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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.

Network254.2.0.0/19
Usable hosts8,190
Subnet mask255.255.224.0
Addresses8,192
Network address
254.2.0.0
Broadcast address
254.2.31.255
First usable
254.2.0.1
Last usable
254.2.31.254
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
Reserved 240.0.0.0/4
Future use; not usable on most systems
Old class
E (reserved)
As numbers
Hex FE020000 · Integer 4261543936 to 4261552127
Reverse DNS zones
0.2.254.in-addr.arpa
1.2.254.in-addr.arpa
2.2.254.in-addr.arpa
3.2.254.in-addr.arpa
4.2.254.in-addr.arpa
5.2.254.in-addr.arpa
6.2.254.in-addr.arpa
7.2.254.in-addr.arpa
8.2.254.in-addr.arpa
9.2.254.in-addr.arpa
10.2.254.in-addr.arpa
11.2.254.in-addr.arpa
12.2.254.in-addr.arpa
13.2.254.in-addr.arpa
14.2.254.in-addr.arpa
15.2.254.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
Address11111110.00000010.00000000.00000000254.2.0.0
Subnet mask11111111.11111111.11100000.00000000255.255.224.0
Network11111110.00000010.00000000.00000000254.2.0.0
Broadcast11111110.00000010.00011111.11111111254.2.31.255
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)

254.2.0.0/19 makes 1,024 subnets of /29; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1254.2.0.0/29254.2.0.1 to 254.2.0.6254.2.0.76
2254.2.0.8/29254.2.0.9 to 254.2.0.14254.2.0.156
3254.2.0.16/29254.2.0.17 to 254.2.0.22254.2.0.236
4254.2.0.24/29254.2.0.25 to 254.2.0.30254.2.0.316
5254.2.0.32/29254.2.0.33 to 254.2.0.38254.2.0.396
6254.2.0.40/29254.2.0.41 to 254.2.0.46254.2.0.476
7254.2.0.48/29254.2.0.49 to 254.2.0.54254.2.0.556
8254.2.0.56/29254.2.0.57 to 254.2.0.62254.2.0.636
9254.2.0.64/29254.2.0.65 to 254.2.0.70254.2.0.716
10254.2.0.72/29254.2.0.73 to 254.2.0.78254.2.0.796
11254.2.0.80/29254.2.0.81 to 254.2.0.86254.2.0.876
12254.2.0.88/29254.2.0.89 to 254.2.0.94254.2.0.956
13254.2.0.96/29254.2.0.97 to 254.2.0.102254.2.0.1036
14254.2.0.104/29254.2.0.105 to 254.2.0.110254.2.0.1116
15254.2.0.112/29254.2.0.113 to 254.2.0.118254.2.0.1196
16254.2.0.120/29254.2.0.121 to 254.2.0.126254.2.0.1276
17254.2.0.128/29254.2.0.129 to 254.2.0.134254.2.0.1356
18254.2.0.136/29254.2.0.137 to 254.2.0.142254.2.0.1436
19254.2.0.144/29254.2.0.145 to 254.2.0.150254.2.0.1516
20254.2.0.152/29254.2.0.153 to 254.2.0.158254.2.0.1596
21254.2.0.160/29254.2.0.161 to 254.2.0.166254.2.0.1676
22254.2.0.168/29254.2.0.169 to 254.2.0.174254.2.0.1756
23254.2.0.176/29254.2.0.177 to 254.2.0.182254.2.0.1836
24254.2.0.184/29254.2.0.185 to 254.2.0.190254.2.0.1916
