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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.

Network166.167.0.0/16
Usable hosts65,534
Subnet mask255.255.0.0
Addresses65,536
Network address
166.167.0.0
Broadcast address
166.167.255.255
First usable
166.167.0.1
Last usable
166.167.255.254
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
Public public
Old class
B (default /16)
As numbers
Hex A6A70000 · Integer 2795962368 to 2796027903
Reverse DNS zone
167.166.in-addr.arpa
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address10100110.10100111..00000000.00000000166.167.0.0
Subnet mask11111111.11111111..00000000.00000000255.255.0.0
Network10100110.10100111..00000000.00000000166.167.0.0
Broadcast10100110.10100111..11111111.11111111166.167.255.255
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)

166.167.0.0/16 makes 4,096 subnets of /28; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1166.167.0.0/28166.167.0.1 to 166.167.0.14166.167.0.1514
2166.167.0.16/28166.167.0.17 to 166.167.0.30166.167.0.3114
3166.167.0.32/28166.167.0.33 to 166.167.0.46166.167.0.4714
4166.167.0.48/28166.167.0.49 to 166.167.0.62166.167.0.6314
5166.167.0.64/28166.167.0.65 to 166.167.0.78166.167.0.7914
6166.167.0.80/28166.167.0.81 to 166.167.0.94166.167.0.9514
7166.167.0.96/28166.167.0.97 to 166.167.0.110166.167.0.11114
8166.167.0.112/28166.167.0.113 to 166.167.0.126166.167.0.12714
9166.167.0.128/28166.167.0.129 to 166.167.0.142166.167.0.14314
10166.167.0.144/28166.167.0.145 to 166.167.0.158166.167.0.15914
11166.167.0.160/28166.167.0.161 to 166.167.0.174166.167.0.17514
12166.167.0.176/28166.167.0.177 to 166.167.0.190166.167.0.19114
13166.167.0.192/28166.167.0.193 to 166.167.0.206166.167.0.20714
14166.167.0.208/28166.167.0.209 to 166.167.0.222166.167.0.22314
15166.167.0.224/28166.167.0.225 to 166.167.0.238166.167.0.23914
16166.167.0.240/28166.167.0.241 to 166.167.0.254166.167.0.25514
17166.167.1.0/28166.167.1.1 to 166.167.1.14166.167.1.1514
18166.167.1.16/28166.167.1.17 to 166.167.1.30166.167.1.3114
19166.167.1.32/28166.167.1.33 to 166.167.1.46166.167.1.4714
20166.167.1.48/28166.167.1.49 to 166.167.1.62166.167.1.6314
21166.167.1.64/28166.167.1.65 to 166.167.1.78166.167.1.7914
22166.167.1.80/28166.167.1.81 to 166.167.1.94166.167.1.9514
23166.167.1.96/28166.167.1.97 to 166.167.1.110166.167.1.11114
24166.167.1.112/28166.167.1.113 to 166.167.1.126166.167.1.12714
25166.167.1.128/28166.167.1.129 to 166.167.1.142166.167.1.14314
26166.167.1.144/28166.167.1.145 to 166.167.1.158166.167.1.15914
27166.167.1.160/28166.167.1.161 to 166.167.1.174166.167.1.17514
28166.167.1.176/28166.167.1.177 to 166.167.1.190166.167.1.19114
29166.167.1.192/28166.167.1.193 to 166.167.1.206166.167.1.20714
30166.167.1.208/28166.167.1.209 to 166.167.1.222166.167.1.22314
31166.167.1.224/28166.167.1.225 to 166.167.1.238166.167.1.23914
32166.167.1.240/28166.167.1.241 to 166.167.1.254166.167.1.25514
