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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.

Network248.87.64.0/19
Usable hosts8,190
Subnet mask255.255.224.0
Addresses8,192
Network address
248.87.64.0
Broadcast address
248.87.95.255
First usable
248.87.64.1
Last usable
248.87.95.254
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
Reserved 240.0.0.0/4
Future use; not usable on most systems
Old class
E (reserved)
As numbers
Hex F8574000 · Integer 4166467584 to 4166475775
Reverse DNS zones
64.87.248.in-addr.arpa
65.87.248.in-addr.arpa
66.87.248.in-addr.arpa
67.87.248.in-addr.arpa
68.87.248.in-addr.arpa
69.87.248.in-addr.arpa
70.87.248.in-addr.arpa
71.87.248.in-addr.arpa
72.87.248.in-addr.arpa
73.87.248.in-addr.arpa
74.87.248.in-addr.arpa
75.87.248.in-addr.arpa
76.87.248.in-addr.arpa
77.87.248.in-addr.arpa
78.87.248.in-addr.arpa
79.87.248.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
Address11111000.01010111.01000000.00000000248.87.64.0
Subnet mask11111111.11111111.11100000.00000000255.255.224.0
Network11111000.01010111.01000000.00000000248.87.64.0
Broadcast11111000.01010111.01011111.11111111248.87.95.255
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)

248.87.64.0/19 makes 512 subnets of /28; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1248.87.64.0/28248.87.64.1 to 248.87.64.14248.87.64.1514
2248.87.64.16/28248.87.64.17 to 248.87.64.30248.87.64.3114
3248.87.64.32/28248.87.64.33 to 248.87.64.46248.87.64.4714
4248.87.64.48/28248.87.64.49 to 248.87.64.62248.87.64.6314
5248.87.64.64/28248.87.64.65 to 248.87.64.78248.87.64.7914
6248.87.64.80/28248.87.64.81 to 248.87.64.94248.87.64.9514
7248.87.64.96/28248.87.64.97 to 248.87.64.110248.87.64.11114
8248.87.64.112/28248.87.64.113 to 248.87.64.126248.87.64.12714
9248.87.64.128/28248.87.64.129 to 248.87.64.142248.87.64.14314
10248.87.64.144/28248.87.64.145 to 248.87.64.158248.87.64.15914
11248.87.64.160/28248.87.64.161 to 248.87.64.174248.87.64.17514
12248.87.64.176/28248.87.64.177 to 248.87.64.190248.87.64.19114
13248.87.64.192/28248.87.64.193 to 248.87.64.206248.87.64.20714
14248.87.64.208/28248.87.64.209 to 248.87.64.222248.87.64.22314
15248.87.64.224/28248.87.64.225 to 248.87.64.238248.87.64.23914
16248.87.64.240/28248.87.64.241 to 248.87.64.254248.87.64.25514
17248.87.65.0/28248.87.65.1 to 248.87.65.14248.87.65.1514
18248.87.65.16/28248.87.65.17 to 248.87.65.30248.87.65.3114
19248.87.65.32/28248.87.65.33 to 248.87.65.46248.87.65.4714
20248.87.65.48/28248.87.65.49 to 248.87.65.62248.87.65.6314
21248.87.65.64/28248.87.65.65 to 248.87.65.78248.87.65.7914
22248.87.65.80/28248.87.65.81 to 248.87.65.94248.87.65.9514
23248.87.65.96/28248.87.65.97 to 248.87.65.110248.87.65.11114
24248.87.65.112/28248.87.65.113 to 248.87.65.126248.87.65.12714
25248.87.65.128/28248.87.65.129 to 248.87.65.142248.87.65.14314
26248.87.65.144/28248.87.65.145 to 248.87.65.158248.87.65.15914
