3.80/29202.78.3.81 to 202.78.3.86202.78.3.876
108202.78.3.88/29202.78.3.89 to 202.78.3.94202.78.3.956
109202.78.3.96/29202.78.3.97 to 202.78.3.102202.78.3.1036
110202.78.3.104/29202.78.3.105 to 202.78.3.110202.78.3.1116
111202.78.3.112/29202.78.3.113 to 202.78.3.118202.78.3.1196
112202.78.3.120/29202.78.3.121 to 202.78.3.126202.78.3.1276
113202.78.3.128/29202.78.3.129 to 202.78.3.134202.78.3.1356
114202.78.3.136/29202.78.3.137 to 202.78.3.142202.78.3.1436
115202.78.3.144/29202.78.3.145 to 202.78.3.150202.78.3.1516
116202.78.3.152/29202.78.3.153 to 202.78.3.158202.78.3.1596
117202.78.3.160/29202.78.3.161 to 202.78.3.166202.78.3.1676
118202.78.3.168/29202.78.3.169 to 202.78.3.174202.78.3.1756
119202.78.3.176/29202.78.3.177 to 202.78.3.182202.78.3.1836
120202.78.3.184/29202.78.3.185 to 202.78.3.190202.78.3.1916
121202.78.3.192/29202.78.3.193 to 202.78.3.198202.78.3.1996
122202.78.3.200/29202.78.3.201 to 202.78.3.206202.78.3.2076
123202.78.3.208/29202.78.3.209 to 202.78.3.214202.78.3.2156
124202.78.3.216/29202.78.3.217 to 202.78.3.222202.78.3.2236
125202.78.3.224/29202.78.3.225 to 202.78.3.230202.78.3.2316
126202.78.3.232/29202.78.3.233 to 202.78.3.238202.78.3.2396
127202.78.3.240/29202.78.3.241 to 202.78.3.246202.78.3.2476
128202.78.3.248/29202.78.3.249 to 202.78.3.254202.78.3.2556
129202.78.4.0/29202.78.4.1 to 202.78.4.6202.78.4.76
130202.78.4.8/29202.78.4.9 to 202.78.4.14202.78.4.156
131202.78.4.16/29202.78.4.17 to 202.78.4.22202.78.4.236
132202.78.4.24/29202.78.4.25 to 202.78.4.30202.78.4.316
133202.78.4.32/29202.78.4.33 to 202.78.4.38202.78.4.396
134202.78.4.40/29202.78.4.41 to 202.78.4.46202.78.4.476
135202.78.4.48/29202.78.4.49 to 202.78.4.54202.78.4.556
136202.78.4.56/29202.78.4.57 to 202.78.4.62202.78.4.636
137202.78.4.64/29202.78.4.65 to 202.78.4.70202.78.4.716
138202.78.4.72/29202.78.4.73 to 202.78.4.78202.78.4.796
139202.78.4.80/29202.78.4.81 to 202.78.4.86202.78.4.876
140202.78.4.88/29202.78.4.89 to 202.78.4.94202.78.4.956
141202.78.4.96/29202.78.4.97 to 202.78.4.102202.78.4.1036
142202.78.4.104/29202.78.4.105 to 202.78.4.110202.78.4.1116
143202.78.4.112/29202.78.4.113 to 202.78.4.118202.78.4.1196
144202.78.4.120/29202.78.4.121 to 202.78.4.126202.78.4.1276
145202.78.4.128/29202.78.4.129 to 202.78.4.134202.78.4.1356
146202.78.4.136/29202.78.4.137 to 202.78.4.142202.78.4.1436
147202.78.4.144/29202.78.4.145 to 202.78.4.150202.78.4.1516
148202.78.4.152/29202.78.4.153 to 202.78.4.158202.78.4.1596
149202.78.4.160/29202.78.4.161 to 202.78.4.166202.78.4.1676
150202.78.4.168/29202.78.4.169 to 202.78.4.174202.78.4.1756
151202.78.4.176/29202.78.4.177 to 202.78.4.182202.78.4.1836
152202.78.4.184/29202.78.4.185 to 202.78.4.190202.78.4.1916
153202.78.4.192/29202.78.4.193 to 202.78.4.198202.78.4.1996
154202.78.4.200/29202.78.4.201 to 202.78.4.206202.78.4.2076
155202.78.4.208/29202.78.4.209 to 202.78.4.214202.78.4.2156
156202.78.4.216/29202.78.4.217 to 202.78.4.222202.78.4.2236