25254.2.0.192/29254.2.0.193 to 254.2.0.198254.2.0.1996
26254.2.0.200/29254.2.0.201 to 254.2.0.206254.2.0.2076
27254.2.0.208/29254.2.0.209 to 254.2.0.214254.2.0.2156
28254.2.0.216/29254.2.0.217 to 254.2.0.222254.2.0.2236
29254.2.0.224/29254.2.0.225 to 254.2.0.230254.2.0.2316
30254.2.0.232/29254.2.0.233 to 254.2.0.238254.2.0.2396
31254.2.0.240/29254.2.0.241 to 254.2.0.246254.2.0.2476
32254.2.0.248/29254.2.0.249 to 254.2.0.254254.2.0.2556
33254.2.1.0/29254.2.1.1 to 254.2.1.6254.2.1.76
34254.2.1.8/29254.2.1.9 to 254.2.1.14254.2.1.156
35254.2.1.16/29254.2.1.17 to 254.2.1.22254.2.1.236
36254.2.1.24/29254.2.1.25 to 254.2.1.30254.2.1.316
37254.2.1.32/29254.2.1.33 to 254.2.1.38254.2.1.396
38254.2.1.40/29254.2.1.41 to 254.2.1.46254.2.1.476
39254.2.1.48/29254.2.1.49 to 254.2.1.54254.2.1.556
40254.2.1.56/29254.2.1.57 to 254.2.1.62254.2.1.636
41254.2.1.64/29254.2.1.65 to 254.2.1.70254.2.1.716
42254.2.1.72/29254.2.1.73 to 254.2.1.78254.2.1.796
43254.2.1.80/29254.2.1.81 to 254.2.1.86254.2.1.876
44254.2.1.88/29254.2.1.89 to 254.2.1.94254.2.1.956
45254.2.1.96/29254.2.1.97 to 254.2.1.102254.2.1.1036
46254.2.1.104/29254.2.1.105 to 254.2.1.110254.2.1.1116
47254.2.1.112/29254.2.1.113 to 254.2.1.118254.2.1.1196
48254.2.1.120/29254.2.1.121 to 254.2.1.126254.2.1.1276
49254.2.1.128/29254.2.1.129 to 254.2.1.134254.2.1.1356
50254.2.1.136/29254.2.1.137 to 254.2.1.142254.2.1.1436
51254.2.1.144/29254.2.1.145 to 254.2.1.150254.2.1.1516
52254.2.1.152/29254.2.1.153 to 254.2.1.158254.2.1.1596
53254.2.1.160/29254.2.1.161 to 254.2.1.166254.2.1.1676
54254.2.1.168/29254.2.1.169 to 254.2.1.174254.2.1.1756
55254.2.1.176/29254.2.1.177 to 254.2.1.182254.2.1.1836
56254.2.1.184/29254.2.1.185 to 254.2.1.190254.2.1.1916
57254.2.1.192/29254.2.1.193 to 254.2.1.198254.2.1.1996
58254.2.1.200/29254.2.1.201 to 254.2.1.206254.2.1.2076
59254.2.1.208/29254.2.1.209 to 254.2.1.214254.2.1.2156
60254.2.1.216/29254.2.1.217 to 254.2.1.222254.2.1.2236
61254.2.1.224/29254.2.1.225 to 254.2.1.230254.2.1.2316
62254.2.1.232/29254.2.1.233 to 254.2.1.238254.2.1.2396
63254.2.1.240/29254.2.1.241 to 254.2.1.246254.2.1.2476
64254.2.1.248/29254.2.1.249 to 254.2.1.254254.2.1.2556
65254.2.2.0/29254.2.2.1 to 254.2.2.6254.2.2.76
66254.2.2.8/29254.2.2.9 to 254.2.2.14254.2.2.156
67254.2.2.16/29254.2.2.17 to 254.2.2.22254.2.2.236
68254.2.2.24/29254.2.2.25 to 254.2.2.30254.2.2.316
69254.2.2.32/29254.2.2.33 to 254.2.2.38254.2.2.396
70254.2.2.40/29254.2.2.41 to 254.2.2.46254.2.2.476
71254.2.2.48/29254.2.2.49 to 254.2.2.54254.2.2.556
