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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.

Network245.95.0.0/19
Usable hosts8,190
Subnet mask255.255.224.0
Addresses8,192
Network address
245.95.0.0
Broadcast address
245.95.31.255
First usable
245.95.0.1
Last usable
245.95.31.254
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 F55F0000 · Integer 4116643840 to 4116652031
Reverse DNS zones
0.95.245.in-addr.arpa
1.95.245.in-addr.arpa
2.95.245.in-addr.arpa
3.95.245.in-addr.arpa
4.95.245.in-addr.arpa
5.95.245.in-addr.arpa
6.95.245.in-addr.arpa
7.95.245.in-addr.arpa
8.95.245.in-addr.arpa
9.95.245.in-addr.arpa
10.95.245.in-addr.arpa
11.95.245.in-addr.arpa
12.95.245.in-addr.arpa
13.95.245.in-addr.arpa
14.95.245.in-addr.arpa
15.95.245.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
Address11110101.01011111.00000000.00000000245.95.0.0
Subnet mask11111111.11111111.11100000.00000000255.255.224.0
Network11110101.01011111.00000000.00000000245.95.0.0
Broadcast11110101.01011111.00011111.11111111245.95.31.255
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)

245.95.0.0/19 makes 1,024 subnets of /29; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1245.95.0.0/29245.95.0.1 to 245.95.0.6245.95.0.76
2245.95.0.8/29245.95.0.9 to 245.95.0.14245.95.0.156
3245.95.0.16/29245.95.0.17 to 245.95.0.22245.95.0.236
4245.95.0.24/29245.95.0.25 to 245.95.0.30245.95.0.316
5245.95.0.32/29245.95.0.33 to 245.95.0.38245.95.0.396
6245.95.0.40/29245.95.0.41 to 245.95.0.46245.95.0.476
7245.95.0.48/29245.95.0.49 to 245.95.0.54245.95.0.556
8245.95.0.56/29245.95.0.57 to 245.95.0.62245.95.0.636
9245.95.0.64/29245.95.0.65 to 245.95.0.70245.95.0.716
10245.95.0.72/29245.95.0.73 to 245.95.0.78245.95.0.796
11245.95.0.80/29245.95.0.81 to 245.95.0.86245.95.0.876
12245.95.0.88/29245.95.0.89 to 245.95.0.94245.95.0.956
13245.95.0.96/29245.95.0.97 to 245.95.0.102245.95.0.1036
14245.95.0.104/29245.95.0.105 to 245.95.0.110245.95.0.1116
15245.95.0.112/29245.95.0.113 to 245.95.0.118245.95.0.1196
16245.95.0.120/29245.95.0.121 to 245.95.0.126245.95.0.1276
17245.95.0.128/29245.95.0.129 to 245.95.0.134245.95.0.1356
18245.95.0.136/29245.95.0.137 to 245.95.0.142245.95.0.1436
19245.95.0.144/29245.95.0.145 to 245.95.0.150245.95.0.1516
20245.95.0.152/29245.95.0.153 to 245.95.0.158245.95.0.1596
21245.95.0.160/29245.95.0.161 to 245.95.0.166245.95.0.1676
22245.95.0.168/29245.95.0.169 to 245.95.0.174245.95.0.1756
23245.95.0.176/29245.95.0.177 to 245.95.0.182245.95.0.1836
24245.95.0.184/29245.95.0.185 to 245.95.0.190245.95.0.1916
25245.95.0.192/29245.95.0.193 to 245.95.0.198245.95.0.1996
26245.95.0.200/29245.95.0.201 to 245.95.0.206245.95.0.2076
