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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.

Network199.26.0.0/17
Usable hosts32,766
Subnet mask255.255.128.0
Addresses32,768
Network address
199.26.0.0
Broadcast address
199.26.127.255
First usable
199.26.0.1
Last usable
199.26.127.254
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 C71A0000 · Integer 3340369920 to 3340402687
Reverse DNS zones
0.26.199.in-addr.arpa
1.26.199.in-addr.arpa
2.26.199.in-addr.arpa
3.26.199.in-addr.arpa
4.26.199.in-addr.arpa
5.26.199.in-addr.arpa
6.26.199.in-addr.arpa
7.26.199.in-addr.arpa
8.26.199.in-addr.arpa
9.26.199.in-addr.arpa
10.26.199.in-addr.arpa
11.26.199.in-addr.arpa
12.26.199.in-addr.arpa
13.26.199.in-addr.arpa
14.26.199.in-addr.arpa
15.26.199.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
Address11000111.00011010.00000000.00000000199.26.0.0
Subnet mask11111111.11111111.10000000.00000000255.255.128.0
Network11000111.00011010.00000000.00000000199.26.0.0
Broadcast11000111.00011010.01111111.11111111199.26.127.255
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)

199.26.0.0/17 makes 4,096 subnets of /29; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1199.26.0.0/29199.26.0.1 to 199.26.0.6199.26.0.76
2199.26.0.8/29199.26.0.9 to 199.26.0.14199.26.0.156
3199.26.0.16/29199.26.0.17 to 199.26.0.22199.26.0.236
4199.26.0.24/29199.26.0.25 to 199.26.0.30199.26.0.316
5199.26.0.32/29199.26.0.33 to 199.26.0.38199.26.0.396
6199.26.0.40/29199.26.0.41 to 199.26.0.46199.26.0.476
7199.26.0.48/29199.26.0.49 to 199.26.0.54199.26.0.556
8199.26.0.56/29199.26.0.57 to 199.26.0.62199.26.0.636
9199.26.0.64/29199.26.0.65 to 199.26.0.70199.26.0.716
10199.26.0.72/29199.26.0.73 to 199.26.0.78199.26.0.796
11199.26.0.80/29199.26.0.81 to 199.26.0.86199.26.0.876
12199.26.0.88/29199.26.0.89 to 199.26.0.94199.26.0.956
13199.26.0.96/29199.26.0.97 to 199.26.0.102199.26.0.1036
14199.26.0.104/29199.26.0.105 to 199.26.0.110199.26.0.1116
15199.26.0.112/29199.26.0.113 to 199.26.0.118199.26.0.1196
16199.26.0.120/29199.26.0.121 to 199.26.0.126199.26.0.1276
17199.26.0.128/29199.26.0.129 to 199.26.0.134199.26.0.1356
18199.26.0.136/29199.26.0.137 to 199.26.0.142199.26.0.1436
19199.26.0.144/29199.26.0.145 to 199.26.0.150199.26.0.1516
20199.26.0.152/29199.26.0.153 to 199.26.0.158199.26.0.1596
21199.26.0.160/29199.26.0.161 to 199.26.0.166199.26.0.1676
22199.26.0.168/29199.26.0.169 to 199.26.0.174199.26.0.1756
23199.26.0.176/29199.26.0.177 to 199.26.0.182199.26.0.1836
24199.26.0.184/29199.26.0.185 to 199.26.0.190199.26.0.1916
25199.26.0.192/29199.26.0.193 to 199.26.0.198199.26.0.1996
26199.26.0.200/29199.26.0.201 to 199.26.0.206199.26.0.2076
