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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.

Network149.2.64.0/20
Usable hosts4,094
Subnet mask255.255.240.0
Addresses4,096
Network address
149.2.64.0
Broadcast address
149.2.79.255
First usable
149.2.64.1
Last usable
149.2.79.254
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
Public public
Old class
B (default /16)
As numbers
Hex 95024000 · Integer 2499952640 to 2499956735
Reverse DNS zones
64.2.149.in-addr.arpa
65.2.149.in-addr.arpa
66.2.149.in-addr.arpa
67.2.149.in-addr.arpa
68.2.149.in-addr.arpa
69.2.149.in-addr.arpa
70.2.149.in-addr.arpa
71.2.149.in-addr.arpa
72.2.149.in-addr.arpa
73.2.149.in-addr.arpa
74.2.149.in-addr.arpa
75.2.149.in-addr.arpa
76.2.149.in-addr.arpa
77.2.149.in-addr.arpa
78.2.149.in-addr.arpa
79.2.149.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
Address10010101.00000010.01000000.00000000149.2.64.0
Subnet mask11111111.11111111.11110000.00000000255.255.240.0
Network10010101.00000010.01000000.00000000149.2.64.0
Broadcast10010101.00000010.01001111.11111111149.2.79.255
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)

149.2.64.0/20 makes 256 subnets of /28.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1149.2.64.0/28149.2.64.1 to 149.2.64.14149.2.64.1514
2149.2.64.16/28149.2.64.17 to 149.2.64.30149.2.64.3114
3149.2.64.32/28149.2.64.33 to 149.2.64.46149.2.64.4714
4149.2.64.48/28149.2.64.49 to 149.2.64.62149.2.64.6314
5149.2.64.64/28149.2.64.65 to 149.2.64.78149.2.64.7914
6149.2.64.80/28149.2.64.81 to 149.2.64.94149.2.64.9514
7149.2.64.96/28149.2.64.97 to 149.2.64.110149.2.64.11114
8149.2.64.112/28149.2.64.113 to 149.2.64.126149.2.64.12714
9149.2.64.128/28149.2.64.129 to 149.2.64.142149.2.64.14314
10149.2.64.144/28149.2.64.145 to 149.2.64.158149.2.64.15914
11149.2.64.160/28149.2.64.161 to 149.2.64.174149.2.64.17514
12149.2.64.176/28149.2.64.177 to 149.2.64.190149.2.64.19114
13149.2.64.192/28149.2.64.193 to 149.2.64.206149.2.64.20714
14149.2.64.208/28149.2.64.209 to 149.2.64.222149.2.64.22314
15149.2.64.224/28149.2.64.225 to 149.2.64.238149.2.64.23914
16149.2.64.240/28149.2.64.241 to 149.2.64.254149.2.64.25514
17149.2.65.0/28149.2.65.1 to 149.2.65.14149.2.65.1514
18149.2.65.16/28149.2.65.17 to 149.2.65.30149.2.65.3114
19149.2.65.32/28149.2.65.33 to 149.2.65.46149.2.65.4714
20149.2.65.48/28149.2.65.49 to 149.2.65.62149.2.65.6314
21149.2.65.64/28149.2.65.65 to 149.2.65.78149.2.65.7914
22149.2.65.80/28149.2.65.81 to 149.2.65.94149.2.65.9514
23149.2.65.96/28149.2.65.97 to 149.2.65.110149.2.65.11114
24149.2.65.112/28149.2.65.113 to 149.2.65.126149.2.65.12714
25149.2.65.128/28149.2.65.129 to 149.2.65.142149.2.65.14314
26149.2.65.144/28149.2.65.145 to 149.2.65.158149.2.65.15914
