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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.

Network140.7.0.0/19
Usable hosts8,190
Subnet mask255.255.224.0
Addresses8,192
Network address
140.7.0.0
Broadcast address
140.7.31.255
First usable
140.7.0.1
Last usable
140.7.31.254
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
Public public
Old class
B (default /16)
As numbers
Hex 8C070000 · Integer 2349268992 to 2349277183
Reverse DNS zones
0.7.140.in-addr.arpa
1.7.140.in-addr.arpa
2.7.140.in-addr.arpa
3.7.140.in-addr.arpa
4.7.140.in-addr.arpa
5.7.140.in-addr.arpa
6.7.140.in-addr.arpa
7.7.140.in-addr.arpa
8.7.140.in-addr.arpa
9.7.140.in-addr.arpa
10.7.140.in-addr.arpa
11.7.140.in-addr.arpa
12.7.140.in-addr.arpa
13.7.140.in-addr.arpa
14.7.140.in-addr.arpa
15.7.140.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
Address10001100.00000111.00000000.00000000140.7.0.0
Subnet mask11111111.11111111.11100000.00000000255.255.224.0
Network10001100.00000111.00000000.00000000140.7.0.0
Broadcast10001100.00000111.00011111.11111111140.7.31.255
Split into smaller subnets/28
/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)

140.7.0.0/19 makes 512 subnets of /28; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1140.7.0.0/28140.7.0.1 to 140.7.0.14140.7.0.1514
2140.7.0.16/28140.7.0.17 to 140.7.0.30140.7.0.3114
3140.7.0.32/28140.7.0.33 to 140.7.0.46140.7.0.4714
4140.7.0.48/28140.7.0.49 to 140.7.0.62140.7.0.6314
5140.7.0.64/28140.7.0.65 to 140.7.0.78140.7.0.7914
6140.7.0.80/28140.7.0.81 to 140.7.0.94140.7.0.9514
7140.7.0.96/28140.7.0.97 to 140.7.0.110140.7.0.11114
8140.7.0.112/28140.7.0.113 to 140.7.0.126140.7.0.12714
9140.7.0.128/28140.7.0.129 to 140.7.0.142140.7.0.14314
10140.7.0.144/28140.7.0.145 to 140.7.0.158140.7.0.15914
11140.7.0.160/28140.7.0.161 to 140.7.0.174140.7.0.17514
12140.7.0.176/28140.7.0.177 to 140.7.0.190140.7.0.19114
13140.7.0.192/28140.7.0.193 to 140.7.0.206140.7.0.20714
14140.7.0.208/28140.7.0.209 to 140.7.0.222140.7.0.22314
15140.7.0.224/28140.7.0.225 to 140.7.0.238140.7.0.23914
16140.7.0.240/28140.7.0.241 to 140.7.0.254140.7.0.25514
17140.7.1.0/28140.7.1.1 to 140.7.1.14140.7.1.1514
18140.7.1.16/28140.7.1.17 to 140.7.1.30140.7.1.3114
19140.7.1.32/28140.7.1.33 to 140.7.1.46140.7.1.4714
20140.7.1.48/28140.7.1.49 to 140.7.1.62140.7.1.6314
21140.7.1.64/28140.7.1.65 to 140.7.1.78140.7.1.7914
22140.7.1.80/28140.7.1.81 to 140.7.1.94140.7.1.9514
23140.7.1.96/28140.7.1.97 to 140.7.1.110140.7.1.11114
24140.7.1.112/28140.7.1.113 to 140.7.1.126140.7.1.12714
25140.7.1.128/28140.7.1.129 to 140.7.1.142140.7.1.14314
26140.7.1.144/28140.7.1.145 to 140.7.1.158140.7.1.15914
