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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.

Network247.207.0.0/16
Usable hosts65,534
Subnet mask255.255.0.0
Addresses65,536
Network address
247.207.0.0
Broadcast address
247.207.255.255
First usable
247.207.0.1
Last usable
247.207.255.254
Usable hosts
65,534 (65,536 less the network and broadcast addresses)
Subnet mask
255.255.0.0
Wildcard mask
0.0.255.255 (Cisco ACLs, OSPF)
Prefix length
/16
Type
Reserved 240.0.0.0/4
Future use; not usable on most systems
Old class
E (reserved)
As numbers
Hex F7CF0000 · Integer 4157538304 to 4157603839
Reverse DNS zone
207.247.in-addr.arpa
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address11110111.11001111..00000000.00000000247.207.0.0
Subnet mask11111111.11111111..00000000.00000000255.255.0.0
Network11110111.11001111..00000000.00000000247.207.0.0
Broadcast11110111.11001111..11111111.11111111247.207.255.255
Split into smaller subnets/28
/17 (2)/18 (4)/19 (8)/20 (16)/21 (32)/22 (64)/23 (128)/24 (256)/25 (512)/26 (1,024)/27 (2,048)/28 (4,096)

247.207.0.0/16 makes 4,096 subnets of /28; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1247.207.0.0/28247.207.0.1 to 247.207.0.14247.207.0.1514
2247.207.0.16/28247.207.0.17 to 247.207.0.30247.207.0.3114
3247.207.0.32/28247.207.0.33 to 247.207.0.46247.207.0.4714
4247.207.0.48/28247.207.0.49 to 247.207.0.62247.207.0.6314
5247.207.0.64/28247.207.0.65 to 247.207.0.78247.207.0.7914
6247.207.0.80/28247.207.0.81 to 247.207.0.94247.207.0.9514
7247.207.0.96/28247.207.0.97 to 247.207.0.110247.207.0.11114
8247.207.0.112/28247.207.0.113 to 247.207.0.126247.207.0.12714
9247.207.0.128/28247.207.0.129 to 247.207.0.142247.207.0.14314
10247.207.0.144/28247.207.0.145 to 247.207.0.158247.207.0.15914
11247.207.0.160/28247.207.0.161 to 247.207.0.174247.207.0.17514
12247.207.0.176/28247.207.0.177 to 247.207.0.190247.207.0.19114
13247.207.0.192/28247.207.0.193 to 247.207.0.206247.207.0.20714
14247.207.0.208/28247.207.0.209 to 247.207.0.222247.207.0.22314
15247.207.0.224/28247.207.0.225 to 247.207.0.238247.207.0.23914
16247.207.0.240/28247.207.0.241 to 247.207.0.254247.207.0.25514
17247.207.1.0/28247.207.1.1 to 247.207.1.14247.207.1.1514
18247.207.1.16/28247.207.1.17 to 247.207.1.30247.207.1.3114
19247.207.1.32/28247.207.1.33 to 247.207.1.46247.207.1.4714
20247.207.1.48/28247.207.1.49 to 247.207.1.62247.207.1.6314
21247.207.1.64/28247.207.1.65 to 247.207.1.78247.207.1.7914
22247.207.1.80/28247.207.1.81 to 247.207.1.94247.207.1.9514
23247.207.1.96/28247.207.1.97 to 247.207.1.110247.207.1.11114
24247.207.1.112/28247.207.1.113 to 247.207.1.126247.207.1.12714
25247.207.1.128/28247.207.1.129 to 247.207.1.142247.207.1.14314
26247.207.1.144/28247.207.1.145 to 247.207.1.158247.207.1.15914
27247.207.1.160/28247.207.1.161 to 247.207.1.174247.207.1.17514
28247.207.1.176/28247.207.1.177 to 247.207.1.190247.207.1.19114
29247.207.1.192/28247.207.1.193 to 247.207.1.206247.207.1.20714