27248.87.65.160/28248.87.65.161 to 248.87.65.174248.87.65.17514
28248.87.65.176/28248.87.65.177 to 248.87.65.190248.87.65.19114
29248.87.65.192/28248.87.65.193 to 248.87.65.206248.87.65.20714
30248.87.65.208/28248.87.65.209 to 248.87.65.222248.87.65.22314
31248.87.65.224/28248.87.65.225 to 248.87.65.238248.87.65.23914
32248.87.65.240/28248.87.65.241 to 248.87.65.254248.87.65.25514
33248.87.66.0/28248.87.66.1 to 248.87.66.14248.87.66.1514
34248.87.66.16/28248.87.66.17 to 248.87.66.30248.87.66.3114
35248.87.66.32/28248.87.66.33 to 248.87.66.46248.87.66.4714
36248.87.66.48/28248.87.66.49 to 248.87.66.62248.87.66.6314
37248.87.66.64/28248.87.66.65 to 248.87.66.78248.87.66.7914
38248.87.66.80/28248.87.66.81 to 248.87.66.94248.87.66.9514
39248.87.66.96/28248.87.66.97 to 248.87.66.110248.87.66.11114
40248.87.66.112/28248.87.66.113 to 248.87.66.126248.87.66.12714
41248.87.66.128/28248.87.66.129 to 248.87.66.142248.87.66.14314
42248.87.66.144/28248.87.66.145 to 248.87.66.158248.87.66.15914
43248.87.66.160/28248.87.66.161 to 248.87.66.174248.87.66.17514
44248.87.66.176/28248.87.66.177 to 248.87.66.190248.87.66.19114
45248.87.66.192/28248.87.66.193 to 248.87.66.206248.87.66.20714
46248.87.66.208/28248.87.66.209 to 248.87.66.222248.87.66.22314
47248.87.66.224/28248.87.66.225 to 248.87.66.238248.87.66.23914
48248.87.66.240/28248.87.66.241 to 248.87.66.254248.87.66.25514
49248.87.67.0/28248.87.67.1 to 248.87.67.14248.87.67.1514
50248.87.67.16/28248.87.67.17 to 248.87.67.30248.87.67.3114
51248.87.67.32/28248.87.67.33 to 248.87.67.46248.87.67.4714
52248.87.67.48/28248.87.67.49 to 248.87.67.62248.87.67.6314
53248.87.67.64/28248.87.67.65 to 248.87.67.78248.87.67.7914
54248.87.67.80/28248.87.67.81 to 248.87.67.94248.87.67.9514
55248.87.67.96/28248.87.67.97 to 248.87.67.110248.87.67.11114
56248.87.67.112/28248.87.67.113 to 248.87.67.126248.87.67.12714
57248.87.67.128/28248.87.67.129 to 248.87.67.142248.87.67.14314
58248.87.67.144/28248.87.67.145 to 248.87.67.158248.87.67.15914
59248.87.67.160/28248.87.67.161 to 248.87.67.174248.87.67.17514
60248.87.67.176/28248.87.67.177 to 248.87.67.190248.87.67.19114
61248.87.67.192/28248.87.67.193 to 248.87.67.206248.87.67.20714
62248.87.67.208/28248.87.67.209 to 248.87.67.222248.87.67.22314
63248.87.67.224/28248.87.67.225 to 248.87.67.238248.87.67.23914
64248.87.67.240/28248.87.67.241 to 248.87.67.254248.87.67.25514
65248.87.68.0/28248.87.68.1 to 248.87.68.14248.87.68.1514
66248.87.68.16/28248.87.68.17 to 248.87.68.30248.87.68.3114
67248.87.68.32/28248.87.68.33 to 248.87.68.46248.87.68.4714
68248.87.68.48/28248.87.68.49 to 248.87.68.62248.87.68.6314
69248.87.68.64/28248.87.68.65 to 248.87.68.78248.87.68.7914
70248.87.68.80/28248.87.68.81 to 248.87.68.94248.87.68.9514
71248.87.68.96/28248.87.68.97 to 248.87.68.110248.87.68.11114
72248.87.68.112/28248.87.68.113 to 248.87.68.126248.87.68.12714
73248.87.68.128/28248.87.68.129 to 248.87.68.142248.87.68.14314
