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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.

Network227.2.64.0/20
Usable hosts4,094
Subnet mask255.255.240.0
Addresses4,096
Network address
227.2.64.0
Broadcast address
227.2.79.255
First usable
227.2.64.1
Last usable
227.2.79.254
Usable hosts
4,094 (4,096 less the network and broadcast addresses)
Subnet mask
255.255.240.0
Wildcard mask
0.0.15.255 (Cisco ACLs, OSPF)
Prefix length
/20
Type
Multicast 224.0.0.0/4
One-to-many traffic, such as IPTV and routing protocols
Old class
D (multicast)
As numbers
Hex E3024000 · Integer 3808575488 to 3808579583
Reverse DNS zones
64.2.227.in-addr.arpa
65.2.227.in-addr.arpa
66.2.227.in-addr.arpa
67.2.227.in-addr.arpa
68.2.227.in-addr.arpa
69.2.227.in-addr.arpa
70.2.227.in-addr.arpa
71.2.227.in-addr.arpa
72.2.227.in-addr.arpa
73.2.227.in-addr.arpa
74.2.227.in-addr.arpa
75.2.227.in-addr.arpa
76.2.227.in-addr.arpa
77.2.227.in-addr.arpa
78.2.227.in-addr.arpa
79.2.227.in-addr.arpa
/20 is not on a 8-bit boundary, so it takes 16 /24 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address11100011.00000010.01000000.00000000227.2.64.0
Subnet mask11111111.11111111.11110000.00000000255.255.240.0
Network11100011.00000010.01000000.00000000227.2.64.0
Broadcast11100011.00000010.01001111.11111111227.2.79.255
Split into smaller subnets/28
/21 (2)/22 (4)/23 (8)/24 (16)/25 (32)/26 (64)/27 (128)/28 (256)/29 (512)/30 (1,024)/31 (2,048)/32 (4,096)

227.2.64.0/20 makes 256 subnets of /28.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1227.2.64.0/28227.2.64.1 to 227.2.64.14227.2.64.1514
2227.2.64.16/28227.2.64.17 to 227.2.64.30227.2.64.3114
3227.2.64.32/28227.2.64.33 to 227.2.64.46227.2.64.4714
4227.2.64.48/28227.2.64.49 to 227.2.64.62227.2.64.6314
5227.2.64.64/28227.2.64.65 to 227.2.64.78227.2.64.7914
6227.2.64.80/28227.2.64.81 to 227.2.64.94227.2.64.9514
7227.2.64.96/28227.2.64.97 to 227.2.64.110227.2.64.11114
8227.2.64.112/28227.2.64.113 to 227.2.64.126227.2.64.12714
9227.2.64.128/28227.2.64.129 to 227.2.64.142227.2.64.14314
10227.2.64.144/28227.2.64.145 to 227.2.64.158227.2.64.15914
11227.2.64.160/28227.2.64.161 to 227.2.64.174227.2.64.17514
12227.2.64.176/28227.2.64.177 to 227.2.64.190227.2.64.19114
13227.2.64.192/28227.2.64.193 to 227.2.64.206227.2.64.20714
14227.2.64.208/28227.2.64.209 to 227.2.64.222227.2.64.22314
15227.2.64.224/28227.2.64.225 to 227.2.64.238227.2.64.23914
16227.2.64.240/28227.2.64.241 to 227.2.64.254227.2.64.25514
17227.2.65.0/28227.2.65.1 to 227.2.65.14227.2.65.1514
18227.2.65.16/28227.2.65.17 to 227.2.65.30227.2.65.3114
19227.2.65.32/28227.2.65.33 to 227.2.65.46227.2.65.4714
20227.2.65.48/28227.2.65.49 to 227.2.65.62227.2.65.6314
21227.2.65.64/28227.2.65.65 to 227.2.65.78227.2.65.7914
22227.2.65.80/28227.2.65.81 to 227.2.65.94227.2.65.9514