27245.95.0.208/29245.95.0.209 to 245.95.0.214245.95.0.2156
28245.95.0.216/29245.95.0.217 to 245.95.0.222245.95.0.2236
29245.95.0.224/29245.95.0.225 to 245.95.0.230245.95.0.2316
30245.95.0.232/29245.95.0.233 to 245.95.0.238245.95.0.2396
31245.95.0.240/29245.95.0.241 to 245.95.0.246245.95.0.2476
32245.95.0.248/29245.95.0.249 to 245.95.0.254245.95.0.2556
33245.95.1.0/29245.95.1.1 to 245.95.1.6245.95.1.76
34245.95.1.8/29245.95.1.9 to 245.95.1.14245.95.1.156
35245.95.1.16/29245.95.1.17 to 245.95.1.22245.95.1.236
36245.95.1.24/29245.95.1.25 to 245.95.1.30245.95.1.316
37245.95.1.32/29245.95.1.33 to 245.95.1.38245.95.1.396
38245.95.1.40/29245.95.1.41 to 245.95.1.46245.95.1.476
39245.95.1.48/29245.95.1.49 to 245.95.1.54245.95.1.556
40245.95.1.56/29245.95.1.57 to 245.95.1.62245.95.1.636
41245.95.1.64/29245.95.1.65 to 245.95.1.70245.95.1.716
42245.95.1.72/29245.95.1.73 to 245.95.1.78245.95.1.796
43245.95.1.80/29245.95.1.81 to 245.95.1.86245.95.1.876
44245.95.1.88/29245.95.1.89 to 245.95.1.94245.95.1.956
45245.95.1.96/29245.95.1.97 to 245.95.1.102245.95.1.1036
46245.95.1.104/29245.95.1.105 to 245.95.1.110245.95.1.1116
47245.95.1.112/29245.95.1.113 to 245.95.1.118245.95.1.1196
48245.95.1.120/29245.95.1.121 to 245.95.1.126245.95.1.1276
49245.95.1.128/29245.95.1.129 to 245.95.1.134245.95.1.1356
50245.95.1.136/29245.95.1.137 to 245.95.1.142245.95.1.1436
51245.95.1.144/29245.95.1.145 to 245.95.1.150245.95.1.1516
52245.95.1.152/29245.95.1.153 to 245.95.1.158245.95.1.1596
53245.95.1.160/29245.95.1.161 to 245.95.1.166245.95.1.1676
54245.95.1.168/29245.95.1.169 to 245.95.1.174245.95.1.1756
55245.95.1.176/29245.95.1.177 to 245.95.1.182245.95.1.1836
56245.95.1.184/29245.95.1.185 to 245.95.1.190245.95.1.1916
57245.95.1.192/29245.95.1.193 to 245.95.1.198245.95.1.1996
58245.95.1.200/29245.95.1.201 to 245.95.1.206245.95.1.2076
59245.95.1.208/29245.95.1.209 to 245.95.1.214245.95.1.2156
60245.95.1.216/29245.95.1.217 to 245.95.1.222245.95.1.2236
61245.95.1.224/29245.95.1.225 to 245.95.1.230245.95.1.2316
62245.95.1.232/29245.95.1.233 to 245.95.1.238245.95.1.2396
63245.95.1.240/29245.95.1.241 to 245.95.1.246245.95.1.2476
64245.95.1.248/29245.95.1.249 to 245.95.1.254245.95.1.2556
65245.95.2.0/29245.95.2.1 to 245.95.2.6245.95.2.76
66245.95.2.8/29245.95.2.9 to 245.95.2.14245.95.2.156
67245.95.2.16/29245.95.2.17 to 245.95.2.22245.95.2.236
68245.95.2.24/29245.95.2.25 to 245.95.2.30245.95.2.316
69245.95.2.32/29245.95.2.33 to 245.95.2.38245.95.2.396
70245.95.2.40/29245.95.2.41 to 245.95.2.46245.95.2.476
71245.95.2.48/29245.95.2.49 to 245.95.2.54245.95.2.556
72245.95.2.56/29245.95.2.57 to 245.95.2.62245.95.2.636
73245.95.2.64/29245.95.2.65 to 245.95.2.70245.95.2.716