74248.87.68.144/28248.87.68.145 to 248.87.68.158248.87.68.15914
75248.87.68.160/28248.87.68.161 to 248.87.68.174248.87.68.17514
76248.87.68.176/28248.87.68.177 to 248.87.68.190248.87.68.19114
77248.87.68.192/28248.87.68.193 to 248.87.68.206248.87.68.20714
78248.87.68.208/28248.87.68.209 to 248.87.68.222248.87.68.22314
79248.87.68.224/28248.87.68.225 to 248.87.68.238248.87.68.23914
80248.87.68.240/28248.87.68.241 to 248.87.68.254248.87.68.25514
81248.87.69.0/28248.87.69.1 to 248.87.69.14248.87.69.1514
82248.87.69.16/28248.87.69.17 to 248.87.69.30248.87.69.3114
83248.87.69.32/28248.87.69.33 to 248.87.69.46248.87.69.4714
84248.87.69.48/28248.87.69.49 to 248.87.69.62248.87.69.6314
85248.87.69.64/28248.87.69.65 to 248.87.69.78248.87.69.7914
86248.87.69.80/28248.87.69.81 to 248.87.69.94248.87.69.9514
87248.87.69.96/28248.87.69.97 to 248.87.69.110248.87.69.11114
88248.87.69.112/28248.87.69.113 to 248.87.69.126248.87.69.12714
89248.87.69.128/28248.87.69.129 to 248.87.69.142248.87.69.14314
90248.87.69.144/28248.87.69.145 to 248.87.69.158248.87.69.15914
91248.87.69.160/28248.87.69.161 to 248.87.69.174248.87.69.17514
92248.87.69.176/28248.87.69.177 to 248.87.69.190248.87.69.19114
93248.87.69.192/28248.87.69.193 to 248.87.69.206248.87.69.20714
94248.87.69.208/28248.87.69.209 to 248.87.69.222248.87.69.22314
95248.87.69.224/28248.87.69.225 to 248.87.69.238248.87.69.23914
96248.87.69.240/28248.87.69.241 to 248.87.69.254248.87.69.25514
97248.87.70.0/28248.87.70.1 to 248.87.70.14248.87.70.1514
98248.87.70.16/28248.87.70.17 to 248.87.70.30248.87.70.3114
99248.87.70.32/28248.87.70.33 to 248.87.70.46248.87.70.4714
100248.87.70.48/28248.87.70.49 to 248.87.70.62248.87.70.6314
101248.87.70.64/28248.87.70.65 to 248.87.70.78248.87.70.7914
102248.87.70.80/28248.87.70.81 to 248.87.70.94248.87.70.9514
103248.87.70.96/28248.87.70.97 to 248.87.70.110248.87.70.11114
104248.87.70.112/28248.87.70.113 to 248.87.70.126248.87.70.12714
105248.87.70.128/28248.87.70.129 to 248.87.70.142248.87.70.14314
106248.87.70.144/28248.87.70.145 to 248.87.70.158248.87.70.15914
107248.87.70.160/28248.87.70.161 to 248.87.70.174248.87.70.17514
108248.87.70.176/28248.87.70.177 to 248.87.70.190248.87.70.19114
109248.87.70.192/28248.87.70.193 to 248.87.70.206248.87.70.20714
110248.87.70.208/28248.87.70.209 to 248.87.70.222248.87.70.22314
111248.87.70.224/28248.87.70.225 to 248.87.70.238248.87.70.23914
112248.87.70.240/28248.87.70.241 to 248.87.70.254248.87.70.25514
113248.87.71.0/28248.87.71.1 to 248.87.71.14248.87.71.1514
114248.87.71.16/28248.87.71.17 to 248.87.71.30248.87.71.3114
115248.87.71.32/28248.87.71.33 to 248.87.71.46248.87.71.4714
116248.87.71.48/28248.87.71.49 to 248.87.71.62248.87.71.6314
117248.87.71.64/28248.87.71.65 to 248.87.71.78248.87.71.7914
118248.87.71.80/28248.87.71.81 to 248.87.71.94248.87.71.9514
119248.87.71.96/28248.87.71.97 to 248.87.71.110248.87.71.11114
