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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.

Network178.4.64.0/19
Usable hosts8,190
Subnet mask255.255.224.0
Addresses8,192
Network address
178.4.64.0
Broadcast address
178.4.95.255
First usable
178.4.64.1
Last usable
178.4.95.254
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 B2044000 · Integer 2986622976 to 2986631167
Reverse DNS zones
64.4.178.in-addr.arpa
65.4.178.in-addr.arpa
66.4.178.in-addr.arpa
67.4.178.in-addr.arpa
68.4.178.in-addr.arpa
69.4.178.in-addr.arpa
70.4.178.in-addr.arpa
71.4.178.in-addr.arpa
72.4.178.in-addr.arpa
73.4.178.in-addr.arpa
74.4.178.in-addr.arpa
75.4.178.in-addr.arpa
76.4.178.in-addr.arpa
77.4.178.in-addr.arpa
78.4.178.in-addr.arpa
79.4.178.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
Address10110010.00000100.01000000.00000000178.4.64.0
Subnet mask11111111.11111111.11100000.00000000255.255.224.0
Network10110010.00000100.01000000.00000000178.4.64.0
Broadcast10110010.00000100.01011111.11111111178.4.95.255
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)

178.4.64.0/19 makes 512 subnets of /28; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1178.4.64.0/28178.4.64.1 to 178.4.64.14178.4.64.1514
2178.4.64.16/28178.4.64.17 to 178.4.64.30178.4.64.3114
3178.4.64.32/28178.4.64.33 to 178.4.64.46178.4.64.4714
4178.4.64.48/28178.4.64.49 to 178.4.64.62178.4.64.6314
5178.4.64.64/28178.4.64.65 to 178.4.64.78178.4.64.7914
6178.4.64.80/28178.4.64.81 to 178.4.64.94178.4.64.9514
7178.4.64.96/28178.4.64.97 to 178.4.64.110178.4.64.11114
8178.4.64.112/28178.4.64.113 to 178.4.64.126178.4.64.12714
9178.4.64.128/28178.4.64.129 to 178.4.64.142178.4.64.14314
10178.4.64.144/28178.4.64.145 to 178.4.64.158178.4.64.15914
11178.4.64.160/28178.4.64.161 to 178.4.64.174178.4.64.17514
12178.4.64.176/28178.4.64.177 to 178.4.64.190178.4.64.19114
13178.4.64.192/28178.4.64.193 to 178.4.64.206178.4.64.20714
14178.4.64.208/28178.4.64.209 to 178.4.64.222178.4.64.22314
15178.4.64.224/28178.4.64.225 to 178.4.64.238178.4.64.23914
16178.4.64.240/28178.4.64.241 to 178.4.64.254178.4.64.25514
17178.4.65.0/28178.4.65.1 to 178.4.65.14178.4.65.1514
18178.4.65.16/28178.4.65.17 to 178.4.65.30178.4.65.3114
19178.4.65.32/28178.4.65.33 to 178.4.65.46178.4.65.4714
20178.4.65.48/28178.4.65.49 to 178.4.65.62178.4.65.6314
21178.4.65.64/28178.4.65.65 to 178.4.65.78178.4.65.7914
22178.4.65.80/28178.4.65.81 to 178.4.65.94178.4.65.9514
23178.4.65.96/28178.4.65.97 to 178.4.65.110178.4.65.11114
24178.4.65.112/28178.4.65.113 to 178.4.65.126178.4.65.12714
25178.4.65.128/28178.4.65.129 to 178.4.65.142178.4.65.14314
26178.4.65.144/28178.4.65.145 to 178.4.65.158178.4.65.15914
27178.4.65.160/28178.4.65.161 to 178.4.65.174178.4.65.17514