23227.2.65.96/28227.2.65.97 to 227.2.65.110227.2.65.11114
24227.2.65.112/28227.2.65.113 to 227.2.65.126227.2.65.12714
25227.2.65.128/28227.2.65.129 to 227.2.65.142227.2.65.14314
26227.2.65.144/28227.2.65.145 to 227.2.65.158227.2.65.15914
27227.2.65.160/28227.2.65.161 to 227.2.65.174227.2.65.17514
28227.2.65.176/28227.2.65.177 to 227.2.65.190227.2.65.19114
29227.2.65.192/28227.2.65.193 to 227.2.65.206227.2.65.20714
30227.2.65.208/28227.2.65.209 to 227.2.65.222227.2.65.22314
31227.2.65.224/28227.2.65.225 to 227.2.65.238227.2.65.23914
32227.2.65.240/28227.2.65.241 to 227.2.65.254227.2.65.25514
33227.2.66.0/28227.2.66.1 to 227.2.66.14227.2.66.1514
34227.2.66.16/28227.2.66.17 to 227.2.66.30227.2.66.3114
35227.2.66.32/28227.2.66.33 to 227.2.66.46227.2.66.4714
36227.2.66.48/28227.2.66.49 to 227.2.66.62227.2.66.6314
37227.2.66.64/28227.2.66.65 to 227.2.66.78227.2.66.7914
38227.2.66.80/28227.2.66.81 to 227.2.66.94227.2.66.9514
39227.2.66.96/28227.2.66.97 to 227.2.66.110227.2.66.11114
40227.2.66.112/28227.2.66.113 to 227.2.66.126227.2.66.12714
41227.2.66.128/28227.2.66.129 to 227.2.66.142227.2.66.14314
42227.2.66.144/28227.2.66.145 to 227.2.66.158227.2.66.15914
43227.2.66.160/28227.2.66.161 to 227.2.66.174227.2.66.17514
44227.2.66.176/28227.2.66.177 to 227.2.66.190227.2.66.19114
45227.2.66.192/28227.2.66.193 to 227.2.66.206227.2.66.20714
46227.2.66.208/28227.2.66.209 to 227.2.66.222227.2.66.22314
47227.2.66.224/28227.2.66.225 to 227.2.66.238227.2.66.23914
48227.2.66.240/28227.2.66.241 to 227.2.66.254227.2.66.25514
49227.2.67.0/28227.2.67.1 to 227.2.67.14227.2.67.1514
50227.2.67.16/28227.2.67.17 to 227.2.67.30227.2.67.3114
51227.2.67.32/28227.2.67.33 to 227.2.67.46227.2.67.4714
52227.2.67.48/28227.2.67.49 to 227.2.67.62227.2.67.6314
53227.2.67.64/28227.2.67.65 to 227.2.67.78227.2.67.7914
54227.2.67.80/28227.2.67.81 to 227.2.67.94227.2.67.9514
55227.2.67.96/28227.2.67.97 to 227.2.67.110227.2.67.11114
56227.2.67.112/28227.2.67.113 to 227.2.67.126227.2.67.12714
57227.2.67.128/28227.2.67.129 to 227.2.67.142227.2.67.14314
58227.2.67.144/28227.2.67.145 to 227.2.67.158227.2.67.15914
59227.2.67.160/28227.2.67.161 to 227.2.67.174227.2.67.17514
60227.2.67.176/28227.2.67.177 to 227.2.67.190227.2.67.19114
61227.2.67.192/28227.2.67.193 to 227.2.67.206227.2.67.20714
62227.2.67.208/28227.2.67.209 to 227.2.67.222227.2.67.22314
63227.2.67.224/28227.2.67.225 to 227.2.67.238227.2.67.23914
64227.2.67.240/28227.2.67.241 to 227.2.67.254227.2.67.25514
65227.2.68.0/28227.2.68.1 to 227.2.68.14227.2.68.1514
66227.2.68.16/28227.2.68.17 to 227.2.68.30227.2.68.3114
67227.2.68.32/28227.2.68.33 to 227.2.68.46227.2.68.4714
68227.2.68.48/28227.2.68.49 to 227.2.68.62227.2.68.6314
69227.2.68.64/28227.2.68.65 to 227.2.68.78227.2.68.7914