74245.95.2.72/29245.95.2.73 to 245.95.2.78245.95.2.796
75245.95.2.80/29245.95.2.81 to 245.95.2.86245.95.2.876
76245.95.2.88/29245.95.2.89 to 245.95.2.94245.95.2.956
77245.95.2.96/29245.95.2.97 to 245.95.2.102245.95.2.1036
78245.95.2.104/29245.95.2.105 to 245.95.2.110245.95.2.1116
79245.95.2.112/29245.95.2.113 to 245.95.2.118245.95.2.1196
80245.95.2.120/29245.95.2.121 to 245.95.2.126245.95.2.1276
81245.95.2.128/29245.95.2.129 to 245.95.2.134245.95.2.1356
82245.95.2.136/29245.95.2.137 to 245.95.2.142245.95.2.1436
83245.95.2.144/29245.95.2.145 to 245.95.2.150245.95.2.1516
84245.95.2.152/29245.95.2.153 to 245.95.2.158245.95.2.1596
85245.95.2.160/29245.95.2.161 to 245.95.2.166245.95.2.1676
86245.95.2.168/29245.95.2.169 to 245.95.2.174245.95.2.1756
87245.95.2.176/29245.95.2.177 to 245.95.2.182245.95.2.1836
88245.95.2.184/29245.95.2.185 to 245.95.2.190245.95.2.1916
89245.95.2.192/29245.95.2.193 to 245.95.2.198245.95.2.1996
90245.95.2.200/29245.95.2.201 to 245.95.2.206245.95.2.2076
91245.95.2.208/29245.95.2.209 to 245.95.2.214245.95.2.2156
92245.95.2.216/29245.95.2.217 to 245.95.2.222245.95.2.2236
93245.95.2.224/29245.95.2.225 to 245.95.2.230245.95.2.2316
94245.95.2.232/29245.95.2.233 to 245.95.2.238245.95.2.2396
95245.95.2.240/29245.95.2.241 to 245.95.2.246245.95.2.2476
96245.95.2.248/29245.95.2.249 to 245.95.2.254245.95.2.2556
97245.95.3.0/29245.95.3.1 to 245.95.3.6245.95.3.76
98245.95.3.8/29245.95.3.9 to 245.95.3.14245.95.3.156
99245.95.3.16/29245.95.3.17 to 245.95.3.22245.95.3.236
100245.95.3.24/29245.95.3.25 to 245.95.3.30245.95.3.316
101245.95.3.32/29245.95.3.33 to 245.95.3.38245.95.3.396
102245.95.3.40/29245.95.3.41 to 245.95.3.46245.95.3.476
103245.95.3.48/29245.95.3.49 to 245.95.3.54245.95.3.556
104245.95.3.56/29245.95.3.57 to 245.95.3.62245.95.3.636
105245.95.3.64/29245.95.3.65 to 245.95.3.70245.95.3.716
106245.95.3.72/29245.95.3.73 to 245.95.3.78245.95.3.796
107245.95.3.80/29245.95.3.81 to 245.95.3.86245.95.3.876
108245.95.3.88/29245.95.3.89 to 245.95.3.94245.95.3.956
109245.95.3.96/29245.95.3.97 to 245.95.3.102245.95.3.1036
110245.95.3.104/29245.95.3.105 to 245.95.3.110245.95.3.1116
111245.95.3.112/29245.95.3.113 to 245.95.3.118245.95.3.1196
112245.95.3.120/29245.95.3.121 to 245.95.3.126245.95.3.1276
113245.95.3.128/29245.95.3.129 to 245.95.3.134245.95.3.1356
114245.95.3.136/29245.95.3.137 to 245.95.3.142245.95.3.1436
115245.95.3.144/29245.95.3.145 to 245.95.3.150245.95.3.1516
116245.95.3.152/29245.95.3.153 to 245.95.3.158245.95.3.1596
117245.95.3.160/29245.95.3.161 to 245.95.3.166245.95.3.1676
118245.95.3.168/29245.95.3.169 to 245.95.3.174245.95.3.1756
119245.95.3.176/29245.95.3.177 to 245.95.3.182245.95.3.1836
