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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.

Network244.78.0.0/17
Usable hosts32,766
Subnet mask255.255.128.0
Addresses32,768
Network address
244.78.0.0
Broadcast address
244.78.127.255
First usable
244.78.0.1
Last usable
244.78.127.254
Usable hosts
32,766 (32,768 less the network and broadcast addresses)
Subnet mask
255.255.128.0
Wildcard mask
0.0.127.255 (Cisco ACLs, OSPF)
Prefix length
/17
Type
Reserved 240.0.0.0/4
Future use; not usable on most systems
Old class
E (reserved)
As numbers
Hex F44E0000 · Integer 4098752512 to 4098785279
Reverse DNS zones
0.78.244.in-addr.arpa
1.78.244.in-addr.arpa
2.78.244.in-addr.arpa
3.78.244.in-addr.arpa
4.78.244.in-addr.arpa
5.78.244.in-addr.arpa
6.78.244.in-addr.arpa
7.78.244.in-addr.arpa
8.78.244.in-addr.arpa
9.78.244.in-addr.arpa
10.78.244.in-addr.arpa
11.78.244.in-addr.arpa
12.78.244.in-addr.arpa
13.78.244.in-addr.arpa
14.78.244.in-addr.arpa
15.78.244.in-addr.arpa
and 112 more
/17 is not on a 8-bit boundary, so it takes 128 /24 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address11110100.01001110.00000000.00000000244.78.0.0
Subnet mask11111111.11111111.10000000.00000000255.255.128.0
Network11110100.01001110.00000000.00000000244.78.0.0
Broadcast11110100.01001110.01111111.11111111244.78.127.255
Split into smaller subnets/28
/18 (2)/19 (4)/20 (8)/21 (16)/22 (32)/23 (64)/24 (128)/25 (256)/26 (512)/27 (1,024)/28 (2,048)/29 (4,096)

244.78.0.0/17 makes 2,048 subnets of /28; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1244.78.0.0/28244.78.0.1 to 244.78.0.14244.78.0.1514
2244.78.0.16/28244.78.0.17 to 244.78.0.30244.78.0.3114
3244.78.0.32/28244.78.0.33 to 244.78.0.46244.78.0.4714
4244.78.0.48/28244.78.0.49 to 244.78.0.62244.78.0.6314
5244.78.0.64/28244.78.0.65 to 244.78.0.78244.78.0.7914
6244.78.0.80/28244.78.0.81 to 244.78.0.94244.78.0.9514
7244.78.0.96/28244.78.0.97 to 244.78.0.110244.78.0.11114
8244.78.0.112/28244.78.0.113 to 244.78.0.126244.78.0.12714
9244.78.0.128/28244.78.0.129 to 244.78.0.142244.78.0.14314
10244.78.0.144/28244.78.0.145 to 244.78.0.158244.78.0.15914
11244.78.0.160/28244.78.0.161 to 244.78.0.174244.78.0.17514
12244.78.0.176/28244.78.0.177 to 244.78.0.190244.78.0.19114
13244.78.0.192/28244.78.0.193 to 244.78.0.206244.78.0.20714
14244.78.0.208/28244.78.0.209 to 244.78.0.222244.78.0.22314
15244.78.0.224/28244.78.0.225 to 244.78.0.238244.78.0.23914
16244.78.0.240/28244.78.0.241 to 244.78.0.254244.78.0.25514
17244.78.1.0/28244.78.1.1 to 244.78.1.14244.78.1.1514
18244.78.1.16/28244.78.1.17 to 244.78.1.30244.78.1.3114
19244.78.1.32/28244.78.1.33 to 244.78.1.46244.78.1.4714
20244.78.1.48/28244.78.1.49 to 244.78.1.62244.78.1.6314
21244.78.1.64/28244.78.1.65 to 244.78.1.78244.78.1.7914
22244.78.1.80/28244.78.1.81 to 244.78.1.94244.78.1.9514