28178.4.65.176/28178.4.65.177 to 178.4.65.190178.4.65.19114
29178.4.65.192/28178.4.65.193 to 178.4.65.206178.4.65.20714
30178.4.65.208/28178.4.65.209 to 178.4.65.222178.4.65.22314
31178.4.65.224/28178.4.65.225 to 178.4.65.238178.4.65.23914
32178.4.65.240/28178.4.65.241 to 178.4.65.254178.4.65.25514
33178.4.66.0/28178.4.66.1 to 178.4.66.14178.4.66.1514
34178.4.66.16/28178.4.66.17 to 178.4.66.30178.4.66.3114
35178.4.66.32/28178.4.66.33 to 178.4.66.46178.4.66.4714
36178.4.66.48/28178.4.66.49 to 178.4.66.62178.4.66.6314
37178.4.66.64/28178.4.66.65 to 178.4.66.78178.4.66.7914
38178.4.66.80/28178.4.66.81 to 178.4.66.94178.4.66.9514
39178.4.66.96/28178.4.66.97 to 178.4.66.110178.4.66.11114
40178.4.66.112/28178.4.66.113 to 178.4.66.126178.4.66.12714
41178.4.66.128/28178.4.66.129 to 178.4.66.142178.4.66.14314
42178.4.66.144/28178.4.66.145 to 178.4.66.158178.4.66.15914
43178.4.66.160/28178.4.66.161 to 178.4.66.174178.4.66.17514
44178.4.66.176/28178.4.66.177 to 178.4.66.190178.4.66.19114
45178.4.66.192/28178.4.66.193 to 178.4.66.206178.4.66.20714
46178.4.66.208/28178.4.66.209 to 178.4.66.222178.4.66.22314
47178.4.66.224/28178.4.66.225 to 178.4.66.238178.4.66.23914
48178.4.66.240/28178.4.66.241 to 178.4.66.254178.4.66.25514
49178.4.67.0/28178.4.67.1 to 178.4.67.14178.4.67.1514
50178.4.67.16/28178.4.67.17 to 178.4.67.30178.4.67.3114
51178.4.67.32/28178.4.67.33 to 178.4.67.46178.4.67.4714
52178.4.67.48/28178.4.67.49 to 178.4.67.62178.4.67.6314
53178.4.67.64/28178.4.67.65 to 178.4.67.78178.4.67.7914
54178.4.67.80/28178.4.67.81 to 178.4.67.94178.4.67.9514
55178.4.67.96/28178.4.67.97 to 178.4.67.110178.4.67.11114
56178.4.67.112/28178.4.67.113 to 178.4.67.126178.4.67.12714
57178.4.67.128/28178.4.67.129 to 178.4.67.142178.4.67.14314
58178.4.67.144/28178.4.67.145 to 178.4.67.158178.4.67.15914
59178.4.67.160/28178.4.67.161 to 178.4.67.174178.4.67.17514
60178.4.67.176/28178.4.67.177 to 178.4.67.190178.4.67.19114
61178.4.67.192/28178.4.67.193 to 178.4.67.206178.4.67.20714
62178.4.67.208/28178.4.67.209 to 178.4.67.222178.4.67.22314
63178.4.67.224/28178.4.67.225 to 178.4.67.238178.4.67.23914
64178.4.67.240/28178.4.67.241 to 178.4.67.254178.4.67.25514
65178.4.68.0/28178.4.68.1 to 178.4.68.14178.4.68.1514
66178.4.68.16/28178.4.68.17 to 178.4.68.30178.4.68.3114
67178.4.68.32/28178.4.68.33 to 178.4.68.46178.4.68.4714
68178.4.68.48/28178.4.68.49 to 178.4.68.62178.4.68.6314
69178.4.68.64/28178.4.68.65 to 178.4.68.78178.4.68.7914
70178.4.68.80/28178.4.68.81 to 178.4.68.94178.4.68.9514
71178.4.68.96/28178.4.68.97 to 178.4.68.110178.4.68.11114
72178.4.68.112/28178.4.68.113 to 178.4.68.126178.4.68.12714
73178.4.68.128/28178.4.68.129 to 178.4.68.142178.4.68.14314