27149.2.65.160/28149.2.65.161 to 149.2.65.174149.2.65.17514
28149.2.65.176/28149.2.65.177 to 149.2.65.190149.2.65.19114
29149.2.65.192/28149.2.65.193 to 149.2.65.206149.2.65.20714
30149.2.65.208/28149.2.65.209 to 149.2.65.222149.2.65.22314
31149.2.65.224/28149.2.65.225 to 149.2.65.238149.2.65.23914
32149.2.65.240/28149.2.65.241 to 149.2.65.254149.2.65.25514
33149.2.66.0/28149.2.66.1 to 149.2.66.14149.2.66.1514
34149.2.66.16/28149.2.66.17 to 149.2.66.30149.2.66.3114
35149.2.66.32/28149.2.66.33 to 149.2.66.46149.2.66.4714
36149.2.66.48/28149.2.66.49 to 149.2.66.62149.2.66.6314
37149.2.66.64/28149.2.66.65 to 149.2.66.78149.2.66.7914
38149.2.66.80/28149.2.66.81 to 149.2.66.94149.2.66.9514
39149.2.66.96/28149.2.66.97 to 149.2.66.110149.2.66.11114
40149.2.66.112/28149.2.66.113 to 149.2.66.126149.2.66.12714
41149.2.66.128/28149.2.66.129 to 149.2.66.142149.2.66.14314
42149.2.66.144/28149.2.66.145 to 149.2.66.158149.2.66.15914
43149.2.66.160/28149.2.66.161 to 149.2.66.174149.2.66.17514
44149.2.66.176/28149.2.66.177 to 149.2.66.190149.2.66.19114
45149.2.66.192/28149.2.66.193 to 149.2.66.206149.2.66.20714
46149.2.66.208/28149.2.66.209 to 149.2.66.222149.2.66.22314
47149.2.66.224/28149.2.66.225 to 149.2.66.238149.2.66.23914
48149.2.66.240/28149.2.66.241 to 149.2.66.254149.2.66.25514
49149.2.67.0/28149.2.67.1 to 149.2.67.14149.2.67.1514
50149.2.67.16/28149.2.67.17 to 149.2.67.30149.2.67.3114
51149.2.67.32/28149.2.67.33 to 149.2.67.46149.2.67.4714
52149.2.67.48/28149.2.67.49 to 149.2.67.62149.2.67.6314
53149.2.67.64/28149.2.67.65 to 149.2.67.78149.2.67.7914
54149.2.67.80/28149.2.67.81 to 149.2.67.94149.2.67.9514
55149.2.67.96/28149.2.67.97 to 149.2.67.110149.2.67.11114
56149.2.67.112/28149.2.67.113 to 149.2.67.126149.2.67.12714
57149.2.67.128/28149.2.67.129 to 149.2.67.142149.2.67.14314
58149.2.67.144/28149.2.67.145 to 149.2.67.158149.2.67.15914
59149.2.67.160/28149.2.67.161 to 149.2.67.174149.2.67.17514
60149.2.67.176/28149.2.67.177 to 149.2.67.190149.2.67.19114
61149.2.67.192/28149.2.67.193 to 149.2.67.206149.2.67.20714
62149.2.67.208/28149.2.67.209 to 149.2.67.222149.2.67.22314
63149.2.67.224/28149.2.67.225 to 149.2.67.238149.2.67.23914
64149.2.67.240/28149.2.67.241 to 149.2.67.254149.2.67.25514
65149.2.68.0/28149.2.68.1 to 149.2.68.14149.2.68.1514
66149.2.68.16/28149.2.68.17 to 149.2.68.30149.2.68.3114
67149.2.68.32/28149.2.68.33 to 149.2.68.46149.2.68.4714
68149.2.68.48/28149.2.68.49 to 149.2.68.62149.2.68.6314
69149.2.68.64/28149.2.68.65 to 149.2.68.78149.2.68.7914
70149.2.68.80/28149.2.68.81 to 149.2.68.94149.2.68.9514
71149.2.68.96/28149.2.68.97 to 149.2.68.110149.2.68.11114
72149.2.68.112/28149.2.68.113 to 149.2.68.126149.2.68.12714
73149.2.68.128/28149.2.68.129 to 149.2.68.142149.2.68.14314
