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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.

Network240.63.0.0/16
Usable hosts65,534
Subnet mask255.255.0.0
Addresses65,536
Network address
240.63.0.0
Broadcast address
240.63.255.255
First usable
240.63.0.1
Last usable
240.63.255.254
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 F03F0000 · Integer 4030660608 to 4030726143
Reverse DNS zone
63.240.in-addr.arpa
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address11110000.00111111..00000000.00000000240.63.0.0
Subnet mask11111111.11111111..00000000.00000000255.255.0.0
Network11110000.00111111..00000000.00000000240.63.0.0
Broadcast11110000.00111111..11111111.11111111240.63.255.255
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)

240.63.0.0/16 makes 4,096 subnets of /28; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1240.63.0.0/28240.63.0.1 to 240.63.0.14240.63.0.1514
2240.63.0.16/28240.63.0.17 to 240.63.0.30240.63.0.3114
3240.63.0.32/28240.63.0.33 to 240.63.0.46240.63.0.4714
4240.63.0.48/28240.63.0.49 to 240.63.0.62240.63.0.6314
5240.63.0.64/28240.63.0.65 to 240.63.0.78240.63.0.7914
6240.63.0.80/28240.63.0.81 to 240.63.0.94240.63.0.9514
7240.63.0.96/28240.63.0.97 to 240.63.0.110240.63.0.11114
8240.63.0.112/28240.63.0.113 to 240.63.0.126240.63.0.12714
9240.63.0.128/28240.63.0.129 to 240.63.0.142240.63.0.14314
10240.63.0.144/28240.63.0.145 to 240.63.0.158240.63.0.15914
11240.63.0.160/28240.63.0.161 to 240.63.0.174240.63.0.17514
12240.63.0.176/28240.63.0.177 to 240.63.0.190240.63.0.19114
13240.63.0.192/28240.63.0.193 to 240.63.0.206240.63.0.20714
14240.63.0.208/28240.63.0.209 to 240.63.0.222240.63.0.22314
15240.63.0.224/28240.63.0.225 to 240.63.0.238240.63.0.23914
16240.63.0.240/28240.63.0.241 to 240.63.0.254240.63.0.25514
17240.63.1.0/28240.63.1.1 to 240.63.1.14240.63.1.1514
18240.63.1.16/28240.63.1.17 to 240.63.1.30240.63.1.3114
19240.63.1.32/28240.63.1.33 to 240.63.1.46240.63.1.4714
20240.63.1.48/28240.63.1.49 to 240.63.1.62240.63.1.6314
21240.63.1.64/28240.63.1.65 to 240.63.1.78240.63.1.7914
22240.63.1.80/28240.63.1.81 to 240.63.1.94240.63.1.9514
23240.63.1.96/28240.63.1.97 to 240.63.1.110240.63.1.11114
24240.63.1.112/28240.63.1.113 to 240.63.1.126240.63.1.12714
25240.63.1.128/28240.63.1.129 to 240.63.1.142240.63.1.14314
26240.63.1.144/28240.63.1.145 to 240.63.1.158240.63.1.15914
27240.63.1.160/28240.63.1.161 to 240.63.1.174240.63.1.17514
28240.63.1.176/28240.63.1.177 to 240.63.1.190240.63.1.19114
29240.63.1.192/28240.63.1.193 to 240.63.1.206240.63.1.20714
30240.63.1.208/28240.63.1.209 to 240.63.1.222240.63.1.22314
31240.63.1.224/28240.63.1.225 to 240.63.1.238240.63.1.23914
32240.63.1.240/28240.63.1.241 to 240.63.1.254240.63.1.25514