27140.7.1.160/28140.7.1.161 to 140.7.1.174140.7.1.17514
28140.7.1.176/28140.7.1.177 to 140.7.1.190140.7.1.19114
29140.7.1.192/28140.7.1.193 to 140.7.1.206140.7.1.20714
30140.7.1.208/28140.7.1.209 to 140.7.1.222140.7.1.22314
31140.7.1.224/28140.7.1.225 to 140.7.1.238140.7.1.23914
32140.7.1.240/28140.7.1.241 to 140.7.1.254140.7.1.25514
33140.7.2.0/28140.7.2.1 to 140.7.2.14140.7.2.1514
34140.7.2.16/28140.7.2.17 to 140.7.2.30140.7.2.3114
35140.7.2.32/28140.7.2.33 to 140.7.2.46140.7.2.4714
36140.7.2.48/28140.7.2.49 to 140.7.2.62140.7.2.6314
37140.7.2.64/28140.7.2.65 to 140.7.2.78140.7.2.7914
38140.7.2.80/28140.7.2.81 to 140.7.2.94140.7.2.9514
39140.7.2.96/28140.7.2.97 to 140.7.2.110140.7.2.11114
40140.7.2.112/28140.7.2.113 to 140.7.2.126140.7.2.12714
41140.7.2.128/28140.7.2.129 to 140.7.2.142140.7.2.14314
42140.7.2.144/28140.7.2.145 to 140.7.2.158140.7.2.15914
43140.7.2.160/28140.7.2.161 to 140.7.2.174140.7.2.17514
44140.7.2.176/28140.7.2.177 to 140.7.2.190140.7.2.19114
45140.7.2.192/28140.7.2.193 to 140.7.2.206140.7.2.20714
46140.7.2.208/28140.7.2.209 to 140.7.2.222140.7.2.22314
47140.7.2.224/28140.7.2.225 to 140.7.2.238140.7.2.23914
48140.7.2.240/28140.7.2.241 to 140.7.2.254140.7.2.25514
49140.7.3.0/28140.7.3.1 to 140.7.3.14140.7.3.1514
50140.7.3.16/28140.7.3.17 to 140.7.3.30140.7.3.3114
51140.7.3.32/28140.7.3.33 to 140.7.3.46140.7.3.4714
52140.7.3.48/28140.7.3.49 to 140.7.3.62140.7.3.6314
53140.7.3.64/28140.7.3.65 to 140.7.3.78140.7.3.7914
54140.7.3.80/28140.7.3.81 to 140.7.3.94140.7.3.9514
55140.7.3.96/28140.7.3.97 to 140.7.3.110140.7.3.11114
56140.7.3.112/28140.7.3.113 to 140.7.3.126140.7.3.12714
57140.7.3.128/28140.7.3.129 to 140.7.3.142140.7.3.14314
58140.7.3.144/28140.7.3.145 to 140.7.3.158140.7.3.15914
59140.7.3.160/28140.7.3.161 to 140.7.3.174140.7.3.17514
60140.7.3.176/28140.7.3.177 to 140.7.3.190140.7.3.19114
61140.7.3.192/28140.7.3.193 to 140.7.3.206140.7.3.20714
62140.7.3.208/28140.7.3.209 to 140.7.3.222140.7.3.22314
63140.7.3.224/28140.7.3.225 to 140.7.3.238140.7.3.23914
64140.7.3.240/28140.7.3.241 to 140.7.3.254140.7.3.25514
65140.7.4.0/28140.7.4.1 to 140.7.4.14140.7.4.1514
66140.7.4.16/28140.7.4.17 to 140.7.4.30140.7.4.3114
67140.7.4.32/28140.7.4.33 to 140.7.4.46140.7.4.4714
68140.7.4.48/28140.7.4.49 to 140.7.4.62140.7.4.6314
69140.7.4.64/28140.7.4.65 to 140.7.4.78140.7.4.7914
70140.7.4.80/28140.7.4.81 to 140.7.4.94140.7.4.9514
71140.7.4.96/28140.7.4.97 to 140.7.4.110140.7.4.11114
72140.7.4.112/28140.7.4.113 to 140.7.4.126140.7.4.12714
73140.7.4.128/28140.7.4.129 to 140.7.4.142140.7.4.14314
74140.7.4.144/28140.7.4.145 to 140.7.4.158140.7.4.15914