70227.2.68.80/28227.2.68.81 to 227.2.68.94227.2.68.9514
71227.2.68.96/28227.2.68.97 to 227.2.68.110227.2.68.11114
72227.2.68.112/28227.2.68.113 to 227.2.68.126227.2.68.12714
73227.2.68.128/28227.2.68.129 to 227.2.68.142227.2.68.14314
74227.2.68.144/28227.2.68.145 to 227.2.68.158227.2.68.15914
75227.2.68.160/28227.2.68.161 to 227.2.68.174227.2.68.17514
76227.2.68.176/28227.2.68.177 to 227.2.68.190227.2.68.19114
77227.2.68.192/28227.2.68.193 to 227.2.68.206227.2.68.20714
78227.2.68.208/28227.2.68.209 to 227.2.68.222227.2.68.22314
79227.2.68.224/28227.2.68.225 to 227.2.68.238227.2.68.23914
80227.2.68.240/28227.2.68.241 to 227.2.68.254227.2.68.25514
81227.2.69.0/28227.2.69.1 to 227.2.69.14227.2.69.1514
82227.2.69.16/28227.2.69.17 to 227.2.69.30227.2.69.3114
83227.2.69.32/28227.2.69.33 to 227.2.69.46227.2.69.4714
84227.2.69.48/28227.2.69.49 to 227.2.69.62227.2.69.6314
85227.2.69.64/28227.2.69.65 to 227.2.69.78227.2.69.7914
86227.2.69.80/28227.2.69.81 to 227.2.69.94227.2.69.9514
87227.2.69.96/28227.2.69.97 to 227.2.69.110227.2.69.11114
88227.2.69.112/28227.2.69.113 to 227.2.69.126227.2.69.12714
89227.2.69.128/28227.2.69.129 to 227.2.69.142227.2.69.14314
90227.2.69.144/28227.2.69.145 to 227.2.69.158227.2.69.15914
91227.2.69.160/28227.2.69.161 to 227.2.69.174227.2.69.17514
92227.2.69.176/28227.2.69.177 to 227.2.69.190227.2.69.19114
93227.2.69.192/28227.2.69.193 to 227.2.69.206227.2.69.20714
94227.2.69.208/28227.2.69.209 to 227.2.69.222227.2.69.22314
95227.2.69.224/28227.2.69.225 to 227.2.69.238227.2.69.23914
96227.2.69.240/28227.2.69.241 to 227.2.69.254227.2.69.25514
97227.2.70.0/28227.2.70.1 to 227.2.70.14227.2.70.1514
98227.2.70.16/28227.2.70.17 to 227.2.70.30227.2.70.3114
99227.2.70.32/28227.2.70.33 to 227.2.70.46227.2.70.4714
100227.2.70.48/28227.2.70.49 to 227.2.70.62227.2.70.6314
101227.2.70.64/28227.2.70.65 to 227.2.70.78227.2.70.7914
102227.2.70.80/28227.2.70.81 to 227.2.70.94227.2.70.9514
103227.2.70.96/28227.2.70.97 to 227.2.70.110227.2.70.11114
104227.2.70.112/28227.2.70.113 to 227.2.70.126227.2.70.12714
105227.2.70.128/28227.2.70.129 to 227.2.70.142227.2.70.14314
106227.2.70.144/28227.2.70.145 to 227.2.70.158227.2.70.15914
107227.2.70.160/28227.2.70.161 to 227.2.70.174227.2.70.17514
108227.2.70.176/28227.2.70.177 to 227.2.70.190227.2.70.19114
109227.2.70.192/28227.2.70.193 to 227.2.70.206227.2.70.20714
110227.2.70.208/28227.2.70.209 to 227.2.70.222227.2.70.22314
111227.2.70.224/28227.2.70.225 to 227.2.70.238227.2.70.23914
112227.2.70.240/28227.2.70.241 to 227.2.70.254227.2.70.25514
113227.2.71.0/28227.2.71.1 to 227.2.71.14227.2.71.1514
114227.2.71.16/28227.2.71.17 to 227.2.71.30227.2.71.3114
115227.2.71.32/28227.2.71.33 to 227.2.71.46227.2.71.4714
116227.2.71.48/28227.2.71.49 to 227.2.71.62227.2.71.6314
117227.2.71.64/28227.2.71.65 to 227.2.71.78227.2.71.7914