33166.167.2.0/28166.167.2.1 to 166.167.2.14166.167.2.1514
34166.167.2.16/28166.167.2.17 to 166.167.2.30166.167.2.3114
35166.167.2.32/28166.167.2.33 to 166.167.2.46166.167.2.4714
36166.167.2.48/28166.167.2.49 to 166.167.2.62166.167.2.6314
37166.167.2.64/28166.167.2.65 to 166.167.2.78166.167.2.7914
38166.167.2.80/28166.167.2.81 to 166.167.2.94166.167.2.9514
39166.167.2.96/28166.167.2.97 to 166.167.2.110166.167.2.11114
40166.167.2.112/28166.167.2.113 to 166.167.2.126166.167.2.12714
41166.167.2.128/28166.167.2.129 to 166.167.2.142166.167.2.14314
42166.167.2.144/28166.167.2.145 to 166.167.2.158166.167.2.15914
43166.167.2.160/28166.167.2.161 to 166.167.2.174166.167.2.17514
44166.167.2.176/28166.167.2.177 to 166.167.2.190166.167.2.19114
45166.167.2.192/28166.167.2.193 to 166.167.2.206166.167.2.20714
46166.167.2.208/28166.167.2.209 to 166.167.2.222166.167.2.22314
47166.167.2.224/28166.167.2.225 to 166.167.2.238166.167.2.23914
48166.167.2.240/28166.167.2.241 to 166.167.2.254166.167.2.25514
49166.167.3.0/28166.167.3.1 to 166.167.3.14166.167.3.1514
50166.167.3.16/28166.167.3.17 to 166.167.3.30166.167.3.3114
51166.167.3.32/28166.167.3.33 to 166.167.3.46166.167.3.4714
52166.167.3.48/28166.167.3.49 to 166.167.3.62166.167.3.6314
53166.167.3.64/28166.167.3.65 to 166.167.3.78166.167.3.7914
54166.167.3.80/28166.167.3.81 to 166.167.3.94166.167.3.9514
55166.167.3.96/28166.167.3.97 to 166.167.3.110166.167.3.11114
56166.167.3.112/28166.167.3.113 to 166.167.3.126166.167.3.12714
57166.167.3.128/28166.167.3.129 to 166.167.3.142166.167.3.14314
58166.167.3.144/28166.167.3.145 to 166.167.3.158166.167.3.15914
59166.167.3.160/28166.167.3.161 to 166.167.3.174166.167.3.17514
60166.167.3.176/28166.167.3.177 to 166.167.3.190166.167.3.19114
61166.167.3.192/28166.167.3.193 to 166.167.3.206166.167.3.20714
62166.167.3.208/28166.167.3.209 to 166.167.3.222166.167.3.22314
63166.167.3.224/28166.167.3.225 to 166.167.3.238166.167.3.23914
64166.167.3.240/28166.167.3.241 to 166.167.3.254166.167.3.25514
65166.167.4.0/28166.167.4.1 to 166.167.4.14166.167.4.1514
66166.167.4.16/28166.167.4.17 to 166.167.4.30166.167.4.3114
67166.167.4.32/28166.167.4.33 to 166.167.4.46166.167.4.4714
68166.167.4.48/28166.167.4.49 to 166.167.4.62166.167.4.6314
69166.167.4.64/28166.167.4.65 to 166.167.4.78166.167.4.7914
70166.167.4.80/28166.167.4.81 to 166.167.4.94166.167.4.9514
71166.167.4.96/28166.167.4.97 to 166.167.4.110166.167.4.11114
72166.167.4.112/28166.167.4.113 to 166.167.4.126166.167.4.12714
73166.167.4.128/28166.167.4.129 to 166.167.4.142166.167.4.14314
74166.167.4.144/28166.167.4.145 to 166.167.4.158166.167.4.15914
75166.167.4.160/28166.167.4.161 to 166.167.4.174166.167.4.17514
76166.167.4.176/28166.167.4.177 to 166.167.4.190166.167.4.19114
77166.167.4.192/28166.167.4.193 to 166.167.4.206166.167.4.20714
78166.167.4.208/28166.167.4.209 to 166.167.4.222166.167.4.22314