120248.87.71.112/28248.87.71.113 to 248.87.71.126248.87.71.12714
121248.87.71.128/28248.87.71.129 to 248.87.71.142248.87.71.14314
122248.87.71.144/28248.87.71.145 to 248.87.71.158248.87.71.15914
123248.87.71.160/28248.87.71.161 to 248.87.71.174248.87.71.17514
124248.87.71.176/28248.87.71.177 to 248.87.71.190248.87.71.19114
125248.87.71.192/28248.87.71.193 to 248.87.71.206248.87.71.20714
126248.87.71.208/28248.87.71.209 to 248.87.71.222248.87.71.22314
127248.87.71.224/28248.87.71.225 to 248.87.71.238248.87.71.23914
128248.87.71.240/28248.87.71.241 to 248.87.71.254248.87.71.25514
129248.87.72.0/28248.87.72.1 to 248.87.72.14248.87.72.1514
130248.87.72.16/28248.87.72.17 to 248.87.72.30248.87.72.3114
131248.87.72.32/28248.87.72.33 to 248.87.72.46248.87.72.4714
132248.87.72.48/28248.87.72.49 to 248.87.72.62248.87.72.6314
133248.87.72.64/28248.87.72.65 to 248.87.72.78248.87.72.7914
134248.87.72.80/28248.87.72.81 to 248.87.72.94248.87.72.9514
135248.87.72.96/28248.87.72.97 to 248.87.72.110248.87.72.11114
136248.87.72.112/28248.87.72.113 to 248.87.72.126248.87.72.12714
137248.87.72.128/28248.87.72.129 to 248.87.72.142248.87.72.14314
138248.87.72.144/28248.87.72.145 to 248.87.72.158248.87.72.15914
139248.87.72.160/28248.87.72.161 to 248.87.72.174248.87.72.17514
140248.87.72.176/28248.87.72.177 to 248.87.72.190248.87.72.19114
141248.87.72.192/28248.87.72.193 to 248.87.72.206248.87.72.20714
142248.87.72.208/28248.87.72.209 to 248.87.72.222248.87.72.22314
143248.87.72.224/28248.87.72.225 to 248.87.72.238248.87.72.23914
144248.87.72.240/28248.87.72.241 to 248.87.72.254248.87.72.25514
145248.87.73.0/28248.87.73.1 to 248.87.73.14248.87.73.1514
146248.87.73.16/28248.87.73.17 to 248.87.73.30248.87.73.3114
147248.87.73.32/28248.87.73.33 to 248.87.73.46248.87.73.4714
148248.87.73.48/28248.87.73.49 to 248.87.73.62248.87.73.6314
149248.87.73.64/28248.87.73.65 to 248.87.73.78248.87.73.7914
150248.87.73.80/28248.87.73.81 to 248.87.73.94248.87.73.9514
151248.87.73.96/28248.87.73.97 to 248.87.73.110248.87.73.11114
152248.87.73.112/28248.87.73.113 to 248.87.73.126248.87.73.12714
153248.87.73.128/28248.87.73.129 to 248.87.73.142248.87.73.14314
154248.87.73.144/28248.87.73.145 to 248.87.73.158248.87.73.15914
155248.87.73.160/28248.87.73.161 to 248.87.73.174248.87.73.17514
156248.87.73.176/28248.87.73.177 to 248.87.73.190248.87.73.19114
157248.87.73.192/28248.87.73.193 to 248.87.73.206248.87.73.20714
158248.87.73.208/28248.87.73.209 to 248.87.73.222248.87.73.22314
159248.87.73.224/28248.87.73.225 to 248.87.73.238248.87.73.23914
160248.87.73.240/28248.87.73.241 to 248.87.73.254248.87.73.25514
161248.87.74.0/28248.87.74.1 to 248.87.74.14248.87.74.1514
162248.87.74.16/28248.87.74.17 to 248.87.74.30248.87.74.3114
163248.87.74.32/28248.87.74.33 to 248.87.74.46248.87.74.4714
164248.87.74.48/28248.87.74.49 to 248.87.74.62248.87.74.6314
165248.87.74.64/28248.87.74.65 to 248.87.74.78248.87.74.7914