27199.26.0.208/29199.26.0.209 to 199.26.0.214199.26.0.2156
28199.26.0.216/29199.26.0.217 to 199.26.0.222199.26.0.2236
29199.26.0.224/29199.26.0.225 to 199.26.0.230199.26.0.2316
30199.26.0.232/29199.26.0.233 to 199.26.0.238199.26.0.2396
31199.26.0.240/29199.26.0.241 to 199.26.0.246199.26.0.2476
32199.26.0.248/29199.26.0.249 to 199.26.0.254199.26.0.2556
33199.26.1.0/29199.26.1.1 to 199.26.1.6199.26.1.76
34199.26.1.8/29199.26.1.9 to 199.26.1.14199.26.1.156
35199.26.1.16/29199.26.1.17 to 199.26.1.22199.26.1.236
36199.26.1.24/29199.26.1.25 to 199.26.1.30199.26.1.316
37199.26.1.32/29199.26.1.33 to 199.26.1.38199.26.1.396
38199.26.1.40/29199.26.1.41 to 199.26.1.46199.26.1.476
39199.26.1.48/29199.26.1.49 to 199.26.1.54199.26.1.556
40199.26.1.56/29199.26.1.57 to 199.26.1.62199.26.1.636
41199.26.1.64/29199.26.1.65 to 199.26.1.70199.26.1.716
42199.26.1.72/29199.26.1.73 to 199.26.1.78199.26.1.796
43199.26.1.80/29199.26.1.81 to 199.26.1.86199.26.1.876
44199.26.1.88/29199.26.1.89 to 199.26.1.94199.26.1.956
45199.26.1.96/29199.26.1.97 to 199.26.1.102199.26.1.1036
46199.26.1.104/29199.26.1.105 to 199.26.1.110199.26.1.1116
47199.26.1.112/29199.26.1.113 to 199.26.1.118199.26.1.1196
48199.26.1.120/29199.26.1.121 to 199.26.1.126199.26.1.1276
49199.26.1.128/29199.26.1.129 to 199.26.1.134199.26.1.1356
50199.26.1.136/29199.26.1.137 to 199.26.1.142199.26.1.1436
51199.26.1.144/29199.26.1.145 to 199.26.1.150199.26.1.1516
52199.26.1.152/29199.26.1.153 to 199.26.1.158199.26.1.1596
53199.26.1.160/29199.26.1.161 to 199.26.1.166199.26.1.1676
54199.26.1.168/29199.26.1.169 to 199.26.1.174199.26.1.1756
55199.26.1.176/29199.26.1.177 to 199.26.1.182199.26.1.1836
56199.26.1.184/29199.26.1.185 to 199.26.1.190199.26.1.1916
57199.26.1.192/29199.26.1.193 to 199.26.1.198199.26.1.1996
58199.26.1.200/29199.26.1.201 to 199.26.1.206199.26.1.2076
59199.26.1.208/29199.26.1.209 to 199.26.1.214199.26.1.2156
60199.26.1.216/29199.26.1.217 to 199.26.1.222199.26.1.2236
61199.26.1.224/29199.26.1.225 to 199.26.1.230199.26.1.2316
62199.26.1.232/29199.26.1.233 to 199.26.1.238199.26.1.2396
63199.26.1.240/29199.26.1.241 to 199.26.1.246199.26.1.2476
64199.26.1.248/29199.26.1.249 to 199.26.1.254199.26.1.2556
65199.26.2.0/29199.26.2.1 to 199.26.2.6199.26.2.76
66199.26.2.8/29199.26.2.9 to 199.26.2.14199.26.2.156
67199.26.2.16/29199.26.2.17 to 199.26.2.22199.26.2.236
68199.26.2.24/29199.26.2.25 to 199.26.2.30199.26.2.316
69199.26.2.32/29199.26.2.33 to 199.26.2.38199.26.2.396
70199.26.2.40/29199.26.2.41 to 199.26.2.46199.26.2.476
71199.26.2.48/29199.26.2.49 to 199.26.2.54199.26.2.556
72199.26.2.56/29199.26.2.57 to 199.26.2.62199.26.2.636
73199.26.2.64/29199.26.2.65 to 199.26.2.70199.26.2.716