120245.95.3.184/29245.95.3.185 to 245.95.3.190245.95.3.1916
121245.95.3.192/29245.95.3.193 to 245.95.3.198245.95.3.1996
122245.95.3.200/29245.95.3.201 to 245.95.3.206245.95.3.2076
123245.95.3.208/29245.95.3.209 to 245.95.3.214245.95.3.2156
124245.95.3.216/29245.95.3.217 to 245.95.3.222245.95.3.2236
125245.95.3.224/29245.95.3.225 to 245.95.3.230245.95.3.2316
126245.95.3.232/29245.95.3.233 to 245.95.3.238245.95.3.2396
127245.95.3.240/29245.95.3.241 to 245.95.3.246245.95.3.2476
128245.95.3.248/29245.95.3.249 to 245.95.3.254245.95.3.2556
129245.95.4.0/29245.95.4.1 to 245.95.4.6245.95.4.76
130245.95.4.8/29245.95.4.9 to 245.95.4.14245.95.4.156
131245.95.4.16/29245.95.4.17 to 245.95.4.22245.95.4.236
132245.95.4.24/29245.95.4.25 to 245.95.4.30245.95.4.316
133245.95.4.32/29245.95.4.33 to 245.95.4.38245.95.4.396
134245.95.4.40/29245.95.4.41 to 245.95.4.46245.95.4.476
135245.95.4.48/29245.95.4.49 to 245.95.4.54245.95.4.556
136245.95.4.56/29245.95.4.57 to 245.95.4.62245.95.4.636
137245.95.4.64/29245.95.4.65 to 245.95.4.70245.95.4.716
138245.95.4.72/29245.95.4.73 to 245.95.4.78245.95.4.796
139245.95.4.80/29245.95.4.81 to 245.95.4.86245.95.4.876
140245.95.4.88/29245.95.4.89 to 245.95.4.94245.95.4.956
141245.95.4.96/29245.95.4.97 to 245.95.4.102245.95.4.1036
142245.95.4.104/29245.95.4.105 to 245.95.4.110245.95.4.1116
143245.95.4.112/29245.95.4.113 to 245.95.4.118245.95.4.1196
144245.95.4.120/29245.95.4.121 to 245.95.4.126245.95.4.1276
145245.95.4.128/29245.95.4.129 to 245.95.4.134245.95.4.1356
146245.95.4.136/29245.95.4.137 to 245.95.4.142245.95.4.1436
147245.95.4.144/29245.95.4.145 to 245.95.4.150245.95.4.1516
148245.95.4.152/29245.95.4.153 to 245.95.4.158245.95.4.1596
149245.95.4.160/29245.95.4.161 to 245.95.4.166245.95.4.1676
150245.95.4.168/29245.95.4.169 to 245.95.4.174245.95.4.1756
151245.95.4.176/29245.95.4.177 to 245.95.4.182245.95.4.1836
152245.95.4.184/29245.95.4.185 to 245.95.4.190245.95.4.1916
153245.95.4.192/29245.95.4.193 to 245.95.4.198245.95.4.1996
154245.95.4.200/29245.95.4.201 to 245.95.4.206245.95.4.2076
155245.95.4.208/29245.95.4.209 to 245.95.4.214245.95.4.2156
156245.95.4.216/29245.95.4.217 to 245.95.4.222245.95.4.2236
157245.95.4.224/29245.95.4.225 to 245.95.4.230245.95.4.2316
158245.95.4.232/29245.95.4.233 to 245.95.4.238245.95.4.2396
159245.95.4.240/29245.95.4.241 to 245.95.4.246245.95.4.2476
160245.95.4.248/29245.95.4.249 to 245.95.4.254245.95.4.2556
161245.95.5.0/29245.95.5.1 to 245.95.5.6245.95.5.76
162245.95.5.8/29245.95.5.9 to 245.95.5.14245.95.5.156
163245.95.5.16/29245.95.5.17 to 245.95.5.22245.95.5.236
164245.95.5.24/29245.95.5.25 to 245.95.5.30245.95.5.316
165245.95.5.32/29245.95.5.33 to 245.95.5.38245.95.5.396