33240.63.2.0/28240.63.2.1 to 240.63.2.14240.63.2.1514
34240.63.2.16/28240.63.2.17 to 240.63.2.30240.63.2.3114
35240.63.2.32/28240.63.2.33 to 240.63.2.46240.63.2.4714
36240.63.2.48/28240.63.2.49 to 240.63.2.62240.63.2.6314
37240.63.2.64/28240.63.2.65 to 240.63.2.78240.63.2.7914
38240.63.2.80/28240.63.2.81 to 240.63.2.94240.63.2.9514
39240.63.2.96/28240.63.2.97 to 240.63.2.110240.63.2.11114
40240.63.2.112/28240.63.2.113 to 240.63.2.126240.63.2.12714
41240.63.2.128/28240.63.2.129 to 240.63.2.142240.63.2.14314
42240.63.2.144/28240.63.2.145 to 240.63.2.158240.63.2.15914
43240.63.2.160/28240.63.2.161 to 240.63.2.174240.63.2.17514
44240.63.2.176/28240.63.2.177 to 240.63.2.190240.63.2.19114
45240.63.2.192/28240.63.2.193 to 240.63.2.206240.63.2.20714
46240.63.2.208/28240.63.2.209 to 240.63.2.222240.63.2.22314
47240.63.2.224/28240.63.2.225 to 240.63.2.238240.63.2.23914
48240.63.2.240/28240.63.2.241 to 240.63.2.254240.63.2.25514
49240.63.3.0/28240.63.3.1 to 240.63.3.14240.63.3.1514
50240.63.3.16/28240.63.3.17 to 240.63.3.30240.63.3.3114
51240.63.3.32/28240.63.3.33 to 240.63.3.46240.63.3.4714
52240.63.3.48/28240.63.3.49 to 240.63.3.62240.63.3.6314
53240.63.3.64/28240.63.3.65 to 240.63.3.78240.63.3.7914
54240.63.3.80/28240.63.3.81 to 240.63.3.94240.63.3.9514
55240.63.3.96/28240.63.3.97 to 240.63.3.110240.63.3.11114
56240.63.3.112/28240.63.3.113 to 240.63.3.126240.63.3.12714
57240.63.3.128/28240.63.3.129 to 240.63.3.142240.63.3.14314
58240.63.3.144/28240.63.3.145 to 240.63.3.158240.63.3.15914
59240.63.3.160/28240.63.3.161 to 240.63.3.174240.63.3.17514
60240.63.3.176/28240.63.3.177 to 240.63.3.190240.63.3.19114
61240.63.3.192/28240.63.3.193 to 240.63.3.206240.63.3.20714
62240.63.3.208/28240.63.3.209 to 240.63.3.222240.63.3.22314
63240.63.3.224/28240.63.3.225 to 240.63.3.238240.63.3.23914
64240.63.3.240/28240.63.3.241 to 240.63.3.254240.63.3.25514
65240.63.4.0/28240.63.4.1 to 240.63.4.14240.63.4.1514
66240.63.4.16/28240.63.4.17 to 240.63.4.30240.63.4.3114
67240.63.4.32/28240.63.4.33 to 240.63.4.46240.63.4.4714
68240.63.4.48/28240.63.4.49 to 240.63.4.62240.63.4.6314
69240.63.4.64/28240.63.4.65 to 240.63.4.78240.63.4.7914
70240.63.4.80/28240.63.4.81 to 240.63.4.94240.63.4.9514
71240.63.4.96/28240.63.4.97 to 240.63.4.110240.63.4.11114
72240.63.4.112/28240.63.4.113 to 240.63.4.126240.63.4.12714
73240.63.4.128/28240.63.4.129 to 240.63.4.142240.63.4.14314
74240.63.4.144/28240.63.4.145 to 240.63.4.158240.63.4.15914
75240.63.4.160/28240.63.4.161 to 240.63.4.174240.63.4.17514
76240.63.4.176/28240.63.4.177 to 240.63.4.190240.63.4.19114
77240.63.4.192/28240.63.4.193 to 240.63.4.206240.63.4.20714
78240.63.4.208/28240.63.4.209 to 240.63.4.222240.63.4.22314
79240.63.4.224/28240.63.4.225 to 240.63.4.238240.63.4.23914