30247.207.1.208/28247.207.1.209 to 247.207.1.222247.207.1.22314
31247.207.1.224/28247.207.1.225 to 247.207.1.238247.207.1.23914
32247.207.1.240/28247.207.1.241 to 247.207.1.254247.207.1.25514
33247.207.2.0/28247.207.2.1 to 247.207.2.14247.207.2.1514
34247.207.2.16/28247.207.2.17 to 247.207.2.30247.207.2.3114
35247.207.2.32/28247.207.2.33 to 247.207.2.46247.207.2.4714
36247.207.2.48/28247.207.2.49 to 247.207.2.62247.207.2.6314
37247.207.2.64/28247.207.2.65 to 247.207.2.78247.207.2.7914
38247.207.2.80/28247.207.2.81 to 247.207.2.94247.207.2.9514
39247.207.2.96/28247.207.2.97 to 247.207.2.110247.207.2.11114
40247.207.2.112/28247.207.2.113 to 247.207.2.126247.207.2.12714
41247.207.2.128/28247.207.2.129 to 247.207.2.142247.207.2.14314
42247.207.2.144/28247.207.2.145 to 247.207.2.158247.207.2.15914
43247.207.2.160/28247.207.2.161 to 247.207.2.174247.207.2.17514
44247.207.2.176/28247.207.2.177 to 247.207.2.190247.207.2.19114
45247.207.2.192/28247.207.2.193 to 247.207.2.206247.207.2.20714
46247.207.2.208/28247.207.2.209 to 247.207.2.222247.207.2.22314
47247.207.2.224/28247.207.2.225 to 247.207.2.238247.207.2.23914
48247.207.2.240/28247.207.2.241 to 247.207.2.254247.207.2.25514
49247.207.3.0/28247.207.3.1 to 247.207.3.14247.207.3.1514
50247.207.3.16/28247.207.3.17 to 247.207.3.30247.207.3.3114
51247.207.3.32/28247.207.3.33 to 247.207.3.46247.207.3.4714
52247.207.3.48/28247.207.3.49 to 247.207.3.62247.207.3.6314
53247.207.3.64/28247.207.3.65 to 247.207.3.78247.207.3.7914
54247.207.3.80/28247.207.3.81 to 247.207.3.94247.207.3.9514
55247.207.3.96/28247.207.3.97 to 247.207.3.110247.207.3.11114
56247.207.3.112/28247.207.3.113 to 247.207.3.126247.207.3.12714
57247.207.3.128/28247.207.3.129 to 247.207.3.142247.207.3.14314
58247.207.3.144/28247.207.3.145 to 247.207.3.158247.207.3.15914
59247.207.3.160/28247.207.3.161 to 247.207.3.174247.207.3.17514
60247.207.3.176/28247.207.3.177 to 247.207.3.190247.207.3.19114
61247.207.3.192/28247.207.3.193 to 247.207.3.206247.207.3.20714
62247.207.3.208/28247.207.3.209 to 247.207.3.222247.207.3.22314
63247.207.3.224/28247.207.3.225 to 247.207.3.238247.207.3.23914
64247.207.3.240/28247.207.3.241 to 247.207.3.254247.207.3.25514
65247.207.4.0/28247.207.4.1 to 247.207.4.14247.207.4.1514
66247.207.4.16/28247.207.4.17 to 247.207.4.30247.207.4.3114
67247.207.4.32/28247.207.4.33 to 247.207.4.46247.207.4.4714
68247.207.4.48/28247.207.4.49 to 247.207.4.62247.207.4.6314
69247.207.4.64/28247.207.4.65 to 247.207.4.78247.207.4.7914
70247.207.4.80/28247.207.4.81 to 247.207.4.94247.207.4.9514
71247.207.4.96/28247.207.4.97 to 247.207.4.110247.207.4.11114
72247.207.4.112/28247.207.4.113 to 247.207.4.126247.207.4.12714
73247.207.4.128/28247.207.4.129 to 247.207.4.142247.207.4.14314
74247.207.4.144/28247.207.4.145 to 247.207.4.158247.207.4.15914
75247.207.4.160/28247.207.4.161 to 247.207.4.174247.207.4.17514
76247.207.4.176/28247.207.4.177 to 247.207.4.190247.207.4.19114