79166.167.4.224/28166.167.4.225 to 166.167.4.238166.167.4.23914
80166.167.4.240/28166.167.4.241 to 166.167.4.254166.167.4.25514
81166.167.5.0/28166.167.5.1 to 166.167.5.14166.167.5.1514
82166.167.5.16/28166.167.5.17 to 166.167.5.30166.167.5.3114
83166.167.5.32/28166.167.5.33 to 166.167.5.46166.167.5.4714
84166.167.5.48/28166.167.5.49 to 166.167.5.62166.167.5.6314
85166.167.5.64/28166.167.5.65 to 166.167.5.78166.167.5.7914
86166.167.5.80/28166.167.5.81 to 166.167.5.94166.167.5.9514
87166.167.5.96/28166.167.5.97 to 166.167.5.110166.167.5.11114
88166.167.5.112/28166.167.5.113 to 166.167.5.126166.167.5.12714
89166.167.5.128/28166.167.5.129 to 166.167.5.142166.167.5.14314
90166.167.5.144/28166.167.5.145 to 166.167.5.158166.167.5.15914
91166.167.5.160/28166.167.5.161 to 166.167.5.174166.167.5.17514
92166.167.5.176/28166.167.5.177 to 166.167.5.190166.167.5.19114
93166.167.5.192/28166.167.5.193 to 166.167.5.206166.167.5.20714
94166.167.5.208/28166.167.5.209 to 166.167.5.222166.167.5.22314
95166.167.5.224/28166.167.5.225 to 166.167.5.238166.167.5.23914
96166.167.5.240/28166.167.5.241 to 166.167.5.254166.167.5.25514
97166.167.6.0/28166.167.6.1 to 166.167.6.14166.167.6.1514
98166.167.6.16/28166.167.6.17 to 166.167.6.30166.167.6.3114
99166.167.6.32/28166.167.6.33 to 166.167.6.46166.167.6.4714
100166.167.6.48/28166.167.6.49 to 166.167.6.62166.167.6.6314
101166.167.6.64/28166.167.6.65 to 166.167.6.78166.167.6.7914
102166.167.6.80/28166.167.6.81 to 166.167.6.94166.167.6.9514
103166.167.6.96/28166.167.6.97 to 166.167.6.110166.167.6.11114
104166.167.6.112/28166.167.6.113 to 166.167.6.126166.167.6.12714
105166.167.6.128/28166.167.6.129 to 166.167.6.142166.167.6.14314
106166.167.6.144/28166.167.6.145 to 166.167.6.158166.167.6.15914
107166.167.6.160/28166.167.6.161 to 166.167.6.174166.167.6.17514
108166.167.6.176/28166.167.6.177 to 166.167.6.190166.167.6.19114
109166.167.6.192/28166.167.6.193 to 166.167.6.206166.167.6.20714
110166.167.6.208/28166.167.6.209 to 166.167.6.222166.167.6.22314
111166.167.6.224/28166.167.6.225 to 166.167.6.238166.167.6.23914
112166.167.6.240/28166.167.6.241 to 166.167.6.254166.167.6.25514
113166.167.7.0/28166.167.7.1 to 166.167.7.14166.167.7.1514
114166.167.7.16/28166.167.7.17 to 166.167.7.30166.167.7.3114
115166.167.7.32/28166.167.7.33 to 166.167.7.46166.167.7.4714
116166.167.7.48/28166.167.7.49 to 166.167.7.62166.167.7.6314
117166.167.7.64/28166.167.7.65 to 166.167.7.78166.167.7.7914
118166.167.7.80/28166.167.7.81 to 166.167.7.94166.167.7.9514
119166.167.7.96/28166.167.7.97 to 166.167.7.110166.167.7.11114
120166.167.7.112/28166.167.7.113 to 166.167.7.126166.167.7.12714
121166.167.7.128/28166.167.7.129 to 166.167.7.142166.167.7.14314
122166.167.7.144/28166.167.7.145 to 166.167.7.158166.167.7.15914
123166.167.7.160/28166.167.7.161 to 166.167.7.174166.167.7.17514
124166.167.7.176/28166.167.7.177 to 166.167.7.190166.167.7.19114