80240.63.4.240/28240.63.4.241 to 240.63.4.254240.63.4.25514
81240.63.5.0/28240.63.5.1 to 240.63.5.14240.63.5.1514
82240.63.5.16/28240.63.5.17 to 240.63.5.30240.63.5.3114
83240.63.5.32/28240.63.5.33 to 240.63.5.46240.63.5.4714
84240.63.5.48/28240.63.5.49 to 240.63.5.62240.63.5.6314
85240.63.5.64/28240.63.5.65 to 240.63.5.78240.63.5.7914
86240.63.5.80/28240.63.5.81 to 240.63.5.94240.63.5.9514
87240.63.5.96/28240.63.5.97 to 240.63.5.110240.63.5.11114
88240.63.5.112/28240.63.5.113 to 240.63.5.126240.63.5.12714
89240.63.5.128/28240.63.5.129 to 240.63.5.142240.63.5.14314
90240.63.5.144/28240.63.5.145 to 240.63.5.158240.63.5.15914
91240.63.5.160/28240.63.5.161 to 240.63.5.174240.63.5.17514
92240.63.5.176/28240.63.5.177 to 240.63.5.190240.63.5.19114
93240.63.5.192/28240.63.5.193 to 240.63.5.206240.63.5.20714
94240.63.5.208/28240.63.5.209 to 240.63.5.222240.63.5.22314
95240.63.5.224/28240.63.5.225 to 240.63.5.238240.63.5.23914
96240.63.5.240/28240.63.5.241 to 240.63.5.254240.63.5.25514
97240.63.6.0/28240.63.6.1 to 240.63.6.14240.63.6.1514
98240.63.6.16/28240.63.6.17 to 240.63.6.30240.63.6.3114
99240.63.6.32/28240.63.6.33 to 240.63.6.46240.63.6.4714
100240.63.6.48/28240.63.6.49 to 240.63.6.62240.63.6.6314
101240.63.6.64/28240.63.6.65 to 240.63.6.78240.63.6.7914
102240.63.6.80/28240.63.6.81 to 240.63.6.94240.63.6.9514
103240.63.6.96/28240.63.6.97 to 240.63.6.110240.63.6.11114
104240.63.6.112/28240.63.6.113 to 240.63.6.126240.63.6.12714
105240.63.6.128/28240.63.6.129 to 240.63.6.142240.63.6.14314
106240.63.6.144/28240.63.6.145 to 240.63.6.158240.63.6.15914
107240.63.6.160/28240.63.6.161 to 240.63.6.174240.63.6.17514
108240.63.6.176/28240.63.6.177 to 240.63.6.190240.63.6.19114
109240.63.6.192/28240.63.6.193 to 240.63.6.206240.63.6.20714
110240.63.6.208/28240.63.6.209 to 240.63.6.222240.63.6.22314
111240.63.6.224/28240.63.6.225 to 240.63.6.238240.63.6.23914
112240.63.6.240/28240.63.6.241 to 240.63.6.254240.63.6.25514
113240.63.7.0/28240.63.7.1 to 240.63.7.14240.63.7.1514
114240.63.7.16/28240.63.7.17 to 240.63.7.30240.63.7.3114
115240.63.7.32/28240.63.7.33 to 240.63.7.46240.63.7.4714
116240.63.7.48/28240.63.7.49 to 240.63.7.62240.63.7.6314
117240.63.7.64/28240.63.7.65 to 240.63.7.78240.63.7.7914
118240.63.7.80/28240.63.7.81 to 240.63.7.94240.63.7.9514
119240.63.7.96/28240.63.7.97 to 240.63.7.110240.63.7.11114
120240.63.7.112/28240.63.7.113 to 240.63.7.126240.63.7.12714
121240.63.7.128/28240.63.7.129 to 240.63.7.142240.63.7.14314
122240.63.7.144/28240.63.7.145 to 240.63.7.158240.63.7.15914
123240.63.7.160/28240.63.7.161 to 240.63.7.174240.63.7.17514
124240.63.7.176/28240.63.7.177 to 240.63.7.190240.63.7.19114
125240.63.7.192/28240.63.7.193 to 240.63.7.206240.63.7.20714