74178.4.68.144/28178.4.68.145 to 178.4.68.158178.4.68.15914
75178.4.68.160/28178.4.68.161 to 178.4.68.174178.4.68.17514
76178.4.68.176/28178.4.68.177 to 178.4.68.190178.4.68.19114
77178.4.68.192/28178.4.68.193 to 178.4.68.206178.4.68.20714
78178.4.68.208/28178.4.68.209 to 178.4.68.222178.4.68.22314
79178.4.68.224/28178.4.68.225 to 178.4.68.238178.4.68.23914
80178.4.68.240/28178.4.68.241 to 178.4.68.254178.4.68.25514
81178.4.69.0/28178.4.69.1 to 178.4.69.14178.4.69.1514
82178.4.69.16/28178.4.69.17 to 178.4.69.30178.4.69.3114
83178.4.69.32/28178.4.69.33 to 178.4.69.46178.4.69.4714
84178.4.69.48/28178.4.69.49 to 178.4.69.62178.4.69.6314
85178.4.69.64/28178.4.69.65 to 178.4.69.78178.4.69.7914
86178.4.69.80/28178.4.69.81 to 178.4.69.94178.4.69.9514
87178.4.69.96/28178.4.69.97 to 178.4.69.110178.4.69.11114
88178.4.69.112/28178.4.69.113 to 178.4.69.126178.4.69.12714
89178.4.69.128/28178.4.69.129 to 178.4.69.142178.4.69.14314
90178.4.69.144/28178.4.69.145 to 178.4.69.158178.4.69.15914
91178.4.69.160/28178.4.69.161 to 178.4.69.174178.4.69.17514
92178.4.69.176/28178.4.69.177 to 178.4.69.190178.4.69.19114
93178.4.69.192/28178.4.69.193 to 178.4.69.206178.4.69.20714
94178.4.69.208/28178.4.69.209 to 178.4.69.222178.4.69.22314
95178.4.69.224/28178.4.69.225 to 178.4.69.238178.4.69.23914
96178.4.69.240/28178.4.69.241 to 178.4.69.254178.4.69.25514
97178.4.70.0/28178.4.70.1 to 178.4.70.14178.4.70.1514
98178.4.70.16/28178.4.70.17 to 178.4.70.30178.4.70.3114
99178.4.70.32/28178.4.70.33 to 178.4.70.46178.4.70.4714
100178.4.70.48/28178.4.70.49 to 178.4.70.62178.4.70.6314
101178.4.70.64/28178.4.70.65 to 178.4.70.78178.4.70.7914
102178.4.70.80/28178.4.70.81 to 178.4.70.94178.4.70.9514
103178.4.70.96/28178.4.70.97 to 178.4.70.110178.4.70.11114
104178.4.70.112/28178.4.70.113 to 178.4.70.126178.4.70.12714
105178.4.70.128/28178.4.70.129 to 178.4.70.142178.4.70.14314
106178.4.70.144/28178.4.70.145 to 178.4.70.158178.4.70.15914
107178.4.70.160/28178.4.70.161 to 178.4.70.174178.4.70.17514
108178.4.70.176/28178.4.70.177 to 178.4.70.190178.4.70.19114
109178.4.70.192/28178.4.70.193 to 178.4.70.206178.4.70.20714
110178.4.70.208/28178.4.70.209 to 178.4.70.222178.4.70.22314
111178.4.70.224/28178.4.70.225 to 178.4.70.238178.4.70.23914
112178.4.70.240/28178.4.70.241 to 178.4.70.254178.4.70.25514
113178.4.71.0/28178.4.71.1 to 178.4.71.14178.4.71.1514
114178.4.71.16/28178.4.71.17 to 178.4.71.30178.4.71.3114
115178.4.71.32/28178.4.71.33 to 178.4.71.46178.4.71.4714
116178.4.71.48/28178.4.71.49 to 178.4.71.62178.4.71.6314
117178.4.71.64/28178.4.71.65 to 178.4.71.78178.4.71.7914
118178.4.71.80/28178.4.71.81 to 178.4.71.94178.4.71.9514
119178.4.71.96/28178.4.71.97 to 178.4.71.110178.4.71.11114
120178.4.71.112/28178.4.71.113 to 178.4.71.126178.4.71.12714