74149.2.68.144/28149.2.68.145 to 149.2.68.158149.2.68.15914
75149.2.68.160/28149.2.68.161 to 149.2.68.174149.2.68.17514
76149.2.68.176/28149.2.68.177 to 149.2.68.190149.2.68.19114
77149.2.68.192/28149.2.68.193 to 149.2.68.206149.2.68.20714
78149.2.68.208/28149.2.68.209 to 149.2.68.222149.2.68.22314
79149.2.68.224/28149.2.68.225 to 149.2.68.238149.2.68.23914
80149.2.68.240/28149.2.68.241 to 149.2.68.254149.2.68.25514
81149.2.69.0/28149.2.69.1 to 149.2.69.14149.2.69.1514
82149.2.69.16/28149.2.69.17 to 149.2.69.30149.2.69.3114
83149.2.69.32/28149.2.69.33 to 149.2.69.46149.2.69.4714
84149.2.69.48/28149.2.69.49 to 149.2.69.62149.2.69.6314
85149.2.69.64/28149.2.69.65 to 149.2.69.78149.2.69.7914
86149.2.69.80/28149.2.69.81 to 149.2.69.94149.2.69.9514
87149.2.69.96/28149.2.69.97 to 149.2.69.110149.2.69.11114
88149.2.69.112/28149.2.69.113 to 149.2.69.126149.2.69.12714
89149.2.69.128/28149.2.69.129 to 149.2.69.142149.2.69.14314
90149.2.69.144/28149.2.69.145 to 149.2.69.158149.2.69.15914
91149.2.69.160/28149.2.69.161 to 149.2.69.174149.2.69.17514
92149.2.69.176/28149.2.69.177 to 149.2.69.190149.2.69.19114
93149.2.69.192/28149.2.69.193 to 149.2.69.206149.2.69.20714
94149.2.69.208/28149.2.69.209 to 149.2.69.222149.2.69.22314
95149.2.69.224/28149.2.69.225 to 149.2.69.238149.2.69.23914
96149.2.69.240/28149.2.69.241 to 149.2.69.254149.2.69.25514
97149.2.70.0/28149.2.70.1 to 149.2.70.14149.2.70.1514
98149.2.70.16/28149.2.70.17 to 149.2.70.30149.2.70.3114
99149.2.70.32/28149.2.70.33 to 149.2.70.46149.2.70.4714
100149.2.70.48/28149.2.70.49 to 149.2.70.62149.2.70.6314
101149.2.70.64/28149.2.70.65 to 149.2.70.78149.2.70.7914
102149.2.70.80/28149.2.70.81 to 149.2.70.94149.2.70.9514
103149.2.70.96/28149.2.70.97 to 149.2.70.110149.2.70.11114
104149.2.70.112/28149.2.70.113 to 149.2.70.126149.2.70.12714
105149.2.70.128/28149.2.70.129 to 149.2.70.142149.2.70.14314
106149.2.70.144/28149.2.70.145 to 149.2.70.158149.2.70.15914
107149.2.70.160/28149.2.70.161 to 149.2.70.174149.2.70.17514
108149.2.70.176/28149.2.70.177 to 149.2.70.190149.2.70.19114
109149.2.70.192/28149.2.70.193 to 149.2.70.206149.2.70.20714
110149.2.70.208/28149.2.70.209 to 149.2.70.222149.2.70.22314
111149.2.70.224/28149.2.70.225 to 149.2.70.238149.2.70.23914
112149.2.70.240/28149.2.70.241 to 149.2.70.254149.2.70.25514
113149.2.71.0/28149.2.71.1 to 149.2.71.14149.2.71.1514
114149.2.71.16/28149.2.71.17 to 149.2.71.30149.2.71.3114
115149.2.71.32/28149.2.71.33 to 149.2.71.46149.2.71.4714
116149.2.71.48/28149.2.71.49 to 149.2.71.62149.2.71.6314
117149.2.71.64/28149.2.71.65 to 149.2.71.78149.2.71.7914
118149.2.71.80/28149.2.71.81 to 149.2.71.94149.2.71.9514
119149.2.71.96/28149.2.71.97 to 149.2.71.110149.2.71.11114