23244.78.1.96/28244.78.1.97 to 244.78.1.110244.78.1.11114
24244.78.1.112/28244.78.1.113 to 244.78.1.126244.78.1.12714
25244.78.1.128/28244.78.1.129 to 244.78.1.142244.78.1.14314
26244.78.1.144/28244.78.1.145 to 244.78.1.158244.78.1.15914
27244.78.1.160/28244.78.1.161 to 244.78.1.174244.78.1.17514
28244.78.1.176/28244.78.1.177 to 244.78.1.190244.78.1.19114
29244.78.1.192/28244.78.1.193 to 244.78.1.206244.78.1.20714
30244.78.1.208/28244.78.1.209 to 244.78.1.222244.78.1.22314
31244.78.1.224/28244.78.1.225 to 244.78.1.238244.78.1.23914
32244.78.1.240/28244.78.1.241 to 244.78.1.254244.78.1.25514
33244.78.2.0/28244.78.2.1 to 244.78.2.14244.78.2.1514
34244.78.2.16/28244.78.2.17 to 244.78.2.30244.78.2.3114
35244.78.2.32/28244.78.2.33 to 244.78.2.46244.78.2.4714
36244.78.2.48/28244.78.2.49 to 244.78.2.62244.78.2.6314
37244.78.2.64/28244.78.2.65 to 244.78.2.78244.78.2.7914
38244.78.2.80/28244.78.2.81 to 244.78.2.94244.78.2.9514
39244.78.2.96/28244.78.2.97 to 244.78.2.110244.78.2.11114
40244.78.2.112/28244.78.2.113 to 244.78.2.126244.78.2.12714
41244.78.2.128/28244.78.2.129 to 244.78.2.142244.78.2.14314
42244.78.2.144/28244.78.2.145 to 244.78.2.158244.78.2.15914
43244.78.2.160/28244.78.2.161 to 244.78.2.174244.78.2.17514
44244.78.2.176/28244.78.2.177 to 244.78.2.190244.78.2.19114
45244.78.2.192/28244.78.2.193 to 244.78.2.206244.78.2.20714
46244.78.2.208/28244.78.2.209 to 244.78.2.222244.78.2.22314
47244.78.2.224/28244.78.2.225 to 244.78.2.238244.78.2.23914
48244.78.2.240/28244.78.2.241 to 244.78.2.254244.78.2.25514
49244.78.3.0/28244.78.3.1 to 244.78.3.14244.78.3.1514
50244.78.3.16/28244.78.3.17 to 244.78.3.30244.78.3.3114
51244.78.3.32/28244.78.3.33 to 244.78.3.46244.78.3.4714
52244.78.3.48/28244.78.3.49 to 244.78.3.62244.78.3.6314
53244.78.3.64/28244.78.3.65 to 244.78.3.78244.78.3.7914
54244.78.3.80/28244.78.3.81 to 244.78.3.94244.78.3.9514
55244.78.3.96/28244.78.3.97 to 244.78.3.110244.78.3.11114
56244.78.3.112/28244.78.3.113 to 244.78.3.126244.78.3.12714
57244.78.3.128/28244.78.3.129 to 244.78.3.142244.78.3.14314
58244.78.3.144/28244.78.3.145 to 244.78.3.158244.78.3.15914
59244.78.3.160/28244.78.3.161 to 244.78.3.174244.78.3.17514
60244.78.3.176/28244.78.3.177 to 244.78.3.190244.78.3.19114
61244.78.3.192/28244.78.3.193 to 244.78.3.206244.78.3.20714
62244.78.3.208/28244.78.3.209 to 244.78.3.222244.78.3.22314
63244.78.3.224/28244.78.3.225 to 244.78.3.238244.78.3.23914
64244.78.3.240/28244.78.3.241 to 244.78.3.254244.78.3.25514
65244.78.4.0/28244.78.4.1 to 244.78.4.14244.78.4.1514
66244.78.4.16/28244.78.4.17 to 244.78.4.30244.78.4.3114
67244.78.4.32/28244.78.4.33 to 244.78.4.46244.78.4.4714
68244.78.4.48/28244.78.4.49 to 244.78.4.62244.78.4.6314
69244.78.4.64/28244.78.4.65 to 244.78.4.78244.78.4.7914
70244.78.4.80/28244.78.4.81 to 244.78.4.94244.78.4.9514
71244.78.4.96/28244.78.4.97 to 244.78.4.110244.78.4.11114