125166.167.7.192/28166.167.7.193 to 166.167.7.206166.167.7.20714
126166.167.7.208/28166.167.7.209 to 166.167.7.222166.167.7.22314
127166.167.7.224/28166.167.7.225 to 166.167.7.238166.167.7.23914
128166.167.7.240/28166.167.7.241 to 166.167.7.254166.167.7.25514
129166.167.8.0/28166.167.8.1 to 166.167.8.14166.167.8.1514
130166.167.8.16/28166.167.8.17 to 166.167.8.30166.167.8.3114
131166.167.8.32/28166.167.8.33 to 166.167.8.46166.167.8.4714
132166.167.8.48/28166.167.8.49 to 166.167.8.62166.167.8.6314
133166.167.8.64/28166.167.8.65 to 166.167.8.78166.167.8.7914
134166.167.8.80/28166.167.8.81 to 166.167.8.94166.167.8.9514
135166.167.8.96/28166.167.8.97 to 166.167.8.110166.167.8.11114
136166.167.8.112/28166.167.8.113 to 166.167.8.126166.167.8.12714
137166.167.8.128/28166.167.8.129 to 166.167.8.142166.167.8.14314
138166.167.8.144/28166.167.8.145 to 166.167.8.158166.167.8.15914
139166.167.8.160/28166.167.8.161 to 166.167.8.174166.167.8.17514
140166.167.8.176/28166.167.8.177 to 166.167.8.190166.167.8.19114
141166.167.8.192/28166.167.8.193 to 166.167.8.206166.167.8.20714
142166.167.8.208/28166.167.8.209 to 166.167.8.222166.167.8.22314
143166.167.8.224/28166.167.8.225 to 166.167.8.238166.167.8.23914
144166.167.8.240/28166.167.8.241 to 166.167.8.254166.167.8.25514
145166.167.9.0/28166.167.9.1 to 166.167.9.14166.167.9.1514
146166.167.9.16/28166.167.9.17 to 166.167.9.30166.167.9.3114
147166.167.9.32/28166.167.9.33 to 166.167.9.46166.167.9.4714
148166.167.9.48/28166.167.9.49 to 166.167.9.62166.167.9.6314
149166.167.9.64/28166.167.9.65 to 166.167.9.78166.167.9.7914
150166.167.9.80/28166.167.9.81 to 166.167.9.94166.167.9.9514
151166.167.9.96/28166.167.9.97 to 166.167.9.110166.167.9.11114
152166.167.9.112/28166.167.9.113 to 166.167.9.126166.167.9.12714
153166.167.9.128/28166.167.9.129 to 166.167.9.142166.167.9.14314
154166.167.9.144/28166.167.9.145 to 166.167.9.158166.167.9.15914
155166.167.9.160/28166.167.9.161 to 166.167.9.174166.167.9.17514
156166.167.9.176/28166.167.9.177 to 166.167.9.190166.167.9.19114
157166.167.9.192/28166.167.9.193 to 166.167.9.206166.167.9.20714
158166.167.9.208/28166.167.9.209 to 166.167.9.222166.167.9.22314
159166.167.9.224/28166.167.9.225 to 166.167.9.238166.167.9.23914
160166.167.9.240/28166.167.9.241 to 166.167.9.254166.167.9.25514
161166.167.10.0/28166.167.10.1 to 166.167.10.14166.167.10.1514
162166.167.10.16/28166.167.10.17 to 166.167.10.30166.167.10.3114
163166.167.10.32/28166.167.10.33 to 166.167.10.46166.167.10.4714
164166.167.10.48/28166.167.10.49 to 166.167.10.62166.167.10.6314
165166.167.10.64/28166.167.10.65 to 166.167.10.78166.167.10.7914
166166.167.10.80/28166.167.10.81 to 166.167.10.94166.167.10.9514
167166.167.10.96/28166.167.10.97 to 166.167.10.110166.167.10.11114
168166.167.10.112/28166.167.10.113 to 166.167.10.126166.167.10.12714
169166.167.10.128/28166.167.10.129 to 166.167.10.142166.167.10.14314