126240.63.7.208/28240.63.7.209 to 240.63.7.222240.63.7.22314
127240.63.7.224/28240.63.7.225 to 240.63.7.238240.63.7.23914
128240.63.7.240/28240.63.7.241 to 240.63.7.254240.63.7.25514
129240.63.8.0/28240.63.8.1 to 240.63.8.14240.63.8.1514
130240.63.8.16/28240.63.8.17 to 240.63.8.30240.63.8.3114
131240.63.8.32/28240.63.8.33 to 240.63.8.46240.63.8.4714
132240.63.8.48/28240.63.8.49 to 240.63.8.62240.63.8.6314
133240.63.8.64/28240.63.8.65 to 240.63.8.78240.63.8.7914
134240.63.8.80/28240.63.8.81 to 240.63.8.94240.63.8.9514
135240.63.8.96/28240.63.8.97 to 240.63.8.110240.63.8.11114
136240.63.8.112/28240.63.8.113 to 240.63.8.126240.63.8.12714
137240.63.8.128/28240.63.8.129 to 240.63.8.142240.63.8.14314
138240.63.8.144/28240.63.8.145 to 240.63.8.158240.63.8.15914
139240.63.8.160/28240.63.8.161 to 240.63.8.174240.63.8.17514
140240.63.8.176/28240.63.8.177 to 240.63.8.190240.63.8.19114
141240.63.8.192/28240.63.8.193 to 240.63.8.206240.63.8.20714
142240.63.8.208/28240.63.8.209 to 240.63.8.222240.63.8.22314
143240.63.8.224/28240.63.8.225 to 240.63.8.238240.63.8.23914
144240.63.8.240/28240.63.8.241 to 240.63.8.254240.63.8.25514
145240.63.9.0/28240.63.9.1 to 240.63.9.14240.63.9.1514
146240.63.9.16/28240.63.9.17 to 240.63.9.30240.63.9.3114
147240.63.9.32/28240.63.9.33 to 240.63.9.46240.63.9.4714
148240.63.9.48/28240.63.9.49 to 240.63.9.62240.63.9.6314
149240.63.9.64/28240.63.9.65 to 240.63.9.78240.63.9.7914
150240.63.9.80/28240.63.9.81 to 240.63.9.94240.63.9.9514
151240.63.9.96/28240.63.9.97 to 240.63.9.110240.63.9.11114
152240.63.9.112/28240.63.9.113 to 240.63.9.126240.63.9.12714
153240.63.9.128/28240.63.9.129 to 240.63.9.142240.63.9.14314
154240.63.9.144/28240.63.9.145 to 240.63.9.158240.63.9.15914
155240.63.9.160/28240.63.9.161 to 240.63.9.174240.63.9.17514
156240.63.9.176/28240.63.9.177 to 240.63.9.190240.63.9.19114
157240.63.9.192/28240.63.9.193 to 240.63.9.206240.63.9.20714
158240.63.9.208/28240.63.9.209 to 240.63.9.222240.63.9.22314
159240.63.9.224/28240.63.9.225 to 240.63.9.238240.63.9.23914
160240.63.9.240/28240.63.9.241 to 240.63.9.254240.63.9.25514
161240.63.10.0/28240.63.10.1 to 240.63.10.14240.63.10.1514
162240.63.10.16/28240.63.10.17 to 240.63.10.30240.63.10.3114
163240.63.10.32/28240.63.10.33 to 240.63.10.46240.63.10.4714
164240.63.10.48/28240.63.10.49 to 240.63.10.62240.63.10.6314
165240.63.10.64/28240.63.10.65 to 240.63.10.78240.63.10.7914
166240.63.10.80/28240.63.10.81 to 240.63.10.94240.63.10.9514
167240.63.10.96/28240.63.10.97 to 240.63.10.110240.63.10.11114
168240.63.10.112/28240.63.10.113 to 240.63.10.126240.63.10.12714
169240.63.10.128/28240.63.10.129 to 240.63.10.142240.63.10.14314
170240.63.10.144/28240.63.10.145 to 240.63.10.158240.63.10.15914
171240.63.10.160/28240.63.10.161 to 240.63.10.174240.63.10.17514