72244.78.4.112/28244.78.4.113 to 244.78.4.126244.78.4.12714
73244.78.4.128/28244.78.4.129 to 244.78.4.142244.78.4.14314
74244.78.4.144/28244.78.4.145 to 244.78.4.158244.78.4.15914
75244.78.4.160/28244.78.4.161 to 244.78.4.174244.78.4.17514
76244.78.4.176/28244.78.4.177 to 244.78.4.190244.78.4.19114
77244.78.4.192/28244.78.4.193 to 244.78.4.206244.78.4.20714
78244.78.4.208/28244.78.4.209 to 244.78.4.222244.78.4.22314
79244.78.4.224/28244.78.4.225 to 244.78.4.238244.78.4.23914
80244.78.4.240/28244.78.4.241 to 244.78.4.254244.78.4.25514
81244.78.5.0/28244.78.5.1 to 244.78.5.14244.78.5.1514
82244.78.5.16/28244.78.5.17 to 244.78.5.30244.78.5.3114
83244.78.5.32/28244.78.5.33 to 244.78.5.46244.78.5.4714
84244.78.5.48/28244.78.5.49 to 244.78.5.62244.78.5.6314
85244.78.5.64/28244.78.5.65 to 244.78.5.78244.78.5.7914
86244.78.5.80/28244.78.5.81 to 244.78.5.94244.78.5.9514
87244.78.5.96/28244.78.5.97 to 244.78.5.110244.78.5.11114
88244.78.5.112/28244.78.5.113 to 244.78.5.126244.78.5.12714
89244.78.5.128/28244.78.5.129 to 244.78.5.142244.78.5.14314
90244.78.5.144/28244.78.5.145 to 244.78.5.158244.78.5.15914
91244.78.5.160/28244.78.5.161 to 244.78.5.174244.78.5.17514
92244.78.5.176/28244.78.5.177 to 244.78.5.190244.78.5.19114
93244.78.5.192/28244.78.5.193 to 244.78.5.206244.78.5.20714
94244.78.5.208/28244.78.5.209 to 244.78.5.222244.78.5.22314
95244.78.5.224/28244.78.5.225 to 244.78.5.238244.78.5.23914
96244.78.5.240/28244.78.5.241 to 244.78.5.254244.78.5.25514
97244.78.6.0/28244.78.6.1 to 244.78.6.14244.78.6.1514
98244.78.6.16/28244.78.6.17 to 244.78.6.30244.78.6.3114
99244.78.6.32/28244.78.6.33 to 244.78.6.46244.78.6.4714
100244.78.6.48/28244.78.6.49 to 244.78.6.62244.78.6.6314
101244.78.6.64/28244.78.6.65 to 244.78.6.78244.78.6.7914
102244.78.6.80/28244.78.6.81 to 244.78.6.94244.78.6.9514
103244.78.6.96/28244.78.6.97 to 244.78.6.110244.78.6.11114
104244.78.6.112/28244.78.6.113 to 244.78.6.126244.78.6.12714
105244.78.6.128/28244.78.6.129 to 244.78.6.142244.78.6.14314
106244.78.6.144/28244.78.6.145 to 244.78.6.158244.78.6.15914
107244.78.6.160/28244.78.6.161 to 244.78.6.174244.78.6.17514
108244.78.6.176/28244.78.6.177 to 244.78.6.190244.78.6.19114
109244.78.6.192/28244.78.6.193 to 244.78.6.206244.78.6.20714
110244.78.6.208/28244.78.6.209 to 244.78.6.222244.78.6.22314
111244.78.6.224/28244.78.6.225 to 244.78.6.238244.78.6.23914
112244.78.6.240/28244.78.6.241 to 244.78.6.254244.78.6.25514
113244.78.7.0/28244.78.7.1 to 244.78.7.14244.78.7.1514
114244.78.7.16/28244.78.7.17 to 244.78.7.30244.78.7.3114
115244.78.7.32/28244.78.7.33 to 244.78.7.46244.78.7.4714
116244.78.7.48/28244.78.7.49 to 244.78.7.62244.78.7.6314
117244.78.7.64/28244.78.7.65 to 244.78.7.78244.78.7.7914
118244.78.7.80/28244.78.7.81 to 244.78.7.94244.78.7.9514
119244.78.7.96/28244.78.7.97 to 244.78.7.110244.78.7.11114
120244.78.7.112/28244.78.7.113 to 244.78.7.126244.78.7.12714