74199.26.2.72/29199.26.2.73 to 199.26.2.78199.26.2.796
75199.26.2.80/29199.26.2.81 to 199.26.2.86199.26.2.876
76199.26.2.88/29199.26.2.89 to 199.26.2.94199.26.2.956
77199.26.2.96/29199.26.2.97 to 199.26.2.102199.26.2.1036
78199.26.2.104/29199.26.2.105 to 199.26.2.110199.26.2.1116
79199.26.2.112/29199.26.2.113 to 199.26.2.118199.26.2.1196
80199.26.2.120/29199.26.2.121 to 199.26.2.126199.26.2.1276
81199.26.2.128/29199.26.2.129 to 199.26.2.134199.26.2.1356
82199.26.2.136/29199.26.2.137 to 199.26.2.142199.26.2.1436
83199.26.2.144/29199.26.2.145 to 199.26.2.150199.26.2.1516
84199.26.2.152/29199.26.2.153 to 199.26.2.158199.26.2.1596
85199.26.2.160/29199.26.2.161 to 199.26.2.166199.26.2.1676
86199.26.2.168/29199.26.2.169 to 199.26.2.174199.26.2.1756
87199.26.2.176/29199.26.2.177 to 199.26.2.182199.26.2.1836
88199.26.2.184/29199.26.2.185 to 199.26.2.190199.26.2.1916
89199.26.2.192/29199.26.2.193 to 199.26.2.198199.26.2.1996
90199.26.2.200/29199.26.2.201 to 199.26.2.206199.26.2.2076
91199.26.2.208/29199.26.2.209 to 199.26.2.214199.26.2.2156
92199.26.2.216/29199.26.2.217 to 199.26.2.222199.26.2.2236
93199.26.2.224/29199.26.2.225 to 199.26.2.230199.26.2.2316
94199.26.2.232/29199.26.2.233 to 199.26.2.238199.26.2.2396
95199.26.2.240/29199.26.2.241 to 199.26.2.246199.26.2.2476
96199.26.2.248/29199.26.2.249 to 199.26.2.254199.26.2.2556
97199.26.3.0/29199.26.3.1 to 199.26.3.6199.26.3.76
98199.26.3.8/29199.26.3.9 to 199.26.3.14199.26.3.156
99199.26.3.16/29199.26.3.17 to 199.26.3.22199.26.3.236
100199.26.3.24/29199.26.3.25 to 199.26.3.30199.26.3.316
101199.26.3.32/29199.26.3.33 to 199.26.3.38199.26.3.396
102199.26.3.40/29199.26.3.41 to 199.26.3.46199.26.3.476
103199.26.3.48/29199.26.3.49 to 199.26.3.54199.26.3.556
104199.26.3.56/29199.26.3.57 to 199.26.3.62199.26.3.636
105199.26.3.64/29199.26.3.65 to 199.26.3.70199.26.3.716
106199.26.3.72/29199.26.3.73 to 199.26.3.78199.26.3.796
107199.26.3.80/29199.26.3.81 to 199.26.3.86199.26.3.876
108199.26.3.88/29199.26.3.89 to 199.26.3.94199.26.3.956
109199.26.3.96/29199.26.3.97 to 199.26.3.102199.26.3.1036
110199.26.3.104/29199.26.3.105 to 199.26.3.110199.26.3.1116
111199.26.3.112/29199.26.3.113 to 199.26.3.118199.26.3.1196
112199.26.3.120/29199.26.3.121 to 199.26.3.126199.26.3.1276
113199.26.3.128/29199.26.3.129 to 199.26.3.134199.26.3.1356
114199.26.3.136/29199.26.3.137 to 199.26.3.142199.26.3.1436
115199.26.3.144/29199.26.3.145 to 199.26.3.150199.26.3.1516
116199.26.3.152/29199.26.3.153 to 199.26.3.158199.26.3.1596
117199.26.3.160/29199.26.3.161 to 199.26.3.166199.26.3.1676
118199.26.3.168/29199.26.3.169 to 199.26.3.174199.26.3.1756
119199.26.3.176/29199.26.3.177 to 199.26.3.182199.26.3.1836