72254.2.2.56/29254.2.2.57 to 254.2.2.62254.2.2.636
73254.2.2.64/29254.2.2.65 to 254.2.2.70254.2.2.716
74254.2.2.72/29254.2.2.73 to 254.2.2.78254.2.2.796
75254.2.2.80/29254.2.2.81 to 254.2.2.86254.2.2.876
76254.2.2.88/29254.2.2.89 to 254.2.2.94254.2.2.956
77254.2.2.96/29254.2.2.97 to 254.2.2.102254.2.2.1036
78254.2.2.104/29254.2.2.105 to 254.2.2.110254.2.2.1116
79254.2.2.112/29254.2.2.113 to 254.2.2.118254.2.2.1196
80254.2.2.120/29254.2.2.121 to 254.2.2.126254.2.2.1276
81254.2.2.128/29254.2.2.129 to 254.2.2.134254.2.2.1356
82254.2.2.136/29254.2.2.137 to 254.2.2.142254.2.2.1436
83254.2.2.144/29254.2.2.145 to 254.2.2.150254.2.2.1516
84254.2.2.152/29254.2.2.153 to 254.2.2.158254.2.2.1596
85254.2.2.160/29254.2.2.161 to 254.2.2.166254.2.2.1676
86254.2.2.168/29254.2.2.169 to 254.2.2.174254.2.2.1756
87254.2.2.176/29254.2.2.177 to 254.2.2.182254.2.2.1836
88254.2.2.184/29254.2.2.185 to 254.2.2.190254.2.2.1916
89254.2.2.192/29254.2.2.193 to 254.2.2.198254.2.2.1996
90254.2.2.200/29254.2.2.201 to 254.2.2.206254.2.2.2076
91254.2.2.208/29254.2.2.209 to 254.2.2.214254.2.2.2156
92254.2.2.216/29254.2.2.217 to 254.2.2.222254.2.2.2236
93254.2.2.224/29254.2.2.225 to 254.2.2.230254.2.2.2316
94254.2.2.232/29254.2.2.233 to 254.2.2.238254.2.2.2396
95254.2.2.240/29254.2.2.241 to 254.2.2.246254.2.2.2476
96254.2.2.248/29254.2.2.249 to 254.2.2.254254.2.2.2556
97254.2.3.0/29254.2.3.1 to 254.2.3.6254.2.3.76
98254.2.3.8/29254.2.3.9 to 254.2.3.14254.2.3.156
99254.2.3.16/29254.2.3.17 to 254.2.3.22254.2.3.236
100254.2.3.24/29254.2.3.25 to 254.2.3.30254.2.3.316
101254.2.3.32/29254.2.3.33 to 254.2.3.38254.2.3.396
102254.2.3.40/29254.2.3.41 to 254.2.3.46254.2.3.476
103254.2.3.48/29254.2.3.49 to 254.2.3.54254.2.3.556
104254.2.3.56/29254.2.3.57 to 254.2.3.62254.2.3.636
105254.2.3.64/29254.2.3.65 to 254.2.3.70254.2.3.716
106254.2.3.72/29254.2.3.73 to 254.2.3.78254.2.3.796
107254.2.3.80/29254.2.3.81 to 254.2.3.86254.2.3.876
108254.2.3.88/29254.2.3.89 to 254.2.3.94254.2.3.956
109254.2.3.96/29254.2.3.97 to 254.2.3.102254.2.3.1036
110254.2.3.104/29254.2.3.105 to 254.2.3.110254.2.3.1116
111254.2.3.112/29254.2.3.113 to 254.2.3.118254.2.3.1196
112254.2.3.120/29254.2.3.121 to 254.2.3.126254.2.3.1276
113254.2.3.128/29254.2.3.129 to 254.2.3.134254.2.3.1356
114254.2.3.136/29254.2.3.137 to 254.2.3.142254.2.3.1436
115254.2.3.144/29254.2.3.145 to 254.2.3.150254.2.3.1516
116254.2.3.152/29254.2.3.153 to 254.2.3.158254.2.3.1596
117254.2.3.160/29254.2.3.161 to 254.2.3.166254.2.3.1676
118254.2.3.168/29254.2.3.169 to 254.2.3.174254.2.3.1756