121244.78.7.128/28244.78.7.129 to 244.78.7.142244.78.7.14314
122244.78.7.144/28244.78.7.145 to 244.78.7.158244.78.7.15914
123244.78.7.160/28244.78.7.161 to 244.78.7.174244.78.7.17514
124244.78.7.176/28244.78.7.177 to 244.78.7.190244.78.7.19114
125244.78.7.192/28244.78.7.193 to 244.78.7.206244.78.7.20714
126244.78.7.208/28244.78.7.209 to 244.78.7.222244.78.7.22314
127244.78.7.224/28244.78.7.225 to 244.78.7.238244.78.7.23914
128244.78.7.240/28244.78.7.241 to 244.78.7.254244.78.7.25514
129244.78.8.0/28244.78.8.1 to 244.78.8.14244.78.8.1514
130244.78.8.16/28244.78.8.17 to 244.78.8.30244.78.8.3114
131244.78.8.32/28244.78.8.33 to 244.78.8.46244.78.8.4714
132244.78.8.48/28244.78.8.49 to 244.78.8.62244.78.8.6314
133244.78.8.64/28244.78.8.65 to 244.78.8.78244.78.8.7914
134244.78.8.80/28244.78.8.81 to 244.78.8.94244.78.8.9514
135244.78.8.96/28244.78.8.97 to 244.78.8.110244.78.8.11114
136244.78.8.112/28244.78.8.113 to 244.78.8.126244.78.8.12714
137244.78.8.128/28244.78.8.129 to 244.78.8.142244.78.8.14314
138244.78.8.144/28244.78.8.145 to 244.78.8.158244.78.8.15914
139244.78.8.160/28244.78.8.161 to 244.78.8.174244.78.8.17514
140244.78.8.176/28244.78.8.177 to 244.78.8.190244.78.8.19114
141244.78.8.192/28244.78.8.193 to 244.78.8.206244.78.8.20714
142244.78.8.208/28244.78.8.209 to 244.78.8.222244.78.8.22314
143244.78.8.224/28244.78.8.225 to 244.78.8.238244.78.8.23914
144244.78.8.240/28244.78.8.241 to 244.78.8.254244.78.8.25514
145244.78.9.0/28244.78.9.1 to 244.78.9.14244.78.9.1514
146244.78.9.16/28244.78.9.17 to 244.78.9.30244.78.9.3114
147244.78.9.32/28244.78.9.33 to 244.78.9.46244.78.9.4714
148244.78.9.48/28244.78.9.49 to 244.78.9.62244.78.9.6314
149244.78.9.64/28244.78.9.65 to 244.78.9.78244.78.9.7914
150244.78.9.80/28244.78.9.81 to 244.78.9.94244.78.9.9514
151244.78.9.96/28244.78.9.97 to 244.78.9.110244.78.9.11114
152244.78.9.112/28244.78.9.113 to 244.78.9.126244.78.9.12714
153244.78.9.128/28244.78.9.129 to 244.78.9.142244.78.9.14314
154244.78.9.144/28244.78.9.145 to 244.78.9.158244.78.9.15914
155244.78.9.160/28244.78.9.161 to 244.78.9.174244.78.9.17514
156244.78.9.176/28244.78.9.177 to 244.78.9.190244.78.9.19114
157244.78.9.192/28244.78.9.193 to 244.78.9.206244.78.9.20714
158244.78.9.208/28244.78.9.209 to 244.78.9.222244.78.9.22314
159244.78.9.224/28244.78.9.225 to 244.78.9.238244.78.9.23914
160244.78.9.240/28244.78.9.241 to 244.78.9.254244.78.9.25514
161244.78.10.0/28244.78.10.1 to 244.78.10.14244.78.10.1514
162244.78.10.16/28244.78.10.17 to 244.78.10.30244.78.10.3114
163244.78.10.32/28244.78.10.33 to 244.78.10.46244.78.10.4714
164244.78.10.48/28244.78.10.49 to 244.78.10.62244.78.10.6314
165244.78.10.64/28244.78.10.65 to 244.78.10.78244.78.10.7914
166244.78.10.80/28244.78.10.81 to 244.78.10.94244.78.10.9514
167244.78.10.96/28244.78.10.97 to 244.78.10.110244.78.10.11114