77247.207.4.192/28247.207.4.193 to 247.207.4.206247.207.4.20714
78247.207.4.208/28247.207.4.209 to 247.207.4.222247.207.4.22314
79247.207.4.224/28247.207.4.225 to 247.207.4.238247.207.4.23914
80247.207.4.240/28247.207.4.241 to 247.207.4.254247.207.4.25514
81247.207.5.0/28247.207.5.1 to 247.207.5.14247.207.5.1514
82247.207.5.16/28247.207.5.17 to 247.207.5.30247.207.5.3114
83247.207.5.32/28247.207.5.33 to 247.207.5.46247.207.5.4714
84247.207.5.48/28247.207.5.49 to 247.207.5.62247.207.5.6314
85247.207.5.64/28247.207.5.65 to 247.207.5.78247.207.5.7914
86247.207.5.80/28247.207.5.81 to 247.207.5.94247.207.5.9514
87247.207.5.96/28247.207.5.97 to 247.207.5.110247.207.5.11114
88247.207.5.112/28247.207.5.113 to 247.207.5.126247.207.5.12714
89247.207.5.128/28247.207.5.129 to 247.207.5.142247.207.5.14314
90247.207.5.144/28247.207.5.145 to 247.207.5.158247.207.5.15914
91247.207.5.160/28247.207.5.161 to 247.207.5.174247.207.5.17514
92247.207.5.176/28247.207.5.177 to 247.207.5.190247.207.5.19114
93247.207.5.192/28247.207.5.193 to 247.207.5.206247.207.5.20714
94247.207.5.208/28247.207.5.209 to 247.207.5.222247.207.5.22314
95247.207.5.224/28247.207.5.225 to 247.207.5.238247.207.5.23914
96247.207.5.240/28247.207.5.241 to 247.207.5.254247.207.5.25514
97247.207.6.0/28247.207.6.1 to 247.207.6.14247.207.6.1514
98247.207.6.16/28247.207.6.17 to 247.207.6.30247.207.6.3114
99247.207.6.32/28247.207.6.33 to 247.207.6.46247.207.6.4714
100247.207.6.48/28247.207.6.49 to 247.207.6.62247.207.6.6314
101247.207.6.64/28247.207.6.65 to 247.207.6.78247.207.6.7914
102247.207.6.80/28247.207.6.81 to 247.207.6.94247.207.6.9514
103247.207.6.96/28247.207.6.97 to 247.207.6.110247.207.6.11114
104247.207.6.112/28247.207.6.113 to 247.207.6.126247.207.6.12714
105247.207.6.128/28247.207.6.129 to 247.207.6.142247.207.6.14314
106247.207.6.144/28247.207.6.145 to 247.207.6.158247.207.6.15914
107247.207.6.160/28247.207.6.161 to 247.207.6.174247.207.6.17514
108247.207.6.176/28247.207.6.177 to 247.207.6.190247.207.6.19114
109247.207.6.192/28247.207.6.193 to 247.207.6.206247.207.6.20714
110247.207.6.208/28247.207.6.209 to 247.207.6.222247.207.6.22314
111247.207.6.224/28247.207.6.225 to 247.207.6.238247.207.6.23914
112247.207.6.240/28247.207.6.241 to 247.207.6.254247.207.6.25514
113247.207.7.0/28247.207.7.1 to 247.207.7.14247.207.7.1514
114247.207.7.16/28247.207.7.17 to 247.207.7.30247.207.7.3114
115247.207.7.32/28247.207.7.33 to 247.207.7.46247.207.7.4714
116247.207.7.48/28247.207.7.49 to 247.207.7.62247.207.7.6314
117247.207.7.64/28247.207.7.65 to 247.207.7.78247.207.7.7914
118247.207.7.80/28247.207.7.81 to 247.207.7.94247.207.7.9514
119247.207.7.96/28247.207.7.97 to 247.207.7.110247.207.7.11114
120247.207.7.112/28247.207.7.113 to 247.207.7.126247.207.7.12714
121247.207.7.128/28247.207.7.129 to 247.207.7.142247.207.7.14314
122247.207.7.144/28247.207.7.145 to 247.207.7.158247.207.7.15914
123247.207.7.160/28247.207.7.161 to 247.207.7.174247.207.7.17514