119254.2.3.176/29254.2.3.177 to 254.2.3.182254.2.3.1836
120254.2.3.184/29254.2.3.185 to 254.2.3.190254.2.3.1916
121254.2.3.192/29254.2.3.193 to 254.2.3.198254.2.3.1996
122254.2.3.200/29254.2.3.201 to 254.2.3.206254.2.3.2076
123254.2.3.208/29254.2.3.209 to 254.2.3.214254.2.3.2156
124254.2.3.216/29254.2.3.217 to 254.2.3.222254.2.3.2236
125254.2.3.224/29254.2.3.225 to 254.2.3.230254.2.3.2316
126254.2.3.232/29254.2.3.233 to 254.2.3.238254.2.3.2396
127254.2.3.240/29254.2.3.241 to 254.2.3.246254.2.3.2476
128254.2.3.248/29254.2.3.249 to 254.2.3.254254.2.3.2556
129254.2.4.0/29254.2.4.1 to 254.2.4.6254.2.4.76
130254.2.4.8/29254.2.4.9 to 254.2.4.14254.2.4.156
131254.2.4.16/29254.2.4.17 to 254.2.4.22254.2.4.236
132254.2.4.24/29254.2.4.25 to 254.2.4.30254.2.4.316
133254.2.4.32/29254.2.4.33 to 254.2.4.38254.2.4.396
134254.2.4.40/29254.2.4.41 to 254.2.4.46254.2.4.476
135254.2.4.48/29254.2.4.49 to 254.2.4.54254.2.4.556
136254.2.4.56/29254.2.4.57 to 254.2.4.62254.2.4.636
137254.2.4.64/29254.2.4.65 to 254.2.4.70254.2.4.716
138254.2.4.72/29254.2.4.73 to 254.2.4.78254.2.4.796
139254.2.4.80/29254.2.4.81 to 254.2.4.86254.2.4.876
140254.2.4.88/29254.2.4.89 to 254.2.4.94254.2.4.956
141254.2.4.96/29254.2.4.97 to 254.2.4.102254.2.4.1036
142254.2.4.104/29254.2.4.105 to 254.2.4.110254.2.4.1116
143254.2.4.112/29254.2.4.113 to 254.2.4.118254.2.4.1196
144254.2.4.120/29254.2.4.121 to 254.2.4.126254.2.4.1276
145254.2.4.128/29254.2.4.129 to 254.2.4.134254.2.4.1356
146254.2.4.136/29254.2.4.137 to 254.2.4.142254.2.4.1436
147254.2.4.144/29254.2.4.145 to 254.2.4.150254.2.4.1516
148254.2.4.152/29254.2.4.153 to 254.2.4.158254.2.4.1596
149254.2.4.160/29254.2.4.161 to 254.2.4.166254.2.4.1676
150254.2.4.168/29254.2.4.169 to 254.2.4.174254.2.4.1756
151254.2.4.176/29254.2.4.177 to 254.2.4.182254.2.4.1836
152254.2.4.184/29254.2.4.185 to 254.2.4.190254.2.4.1916
153254.2.4.192/29254.2.4.193 to 254.2.4.198254.2.4.1996
154254.2.4.200/29254.2.4.201 to 254.2.4.206254.2.4.2076
155254.2.4.208/29254.2.4.209 to 254.2.4.214254.2.4.2156
156254.2.4.216/29254.2.4.217 to 254.2.4.222254.2.4.2236
157254.2.4.224/29254.2.4.225 to 254.2.4.230254.2.4.2316
158254.2.4.232/29254.2.4.233 to 254.2.4.238254.2.4.2396
159254.2.4.240/29254.2.4.241 to 254.2.4.246254.2.4.2476
160254.2.4.248/29254.2.4.249 to 254.2.4.254254.2.4.2556
161254.2.5.0/29254.2.5.1 to 254.2.5.6254.2.5.76
162254.2.5.8/29254.2.5.9 to 254.2.5.14254.2.5.156
163254.2.5.16/29254.2.5.17 to 254.2.5.22254.2.5.236
164254.2.5.24/29254.2.5.25 to 254.2.5.30254.2.5.316
165254.2.5.32/29254.2.5.33 to 254.2.5.38254.2.5.396