75140.7.4.160/28140.7.4.161 to 140.7.4.174140.7.4.17514
76140.7.4.176/28140.7.4.177 to 140.7.4.190140.7.4.19114
77140.7.4.192/28140.7.4.193 to 140.7.4.206140.7.4.20714
78140.7.4.208/28140.7.4.209 to 140.7.4.222140.7.4.22314
79140.7.4.224/28140.7.4.225 to 140.7.4.238140.7.4.23914
80140.7.4.240/28140.7.4.241 to 140.7.4.254140.7.4.25514
81140.7.5.0/28140.7.5.1 to 140.7.5.14140.7.5.1514
82140.7.5.16/28140.7.5.17 to 140.7.5.30140.7.5.3114
83140.7.5.32/28140.7.5.33 to 140.7.5.46140.7.5.4714
84140.7.5.48/28140.7.5.49 to 140.7.5.62140.7.5.6314
85140.7.5.64/28140.7.5.65 to 140.7.5.78140.7.5.7914
86140.7.5.80/28140.7.5.81 to 140.7.5.94140.7.5.9514
87140.7.5.96/28140.7.5.97 to 140.7.5.110140.7.5.11114
88140.7.5.112/28140.7.5.113 to 140.7.5.126140.7.5.12714
89140.7.5.128/28140.7.5.129 to 140.7.5.142140.7.5.14314
90140.7.5.144/28140.7.5.145 to 140.7.5.158140.7.5.15914
91140.7.5.160/28140.7.5.161 to 140.7.5.174140.7.5.17514
92140.7.5.176/28140.7.5.177 to 140.7.5.190140.7.5.19114
93140.7.5.192/28140.7.5.193 to 140.7.5.206140.7.5.20714
94140.7.5.208/28140.7.5.209 to 140.7.5.222140.7.5.22314
95140.7.5.224/28140.7.5.225 to 140.7.5.238140.7.5.23914
96140.7.5.240/28140.7.5.241 to 140.7.5.254140.7.5.25514
97140.7.6.0/28140.7.6.1 to 140.7.6.14140.7.6.1514
98140.7.6.16/28140.7.6.17 to 140.7.6.30140.7.6.3114
99140.7.6.32/28140.7.6.33 to 140.7.6.46140.7.6.4714
100140.7.6.48/28140.7.6.49 to 140.7.6.62140.7.6.6314
101140.7.6.64/28140.7.6.65 to 140.7.6.78140.7.6.7914
102140.7.6.80/28140.7.6.81 to 140.7.6.94140.7.6.9514
103140.7.6.96/28140.7.6.97 to 140.7.6.110140.7.6.11114
104140.7.6.112/28140.7.6.113 to 140.7.6.126140.7.6.12714
105140.7.6.128/28140.7.6.129 to 140.7.6.142140.7.6.14314
106140.7.6.144/28140.7.6.145 to 140.7.6.158140.7.6.15914
107140.7.6.160/28140.7.6.161 to 140.7.6.174140.7.6.17514
108140.7.6.176/28140.7.6.177 to 140.7.6.190140.7.6.19114
109140.7.6.192/28140.7.6.193 to 140.7.6.206140.7.6.20714
110140.7.6.208/28140.7.6.209 to 140.7.6.222140.7.6.22314
111140.7.6.224/28140.7.6.225 to 140.7.6.238140.7.6.23914
112140.7.6.240/28140.7.6.241 to 140.7.6.254140.7.6.25514
113140.7.7.0/28140.7.7.1 to 140.7.7.14140.7.7.1514
114140.7.7.16/28140.7.7.17 to 140.7.7.30140.7.7.3114
115140.7.7.32/28140.7.7.33 to 140.7.7.46140.7.7.4714
116140.7.7.48/28140.7.7.49 to 140.7.7.62140.7.7.6314
117140.7.7.64/28140.7.7.65 to 140.7.7.78140.7.7.7914
118140.7.7.80/28140.7.7.81 to 140.7.7.94140.7.7.9514
119140.7.7.96/28140.7.7.97 to 140.7.7.110140.7.7.11114
120140.7.7.112/28140.7.7.113 to 140.7.7.126140.7.7.12714
121140.7.7.128/28140.7.7.129 to 140.7.7.142140.7.7.14314
122140.7.7.144/28140.7.7.145 to 140.7.7.158140.7.7.15914