121178.4.71.128/28178.4.71.129 to 178.4.71.142178.4.71.14314
122178.4.71.144/28178.4.71.145 to 178.4.71.158178.4.71.15914
123178.4.71.160/28178.4.71.161 to 178.4.71.174178.4.71.17514
124178.4.71.176/28178.4.71.177 to 178.4.71.190178.4.71.19114
125178.4.71.192/28178.4.71.193 to 178.4.71.206178.4.71.20714
126178.4.71.208/28178.4.71.209 to 178.4.71.222178.4.71.22314
127178.4.71.224/28178.4.71.225 to 178.4.71.238178.4.71.23914
128178.4.71.240/28178.4.71.241 to 178.4.71.254178.4.71.25514
129178.4.72.0/28178.4.72.1 to 178.4.72.14178.4.72.1514
130178.4.72.16/28178.4.72.17 to 178.4.72.30178.4.72.3114
131178.4.72.32/28178.4.72.33 to 178.4.72.46178.4.72.4714
132178.4.72.48/28178.4.72.49 to 178.4.72.62178.4.72.6314
133178.4.72.64/28178.4.72.65 to 178.4.72.78178.4.72.7914
134178.4.72.80/28178.4.72.81 to 178.4.72.94178.4.72.9514
135178.4.72.96/28178.4.72.97 to 178.4.72.110178.4.72.11114
136178.4.72.112/28178.4.72.113 to 178.4.72.126178.4.72.12714
137178.4.72.128/28178.4.72.129 to 178.4.72.142178.4.72.14314
138178.4.72.144/28178.4.72.145 to 178.4.72.158178.4.72.15914
139178.4.72.160/28178.4.72.161 to 178.4.72.174178.4.72.17514
140178.4.72.176/28178.4.72.177 to 178.4.72.190178.4.72.19114
141178.4.72.192/28178.4.72.193 to 178.4.72.206178.4.72.20714
142178.4.72.208/28178.4.72.209 to 178.4.72.222178.4.72.22314
143178.4.72.224/28178.4.72.225 to 178.4.72.238178.4.72.23914
144178.4.72.240/28178.4.72.241 to 178.4.72.254178.4.72.25514
145178.4.73.0/28178.4.73.1 to 178.4.73.14178.4.73.1514
146178.4.73.16/28178.4.73.17 to 178.4.73.30178.4.73.3114
147178.4.73.32/28178.4.73.33 to 178.4.73.46178.4.73.4714
148178.4.73.48/28178.4.73.49 to 178.4.73.62178.4.73.6314
149178.4.73.64/28178.4.73.65 to 178.4.73.78178.4.73.7914
150178.4.73.80/28178.4.73.81 to 178.4.73.94178.4.73.9514
151178.4.73.96/28178.4.73.97 to 178.4.73.110178.4.73.11114
152178.4.73.112/28178.4.73.113 to 178.4.73.126178.4.73.12714
153178.4.73.128/28178.4.73.129 to 178.4.73.142178.4.73.14314
154178.4.73.144/28178.4.73.145 to 178.4.73.158178.4.73.15914
155178.4.73.160/28178.4.73.161 to 178.4.73.174178.4.73.17514
156178.4.73.176/28178.4.73.177 to 178.4.73.190178.4.73.19114
157178.4.73.192/28178.4.73.193 to 178.4.73.206178.4.73.20714
158178.4.73.208/28178.4.73.209 to 178.4.73.222178.4.73.22314
159178.4.73.224/28178.4.73.225 to 178.4.73.238178.4.73.23914
160178.4.73.240/28178.4.73.241 to 178.4.73.254178.4.73.25514
161178.4.74.0/28178.4.74.1 to 178.4.74.14178.4.74.1514
162178.4.74.16/28178.4.74.17 to 178.4.74.30178.4.74.3114
163178.4.74.32/28178.4.74.33 to 178.4.74.46178.4.74.4714
164178.4.74.48/28178.4.74.49 to 178.4.74.62178.4.74.6314
165178.4.74.64/28178.4.74.65 to 178.4.74.78178.4.74.7914
166178.4.74.80/28178.4.74.81 to 178.4.74.94178.4.74.9514