118227.2.71.80/28227.2.71.81 to 227.2.71.94227.2.71.9514
119227.2.71.96/28227.2.71.97 to 227.2.71.110227.2.71.11114
120227.2.71.112/28227.2.71.113 to 227.2.71.126227.2.71.12714
121227.2.71.128/28227.2.71.129 to 227.2.71.142227.2.71.14314
122227.2.71.144/28227.2.71.145 to 227.2.71.158227.2.71.15914
123227.2.71.160/28227.2.71.161 to 227.2.71.174227.2.71.17514
124227.2.71.176/28227.2.71.177 to 227.2.71.190227.2.71.19114
125227.2.71.192/28227.2.71.193 to 227.2.71.206227.2.71.20714
126227.2.71.208/28227.2.71.209 to 227.2.71.222227.2.71.22314
127227.2.71.224/28227.2.71.225 to 227.2.71.238227.2.71.23914
128227.2.71.240/28227.2.71.241 to 227.2.71.254227.2.71.25514
129227.2.72.0/28227.2.72.1 to 227.2.72.14227.2.72.1514
130227.2.72.16/28227.2.72.17 to 227.2.72.30227.2.72.3114
131227.2.72.32/28227.2.72.33 to 227.2.72.46227.2.72.4714
132227.2.72.48/28227.2.72.49 to 227.2.72.62227.2.72.6314
133227.2.72.64/28227.2.72.65 to 227.2.72.78227.2.72.7914
134227.2.72.80/28227.2.72.81 to 227.2.72.94227.2.72.9514
135227.2.72.96/28227.2.72.97 to 227.2.72.110227.2.72.11114
136227.2.72.112/28227.2.72.113 to 227.2.72.126227.2.72.12714
137227.2.72.128/28227.2.72.129 to 227.2.72.142227.2.72.14314
138227.2.72.144/28227.2.72.145 to 227.2.72.158227.2.72.15914
139227.2.72.160/28227.2.72.161 to 227.2.72.174227.2.72.17514
140227.2.72.176/28227.2.72.177 to 227.2.72.190227.2.72.19114
141227.2.72.192/28227.2.72.193 to 227.2.72.206227.2.72.20714
142227.2.72.208/28227.2.72.209 to 227.2.72.222227.2.72.22314
143227.2.72.224/28227.2.72.225 to 227.2.72.238227.2.72.23914
144227.2.72.240/28227.2.72.241 to 227.2.72.254227.2.72.25514
145227.2.73.0/28227.2.73.1 to 227.2.73.14227.2.73.1514
146227.2.73.16/28227.2.73.17 to 227.2.73.30227.2.73.3114
147227.2.73.32/28227.2.73.33 to 227.2.73.46227.2.73.4714
148227.2.73.48/28227.2.73.49 to 227.2.73.62227.2.73.6314
149227.2.73.64/28227.2.73.65 to 227.2.73.78227.2.73.7914
150227.2.73.80/28227.2.73.81 to 227.2.73.94227.2.73.9514
151227.2.73.96/28227.2.73.97 to 227.2.73.110227.2.73.11114
152227.2.73.112/28227.2.73.113 to 227.2.73.126227.2.73.12714
153227.2.73.128/28227.2.73.129 to 227.2.73.142227.2.73.14314
154227.2.73.144/28227.2.73.145 to 227.2.73.158227.2.73.15914
155227.2.73.160/28227.2.73.161 to 227.2.73.174227.2.73.17514
156227.2.73.176/28227.2.73.177 to 227.2.73.190227.2.73.19114
157227.2.73.192/28227.2.73.193 to 227.2.73.206227.2.73.20714
158227.2.73.208/28227.2.73.209 to 227.2.73.222227.2.73.22314
159227.2.73.224/28227.2.73.225 to 227.2.73.238227.2.73.23914
160227.2.73.240/28227.2.73.241 to 227.2.73.254227.2.73.25514
161227.2.74.0/28227.2.74.1 to 227.2.74.14227.2.74.1514
162227.2.74.16/28227.2.74.17 to 227.2.74.30227.2.74.3114
163227.2.74.32/28227.2.74.33 to 227.2.74.46227.2.74.4714