120199.26.3.184/29199.26.3.185 to 199.26.3.190199.26.3.1916
121199.26.3.192/29199.26.3.193 to 199.26.3.198199.26.3.1996
122199.26.3.200/29199.26.3.201 to 199.26.3.206199.26.3.2076
123199.26.3.208/29199.26.3.209 to 199.26.3.214199.26.3.2156
124199.26.3.216/29199.26.3.217 to 199.26.3.222199.26.3.2236
125199.26.3.224/29199.26.3.225 to 199.26.3.230199.26.3.2316
126199.26.3.232/29199.26.3.233 to 199.26.3.238199.26.3.2396
127199.26.3.240/29199.26.3.241 to 199.26.3.246199.26.3.2476
128199.26.3.248/29199.26.3.249 to 199.26.3.254199.26.3.2556
129199.26.4.0/29199.26.4.1 to 199.26.4.6199.26.4.76
130199.26.4.8/29199.26.4.9 to 199.26.4.14199.26.4.156
131199.26.4.16/29199.26.4.17 to 199.26.4.22199.26.4.236
132199.26.4.24/29199.26.4.25 to 199.26.4.30199.26.4.316
133199.26.4.32/29199.26.4.33 to 199.26.4.38199.26.4.396
134199.26.4.40/29199.26.4.41 to 199.26.4.46199.26.4.476
135199.26.4.48/29199.26.4.49 to 199.26.4.54199.26.4.556
136199.26.4.56/29199.26.4.57 to 199.26.4.62199.26.4.636
137199.26.4.64/29199.26.4.65 to 199.26.4.70199.26.4.716
138199.26.4.72/29199.26.4.73 to 199.26.4.78199.26.4.796
139199.26.4.80/29199.26.4.81 to 199.26.4.86199.26.4.876
140199.26.4.88/29199.26.4.89 to 199.26.4.94199.26.4.956
141199.26.4.96/29199.26.4.97 to 199.26.4.102199.26.4.1036
142199.26.4.104/29199.26.4.105 to 199.26.4.110199.26.4.1116
143199.26.4.112/29199.26.4.113 to 199.26.4.118199.26.4.1196
144199.26.4.120/29199.26.4.121 to 199.26.4.126199.26.4.1276
145199.26.4.128/29199.26.4.129 to 199.26.4.134199.26.4.1356
146199.26.4.136/29199.26.4.137 to 199.26.4.142199.26.4.1436
147199.26.4.144/29199.26.4.145 to 199.26.4.150199.26.4.1516
148199.26.4.152/29199.26.4.153 to 199.26.4.158199.26.4.1596
149199.26.4.160/29199.26.4.161 to 199.26.4.166199.26.4.1676
150199.26.4.168/29199.26.4.169 to 199.26.4.174199.26.4.1756
151199.26.4.176/29199.26.4.177 to 199.26.4.182199.26.4.1836
152199.26.4.184/29199.26.4.185 to 199.26.4.190199.26.4.1916
153199.26.4.192/29199.26.4.193 to 199.26.4.198199.26.4.1996
154199.26.4.200/29199.26.4.201 to 199.26.4.206199.26.4.2076
155199.26.4.208/29199.26.4.209 to 199.26.4.214199.26.4.2156
156199.26.4.216/29199.26.4.217 to 199.26.4.222199.26.4.2236
157199.26.4.224/29199.26.4.225 to 199.26.4.230199.26.4.2316
158199.26.4.232/29199.26.4.233 to 199.26.4.238199.26.4.2396
159199.26.4.240/29199.26.4.241 to 199.26.4.246199.26.4.2476
160199.26.4.248/29199.26.4.249 to 199.26.4.254199.26.4.2556
161199.26.5.0/29199.26.5.1 to 199.26.5.6199.26.5.76
162199.26.5.8/29199.26.5.9 to 199.26.5.14199.26.5.156
163199.26.5.16/29199.26.5.17 to 199.26.5.22199.26.5.236
164199.26.5.24/29199.26.5.25 to 199.26.5.30199.26.5.316
165199.26.5.32/29199.26.5.33 to 199.26.5.38199.26.5.396