124247.207.7.176/28247.207.7.177 to 247.207.7.190247.207.7.19114
125247.207.7.192/28247.207.7.193 to 247.207.7.206247.207.7.20714
126247.207.7.208/28247.207.7.209 to 247.207.7.222247.207.7.22314
127247.207.7.224/28247.207.7.225 to 247.207.7.238247.207.7.23914
128247.207.7.240/28247.207.7.241 to 247.207.7.254247.207.7.25514
129247.207.8.0/28247.207.8.1 to 247.207.8.14247.207.8.1514
130247.207.8.16/28247.207.8.17 to 247.207.8.30247.207.8.3114
131247.207.8.32/28247.207.8.33 to 247.207.8.46247.207.8.4714
132247.207.8.48/28247.207.8.49 to 247.207.8.62247.207.8.6314
133247.207.8.64/28247.207.8.65 to 247.207.8.78247.207.8.7914
134247.207.8.80/28247.207.8.81 to 247.207.8.94247.207.8.9514
135247.207.8.96/28247.207.8.97 to 247.207.8.110247.207.8.11114
136247.207.8.112/28247.207.8.113 to 247.207.8.126247.207.8.12714
137247.207.8.128/28247.207.8.129 to 247.207.8.142247.207.8.14314
138247.207.8.144/28247.207.8.145 to 247.207.8.158247.207.8.15914
139247.207.8.160/28247.207.8.161 to 247.207.8.174247.207.8.17514
140247.207.8.176/28247.207.8.177 to 247.207.8.190247.207.8.19114
141247.207.8.192/28247.207.8.193 to 247.207.8.206247.207.8.20714
142247.207.8.208/28247.207.8.209 to 247.207.8.222247.207.8.22314
143247.207.8.224/28247.207.8.225 to 247.207.8.238247.207.8.23914
144247.207.8.240/28247.207.8.241 to 247.207.8.254247.207.8.25514
145247.207.9.0/28247.207.9.1 to 247.207.9.14247.207.9.1514
146247.207.9.16/28247.207.9.17 to 247.207.9.30247.207.9.3114
147247.207.9.32/28247.207.9.33 to 247.207.9.46247.207.9.4714
148247.207.9.48/28247.207.9.49 to 247.207.9.62247.207.9.6314
149247.207.9.64/28247.207.9.65 to 247.207.9.78247.207.9.7914
150247.207.9.80/28247.207.9.81 to 247.207.9.94247.207.9.9514
151247.207.9.96/28247.207.9.97 to 247.207.9.110247.207.9.11114
152247.207.9.112/28247.207.9.113 to 247.207.9.126247.207.9.12714
153247.207.9.128/28247.207.9.129 to 247.207.9.142247.207.9.14314
154247.207.9.144/28247.207.9.145 to 247.207.9.158247.207.9.15914
155247.207.9.160/28247.207.9.161 to 247.207.9.174247.207.9.17514
156247.207.9.176/28247.207.9.177 to 247.207.9.190247.207.9.19114
157247.207.9.192/28247.207.9.193 to 247.207.9.206247.207.9.20714
158247.207.9.208/28247.207.9.209 to 247.207.9.222247.207.9.22314
159247.207.9.224/28247.207.9.225 to 247.207.9.238247.207.9.23914
160247.207.9.240/28247.207.9.241 to 247.207.9.254247.207.9.25514
161247.207.10.0/28247.207.10.1 to 247.207.10.14247.207.10.1514
162247.207.10.16/28247.207.10.17 to 247.207.10.30247.207.10.3114
163247.207.10.32/28247.207.10.33 to 247.207.10.46247.207.10.4714
164247.207.10.48/28247.207.10.49 to 247.207.10.62247.207.10.6314
165247.207.10.64/28247.207.10.65 to 247.207.10.78247.207.10.7914
166247.207.10.80/28247.207.10.81 to 247.207.10.94247.207.10.9514
167247.207.10.96/28247.207.10.97 to 247.207.10.110247.207.10.11114
168247.207.10.112/28247.207.10.113 to 247.207.10.126247.207.10.12714
169247.207.10.128/28247.207.10.129 to 247.207.10.142247.207.10.14314