123140.7.7.160/28140.7.7.161 to 140.7.7.174140.7.7.17514
124140.7.7.176/28140.7.7.177 to 140.7.7.190140.7.7.19114
125140.7.7.192/28140.7.7.193 to 140.7.7.206140.7.7.20714
126140.7.7.208/28140.7.7.209 to 140.7.7.222140.7.7.22314
127140.7.7.224/28140.7.7.225 to 140.7.7.238140.7.7.23914
128140.7.7.240/28140.7.7.241 to 140.7.7.254140.7.7.25514
129140.7.8.0/28140.7.8.1 to 140.7.8.14140.7.8.1514
130140.7.8.16/28140.7.8.17 to 140.7.8.30140.7.8.3114
131140.7.8.32/28140.7.8.33 to 140.7.8.46140.7.8.4714
132140.7.8.48/28140.7.8.49 to 140.7.8.62140.7.8.6314
133140.7.8.64/28140.7.8.65 to 140.7.8.78140.7.8.7914
134140.7.8.80/28140.7.8.81 to 140.7.8.94140.7.8.9514
135140.7.8.96/28140.7.8.97 to 140.7.8.110140.7.8.11114
136140.7.8.112/28140.7.8.113 to 140.7.8.126140.7.8.12714
137140.7.8.128/28140.7.8.129 to 140.7.8.142140.7.8.14314
138140.7.8.144/28140.7.8.145 to 140.7.8.158140.7.8.15914
139140.7.8.160/28140.7.8.161 to 140.7.8.174140.7.8.17514
140140.7.8.176/28140.7.8.177 to 140.7.8.190140.7.8.19114
141140.7.8.192/28140.7.8.193 to 140.7.8.206140.7.8.20714
142140.7.8.208/28140.7.8.209 to 140.7.8.222140.7.8.22314
143140.7.8.224/28140.7.8.225 to 140.7.8.238140.7.8.23914
144140.7.8.240/28140.7.8.241 to 140.7.8.254140.7.8.25514
145140.7.9.0/28140.7.9.1 to 140.7.9.14140.7.9.1514
146140.7.9.16/28140.7.9.17 to 140.7.9.30140.7.9.3114
147140.7.9.32/28140.7.9.33 to 140.7.9.46140.7.9.4714
148140.7.9.48/28140.7.9.49 to 140.7.9.62140.7.9.6314
149140.7.9.64/28140.7.9.65 to 140.7.9.78140.7.9.7914
150140.7.9.80/28140.7.9.81 to 140.7.9.94140.7.9.9514
151140.7.9.96/28140.7.9.97 to 140.7.9.110140.7.9.11114
152140.7.9.112/28140.7.9.113 to 140.7.9.126140.7.9.12714
153140.7.9.128/28140.7.9.129 to 140.7.9.142140.7.9.14314
154140.7.9.144/28140.7.9.145 to 140.7.9.158140.7.9.15914
155140.7.9.160/28140.7.9.161 to 140.7.9.174140.7.9.17514
156140.7.9.176/28140.7.9.177 to 140.7.9.190140.7.9.19114
157140.7.9.192/28140.7.9.193 to 140.7.9.206140.7.9.20714
158140.7.9.208/28140.7.9.209 to 140.7.9.222140.7.9.22314
159140.7.9.224/28140.7.9.225 to 140.7.9.238140.7.9.23914
160140.7.9.240/28140.7.9.241 to 140.7.9.254140.7.9.25514
161140.7.10.0/28140.7.10.1 to 140.7.10.14140.7.10.1514
162140.7.10.16/28140.7.10.17 to 140.7.10.30140.7.10.3114
163140.7.10.32/28140.7.10.33 to 140.7.10.46140.7.10.4714
164140.7.10.48/28140.7.10.49 to 140.7.10.62140.7.10.6314
165140.7.10.64/28140.7.10.65 to 140.7.10.78140.7.10.7914
166140.7.10.80/28140.7.10.81 to 140.7.10.94140.7.10.9514
167140.7.10.96/28140.7.10.97 to 140.7.10.110140.7.10.11114
168140.7.10.112/28140.7.10.113 to 140.7.10.126140.7.10.12714
169140.7.10.128/28140.7.10.129 to 140.7.10.142140.7.10.14314