120149.2.71.112/28149.2.71.113 to 149.2.71.126149.2.71.12714
121149.2.71.128/28149.2.71.129 to 149.2.71.142149.2.71.14314
122149.2.71.144/28149.2.71.145 to 149.2.71.158149.2.71.15914
123149.2.71.160/28149.2.71.161 to 149.2.71.174149.2.71.17514
124149.2.71.176/28149.2.71.177 to 149.2.71.190149.2.71.19114
125149.2.71.192/28149.2.71.193 to 149.2.71.206149.2.71.20714
126149.2.71.208/28149.2.71.209 to 149.2.71.222149.2.71.22314
127149.2.71.224/28149.2.71.225 to 149.2.71.238149.2.71.23914
128149.2.71.240/28149.2.71.241 to 149.2.71.254149.2.71.25514
129149.2.72.0/28149.2.72.1 to 149.2.72.14149.2.72.1514
130149.2.72.16/28149.2.72.17 to 149.2.72.30149.2.72.3114
131149.2.72.32/28149.2.72.33 to 149.2.72.46149.2.72.4714
132149.2.72.48/28149.2.72.49 to 149.2.72.62149.2.72.6314
133149.2.72.64/28149.2.72.65 to 149.2.72.78149.2.72.7914
134149.2.72.80/28149.2.72.81 to 149.2.72.94149.2.72.9514
135149.2.72.96/28149.2.72.97 to 149.2.72.110149.2.72.11114
136149.2.72.112/28149.2.72.113 to 149.2.72.126149.2.72.12714
137149.2.72.128/28149.2.72.129 to 149.2.72.142149.2.72.14314
138149.2.72.144/28149.2.72.145 to 149.2.72.158149.2.72.15914
139149.2.72.160/28149.2.72.161 to 149.2.72.174149.2.72.17514
140149.2.72.176/28149.2.72.177 to 149.2.72.190149.2.72.19114
141149.2.72.192/28149.2.72.193 to 149.2.72.206149.2.72.20714
142149.2.72.208/28149.2.72.209 to 149.2.72.222149.2.72.22314
143149.2.72.224/28149.2.72.225 to 149.2.72.238149.2.72.23914
144149.2.72.240/28149.2.72.241 to 149.2.72.254149.2.72.25514
145149.2.73.0/28149.2.73.1 to 149.2.73.14149.2.73.1514
146149.2.73.16/28149.2.73.17 to 149.2.73.30149.2.73.3114
147149.2.73.32/28149.2.73.33 to 149.2.73.46149.2.73.4714
148149.2.73.48/28149.2.73.49 to 149.2.73.62149.2.73.6314
149149.2.73.64/28149.2.73.65 to 149.2.73.78149.2.73.7914
150149.2.73.80/28149.2.73.81 to 149.2.73.94149.2.73.9514
151149.2.73.96/28149.2.73.97 to 149.2.73.110149.2.73.11114
152149.2.73.112/28149.2.73.113 to 149.2.73.126149.2.73.12714
153149.2.73.128/28149.2.73.129 to 149.2.73.142149.2.73.14314
154149.2.73.144/28149.2.73.145 to 149.2.73.158149.2.73.15914
155149.2.73.160/28149.2.73.161 to 149.2.73.174149.2.73.17514
156149.2.73.176/28149.2.73.177 to 149.2.73.190149.2.73.19114
157149.2.73.192/28149.2.73.193 to 149.2.73.206149.2.73.20714
158149.2.73.208/28149.2.73.209 to 149.2.73.222149.2.73.22314
159149.2.73.224/28149.2.73.225 to 149.2.73.238149.2.73.23914
160149.2.73.240/28149.2.73.241 to 149.2.73.254149.2.73.25514
161149.2.74.0/28149.2.74.1 to 149.2.74.14149.2.74.1514
162149.2.74.16/28149.2.74.17 to 149.2.74.30149.2.74.3114
163149.2.74.32/28149.2.74.33 to 149.2.74.46149.2.74.4714
164149.2.74.48/28149.2.74.49 to 149.2.74.62149.2.74.6314
165149.2.74.64/28149.2.74.65 to 149.2.74.78149.2.74.7914