166245.95.5.40/29245.95.5.41 to 245.95.5.46245.95.5.476
167245.95.5.48/29245.95.5.49 to 245.95.5.54245.95.5.556
168245.95.5.56/29245.95.5.57 to 245.95.5.62245.95.5.636
169245.95.5.64/29245.95.5.65 to 245.95.5.70245.95.5.716
170245.95.5.72/29245.95.5.73 to 245.95.5.78245.95.5.796
171245.95.5.80/29245.95.5.81 to 245.95.5.86245.95.5.876
172245.95.5.88/29245.95.5.89 to 245.95.5.94245.95.5.956
173245.95.5.96/29245.95.5.97 to 245.95.5.102245.95.5.1036
174245.95.5.104/29245.95.5.105 to 245.95.5.110245.95.5.1116
175245.95.5.112/29245.95.5.113 to 245.95.5.118245.95.5.1196
176245.95.5.120/29245.95.5.121 to 245.95.5.126245.95.5.1276
177245.95.5.128/29245.95.5.129 to 245.95.5.134245.95.5.1356
178245.95.5.136/29245.95.5.137 to 245.95.5.142245.95.5.1436
179245.95.5.144/29245.95.5.145 to 245.95.5.150245.95.5.1516
180245.95.5.152/29245.95.5.153 to 245.95.5.158245.95.5.1596
181245.95.5.160/29245.95.5.161 to 245.95.5.166245.95.5.1676
182245.95.5.168/29245.95.5.169 to 245.95.5.174245.95.5.1756
183245.95.5.176/29245.95.5.177 to 245.95.5.182245.95.5.1836
184245.95.5.184/29245.95.5.185 to 245.95.5.190245.95.5.1916
185245.95.5.192/29245.95.5.193 to 245.95.5.198245.95.5.1996
186245.95.5.200/29245.95.5.201 to 245.95.5.206245.95.5.2076
187245.95.5.208/29245.95.5.209 to 245.95.5.214245.95.5.2156
188245.95.5.216/29245.95.5.217 to 245.95.5.222245.95.5.2236
189245.95.5.224/29245.95.5.225 to 245.95.5.230245.95.5.2316
190245.95.5.232/29245.95.5.233 to 245.95.5.238245.95.5.2396
191245.95.5.240/29245.95.5.241 to 245.95.5.246245.95.5.2476
192245.95.5.248/29245.95.5.249 to 245.95.5.254245.95.5.2556
193245.95.6.0/29245.95.6.1 to 245.95.6.6245.95.6.76
194245.95.6.8/29245.95.6.9 to 245.95.6.14245.95.6.156
195245.95.6.16/29245.95.6.17 to 245.95.6.22245.95.6.236
196245.95.6.24/29245.95.6.25 to 245.95.6.30245.95.6.316
197245.95.6.32/29245.95.6.33 to 245.95.6.38245.95.6.396
198245.95.6.40/29245.95.6.41 to 245.95.6.46245.95.6.476
199245.95.6.48/29245.95.6.49 to 245.95.6.54245.95.6.556
200245.95.6.56/29245.95.6.57 to 245.95.6.62245.95.6.636
201245.95.6.64/29245.95.6.65 to 245.95.6.70245.95.6.716
202245.95.6.72/29245.95.6.73 to 245.95.6.78245.95.6.796
203245.95.6.80/29245.95.6.81 to 245.95.6.86245.95.6.876
204245.95.6.88/29245.95.6.89 to 245.95.6.94245.95.6.956
205245.95.6.96/29245.95.6.97 to 245.95.6.102245.95.6.1036
206245.95.6.104/29245.95.6.105 to 245.95.6.110245.95.6.1116
207245.95.6.112/29245.95.6.113 to 245.95.6.118245.95.6.1196
208245.95.6.120/29245.95.6.121 to 245.95.6.126245.95.6.1276
209245.95.6.128/29245.95.6.129 to 245.95.6.134245.95.6.1356
210245.95.6.136/29245.95.6.137 to 245.95.6.142245.95.6.1436
211245.95.6.144/29245.95.6.145 to 245.95.6.150245.95.6.1516