166254.2.5.40/29254.2.5.41 to 254.2.5.46254.2.5.476
167254.2.5.48/29254.2.5.49 to 254.2.5.54254.2.5.556
168254.2.5.56/29254.2.5.57 to 254.2.5.62254.2.5.636
169254.2.5.64/29254.2.5.65 to 254.2.5.70254.2.5.716
170254.2.5.72/29254.2.5.73 to 254.2.5.78254.2.5.796
171254.2.5.80/29254.2.5.81 to 254.2.5.86254.2.5.876
172254.2.5.88/29254.2.5.89 to 254.2.5.94254.2.5.956
173254.2.5.96/29254.2.5.97 to 254.2.5.102254.2.5.1036
174254.2.5.104/29254.2.5.105 to 254.2.5.110254.2.5.1116
175254.2.5.112/29254.2.5.113 to 254.2.5.118254.2.5.1196
176254.2.5.120/29254.2.5.121 to 254.2.5.126254.2.5.1276
177254.2.5.128/29254.2.5.129 to 254.2.5.134254.2.5.1356
178254.2.5.136/29254.2.5.137 to 254.2.5.142254.2.5.1436
179254.2.5.144/29254.2.5.145 to 254.2.5.150254.2.5.1516
180254.2.5.152/29254.2.5.153 to 254.2.5.158254.2.5.1596
181254.2.5.160/29254.2.5.161 to 254.2.5.166254.2.5.1676
182254.2.5.168/29254.2.5.169 to 254.2.5.174254.2.5.1756
183254.2.5.176/29254.2.5.177 to 254.2.5.182254.2.5.1836
184254.2.5.184/29254.2.5.185 to 254.2.5.190254.2.5.1916
185254.2.5.192/29254.2.5.193 to 254.2.5.198254.2.5.1996
186254.2.5.200/29254.2.5.201 to 254.2.5.206254.2.5.2076
187254.2.5.208/29254.2.5.209 to 254.2.5.214254.2.5.2156
188254.2.5.216/29254.2.5.217 to 254.2.5.222254.2.5.2236
189254.2.5.224/29254.2.5.225 to 254.2.5.230254.2.5.2316
190254.2.5.232/29254.2.5.233 to 254.2.5.238254.2.5.2396
191254.2.5.240/29254.2.5.241 to 254.2.5.246254.2.5.2476
192254.2.5.248/29254.2.5.249 to 254.2.5.254254.2.5.2556
193254.2.6.0/29254.2.6.1 to 254.2.6.6254.2.6.76
194254.2.6.8/29254.2.6.9 to 254.2.6.14254.2.6.156
195254.2.6.16/29254.2.6.17 to 254.2.6.22254.2.6.236
196254.2.6.24/29254.2.6.25 to 254.2.6.30254.2.6.316
197254.2.6.32/29254.2.6.33 to 254.2.6.38254.2.6.396
198254.2.6.40/29254.2.6.41 to 254.2.6.46254.2.6.476
199254.2.6.48/29254.2.6.49 to 254.2.6.54254.2.6.556
200254.2.6.56/29254.2.6.57 to 254.2.6.62254.2.6.636
201254.2.6.64/29254.2.6.65 to 254.2.6.70254.2.6.716
202254.2.6.72/29254.2.6.73 to 254.2.6.78254.2.6.796
203254.2.6.80/29254.2.6.81 to 254.2.6.86254.2.6.876
204254.2.6.88/29254.2.6.89 to 254.2.6.94254.2.6.956
205254.2.6.96/29254.2.6.97 to 254.2.6.102254.2.6.1036
206254.2.6.104/29254.2.6.105 to 254.2.6.110254.2.6.1116
207254.2.6.112/29254.2.6.113 to 254.2.6.118254.2.6.1196
208254.2.6.120/29254.2.6.121 to 254.2.6.126254.2.6.1276
209254.2.6.128/29254.2.6.129 to 254.2.6.134254.2.6.1356
210254.2.6.136/29254.2.6.137 to 254.2.6.142254.2.6.1436
211254.2.6.144/29254.2.6.145 to 254.2.6.150254.2.6.1516