166199.26.5.40/29199.26.5.41 to 199.26.5.46199.26.5.476
167199.26.5.48/29199.26.5.49 to 199.26.5.54199.26.5.556
168199.26.5.56/29199.26.5.57 to 199.26.5.62199.26.5.636
169199.26.5.64/29199.26.5.65 to 199.26.5.70199.26.5.716
170199.26.5.72/29199.26.5.73 to 199.26.5.78199.26.5.796
171199.26.5.80/29199.26.5.81 to 199.26.5.86199.26.5.876
172199.26.5.88/29199.26.5.89 to 199.26.5.94199.26.5.956
173199.26.5.96/29199.26.5.97 to 199.26.5.102199.26.5.1036
174199.26.5.104/29199.26.5.105 to 199.26.5.110199.26.5.1116
175199.26.5.112/29199.26.5.113 to 199.26.5.118199.26.5.1196
176199.26.5.120/29199.26.5.121 to 199.26.5.126199.26.5.1276
177199.26.5.128/29199.26.5.129 to 199.26.5.134199.26.5.1356
178199.26.5.136/29199.26.5.137 to 199.26.5.142199.26.5.1436
179199.26.5.144/29199.26.5.145 to 199.26.5.150199.26.5.1516
180199.26.5.152/29199.26.5.153 to 199.26.5.158199.26.5.1596
181199.26.5.160/29199.26.5.161 to 199.26.5.166199.26.5.1676
182199.26.5.168/29199.26.5.169 to 199.26.5.174199.26.5.1756
183199.26.5.176/29199.26.5.177 to 199.26.5.182199.26.5.1836
184199.26.5.184/29199.26.5.185 to 199.26.5.190199.26.5.1916
185199.26.5.192/29199.26.5.193 to 199.26.5.198199.26.5.1996
186199.26.5.200/29199.26.5.201 to 199.26.5.206199.26.5.2076
187199.26.5.208/29199.26.5.209 to 199.26.5.214199.26.5.2156
188199.26.5.216/29199.26.5.217 to 199.26.5.222199.26.5.2236
189199.26.5.224/29199.26.5.225 to 199.26.5.230199.26.5.2316
190199.26.5.232/29199.26.5.233 to 199.26.5.238199.26.5.2396
191199.26.5.240/29199.26.5.241 to 199.26.5.246199.26.5.2476
192199.26.5.248/29199.26.5.249 to 199.26.5.254199.26.5.2556
193199.26.6.0/29199.26.6.1 to 199.26.6.6199.26.6.76
194199.26.6.8/29199.26.6.9 to 199.26.6.14199.26.6.156
195199.26.6.16/29199.26.6.17 to 199.26.6.22199.26.6.236
196199.26.6.24/29199.26.6.25 to 199.26.6.30199.26.6.316
197199.26.6.32/29199.26.6.33 to 199.26.6.38199.26.6.396
198199.26.6.40/29199.26.6.41 to 199.26.6.46199.26.6.476
199199.26.6.48/29199.26.6.49 to 199.26.6.54199.26.6.556
200199.26.6.56/29199.26.6.57 to 199.26.6.62199.26.6.636
201199.26.6.64/29199.26.6.65 to 199.26.6.70199.26.6.716
202199.26.6.72/29199.26.6.73 to 199.26.6.78199.26.6.796
203199.26.6.80/29199.26.6.81 to 199.26.6.86199.26.6.876
204199.26.6.88/29199.26.6.89 to 199.26.6.94199.26.6.956
205199.26.6.96/29199.26.6.97 to 199.26.6.102199.26.6.1036
206199.26.6.104/29199.26.6.105 to 199.26.6.110199.26.6.1116
207199.26.6.112/29199.26.6.113 to 199.26.6.118199.26.6.1196
208199.26.6.120/29199.26.6.121 to 199.26.6.126199.26.6.1276
209199.26.6.128/29199.26.6.129 to 199.26.6.134199.26.6.1356
210199.26.6.136/29199.26.6.137 to 199.26.6.142199.26.6.1436
211199.26.6.144/29199.26.6.145 to 199.26.6.150199.26.6.1516