212245.95.6.152/29245.95.6.153 to 245.95.6.158245.95.6.1596
213245.95.6.160/29245.95.6.161 to 245.95.6.166245.95.6.1676
214245.95.6.168/29245.95.6.169 to 245.95.6.174245.95.6.1756
215245.95.6.176/29245.95.6.177 to 245.95.6.182245.95.6.1836
216245.95.6.184/29245.95.6.185 to 245.95.6.190245.95.6.1916
217245.95.6.192/29245.95.6.193 to 245.95.6.198245.95.6.1996
218245.95.6.200/29245.95.6.201 to 245.95.6.206245.95.6.2076
219245.95.6.208/29245.95.6.209 to 245.95.6.214245.95.6.2156
220245.95.6.216/29245.95.6.217 to 245.95.6.222245.95.6.2236
221245.95.6.224/29245.95.6.225 to 245.95.6.230245.95.6.2316
222245.95.6.232/29245.95.6.233 to 245.95.6.238245.95.6.2396
223245.95.6.240/29245.95.6.241 to 245.95.6.246245.95.6.2476
224245.95.6.248/29245.95.6.249 to 245.95.6.254245.95.6.2556
225245.95.7.0/29245.95.7.1 to 245.95.7.6245.95.7.76
226245.95.7.8/29245.95.7.9 to 245.95.7.14245.95.7.156
227245.95.7.16/29245.95.7.17 to 245.95.7.22245.95.7.236
228245.95.7.24/29245.95.7.25 to 245.95.7.30245.95.7.316
229245.95.7.32/29245.95.7.33 to 245.95.7.38245.95.7.396
230245.95.7.40/29245.95.7.41 to 245.95.7.46245.95.7.476
231245.95.7.48/29245.95.7.49 to 245.95.7.54245.95.7.556
232245.95.7.56/29245.95.7.57 to 245.95.7.62245.95.7.636
233245.95.7.64/29245.95.7.65 to 245.95.7.70245.95.7.716
234245.95.7.72/29245.95.7.73 to 245.95.7.78245.95.7.796
235245.95.7.80/29245.95.7.81 to 245.95.7.86245.95.7.876
236245.95.7.88/29245.95.7.89 to 245.95.7.94245.95.7.956
237245.95.7.96/29245.95.7.97 to 245.95.7.102245.95.7.1036
238245.95.7.104/29245.95.7.105 to 245.95.7.110245.95.7.1116
239245.95.7.112/29245.95.7.113 to 245.95.7.118245.95.7.1196
240245.95.7.120/29245.95.7.121 to 245.95.7.126245.95.7.1276
241245.95.7.128/29245.95.7.129 to 245.95.7.134245.95.7.1356
242245.95.7.136/29245.95.7.137 to 245.95.7.142245.95.7.1436
243245.95.7.144/29245.95.7.145 to 245.95.7.150245.95.7.1516
244245.95.7.152/29245.95.7.153 to 245.95.7.158245.95.7.1596
245245.95.7.160/29245.95.7.161 to 245.95.7.166245.95.7.1676
246245.95.7.168/29245.95.7.169 to 245.95.7.174245.95.7.1756
247245.95.7.176/29245.95.7.177 to 245.95.7.182245.95.7.1836
248245.95.7.184/29245.95.7.185 to 245.95.7.190245.95.7.1916
249245.95.7.192/29245.95.7.193 to 245.95.7.198245.95.7.1996
250245.95.7.200/29245.95.7.201 to 245.95.7.206245.95.7.2076
251245.95.7.208/29245.95.7.209 to 245.95.7.214245.95.7.2156
252245.95.7.216/29245.95.7.217 to 245.95.7.222245.95.7.2236
253245.95.7.224/29245.95.7.225 to 245.95.7.230245.95.7.2316
254245.95.7.232/29245.95.7.233 to 245.95.7.238245.95.7.2396
255245.95.7.240/29245.95.7.241 to 245.95.7.246245.95.7.2476
256245.95.7.248/29245.95.7.249 to 245.95.7.254245.95.7.2556

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.