170166.167.10.144/28166.167.10.145 to 166.167.10.158166.167.10.15914
171166.167.10.160/28166.167.10.161 to 166.167.10.174166.167.10.17514
172166.167.10.176/28166.167.10.177 to 166.167.10.190166.167.10.19114
173166.167.10.192/28166.167.10.193 to 166.167.10.206166.167.10.20714
174166.167.10.208/28166.167.10.209 to 166.167.10.222166.167.10.22314
175166.167.10.224/28166.167.10.225 to 166.167.10.238166.167.10.23914
176166.167.10.240/28166.167.10.241 to 166.167.10.254166.167.10.25514
177166.167.11.0/28166.167.11.1 to 166.167.11.14166.167.11.1514
178166.167.11.16/28166.167.11.17 to 166.167.11.30166.167.11.3114
179166.167.11.32/28166.167.11.33 to 166.167.11.46166.167.11.4714
180166.167.11.48/28166.167.11.49 to 166.167.11.62166.167.11.6314
181166.167.11.64/28166.167.11.65 to 166.167.11.78166.167.11.7914
182166.167.11.80/28166.167.11.81 to 166.167.11.94166.167.11.9514
183166.167.11.96/28166.167.11.97 to 166.167.11.110166.167.11.11114
184166.167.11.112/28166.167.11.113 to 166.167.11.126166.167.11.12714
185166.167.11.128/28166.167.11.129 to 166.167.11.142166.167.11.14314
186166.167.11.144/28166.167.11.145 to 166.167.11.158166.167.11.15914
187166.167.11.160/28166.167.11.161 to 166.167.11.174166.167.11.17514
188166.167.11.176/28166.167.11.177 to 166.167.11.190166.167.11.19114
189166.167.11.192/28166.167.11.193 to 166.167.11.206166.167.11.20714
190166.167.11.208/28166.167.11.209 to 166.167.11.222166.167.11.22314
191166.167.11.224/28166.167.11.225 to 166.167.11.238166.167.11.23914
192166.167.11.240/28166.167.11.241 to 166.167.11.254166.167.11.25514
193166.167.12.0/28166.167.12.1 to 166.167.12.14166.167.12.1514
194166.167.12.16/28166.167.12.17 to 166.167.12.30166.167.12.3114
195166.167.12.32/28166.167.12.33 to 166.167.12.46166.167.12.4714
196166.167.12.48/28166.167.12.49 to 166.167.12.62166.167.12.6314
197166.167.12.64/28166.167.12.65 to 166.167.12.78166.167.12.7914
198166.167.12.80/28166.167.12.81 to 166.167.12.94166.167.12.9514
199166.167.12.96/28166.167.12.97 to 166.167.12.110166.167.12.11114
200166.167.12.112/28166.167.12.113 to 166.167.12.126166.167.12.12714
201166.167.12.128/28166.167.12.129 to 166.167.12.142166.167.12.14314
202166.167.12.144/28166.167.12.145 to 166.167.12.158166.167.12.15914
203166.167.12.160/28166.167.12.161 to 166.167.12.174166.167.12.17514
204166.167.12.176/28166.167.12.177 to 166.167.12.190166.167.12.19114
205166.167.12.192/28166.167.12.193 to 166.167.12.206166.167.12.20714
206166.167.12.208/28166.167.12.209 to 166.167.12.222166.167.12.22314
207166.167.12.224/28166.167.12.225 to 166.167.12.238166.167.12.23914
208166.167.12.240/28166.167.12.241 to 166.167.12.254166.167.12.25514
209166.167.13.0/28166.167.13.1 to 166.167.13.14166.167.13.1514
210166.167.13.16/28166.167.13.17 to 166.167.13.30166.167.13.3114
211166.167.13.32/28166.167.13.33 to 166.167.13.46166.167.13.4714
212166.167.13.48/28166.167.13.49 to 166.167.13.62166.167.13.6314