170140.7.10.144/28140.7.10.145 to 140.7.10.158140.7.10.15914
171140.7.10.160/28140.7.10.161 to 140.7.10.174140.7.10.17514
172140.7.10.176/28140.7.10.177 to 140.7.10.190140.7.10.19114
173140.7.10.192/28140.7.10.193 to 140.7.10.206140.7.10.20714
174140.7.10.208/28140.7.10.209 to 140.7.10.222140.7.10.22314
175140.7.10.224/28140.7.10.225 to 140.7.10.238140.7.10.23914
176140.7.10.240/28140.7.10.241 to 140.7.10.254140.7.10.25514
177140.7.11.0/28140.7.11.1 to 140.7.11.14140.7.11.1514
178140.7.11.16/28140.7.11.17 to 140.7.11.30140.7.11.3114
179140.7.11.32/28140.7.11.33 to 140.7.11.46140.7.11.4714
180140.7.11.48/28140.7.11.49 to 140.7.11.62140.7.11.6314
181140.7.11.64/28140.7.11.65 to 140.7.11.78140.7.11.7914
182140.7.11.80/28140.7.11.81 to 140.7.11.94140.7.11.9514
183140.7.11.96/28140.7.11.97 to 140.7.11.110140.7.11.11114
184140.7.11.112/28140.7.11.113 to 140.7.11.126140.7.11.12714
185140.7.11.128/28140.7.11.129 to 140.7.11.142140.7.11.14314
186140.7.11.144/28140.7.11.145 to 140.7.11.158140.7.11.15914
187140.7.11.160/28140.7.11.161 to 140.7.11.174140.7.11.17514
188140.7.11.176/28140.7.11.177 to 140.7.11.190140.7.11.19114
189140.7.11.192/28140.7.11.193 to 140.7.11.206140.7.11.20714
190140.7.11.208/28140.7.11.209 to 140.7.11.222140.7.11.22314
191140.7.11.224/28140.7.11.225 to 140.7.11.238140.7.11.23914
192140.7.11.240/28140.7.11.241 to 140.7.11.254140.7.11.25514
193140.7.12.0/28140.7.12.1 to 140.7.12.14140.7.12.1514
194140.7.12.16/28140.7.12.17 to 140.7.12.30140.7.12.3114
195140.7.12.32/28140.7.12.33 to 140.7.12.46140.7.12.4714
196140.7.12.48/28140.7.12.49 to 140.7.12.62140.7.12.6314
197140.7.12.64/28140.7.12.65 to 140.7.12.78140.7.12.7914
198140.7.12.80/28140.7.12.81 to 140.7.12.94140.7.12.9514
199140.7.12.96/28140.7.12.97 to 140.7.12.110140.7.12.11114
200140.7.12.112/28140.7.12.113 to 140.7.12.126140.7.12.12714
201140.7.12.128/28140.7.12.129 to 140.7.12.142140.7.12.14314
202140.7.12.144/28140.7.12.145 to 140.7.12.158140.7.12.15914
203140.7.12.160/28140.7.12.161 to 140.7.12.174140.7.12.17514
204140.7.12.176/28140.7.12.177 to 140.7.12.190140.7.12.19114
205140.7.12.192/28140.7.12.193 to 140.7.12.206140.7.12.20714
206140.7.12.208/28140.7.12.209 to 140.7.12.222140.7.12.22314
207140.7.12.224/28140.7.12.225 to 140.7.12.238140.7.12.23914
208140.7.12.240/28140.7.12.241 to 140.7.12.254140.7.12.25514
209140.7.13.0/28140.7.13.1 to 140.7.13.14140.7.13.1514
210140.7.13.16/28140.7.13.17 to 140.7.13.30140.7.13.3114
211140.7.13.32/28140.7.13.33 to 140.7.13.46140.7.13.4714
212140.7.13.48/28140.7.13.49 to 140.7.13.62140.7.13.6314
213140.7.13.64/28140.7.13.65 to 140.7.13.78140.7.13.7914