212254.2.6.152/29254.2.6.153 to 254.2.6.158254.2.6.1596
213254.2.6.160/29254.2.6.161 to 254.2.6.166254.2.6.1676
214254.2.6.168/29254.2.6.169 to 254.2.6.174254.2.6.1756
215254.2.6.176/29254.2.6.177 to 254.2.6.182254.2.6.1836
216254.2.6.184/29254.2.6.185 to 254.2.6.190254.2.6.1916
217254.2.6.192/29254.2.6.193 to 254.2.6.198254.2.6.1996
218254.2.6.200/29254.2.6.201 to 254.2.6.206254.2.6.2076
219254.2.6.208/29254.2.6.209 to 254.2.6.214254.2.6.2156
220254.2.6.216/29254.2.6.217 to 254.2.6.222254.2.6.2236
221254.2.6.224/29254.2.6.225 to 254.2.6.230254.2.6.2316
222254.2.6.232/29254.2.6.233 to 254.2.6.238254.2.6.2396
223254.2.6.240/29254.2.6.241 to 254.2.6.246254.2.6.2476
224254.2.6.248/29254.2.6.249 to 254.2.6.254254.2.6.2556
225254.2.7.0/29254.2.7.1 to 254.2.7.6254.2.7.76
226254.2.7.8/29254.2.7.9 to 254.2.7.14254.2.7.156
227254.2.7.16/29254.2.7.17 to 254.2.7.22254.2.7.236
228254.2.7.24/29254.2.7.25 to 254.2.7.30254.2.7.316
229254.2.7.32/29254.2.7.33 to 254.2.7.38254.2.7.396
230254.2.7.40/29254.2.7.41 to 254.2.7.46254.2.7.476
231254.2.7.48/29254.2.7.49 to 254.2.7.54254.2.7.556
232254.2.7.56/29254.2.7.57 to 254.2.7.62254.2.7.636
233254.2.7.64/29254.2.7.65 to 254.2.7.70254.2.7.716
234254.2.7.72/29254.2.7.73 to 254.2.7.78254.2.7.796
235254.2.7.80/29254.2.7.81 to 254.2.7.86254.2.7.876
236254.2.7.88/29254.2.7.89 to 254.2.7.94254.2.7.956
237254.2.7.96/29254.2.7.97 to 254.2.7.102254.2.7.1036
238254.2.7.104/29254.2.7.105 to 254.2.7.110254.2.7.1116
239254.2.7.112/29254.2.7.113 to 254.2.7.118254.2.7.1196
240254.2.7.120/29254.2.7.121 to 254.2.7.126254.2.7.1276
241254.2.7.128/29254.2.7.129 to 254.2.7.134254.2.7.1356
242254.2.7.136/29254.2.7.137 to 254.2.7.142254.2.7.1436
243254.2.7.144/29254.2.7.145 to 254.2.7.150254.2.7.1516
244254.2.7.152/29254.2.7.153 to 254.2.7.158254.2.7.1596
245254.2.7.160/29254.2.7.161 to 254.2.7.166254.2.7.1676
246254.2.7.168/29254.2.7.169 to 254.2.7.174254.2.7.1756
247254.2.7.176/29254.2.7.177 to 254.2.7.182254.2.7.1836
248254.2.7.184/29254.2.7.185 to 254.2.7.190254.2.7.1916
249254.2.7.192/29254.2.7.193 to 254.2.7.198254.2.7.1996
250254.2.7.200/29254.2.7.201 to 254.2.7.206254.2.7.2076
251254.2.7.208/29254.2.7.209 to 254.2.7.214254.2.7.2156
252254.2.7.216/29254.2.7.217 to 254.2.7.222254.2.7.2236
253254.2.7.224/29254.2.7.225 to 254.2.7.230254.2.7.2316
254254.2.7.232/29254.2.7.233 to 254.2.7.238254.2.7.2396
255254.2.7.240/29254.2.7.241 to 254.2.7.246254.2.7.2476
256254.2.7.248/29254.2.7.249 to 254.2.7.254254.2.7.2556

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.