166248.87.74.80/28248.87.74.81 to 248.87.74.94248.87.74.9514
167248.87.74.96/28248.87.74.97 to 248.87.74.110248.87.74.11114
168248.87.74.112/28248.87.74.113 to 248.87.74.126248.87.74.12714
169248.87.74.128/28248.87.74.129 to 248.87.74.142248.87.74.14314
170248.87.74.144/28248.87.74.145 to 248.87.74.158248.87.74.15914
171248.87.74.160/28248.87.74.161 to 248.87.74.174248.87.74.17514
172248.87.74.176/28248.87.74.177 to 248.87.74.190248.87.74.19114
173248.87.74.192/28248.87.74.193 to 248.87.74.206248.87.74.20714
174248.87.74.208/28248.87.74.209 to 248.87.74.222248.87.74.22314
175248.87.74.224/28248.87.74.225 to 248.87.74.238248.87.74.23914
176248.87.74.240/28248.87.74.241 to 248.87.74.254248.87.74.25514
177248.87.75.0/28248.87.75.1 to 248.87.75.14248.87.75.1514
178248.87.75.16/28248.87.75.17 to 248.87.75.30248.87.75.3114
179248.87.75.32/28248.87.75.33 to 248.87.75.46248.87.75.4714
180248.87.75.48/28248.87.75.49 to 248.87.75.62248.87.75.6314
181248.87.75.64/28248.87.75.65 to 248.87.75.78248.87.75.7914
182248.87.75.80/28248.87.75.81 to 248.87.75.94248.87.75.9514
183248.87.75.96/28248.87.75.97 to 248.87.75.110248.87.75.11114
184248.87.75.112/28248.87.75.113 to 248.87.75.126248.87.75.12714
185248.87.75.128/28248.87.75.129 to 248.87.75.142248.87.75.14314
186248.87.75.144/28248.87.75.145 to 248.87.75.158248.87.75.15914
187248.87.75.160/28248.87.75.161 to 248.87.75.174248.87.75.17514
188248.87.75.176/28248.87.75.177 to 248.87.75.190248.87.75.19114
189248.87.75.192/28248.87.75.193 to 248.87.75.206248.87.75.20714
190248.87.75.208/28248.87.75.209 to 248.87.75.222248.87.75.22314
191248.87.75.224/28248.87.75.225 to 248.87.75.238248.87.75.23914
192248.87.75.240/28248.87.75.241 to 248.87.75.254248.87.75.25514
193248.87.76.0/28248.87.76.1 to 248.87.76.14248.87.76.1514
194248.87.76.16/28248.87.76.17 to 248.87.76.30248.87.76.3114
195248.87.76.32/28248.87.76.33 to 248.87.76.46248.87.76.4714
196248.87.76.48/28248.87.76.49 to 248.87.76.62248.87.76.6314
197248.87.76.64/28248.87.76.65 to 248.87.76.78248.87.76.7914
198248.87.76.80/28248.87.76.81 to 248.87.76.94248.87.76.9514
199248.87.76.96/28248.87.76.97 to 248.87.76.110248.87.76.11114
200248.87.76.112/28248.87.76.113 to 248.87.76.126248.87.76.12714
201248.87.76.128/28248.87.76.129 to 248.87.76.142248.87.76.14314
202248.87.76.144/28248.87.76.145 to 248.87.76.158248.87.76.15914
203248.87.76.160/28248.87.76.161 to 248.87.76.174248.87.76.17514
204248.87.76.176/28248.87.76.177 to 248.87.76.190248.87.76.19114
205248.87.76.192/28248.87.76.193 to 248.87.76.206248.87.76.20714
206248.87.76.208/28248.87.76.209 to 248.87.76.222248.87.76.22314
207248.87.76.224/28248.87.76.225 to 248.87.76.238248.87.76.23914
208248.87.76.240/28248.87.76.241 to 248.87.76.254248.87.76.25514
209248.87.77.0/28248.87.77.1 to 248.87.77.14248.87.77.1514
210248.87.77.16/28248.87.77.17 to 248.87.77.30248.87.77.3114
211248.87.77.32/28248.87.77.33 to 248.87.77.46248.87.77.4714