170247.207.10.144/28247.207.10.145 to 247.207.10.158247.207.10.15914
171247.207.10.160/28247.207.10.161 to 247.207.10.174247.207.10.17514
172247.207.10.176/28247.207.10.177 to 247.207.10.190247.207.10.19114
173247.207.10.192/28247.207.10.193 to 247.207.10.206247.207.10.20714
174247.207.10.208/28247.207.10.209 to 247.207.10.222247.207.10.22314
175247.207.10.224/28247.207.10.225 to 247.207.10.238247.207.10.23914
176247.207.10.240/28247.207.10.241 to 247.207.10.254247.207.10.25514
177247.207.11.0/28247.207.11.1 to 247.207.11.14247.207.11.1514
178247.207.11.16/28247.207.11.17 to 247.207.11.30247.207.11.3114
179247.207.11.32/28247.207.11.33 to 247.207.11.46247.207.11.4714
180247.207.11.48/28247.207.11.49 to 247.207.11.62247.207.11.6314
181247.207.11.64/28247.207.11.65 to 247.207.11.78247.207.11.7914
182247.207.11.80/28247.207.11.81 to 247.207.11.94247.207.11.9514
183247.207.11.96/28247.207.11.97 to 247.207.11.110247.207.11.11114
184247.207.11.112/28247.207.11.113 to 247.207.11.126247.207.11.12714
185247.207.11.128/28247.207.11.129 to 247.207.11.142247.207.11.14314
186247.207.11.144/28247.207.11.145 to 247.207.11.158247.207.11.15914
187247.207.11.160/28247.207.11.161 to 247.207.11.174247.207.11.17514
188247.207.11.176/28247.207.11.177 to 247.207.11.190247.207.11.19114
189247.207.11.192/28247.207.11.193 to 247.207.11.206247.207.11.20714
190247.207.11.208/28247.207.11.209 to 247.207.11.222247.207.11.22314
191247.207.11.224/28247.207.11.225 to 247.207.11.238247.207.11.23914
192247.207.11.240/28247.207.11.241 to 247.207.11.254247.207.11.25514
193247.207.12.0/28247.207.12.1 to 247.207.12.14247.207.12.1514
194247.207.12.16/28247.207.12.17 to 247.207.12.30247.207.12.3114
195247.207.12.32/28247.207.12.33 to 247.207.12.46247.207.12.4714
196247.207.12.48/28247.207.12.49 to 247.207.12.62247.207.12.6314
197247.207.12.64/28247.207.12.65 to 247.207.12.78247.207.12.7914
198247.207.12.80/28247.207.12.81 to 247.207.12.94247.207.12.9514
199247.207.12.96/28247.207.12.97 to 247.207.12.110247.207.12.11114
200247.207.12.112/28247.207.12.113 to 247.207.12.126247.207.12.12714
201247.207.12.128/28247.207.12.129 to 247.207.12.142247.207.12.14314
202247.207.12.144/28247.207.12.145 to 247.207.12.158247.207.12.15914
203247.207.12.160/28247.207.12.161 to 247.207.12.174247.207.12.17514
204247.207.12.176/28247.207.12.177 to 247.207.12.190247.207.12.19114
205247.207.12.192/28247.207.12.193 to 247.207.12.206247.207.12.20714
206247.207.12.208/28247.207.12.209 to 247.207.12.222247.207.12.22314
207247.207.12.224/28247.207.12.225 to 247.207.12.238247.207.12.23914
208247.207.12.240/28247.207.12.241 to 247.207.12.254247.207.12.25514
209247.207.13.0/28247.207.13.1 to 247.207.13.14247.207.13.1514
210247.207.13.16/28247.207.13.17 to 247.207.13.30247.207.13.3114
211247.207.13.32/28247.207.13.33 to 247.207.13.46247.207.13.4714
212247.207.13.48/28247.207.13.49 to 247.207.13.62247.207.13.6314
213247.207.13.64/28247.207.13.65 to 247.207.13.78247.207.13.7914