172240.63.10.176/28240.63.10.177 to 240.63.10.190240.63.10.19114
173240.63.10.192/28240.63.10.193 to 240.63.10.206240.63.10.20714
174240.63.10.208/28240.63.10.209 to 240.63.10.222240.63.10.22314
175240.63.10.224/28240.63.10.225 to 240.63.10.238240.63.10.23914
176240.63.10.240/28240.63.10.241 to 240.63.10.254240.63.10.25514
177240.63.11.0/28240.63.11.1 to 240.63.11.14240.63.11.1514
178240.63.11.16/28240.63.11.17 to 240.63.11.30240.63.11.3114
179240.63.11.32/28240.63.11.33 to 240.63.11.46240.63.11.4714
180240.63.11.48/28240.63.11.49 to 240.63.11.62240.63.11.6314
181240.63.11.64/28240.63.11.65 to 240.63.11.78240.63.11.7914
182240.63.11.80/28240.63.11.81 to 240.63.11.94240.63.11.9514
183240.63.11.96/28240.63.11.97 to 240.63.11.110240.63.11.11114
184240.63.11.112/28240.63.11.113 to 240.63.11.126240.63.11.12714
185240.63.11.128/28240.63.11.129 to 240.63.11.142240.63.11.14314
186240.63.11.144/28240.63.11.145 to 240.63.11.158240.63.11.15914
187240.63.11.160/28240.63.11.161 to 240.63.11.174240.63.11.17514
188240.63.11.176/28240.63.11.177 to 240.63.11.190240.63.11.19114
189240.63.11.192/28240.63.11.193 to 240.63.11.206240.63.11.20714
190240.63.11.208/28240.63.11.209 to 240.63.11.222240.63.11.22314
191240.63.11.224/28240.63.11.225 to 240.63.11.238240.63.11.23914
192240.63.11.240/28240.63.11.241 to 240.63.11.254240.63.11.25514
193240.63.12.0/28240.63.12.1 to 240.63.12.14240.63.12.1514
194240.63.12.16/28240.63.12.17 to 240.63.12.30240.63.12.3114
195240.63.12.32/28240.63.12.33 to 240.63.12.46240.63.12.4714
196240.63.12.48/28240.63.12.49 to 240.63.12.62240.63.12.6314
197240.63.12.64/28240.63.12.65 to 240.63.12.78240.63.12.7914
198240.63.12.80/28240.63.12.81 to 240.63.12.94240.63.12.9514
199240.63.12.96/28240.63.12.97 to 240.63.12.110240.63.12.11114
200240.63.12.112/28240.63.12.113 to 240.63.12.126240.63.12.12714
201240.63.12.128/28240.63.12.129 to 240.63.12.142240.63.12.14314
202240.63.12.144/28240.63.12.145 to 240.63.12.158240.63.12.15914
203240.63.12.160/28240.63.12.161 to 240.63.12.174240.63.12.17514
204240.63.12.176/28240.63.12.177 to 240.63.12.190240.63.12.19114
205240.63.12.192/28240.63.12.193 to 240.63.12.206240.63.12.20714
206240.63.12.208/28240.63.12.209 to 240.63.12.222240.63.12.22314
207240.63.12.224/28240.63.12.225 to 240.63.12.238240.63.12.23914
208240.63.12.240/28240.63.12.241 to 240.63.12.254240.63.12.25514
209240.63.13.0/28240.63.13.1 to 240.63.13.14240.63.13.1514
210240.63.13.16/28240.63.13.17 to 240.63.13.30240.63.13.3114
211240.63.13.32/28240.63.13.33 to 240.63.13.46240.63.13.4714
212240.63.13.48/28240.63.13.49 to 240.63.13.62240.63.13.6314
213240.63.13.64/28240.63.13.65 to 240.63.13.78240.63.13.7914
214240.63.13.80/28240.63.13.81 to 240.63.13.94240.63.13.9514