166149.2.74.80/28149.2.74.81 to 149.2.74.94149.2.74.9514
167149.2.74.96/28149.2.74.97 to 149.2.74.110149.2.74.11114
168149.2.74.112/28149.2.74.113 to 149.2.74.126149.2.74.12714
169149.2.74.128/28149.2.74.129 to 149.2.74.142149.2.74.14314
170149.2.74.144/28149.2.74.145 to 149.2.74.158149.2.74.15914
171149.2.74.160/28149.2.74.161 to 149.2.74.174149.2.74.17514
172149.2.74.176/28149.2.74.177 to 149.2.74.190149.2.74.19114
173149.2.74.192/28149.2.74.193 to 149.2.74.206149.2.74.20714
174149.2.74.208/28149.2.74.209 to 149.2.74.222149.2.74.22314
175149.2.74.224/28149.2.74.225 to 149.2.74.238149.2.74.23914
176149.2.74.240/28149.2.74.241 to 149.2.74.254149.2.74.25514
177149.2.75.0/28149.2.75.1 to 149.2.75.14149.2.75.1514
178149.2.75.16/28149.2.75.17 to 149.2.75.30149.2.75.3114
179149.2.75.32/28149.2.75.33 to 149.2.75.46149.2.75.4714
180149.2.75.48/28149.2.75.49 to 149.2.75.62149.2.75.6314
181149.2.75.64/28149.2.75.65 to 149.2.75.78149.2.75.7914
182149.2.75.80/28149.2.75.81 to 149.2.75.94149.2.75.9514
183149.2.75.96/28149.2.75.97 to 149.2.75.110149.2.75.11114
184149.2.75.112/28149.2.75.113 to 149.2.75.126149.2.75.12714
185149.2.75.128/28149.2.75.129 to 149.2.75.142149.2.75.14314
186149.2.75.144/28149.2.75.145 to 149.2.75.158149.2.75.15914
187149.2.75.160/28149.2.75.161 to 149.2.75.174149.2.75.17514
188149.2.75.176/28149.2.75.177 to 149.2.75.190149.2.75.19114
189149.2.75.192/28149.2.75.193 to 149.2.75.206149.2.75.20714
190149.2.75.208/28149.2.75.209 to 149.2.75.222149.2.75.22314
191149.2.75.224/28149.2.75.225 to 149.2.75.238149.2.75.23914
192149.2.75.240/28149.2.75.241 to 149.2.75.254149.2.75.25514
193149.2.76.0/28149.2.76.1 to 149.2.76.14149.2.76.1514
194149.2.76.16/28149.2.76.17 to 149.2.76.30149.2.76.3114
195149.2.76.32/28149.2.76.33 to 149.2.76.46149.2.76.4714
196149.2.76.48/28149.2.76.49 to 149.2.76.62149.2.76.6314
197149.2.76.64/28149.2.76.65 to 149.2.76.78149.2.76.7914
198149.2.76.80/28149.2.76.81 to 149.2.76.94149.2.76.9514
199149.2.76.96/28149.2.76.97 to 149.2.76.110149.2.76.11114
200149.2.76.112/28149.2.76.113 to 149.2.76.126149.2.76.12714
201149.2.76.128/28149.2.76.129 to 149.2.76.142149.2.76.14314
202149.2.76.144/28149.2.76.145 to 149.2.76.158149.2.76.15914
203149.2.76.160/28149.2.76.161 to 149.2.76.174149.2.76.17514
204149.2.76.176/28149.2.76.177 to 149.2.76.190149.2.76.19114
205149.2.76.192/28149.2.76.193 to 149.2.76.206149.2.76.20714
206149.2.76.208/28149.2.76.209 to 149.2.76.222149.2.76.22314
207149.2.76.224/28149.2.76.225 to 149.2.76.238149.2.76.23914
208149.2.76.240/28149.2.76.241 to 149.2.76.254149.2.76.25514
209149.2.77.0/28149.2.77.1 to 149.2.77.14149.2.77.1514
210149.2.77.16/28149.2.77.17 to 149.2.77.30149.2.77.3114
211149.2.77.32/28149.2.77.33 to 149.2.77.46149.2.77.4714