212248.87.77.48/28248.87.77.49 to 248.87.77.62248.87.77.6314
213248.87.77.64/28248.87.77.65 to 248.87.77.78248.87.77.7914
214248.87.77.80/28248.87.77.81 to 248.87.77.94248.87.77.9514
215248.87.77.96/28248.87.77.97 to 248.87.77.110248.87.77.11114
216248.87.77.112/28248.87.77.113 to 248.87.77.126248.87.77.12714
217248.87.77.128/28248.87.77.129 to 248.87.77.142248.87.77.14314
218248.87.77.144/28248.87.77.145 to 248.87.77.158248.87.77.15914
219248.87.77.160/28248.87.77.161 to 248.87.77.174248.87.77.17514
220248.87.77.176/28248.87.77.177 to 248.87.77.190248.87.77.19114
221248.87.77.192/28248.87.77.193 to 248.87.77.206248.87.77.20714
222248.87.77.208/28248.87.77.209 to 248.87.77.222248.87.77.22314
223248.87.77.224/28248.87.77.225 to 248.87.77.238248.87.77.23914
224248.87.77.240/28248.87.77.241 to 248.87.77.254248.87.77.25514
225248.87.78.0/28248.87.78.1 to 248.87.78.14248.87.78.1514
226248.87.78.16/28248.87.78.17 to 248.87.78.30248.87.78.3114
227248.87.78.32/28248.87.78.33 to 248.87.78.46248.87.78.4714
228248.87.78.48/28248.87.78.49 to 248.87.78.62248.87.78.6314
229248.87.78.64/28248.87.78.65 to 248.87.78.78248.87.78.7914
230248.87.78.80/28248.87.78.81 to 248.87.78.94248.87.78.9514
231248.87.78.96/28248.87.78.97 to 248.87.78.110248.87.78.11114
232248.87.78.112/28248.87.78.113 to 248.87.78.126248.87.78.12714
233248.87.78.128/28248.87.78.129 to 248.87.78.142248.87.78.14314
234248.87.78.144/28248.87.78.145 to 248.87.78.158248.87.78.15914
235248.87.78.160/28248.87.78.161 to 248.87.78.174248.87.78.17514
236248.87.78.176/28248.87.78.177 to 248.87.78.190248.87.78.19114
237248.87.78.192/28248.87.78.193 to 248.87.78.206248.87.78.20714
238248.87.78.208/28248.87.78.209 to 248.87.78.222248.87.78.22314
239248.87.78.224/28248.87.78.225 to 248.87.78.238248.87.78.23914
240248.87.78.240/28248.87.78.241 to 248.87.78.254248.87.78.25514
241248.87.79.0/28248.87.79.1 to 248.87.79.14248.87.79.1514
242248.87.79.16/28248.87.79.17 to 248.87.79.30248.87.79.3114
243248.87.79.32/28248.87.79.33 to 248.87.79.46248.87.79.4714
244248.87.79.48/28248.87.79.49 to 248.87.79.62248.87.79.6314
245248.87.79.64/28248.87.79.65 to 248.87.79.78248.87.79.7914
246248.87.79.80/28248.87.79.81 to 248.87.79.94248.87.79.9514
247248.87.79.96/28248.87.79.97 to 248.87.79.110248.87.79.11114
248248.87.79.112/28248.87.79.113 to 248.87.79.126248.87.79.12714
249248.87.79.128/28248.87.79.129 to 248.87.79.142248.87.79.14314
250248.87.79.144/28248.87.79.145 to 248.87.79.158248.87.79.15914
251248.87.79.160/28248.87.79.161 to 248.87.79.174248.87.79.17514
252248.87.79.176/28248.87.79.177 to 248.87.79.190248.87.79.19114
253248.87.79.192/28248.87.79.193 to 248.87.79.206248.87.79.20714
254248.87.79.208/28248.87.79.209 to 248.87.79.222248.87.79.22314
255248.87.79.224/28248.87.79.225 to 248.87.79.238248.87.79.23914
256248.87.79.240/28248.87.79.241 to 248.87.79.254248.87.79.25514

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.