168244.78.10.112/28244.78.10.113 to 244.78.10.126244.78.10.12714
169244.78.10.128/28244.78.10.129 to 244.78.10.142244.78.10.14314
170244.78.10.144/28244.78.10.145 to 244.78.10.158244.78.10.15914
171244.78.10.160/28244.78.10.161 to 244.78.10.174244.78.10.17514
172244.78.10.176/28244.78.10.177 to 244.78.10.190244.78.10.19114
173244.78.10.192/28244.78.10.193 to 244.78.10.206244.78.10.20714
174244.78.10.208/28244.78.10.209 to 244.78.10.222244.78.10.22314
175244.78.10.224/28244.78.10.225 to 244.78.10.238244.78.10.23914
176244.78.10.240/28244.78.10.241 to 244.78.10.254244.78.10.25514
177244.78.11.0/28244.78.11.1 to 244.78.11.14244.78.11.1514
178244.78.11.16/28244.78.11.17 to 244.78.11.30244.78.11.3114
179244.78.11.32/28244.78.11.33 to 244.78.11.46244.78.11.4714
180244.78.11.48/28244.78.11.49 to 244.78.11.62244.78.11.6314
181244.78.11.64/28244.78.11.65 to 244.78.11.78244.78.11.7914
182244.78.11.80/28244.78.11.81 to 244.78.11.94244.78.11.9514
183244.78.11.96/28244.78.11.97 to 244.78.11.110244.78.11.11114
184244.78.11.112/28244.78.11.113 to 244.78.11.126244.78.11.12714
185244.78.11.128/28244.78.11.129 to 244.78.11.142244.78.11.14314
186244.78.11.144/28244.78.11.145 to 244.78.11.158244.78.11.15914
187244.78.11.160/28244.78.11.161 to 244.78.11.174244.78.11.17514
188244.78.11.176/28244.78.11.177 to 244.78.11.190244.78.11.19114
189244.78.11.192/28244.78.11.193 to 244.78.11.206244.78.11.20714
190244.78.11.208/28244.78.11.209 to 244.78.11.222244.78.11.22314
191244.78.11.224/28244.78.11.225 to 244.78.11.238244.78.11.23914
192244.78.11.240/28244.78.11.241 to 244.78.11.254244.78.11.25514
193244.78.12.0/28244.78.12.1 to 244.78.12.14244.78.12.1514
194244.78.12.16/28244.78.12.17 to 244.78.12.30244.78.12.3114
195244.78.12.32/28244.78.12.33 to 244.78.12.46244.78.12.4714
196244.78.12.48/28244.78.12.49 to 244.78.12.62244.78.12.6314
197244.78.12.64/28244.78.12.65 to 244.78.12.78244.78.12.7914
198244.78.12.80/28244.78.12.81 to 244.78.12.94244.78.12.9514
199244.78.12.96/28244.78.12.97 to 244.78.12.110244.78.12.11114
200244.78.12.112/28244.78.12.113 to 244.78.12.126244.78.12.12714
201244.78.12.128/28244.78.12.129 to 244.78.12.142244.78.12.14314
202244.78.12.144/28244.78.12.145 to 244.78.12.158244.78.12.15914
203244.78.12.160/28244.78.12.161 to 244.78.12.174244.78.12.17514
204244.78.12.176/28244.78.12.177 to 244.78.12.190244.78.12.19114
205244.78.12.192/28244.78.12.193 to 244.78.12.206244.78.12.20714
206244.78.12.208/28244.78.12.209 to 244.78.12.222244.78.12.22314
207244.78.12.224/28244.78.12.225 to 244.78.12.238244.78.12.23914
208244.78.12.240/28244.78.12.241 to 244.78.12.254244.78.12.25514
209244.78.13.0/28244.78.13.1 to 244.78.13.14244.78.13.1514
210244.78.13.16/28244.78.13.17 to 244.78.13.30244.78.13.3114
211244.78.13.32/28244.78.13.33 to 244.78.13.46244.78.13.4714
212244.78.13.48/28244.78.13.49 to 244.78.13.62244.78.13.6314