167178.4.74.96/28178.4.74.97 to 178.4.74.110178.4.74.11114
168178.4.74.112/28178.4.74.113 to 178.4.74.126178.4.74.12714
169178.4.74.128/28178.4.74.129 to 178.4.74.142178.4.74.14314
170178.4.74.144/28178.4.74.145 to 178.4.74.158178.4.74.15914
171178.4.74.160/28178.4.74.161 to 178.4.74.174178.4.74.17514
172178.4.74.176/28178.4.74.177 to 178.4.74.190178.4.74.19114
173178.4.74.192/28178.4.74.193 to 178.4.74.206178.4.74.20714
174178.4.74.208/28178.4.74.209 to 178.4.74.222178.4.74.22314
175178.4.74.224/28178.4.74.225 to 178.4.74.238178.4.74.23914
176178.4.74.240/28178.4.74.241 to 178.4.74.254178.4.74.25514
177178.4.75.0/28178.4.75.1 to 178.4.75.14178.4.75.1514
178178.4.75.16/28178.4.75.17 to 178.4.75.30178.4.75.3114
179178.4.75.32/28178.4.75.33 to 178.4.75.46178.4.75.4714
180178.4.75.48/28178.4.75.49 to 178.4.75.62178.4.75.6314
181178.4.75.64/28178.4.75.65 to 178.4.75.78178.4.75.7914
182178.4.75.80/28178.4.75.81 to 178.4.75.94178.4.75.9514
183178.4.75.96/28178.4.75.97 to 178.4.75.110178.4.75.11114
184178.4.75.112/28178.4.75.113 to 178.4.75.126178.4.75.12714
185178.4.75.128/28178.4.75.129 to 178.4.75.142178.4.75.14314
186178.4.75.144/28178.4.75.145 to 178.4.75.158178.4.75.15914
187178.4.75.160/28178.4.75.161 to 178.4.75.174178.4.75.17514
188178.4.75.176/28178.4.75.177 to 178.4.75.190178.4.75.19114
189178.4.75.192/28178.4.75.193 to 178.4.75.206178.4.75.20714
190178.4.75.208/28178.4.75.209 to 178.4.75.222178.4.75.22314
191178.4.75.224/28178.4.75.225 to 178.4.75.238178.4.75.23914
192178.4.75.240/28178.4.75.241 to 178.4.75.254178.4.75.25514
193178.4.76.0/28178.4.76.1 to 178.4.76.14178.4.76.1514
194178.4.76.16/28178.4.76.17 to 178.4.76.30178.4.76.3114
195178.4.76.32/28178.4.76.33 to 178.4.76.46178.4.76.4714
196178.4.76.48/28178.4.76.49 to 178.4.76.62178.4.76.6314
197178.4.76.64/28178.4.76.65 to 178.4.76.78178.4.76.7914
198178.4.76.80/28178.4.76.81 to 178.4.76.94178.4.76.9514
199178.4.76.96/28178.4.76.97 to 178.4.76.110178.4.76.11114
200178.4.76.112/28178.4.76.113 to 178.4.76.126178.4.76.12714
201178.4.76.128/28178.4.76.129 to 178.4.76.142178.4.76.14314
202178.4.76.144/28178.4.76.145 to 178.4.76.158178.4.76.15914
203178.4.76.160/28178.4.76.161 to 178.4.76.174178.4.76.17514
204178.4.76.176/28178.4.76.177 to 178.4.76.190178.4.76.19114
205178.4.76.192/28178.4.76.193 to 178.4.76.206178.4.76.20714
206178.4.76.208/28178.4.76.209 to 178.4.76.222178.4.76.22314
207178.4.76.224/28178.4.76.225 to 178.4.76.238178.4.76.23914
208178.4.76.240/28178.4.76.241 to 178.4.76.254178.4.76.25514
209178.4.77.0/28178.4.77.1 to 178.4.77.14178.4.77.1514
210178.4.77.16/28178.4.77.17 to 178.4.77.30178.4.77.3114
211178.4.77.32/28178.4.77.33 to 178.4.77.46178.4.77.4714