214247.207.13.80/28247.207.13.81 to 247.207.13.94247.207.13.9514
215247.207.13.96/28247.207.13.97 to 247.207.13.110247.207.13.11114
216247.207.13.112/28247.207.13.113 to 247.207.13.126247.207.13.12714
217247.207.13.128/28247.207.13.129 to 247.207.13.142247.207.13.14314
218247.207.13.144/28247.207.13.145 to 247.207.13.158247.207.13.15914
219247.207.13.160/28247.207.13.161 to 247.207.13.174247.207.13.17514
220247.207.13.176/28247.207.13.177 to 247.207.13.190247.207.13.19114
221247.207.13.192/28247.207.13.193 to 247.207.13.206247.207.13.20714
222247.207.13.208/28247.207.13.209 to 247.207.13.222247.207.13.22314
223247.207.13.224/28247.207.13.225 to 247.207.13.238247.207.13.23914
224247.207.13.240/28247.207.13.241 to 247.207.13.254247.207.13.25514
225247.207.14.0/28247.207.14.1 to 247.207.14.14247.207.14.1514
226247.207.14.16/28247.207.14.17 to 247.207.14.30247.207.14.3114
227247.207.14.32/28247.207.14.33 to 247.207.14.46247.207.14.4714
228247.207.14.48/28247.207.14.49 to 247.207.14.62247.207.14.6314
229247.207.14.64/28247.207.14.65 to 247.207.14.78247.207.14.7914
230247.207.14.80/28247.207.14.81 to 247.207.14.94247.207.14.9514
231247.207.14.96/28247.207.14.97 to 247.207.14.110247.207.14.11114
232247.207.14.112/28247.207.14.113 to 247.207.14.126247.207.14.12714
233247.207.14.128/28247.207.14.129 to 247.207.14.142247.207.14.14314
234247.207.14.144/28247.207.14.145 to 247.207.14.158247.207.14.15914
235247.207.14.160/28247.207.14.161 to 247.207.14.174247.207.14.17514
236247.207.14.176/28247.207.14.177 to 247.207.14.190247.207.14.19114
237247.207.14.192/28247.207.14.193 to 247.207.14.206247.207.14.20714
238247.207.14.208/28247.207.14.209 to 247.207.14.222247.207.14.22314
239247.207.14.224/28247.207.14.225 to 247.207.14.238247.207.14.23914
240247.207.14.240/28247.207.14.241 to 247.207.14.254247.207.14.25514
241247.207.15.0/28247.207.15.1 to 247.207.15.14247.207.15.1514
242247.207.15.16/28247.207.15.17 to 247.207.15.30247.207.15.3114
243247.207.15.32/28247.207.15.33 to 247.207.15.46247.207.15.4714
244247.207.15.48/28247.207.15.49 to 247.207.15.62247.207.15.6314
245247.207.15.64/28247.207.15.65 to 247.207.15.78247.207.15.7914
246247.207.15.80/28247.207.15.81 to 247.207.15.94247.207.15.9514
247247.207.15.96/28247.207.15.97 to 247.207.15.110247.207.15.11114
248247.207.15.112/28247.207.15.113 to 247.207.15.126247.207.15.12714
249247.207.15.128/28247.207.15.129 to 247.207.15.142247.207.15.14314
250247.207.15.144/28247.207.15.145 to 247.207.15.158247.207.15.15914
251247.207.15.160/28247.207.15.161 to 247.207.15.174247.207.15.17514
252247.207.15.176/28247.207.15.177 to 247.207.15.190247.207.15.19114
253247.207.15.192/28247.207.15.193 to 247.207.15.206247.207.15.20714
254247.207.15.208/28247.207.15.209 to 247.207.15.222247.207.15.22314
255247.207.15.224/28247.207.15.225 to 247.207.15.238247.207.15.23914
256247.207.15.240/28247.207.15.241 to 247.207.15.254247.207.15.25514

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.