214140.7.13.80/28140.7.13.81 to 140.7.13.94140.7.13.9514
215140.7.13.96/28140.7.13.97 to 140.7.13.110140.7.13.11114
216140.7.13.112/28140.7.13.113 to 140.7.13.126140.7.13.12714
217140.7.13.128/28140.7.13.129 to 140.7.13.142140.7.13.14314
218140.7.13.144/28140.7.13.145 to 140.7.13.158140.7.13.15914
219140.7.13.160/28140.7.13.161 to 140.7.13.174140.7.13.17514
220140.7.13.176/28140.7.13.177 to 140.7.13.190140.7.13.19114
221140.7.13.192/28140.7.13.193 to 140.7.13.206140.7.13.20714
222140.7.13.208/28140.7.13.209 to 140.7.13.222140.7.13.22314
223140.7.13.224/28140.7.13.225 to 140.7.13.238140.7.13.23914
224140.7.13.240/28140.7.13.241 to 140.7.13.254140.7.13.25514
225140.7.14.0/28140.7.14.1 to 140.7.14.14140.7.14.1514
226140.7.14.16/28140.7.14.17 to 140.7.14.30140.7.14.3114
227140.7.14.32/28140.7.14.33 to 140.7.14.46140.7.14.4714
228140.7.14.48/28140.7.14.49 to 140.7.14.62140.7.14.6314
229140.7.14.64/28140.7.14.65 to 140.7.14.78140.7.14.7914
230140.7.14.80/28140.7.14.81 to 140.7.14.94140.7.14.9514
231140.7.14.96/28140.7.14.97 to 140.7.14.110140.7.14.11114
232140.7.14.112/28140.7.14.113 to 140.7.14.126140.7.14.12714
233140.7.14.128/28140.7.14.129 to 140.7.14.142140.7.14.14314
234140.7.14.144/28140.7.14.145 to 140.7.14.158140.7.14.15914
235140.7.14.160/28140.7.14.161 to 140.7.14.174140.7.14.17514
236140.7.14.176/28140.7.14.177 to 140.7.14.190140.7.14.19114
237140.7.14.192/28140.7.14.193 to 140.7.14.206140.7.14.20714
238140.7.14.208/28140.7.14.209 to 140.7.14.222140.7.14.22314
239140.7.14.224/28140.7.14.225 to 140.7.14.238140.7.14.23914
240140.7.14.240/28140.7.14.241 to 140.7.14.254140.7.14.25514
241140.7.15.0/28140.7.15.1 to 140.7.15.14140.7.15.1514
242140.7.15.16/28140.7.15.17 to 140.7.15.30140.7.15.3114
243140.7.15.32/28140.7.15.33 to 140.7.15.46140.7.15.4714
244140.7.15.48/28140.7.15.49 to 140.7.15.62140.7.15.6314
245140.7.15.64/28140.7.15.65 to 140.7.15.78140.7.15.7914
246140.7.15.80/28140.7.15.81 to 140.7.15.94140.7.15.9514
247140.7.15.96/28140.7.15.97 to 140.7.15.110140.7.15.11114
248140.7.15.112/28140.7.15.113 to 140.7.15.126140.7.15.12714
249140.7.15.128/28140.7.15.129 to 140.7.15.142140.7.15.14314
250140.7.15.144/28140.7.15.145 to 140.7.15.158140.7.15.15914
251140.7.15.160/28140.7.15.161 to 140.7.15.174140.7.15.17514
252140.7.15.176/28140.7.15.177 to 140.7.15.190140.7.15.19114
253140.7.15.192/28140.7.15.193 to 140.7.15.206140.7.15.20714
254140.7.15.208/28140.7.15.209 to 140.7.15.222140.7.15.22314
255140.7.15.224/28140.7.15.225 to 140.7.15.238140.7.15.23914
256140.7.15.240/28140.7.15.241 to 140.7.15.254140.7.15.25514

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.