212178.4.77.48/28178.4.77.49 to 178.4.77.62178.4.77.6314
213178.4.77.64/28178.4.77.65 to 178.4.77.78178.4.77.7914
214178.4.77.80/28178.4.77.81 to 178.4.77.94178.4.77.9514
215178.4.77.96/28178.4.77.97 to 178.4.77.110178.4.77.11114
216178.4.77.112/28178.4.77.113 to 178.4.77.126178.4.77.12714
217178.4.77.128/28178.4.77.129 to 178.4.77.142178.4.77.14314
218178.4.77.144/28178.4.77.145 to 178.4.77.158178.4.77.15914
219178.4.77.160/28178.4.77.161 to 178.4.77.174178.4.77.17514
220178.4.77.176/28178.4.77.177 to 178.4.77.190178.4.77.19114
221178.4.77.192/28178.4.77.193 to 178.4.77.206178.4.77.20714
222178.4.77.208/28178.4.77.209 to 178.4.77.222178.4.77.22314
223178.4.77.224/28178.4.77.225 to 178.4.77.238178.4.77.23914
224178.4.77.240/28178.4.77.241 to 178.4.77.254178.4.77.25514
225178.4.78.0/28178.4.78.1 to 178.4.78.14178.4.78.1514
226178.4.78.16/28178.4.78.17 to 178.4.78.30178.4.78.3114
227178.4.78.32/28178.4.78.33 to 178.4.78.46178.4.78.4714
228178.4.78.48/28178.4.78.49 to 178.4.78.62178.4.78.6314
229178.4.78.64/28178.4.78.65 to 178.4.78.78178.4.78.7914
230178.4.78.80/28178.4.78.81 to 178.4.78.94178.4.78.9514
231178.4.78.96/28178.4.78.97 to 178.4.78.110178.4.78.11114
232178.4.78.112/28178.4.78.113 to 178.4.78.126178.4.78.12714
233178.4.78.128/28178.4.78.129 to 178.4.78.142178.4.78.14314
234178.4.78.144/28178.4.78.145 to 178.4.78.158178.4.78.15914
235178.4.78.160/28178.4.78.161 to 178.4.78.174178.4.78.17514
236178.4.78.176/28178.4.78.177 to 178.4.78.190178.4.78.19114
237178.4.78.192/28178.4.78.193 to 178.4.78.206178.4.78.20714
238178.4.78.208/28178.4.78.209 to 178.4.78.222178.4.78.22314
239178.4.78.224/28178.4.78.225 to 178.4.78.238178.4.78.23914
240178.4.78.240/28178.4.78.241 to 178.4.78.254178.4.78.25514
241178.4.79.0/28178.4.79.1 to 178.4.79.14178.4.79.1514
242178.4.79.16/28178.4.79.17 to 178.4.79.30178.4.79.3114
243178.4.79.32/28178.4.79.33 to 178.4.79.46178.4.79.4714
244178.4.79.48/28178.4.79.49 to 178.4.79.62178.4.79.6314
245178.4.79.64/28178.4.79.65 to 178.4.79.78178.4.79.7914
246178.4.79.80/28178.4.79.81 to 178.4.79.94178.4.79.9514
247178.4.79.96/28178.4.79.97 to 178.4.79.110178.4.79.11114
248178.4.79.112/28178.4.79.113 to 178.4.79.126178.4.79.12714
249178.4.79.128/28178.4.79.129 to 178.4.79.142178.4.79.14314
250178.4.79.144/28178.4.79.145 to 178.4.79.158178.4.79.15914
251178.4.79.160/28178.4.79.161 to 178.4.79.174178.4.79.17514
252178.4.79.176/28178.4.79.177 to 178.4.79.190178.4.79.19114
253178.4.79.192/28178.4.79.193 to 178.4.79.206178.4.79.20714
254178.4.79.208/28178.4.79.209 to 178.4.79.222178.4.79.22314
255178.4.79.224/28178.4.79.225 to 178.4.79.238178.4.79.23914
256178.4.79.240/28178.4.79.241 to 178.4.79.254178.4.79.25514

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.