157202.78.4.224/29202.78.4.225 to 202.78.4.230202.78.4.2316
158202.78.4.232/29202.78.4.233 to 202.78.4.238202.78.4.2396
159202.78.4.240/29202.78.4.241 to 202.78.4.246202.78.4.2476
160202.78.4.248/29202.78.4.249 to 202.78.4.254202.78.4.2556
161202.78.5.0/29202.78.5.1 to 202.78.5.6202.78.5.76
162202.78.5.8/29202.78.5.9 to 202.78.5.14202.78.5.156
163202.78.5.16/29202.78.5.17 to 202.78.5.22202.78.5.236
164202.78.5.24/29202.78.5.25 to 202.78.5.30202.78.5.316
165202.78.5.32/29202.78.5.33 to 202.78.5.38202.78.5.396
166202.78.5.40/29202.78.5.41 to 202.78.5.46202.78.5.476
167202.78.5.48/29202.78.5.49 to 202.78.5.54202.78.5.556
168202.78.5.56/29202.78.5.57 to 202.78.5.62202.78.5.636
169202.78.5.64/29202.78.5.65 to 202.78.5.70202.78.5.716
170202.78.5.72/29202.78.5.73 to 202.78.5.78202.78.5.796
171202.78.5.80/29202.78.5.81 to 202.78.5.86202.78.5.876
172202.78.5.88/29202.78.5.89 to 202.78.5.94202.78.5.956
173202.78.5.96/29202.78.5.97 to 202.78.5.102202.78.5.1036
174202.78.5.104/29202.78.5.105 to 202.78.5.110202.78.5.1116
175202.78.5.112/29202.78.5.113 to 202.78.5.118202.78.5.1196
176202.78.5.120/29202.78.5.121 to 202.78.5.126202.78.5.1276
177202.78.5.128/29202.78.5.129 to 202.78.5.134202.78.5.1356
178202.78.5.136/29202.78.5.137 to 202.78.5.142202.78.5.1436
179202.78.5.144/29202.78.5.145 to 202.78.5.150202.78.5.1516
180202.78.5.152/29202.78.5.153 to 202.78.5.158202.78.5.1596
181202.78.5.160/29202.78.5.161 to 202.78.5.166202.78.5.1676
182202.78.5.168/29202.78.5.169 to 202.78.5.174202.78.5.1756
183202.78.5.176/29202.78.5.177 to 202.78.5.182202.78.5.1836
184202.78.5.184/29202.78.5.185 to 202.78.5.190202.78.5.1916
185202.78.5.192/29202.78.5.193 to 202.78.5.198202.78.5.1996
186202.78.5.200/29202.78.5.201 to 202.78.5.206202.78.5.2076
187202.78.5.208/29202.78.5.209 to 202.78.5.214202.78.5.2156
188202.78.5.216/29202.78.5.217 to 202.78.5.222202.78.5.2236
189202.78.5.224/29202.78.5.225 to 202.78.5.230202.78.5.2316
190202.78.5.232/29202.78.5.233 to 202.78.5.238202.78.5.2396
191202.78.5.240/29202.78.5.241 to 202.78.5.246202.78.5.2476
192202.78.5.248/29202.78.5.249 to 202.78.5.254202.78.5.2556
193202.78.6.0/29202.78.6.1 to 202.78.6.6202.78.6.76
194202.78.6.8/29202.78.6.9 to 202.78.6.14202.78.6.156
195202.78.6.16/29202.78.6.17 to 202.78.6.22202.78.6.236
196202.78.6.24/29202.78.6.25 to 202.78.6.30202.78.6.316
197202.78.6.32/29202.78.6.33 to 202.78.6.38202.78.6.396
198202.78.6.40/29202.78.6.41 to 202.78.6.46202.78.6.476
199202.78.6.48/29202.78.6.49 to 202.78.6.54202.78.6.556
200202.78.6.56/29202.78.6.57 to 202.78.6.62202.78.6.636
201202.78.6.64/29202.78.6.65 to 202.78.6.70202.78.6.716
202202.78.6.72/29202.78.6.73 to 202.78.6.78202.78.6.796
203202.78.6.80/29202.78.6.81 to 202.78.6.86202.78.6.876
204202.78.6.88/29202.78.6.89 to 202.78.6.94202.78.6.956
205202.78.6.96/29202.78.6.97 to 202.78.6.102202.78.6.1036
206202.78.6.104/29202.78.6.105 to 202.78.6.110202.78.6.1116
207202.78.6.112/29202.78.6.113 to 202.78.6.118202.78.6.1196