212199.26.6.152/29199.26.6.153 to 199.26.6.158199.26.6.1596
213199.26.6.160/29199.26.6.161 to 199.26.6.166199.26.6.1676
214199.26.6.168/29199.26.6.169 to 199.26.6.174199.26.6.1756
215199.26.6.176/29199.26.6.177 to 199.26.6.182199.26.6.1836
216199.26.6.184/29199.26.6.185 to 199.26.6.190199.26.6.1916
217199.26.6.192/29199.26.6.193 to 199.26.6.198199.26.6.1996
218199.26.6.200/29199.26.6.201 to 199.26.6.206199.26.6.2076
219199.26.6.208/29199.26.6.209 to 199.26.6.214199.26.6.2156
220199.26.6.216/29199.26.6.217 to 199.26.6.222199.26.6.2236
221199.26.6.224/29199.26.6.225 to 199.26.6.230199.26.6.2316
222199.26.6.232/29199.26.6.233 to 199.26.6.238199.26.6.2396
223199.26.6.240/29199.26.6.241 to 199.26.6.246199.26.6.2476
224199.26.6.248/29199.26.6.249 to 199.26.6.254199.26.6.2556
225199.26.7.0/29199.26.7.1 to 199.26.7.6199.26.7.76
226199.26.7.8/29199.26.7.9 to 199.26.7.14199.26.7.156
227199.26.7.16/29199.26.7.17 to 199.26.7.22199.26.7.236
228199.26.7.24/29199.26.7.25 to 199.26.7.30199.26.7.316
229199.26.7.32/29199.26.7.33 to 199.26.7.38199.26.7.396
230199.26.7.40/29199.26.7.41 to 199.26.7.46199.26.7.476
231199.26.7.48/29199.26.7.49 to 199.26.7.54199.26.7.556
232199.26.7.56/29199.26.7.57 to 199.26.7.62199.26.7.636
233199.26.7.64/29199.26.7.65 to 199.26.7.70199.26.7.716
234199.26.7.72/29199.26.7.73 to 199.26.7.78199.26.7.796
235199.26.7.80/29199.26.7.81 to 199.26.7.86199.26.7.876
236199.26.7.88/29199.26.7.89 to 199.26.7.94199.26.7.956
237199.26.7.96/29199.26.7.97 to 199.26.7.102199.26.7.1036
238199.26.7.104/29199.26.7.105 to 199.26.7.110199.26.7.1116
239199.26.7.112/29199.26.7.113 to 199.26.7.118199.26.7.1196
240199.26.7.120/29199.26.7.121 to 199.26.7.126199.26.7.1276
241199.26.7.128/29199.26.7.129 to 199.26.7.134199.26.7.1356
242199.26.7.136/29199.26.7.137 to 199.26.7.142199.26.7.1436
243199.26.7.144/29199.26.7.145 to 199.26.7.150199.26.7.1516
244199.26.7.152/29199.26.7.153 to 199.26.7.158199.26.7.1596
245199.26.7.160/29199.26.7.161 to 199.26.7.166199.26.7.1676
246199.26.7.168/29199.26.7.169 to 199.26.7.174199.26.7.1756
247199.26.7.176/29199.26.7.177 to 199.26.7.182199.26.7.1836
248199.26.7.184/29199.26.7.185 to 199.26.7.190199.26.7.1916
249199.26.7.192/29199.26.7.193 to 199.26.7.198199.26.7.1996
250199.26.7.200/29199.26.7.201 to 199.26.7.206199.26.7.2076
251199.26.7.208/29199.26.7.209 to 199.26.7.214199.26.7.2156
252199.26.7.216/29199.26.7.217 to 199.26.7.222199.26.7.2236
253199.26.7.224/29199.26.7.225 to 199.26.7.230199.26.7.2316
254199.26.7.232/29199.26.7.233 to 199.26.7.238199.26.7.2396
255199.26.7.240/29199.26.7.241 to 199.26.7.246199.26.7.2476
256199.26.7.248/29199.26.7.249 to 199.26.7.254199.26.7.2556

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.