215240.63.13.96/28240.63.13.97 to 240.63.13.110240.63.13.11114
216240.63.13.112/28240.63.13.113 to 240.63.13.126240.63.13.12714
217240.63.13.128/28240.63.13.129 to 240.63.13.142240.63.13.14314
218240.63.13.144/28240.63.13.145 to 240.63.13.158240.63.13.15914
219240.63.13.160/28240.63.13.161 to 240.63.13.174240.63.13.17514
220240.63.13.176/28240.63.13.177 to 240.63.13.190240.63.13.19114
221240.63.13.192/28240.63.13.193 to 240.63.13.206240.63.13.20714
222240.63.13.208/28240.63.13.209 to 240.63.13.222240.63.13.22314
223240.63.13.224/28240.63.13.225 to 240.63.13.238240.63.13.23914
224240.63.13.240/28240.63.13.241 to 240.63.13.254240.63.13.25514
225240.63.14.0/28240.63.14.1 to 240.63.14.14240.63.14.1514
226240.63.14.16/28240.63.14.17 to 240.63.14.30240.63.14.3114
227240.63.14.32/28240.63.14.33 to 240.63.14.46240.63.14.4714
228240.63.14.48/28240.63.14.49 to 240.63.14.62240.63.14.6314
229240.63.14.64/28240.63.14.65 to 240.63.14.78240.63.14.7914
230240.63.14.80/28240.63.14.81 to 240.63.14.94240.63.14.9514
231240.63.14.96/28240.63.14.97 to 240.63.14.110240.63.14.11114
232240.63.14.112/28240.63.14.113 to 240.63.14.126240.63.14.12714
233240.63.14.128/28240.63.14.129 to 240.63.14.142240.63.14.14314
234240.63.14.144/28240.63.14.145 to 240.63.14.158240.63.14.15914
235240.63.14.160/28240.63.14.161 to 240.63.14.174240.63.14.17514
236240.63.14.176/28240.63.14.177 to 240.63.14.190240.63.14.19114
237240.63.14.192/28240.63.14.193 to 240.63.14.206240.63.14.20714
238240.63.14.208/28240.63.14.209 to 240.63.14.222240.63.14.22314
239240.63.14.224/28240.63.14.225 to 240.63.14.238240.63.14.23914
240240.63.14.240/28240.63.14.241 to 240.63.14.254240.63.14.25514
241240.63.15.0/28240.63.15.1 to 240.63.15.14240.63.15.1514
242240.63.15.16/28240.63.15.17 to 240.63.15.30240.63.15.3114
243240.63.15.32/28240.63.15.33 to 240.63.15.46240.63.15.4714
244240.63.15.48/28240.63.15.49 to 240.63.15.62240.63.15.6314
245240.63.15.64/28240.63.15.65 to 240.63.15.78240.63.15.7914
246240.63.15.80/28240.63.15.81 to 240.63.15.94240.63.15.9514
247240.63.15.96/28240.63.15.97 to 240.63.15.110240.63.15.11114
248240.63.15.112/28240.63.15.113 to 240.63.15.126240.63.15.12714
249240.63.15.128/28240.63.15.129 to 240.63.15.142240.63.15.14314
250240.63.15.144/28240.63.15.145 to 240.63.15.158240.63.15.15914
251240.63.15.160/28240.63.15.161 to 240.63.15.174240.63.15.17514
252240.63.15.176/28240.63.15.177 to 240.63.15.190240.63.15.19114
253240.63.15.192/28240.63.15.193 to 240.63.15.206240.63.15.20714
254240.63.15.208/28240.63.15.209 to 240.63.15.222240.63.15.22314
255240.63.15.224/28240.63.15.225 to 240.63.15.238240.63.15.23914
256240.63.15.240/28240.63.15.241 to 240.63.15.254240.63.15.25514

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.