164227.2.74.48/28227.2.74.49 to 227.2.74.62227.2.74.6314
165227.2.74.64/28227.2.74.65 to 227.2.74.78227.2.74.7914
166227.2.74.80/28227.2.74.81 to 227.2.74.94227.2.74.9514
167227.2.74.96/28227.2.74.97 to 227.2.74.110227.2.74.11114
168227.2.74.112/28227.2.74.113 to 227.2.74.126227.2.74.12714
169227.2.74.128/28227.2.74.129 to 227.2.74.142227.2.74.14314
170227.2.74.144/28227.2.74.145 to 227.2.74.158227.2.74.15914
171227.2.74.160/28227.2.74.161 to 227.2.74.174227.2.74.17514
172227.2.74.176/28227.2.74.177 to 227.2.74.190227.2.74.19114
173227.2.74.192/28227.2.74.193 to 227.2.74.206227.2.74.20714
174227.2.74.208/28227.2.74.209 to 227.2.74.222227.2.74.22314
175227.2.74.224/28227.2.74.225 to 227.2.74.238227.2.74.23914
176227.2.74.240/28227.2.74.241 to 227.2.74.254227.2.74.25514
177227.2.75.0/28227.2.75.1 to 227.2.75.14227.2.75.1514
178227.2.75.16/28227.2.75.17 to 227.2.75.30227.2.75.3114
179227.2.75.32/28227.2.75.33 to 227.2.75.46227.2.75.4714
180227.2.75.48/28227.2.75.49 to 227.2.75.62227.2.75.6314
181227.2.75.64/28227.2.75.65 to 227.2.75.78227.2.75.7914
182227.2.75.80/28227.2.75.81 to 227.2.75.94227.2.75.9514
183227.2.75.96/28227.2.75.97 to 227.2.75.110227.2.75.11114
184227.2.75.112/28227.2.75.113 to 227.2.75.126227.2.75.12714
185227.2.75.128/28227.2.75.129 to 227.2.75.142227.2.75.14314
186227.2.75.144/28227.2.75.145 to 227.2.75.158227.2.75.15914
187227.2.75.160/28227.2.75.161 to 227.2.75.174227.2.75.17514
188227.2.75.176/28227.2.75.177 to 227.2.75.190227.2.75.19114
189227.2.75.192/28227.2.75.193 to 227.2.75.206227.2.75.20714
190227.2.75.208/28227.2.75.209 to 227.2.75.222227.2.75.22314
191227.2.75.224/28227.2.75.225 to 227.2.75.238227.2.75.23914
192227.2.75.240/28227.2.75.241 to 227.2.75.254227.2.75.25514
193227.2.76.0/28227.2.76.1 to 227.2.76.14227.2.76.1514
194227.2.76.16/28227.2.76.17 to 227.2.76.30227.2.76.3114
195227.2.76.32/28227.2.76.33 to 227.2.76.46227.2.76.4714
196227.2.76.48/28227.2.76.49 to 227.2.76.62227.2.76.6314
197227.2.76.64/28227.2.76.65 to 227.2.76.78227.2.76.7914
198227.2.76.80/28227.2.76.81 to 227.2.76.94227.2.76.9514
199227.2.76.96/28227.2.76.97 to 227.2.76.110227.2.76.11114
200227.2.76.112/28227.2.76.113 to 227.2.76.126227.2.76.12714
201227.2.76.128/28227.2.76.129 to 227.2.76.142227.2.76.14314
202227.2.76.144/28227.2.76.145 to 227.2.76.158227.2.76.15914
203227.2.76.160/28227.2.76.161 to 227.2.76.174227.2.76.17514
204227.2.76.176/28227.2.76.177 to 227.2.76.190227.2.76.19114
205227.2.76.192/28227.2.76.193 to 227.2.76.206227.2.76.20714
206227.2.76.208/28227.2.76.209 to 227.2.76.222227.2.76.22314
207227.2.76.224/28227.2.76.225 to 227.2.76.238227.2.76.23914
208227.2.76.240/28227.2.76.241 to 227.2.76.254227.2.76.25514
209227.2.77.0/28227.2.77.1 to 227.2.77.14227.2.77.1514
210227.2.77.16/28227.2.77.17 to 227.2.77.30227.2.77.3114