213244.78.13.64/28244.78.13.65 to 244.78.13.78244.78.13.7914
214244.78.13.80/28244.78.13.81 to 244.78.13.94244.78.13.9514
215244.78.13.96/28244.78.13.97 to 244.78.13.110244.78.13.11114
216244.78.13.112/28244.78.13.113 to 244.78.13.126244.78.13.12714
217244.78.13.128/28244.78.13.129 to 244.78.13.142244.78.13.14314
218244.78.13.144/28244.78.13.145 to 244.78.13.158244.78.13.15914
219244.78.13.160/28244.78.13.161 to 244.78.13.174244.78.13.17514
220244.78.13.176/28244.78.13.177 to 244.78.13.190244.78.13.19114
221244.78.13.192/28244.78.13.193 to 244.78.13.206244.78.13.20714
222244.78.13.208/28244.78.13.209 to 244.78.13.222244.78.13.22314
223244.78.13.224/28244.78.13.225 to 244.78.13.238244.78.13.23914
224244.78.13.240/28244.78.13.241 to 244.78.13.254244.78.13.25514
225244.78.14.0/28244.78.14.1 to 244.78.14.14244.78.14.1514
226244.78.14.16/28244.78.14.17 to 244.78.14.30244.78.14.3114
227244.78.14.32/28244.78.14.33 to 244.78.14.46244.78.14.4714
228244.78.14.48/28244.78.14.49 to 244.78.14.62244.78.14.6314
229244.78.14.64/28244.78.14.65 to 244.78.14.78244.78.14.7914
230244.78.14.80/28244.78.14.81 to 244.78.14.94244.78.14.9514
231244.78.14.96/28244.78.14.97 to 244.78.14.110244.78.14.11114
232244.78.14.112/28244.78.14.113 to 244.78.14.126244.78.14.12714
233244.78.14.128/28244.78.14.129 to 244.78.14.142244.78.14.14314
234244.78.14.144/28244.78.14.145 to 244.78.14.158244.78.14.15914
235244.78.14.160/28244.78.14.161 to 244.78.14.174244.78.14.17514
236244.78.14.176/28244.78.14.177 to 244.78.14.190244.78.14.19114
237244.78.14.192/28244.78.14.193 to 244.78.14.206244.78.14.20714
238244.78.14.208/28244.78.14.209 to 244.78.14.222244.78.14.22314
239244.78.14.224/28244.78.14.225 to 244.78.14.238244.78.14.23914
240244.78.14.240/28244.78.14.241 to 244.78.14.254244.78.14.25514
241244.78.15.0/28244.78.15.1 to 244.78.15.14244.78.15.1514
242244.78.15.16/28244.78.15.17 to 244.78.15.30244.78.15.3114
243244.78.15.32/28244.78.15.33 to 244.78.15.46244.78.15.4714
244244.78.15.48/28244.78.15.49 to 244.78.15.62244.78.15.6314
245244.78.15.64/28244.78.15.65 to 244.78.15.78244.78.15.7914
246244.78.15.80/28244.78.15.81 to 244.78.15.94244.78.15.9514
247244.78.15.96/28244.78.15.97 to 244.78.15.110244.78.15.11114
248244.78.15.112/28244.78.15.113 to 244.78.15.126244.78.15.12714
249244.78.15.128/28244.78.15.129 to 244.78.15.142244.78.15.14314
250244.78.15.144/28244.78.15.145 to 244.78.15.158244.78.15.15914
251244.78.15.160/28244.78.15.161 to 244.78.15.174244.78.15.17514
252244.78.15.176/28244.78.15.177 to 244.78.15.190244.78.15.19114
253244.78.15.192/28244.78.15.193 to 244.78.15.206244.78.15.20714
254244.78.15.208/28244.78.15.209 to 244.78.15.222244.78.15.22314
255244.78.15.224/28244.78.15.225 to 244.78.15.238244.78.15.23914
256244.78.15.240/28244.78.15.241 to 244.78.15.254244.78.15.25514

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.