208202.78.6.120/29202.78.6.121 to 202.78.6.126202.78.6.1276
209202.78.6.128/29202.78.6.129 to 202.78.6.134202.78.6.1356
210202.78.6.136/29202.78.6.137 to 202.78.6.142202.78.6.1436
211202.78.6.144/29202.78.6.145 to 202.78.6.150202.78.6.1516
212202.78.6.152/29202.78.6.153 to 202.78.6.158202.78.6.1596
213202.78.6.160/29202.78.6.161 to 202.78.6.166202.78.6.1676
214202.78.6.168/29202.78.6.169 to 202.78.6.174202.78.6.1756
215202.78.6.176/29202.78.6.177 to 202.78.6.182202.78.6.1836
216202.78.6.184/29202.78.6.185 to 202.78.6.190202.78.6.1916
217202.78.6.192/29202.78.6.193 to 202.78.6.198202.78.6.1996
218202.78.6.200/29202.78.6.201 to 202.78.6.206202.78.6.2076
219202.78.6.208/29202.78.6.209 to 202.78.6.214202.78.6.2156
220202.78.6.216/29202.78.6.217 to 202.78.6.222202.78.6.2236
221202.78.6.224/29202.78.6.225 to 202.78.6.230202.78.6.2316
222202.78.6.232/29202.78.6.233 to 202.78.6.238202.78.6.2396
223202.78.6.240/29202.78.6.241 to 202.78.6.246202.78.6.2476
224202.78.6.248/29202.78.6.249 to 202.78.6.254202.78.6.2556
225202.78.7.0/29202.78.7.1 to 202.78.7.6202.78.7.76
226202.78.7.8/29202.78.7.9 to 202.78.7.14202.78.7.156
227202.78.7.16/29202.78.7.17 to 202.78.7.22202.78.7.236
228202.78.7.24/29202.78.7.25 to 202.78.7.30202.78.7.316
229202.78.7.32/29202.78.7.33 to 202.78.7.38202.78.7.396
230202.78.7.40/29202.78.7.41 to 202.78.7.46202.78.7.476
231202.78.7.48/29202.78.7.49 to 202.78.7.54202.78.7.556
232202.78.7.56/29202.78.7.57 to 202.78.7.62202.78.7.636
233202.78.7.64/29202.78.7.65 to 202.78.7.70202.78.7.716
234202.78.7.72/29202.78.7.73 to 202.78.7.78202.78.7.796
235202.78.7.80/29202.78.7.81 to 202.78.7.86202.78.7.876
236202.78.7.88/29202.78.7.89 to 202.78.7.94202.78.7.956
237202.78.7.96/29202.78.7.97 to 202.78.7.102202.78.7.1036
238202.78.7.104/29202.78.7.105 to 202.78.7.110202.78.7.1116
239202.78.7.112/29202.78.7.113 to 202.78.7.118202.78.7.1196
240202.78.7.120/29202.78.7.121 to 202.78.7.126202.78.7.1276
241202.78.7.128/29202.78.7.129 to 202.78.7.134202.78.7.1356
242202.78.7.136/29202.78.7.137 to 202.78.7.142202.78.7.1436
243202.78.7.144/29202.78.7.145 to 202.78.7.150202.78.7.1516
244202.78.7.152/29202.78.7.153 to 202.78.7.158202.78.7.1596
245202.78.7.160/29202.78.7.161 to 202.78.7.166202.78.7.1676
246202.78.7.168/29202.78.7.169 to 202.78.7.174202.78.7.1756
247202.78.7.176/29202.78.7.177 to 202.78.7.182202.78.7.1836
248202.78.7.184/29202.78.7.185 to 202.78.7.190202.78.7.1916
249202.78.7.192/29202.78.7.193 to 202.78.7.198202.78.7.1996
250202.78.7.200/29202.78.7.201 to 202.78.7.206202.78.7.2076
251202.78.7.208/29202.78.7.209 to 202.78.7.214202.78.7.2156
252202.78.7.216/29202.78.7.217 to 202.78.7.222202.78.7.2236
253202.78.7.224/29202.78.7.225 to 202.78.7.230202.78.7.2316
254202.78.7.232/29202.78.7.233 to 202.78.7.238202.78.7.2396
255202.78.7.240/29202.78.7.241 to 202.78.7.246202.78.7.2476
256202.78.7.248/29202.78.7.249 to 202.78.7.254202.78.7.2556

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.