212149.2.77.48/28149.2.77.49 to 149.2.77.62149.2.77.6314
213149.2.77.64/28149.2.77.65 to 149.2.77.78149.2.77.7914
214149.2.77.80/28149.2.77.81 to 149.2.77.94149.2.77.9514
215149.2.77.96/28149.2.77.97 to 149.2.77.110149.2.77.11114
216149.2.77.112/28149.2.77.113 to 149.2.77.126149.2.77.12714
217149.2.77.128/28149.2.77.129 to 149.2.77.142149.2.77.14314
218149.2.77.144/28149.2.77.145 to 149.2.77.158149.2.77.15914
219149.2.77.160/28149.2.77.161 to 149.2.77.174149.2.77.17514
220149.2.77.176/28149.2.77.177 to 149.2.77.190149.2.77.19114
221149.2.77.192/28149.2.77.193 to 149.2.77.206149.2.77.20714
222149.2.77.208/28149.2.77.209 to 149.2.77.222149.2.77.22314
223149.2.77.224/28149.2.77.225 to 149.2.77.238149.2.77.23914
224149.2.77.240/28149.2.77.241 to 149.2.77.254149.2.77.25514
225149.2.78.0/28149.2.78.1 to 149.2.78.14149.2.78.1514
226149.2.78.16/28149.2.78.17 to 149.2.78.30149.2.78.3114
227149.2.78.32/28149.2.78.33 to 149.2.78.46149.2.78.4714
228149.2.78.48/28149.2.78.49 to 149.2.78.62149.2.78.6314
229149.2.78.64/28149.2.78.65 to 149.2.78.78149.2.78.7914
230149.2.78.80/28149.2.78.81 to 149.2.78.94149.2.78.9514
231149.2.78.96/28149.2.78.97 to 149.2.78.110149.2.78.11114
232149.2.78.112/28149.2.78.113 to 149.2.78.126149.2.78.12714
233149.2.78.128/28149.2.78.129 to 149.2.78.142149.2.78.14314
234149.2.78.144/28149.2.78.145 to 149.2.78.158149.2.78.15914
235149.2.78.160/28149.2.78.161 to 149.2.78.174149.2.78.17514
236149.2.78.176/28149.2.78.177 to 149.2.78.190149.2.78.19114
237149.2.78.192/28149.2.78.193 to 149.2.78.206149.2.78.20714
238149.2.78.208/28149.2.78.209 to 149.2.78.222149.2.78.22314
239149.2.78.224/28149.2.78.225 to 149.2.78.238149.2.78.23914
240149.2.78.240/28149.2.78.241 to 149.2.78.254149.2.78.25514
241149.2.79.0/28149.2.79.1 to 149.2.79.14149.2.79.1514
242149.2.79.16/28149.2.79.17 to 149.2.79.30149.2.79.3114
243149.2.79.32/28149.2.79.33 to 149.2.79.46149.2.79.4714
244149.2.79.48/28149.2.79.49 to 149.2.79.62149.2.79.6314
245149.2.79.64/28149.2.79.65 to 149.2.79.78149.2.79.7914
246149.2.79.80/28149.2.79.81 to 149.2.79.94149.2.79.9514
247149.2.79.96/28149.2.79.97 to 149.2.79.110149.2.79.11114
248149.2.79.112/28149.2.79.113 to 149.2.79.126149.2.79.12714
249149.2.79.128/28149.2.79.129 to 149.2.79.142149.2.79.14314
250149.2.79.144/28149.2.79.145 to 149.2.79.158149.2.79.15914
251149.2.79.160/28149.2.79.161 to 149.2.79.174149.2.79.17514
252149.2.79.176/28149.2.79.177 to 149.2.79.190149.2.79.19114
253149.2.79.192/28149.2.79.193 to 149.2.79.206149.2.79.20714
254149.2.79.208/28149.2.79.209 to 149.2.79.222149.2.79.22314
255149.2.79.224/28149.2.79.225 to 149.2.79.238149.2.79.23914
256149.2.79.240/28149.2.79.241 to 149.2.79.254149.2.79.25514

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.