211227.2.77.32/28227.2.77.33 to 227.2.77.46227.2.77.4714
212227.2.77.48/28227.2.77.49 to 227.2.77.62227.2.77.6314
213227.2.77.64/28227.2.77.65 to 227.2.77.78227.2.77.7914
214227.2.77.80/28227.2.77.81 to 227.2.77.94227.2.77.9514
215227.2.77.96/28227.2.77.97 to 227.2.77.110227.2.77.11114
216227.2.77.112/28227.2.77.113 to 227.2.77.126227.2.77.12714
217227.2.77.128/28227.2.77.129 to 227.2.77.142227.2.77.14314
218227.2.77.144/28227.2.77.145 to 227.2.77.158227.2.77.15914
219227.2.77.160/28227.2.77.161 to 227.2.77.174227.2.77.17514
220227.2.77.176/28227.2.77.177 to 227.2.77.190227.2.77.19114
221227.2.77.192/28227.2.77.193 to 227.2.77.206227.2.77.20714
222227.2.77.208/28227.2.77.209 to 227.2.77.222227.2.77.22314
223227.2.77.224/28227.2.77.225 to 227.2.77.238227.2.77.23914
224227.2.77.240/28227.2.77.241 to 227.2.77.254227.2.77.25514
225227.2.78.0/28227.2.78.1 to 227.2.78.14227.2.78.1514
226227.2.78.16/28227.2.78.17 to 227.2.78.30227.2.78.3114
227227.2.78.32/28227.2.78.33 to 227.2.78.46227.2.78.4714
228227.2.78.48/28227.2.78.49 to 227.2.78.62227.2.78.6314
229227.2.78.64/28227.2.78.65 to 227.2.78.78227.2.78.7914
230227.2.78.80/28227.2.78.81 to 227.2.78.94227.2.78.9514
231227.2.78.96/28227.2.78.97 to 227.2.78.110227.2.78.11114
232227.2.78.112/28227.2.78.113 to 227.2.78.126227.2.78.12714
233227.2.78.128/28227.2.78.129 to 227.2.78.142227.2.78.14314
234227.2.78.144/28227.2.78.145 to 227.2.78.158227.2.78.15914
235227.2.78.160/28227.2.78.161 to 227.2.78.174227.2.78.17514
236227.2.78.176/28227.2.78.177 to 227.2.78.190227.2.78.19114
237227.2.78.192/28227.2.78.193 to 227.2.78.206227.2.78.20714
238227.2.78.208/28227.2.78.209 to 227.2.78.222227.2.78.22314
239227.2.78.224/28227.2.78.225 to 227.2.78.238227.2.78.23914
240227.2.78.240/28227.2.78.241 to 227.2.78.254227.2.78.25514
241227.2.79.0/28227.2.79.1 to 227.2.79.14227.2.79.1514
242227.2.79.16/28227.2.79.17 to 227.2.79.30227.2.79.3114
243227.2.79.32/28227.2.79.33 to 227.2.79.46227.2.79.4714
244227.2.79.48/28227.2.79.49 to 227.2.79.62227.2.79.6314
245227.2.79.64/28227.2.79.65 to 227.2.79.78227.2.79.7914
246227.2.79.80/28227.2.79.81 to 227.2.79.94227.2.79.9514
247227.2.79.96/28227.2.79.97 to 227.2.79.110227.2.79.11114
248227.2.79.112/28227.2.79.113 to 227.2.79.126227.2.79.12714
249227.2.79.128/28227.2.79.129 to 227.2.79.142227.2.79.14314
250227.2.79.144/28227.2.79.145 to 227.2.79.158227.2.79.15914
251227.2.79.160/28227.2.79.161 to 227.2.79.174227.2.79.17514
252227.2.79.176/28227.2.79.177 to 227.2.79.190227.2.79.19114
253227.2.79.192/28227.2.79.193 to 227.2.79.206227.2.79.20714
254227.2.79.208/28227.2.79.209 to 227.2.79.222227.2.79.22314
255227.2.79.224/28227.2.79.225 to 227.2.79.238227.2.79.23914
256227.2.79.240/28227.2.79.241 to 227.2.79.254227.2.79.25514

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.