213166.167.13.64/28166.167.13.65 to 166.167.13.78166.167.13.7914
214166.167.13.80/28166.167.13.81 to 166.167.13.94166.167.13.9514
215166.167.13.96/28166.167.13.97 to 166.167.13.110166.167.13.11114
216166.167.13.112/28166.167.13.113 to 166.167.13.126166.167.13.12714
217166.167.13.128/28166.167.13.129 to 166.167.13.142166.167.13.14314
218166.167.13.144/28166.167.13.145 to 166.167.13.158166.167.13.15914
219166.167.13.160/28166.167.13.161 to 166.167.13.174166.167.13.17514
220166.167.13.176/28166.167.13.177 to 166.167.13.190166.167.13.19114
221166.167.13.192/28166.167.13.193 to 166.167.13.206166.167.13.20714
222166.167.13.208/28166.167.13.209 to 166.167.13.222166.167.13.22314
223166.167.13.224/28166.167.13.225 to 166.167.13.238166.167.13.23914
224166.167.13.240/28166.167.13.241 to 166.167.13.254166.167.13.25514
225166.167.14.0/28166.167.14.1 to 166.167.14.14166.167.14.1514
226166.167.14.16/28166.167.14.17 to 166.167.14.30166.167.14.3114
227166.167.14.32/28166.167.14.33 to 166.167.14.46166.167.14.4714
228166.167.14.48/28166.167.14.49 to 166.167.14.62166.167.14.6314
229166.167.14.64/28166.167.14.65 to 166.167.14.78166.167.14.7914
230166.167.14.80/28166.167.14.81 to 166.167.14.94166.167.14.9514
231166.167.14.96/28166.167.14.97 to 166.167.14.110166.167.14.11114
232166.167.14.112/28166.167.14.113 to 166.167.14.126166.167.14.12714
233166.167.14.128/28166.167.14.129 to 166.167.14.142166.167.14.14314
234166.167.14.144/28166.167.14.145 to 166.167.14.158166.167.14.15914
235166.167.14.160/28166.167.14.161 to 166.167.14.174166.167.14.17514
236166.167.14.176/28166.167.14.177 to 166.167.14.190166.167.14.19114
237166.167.14.192/28166.167.14.193 to 166.167.14.206166.167.14.20714
238166.167.14.208/28166.167.14.209 to 166.167.14.222166.167.14.22314
239166.167.14.224/28166.167.14.225 to 166.167.14.238166.167.14.23914
240166.167.14.240/28166.167.14.241 to 166.167.14.254166.167.14.25514
241166.167.15.0/28166.167.15.1 to 166.167.15.14166.167.15.1514
242166.167.15.16/28166.167.15.17 to 166.167.15.30166.167.15.3114
243166.167.15.32/28166.167.15.33 to 166.167.15.46166.167.15.4714
244166.167.15.48/28166.167.15.49 to 166.167.15.62166.167.15.6314
245166.167.15.64/28166.167.15.65 to 166.167.15.78166.167.15.7914
246166.167.15.80/28166.167.15.81 to 166.167.15.94166.167.15.9514
247166.167.15.96/28166.167.15.97 to 166.167.15.110166.167.15.11114
248166.167.15.112/28166.167.15.113 to 166.167.15.126166.167.15.12714
249166.167.15.128/28166.167.15.129 to 166.167.15.142166.167.15.14314
250166.167.15.144/28166.167.15.145 to 166.167.15.158166.167.15.15914
251166.167.15.160/28166.167.15.161 to 166.167.15.174166.167.15.17514
252166.167.15.176/28166.167.15.177 to 166.167.15.190166.167.15.19114
253166.167.15.192/28166.167.15.193 to 166.167.15.206166.167.15.20714
254166.167.15.208/28166.167.15.209 to 166.167.15.222166.167.15.22314
255166.167.15.224/28166.167.15.225 to 166.167.15.238166.167.15.23914
256166.167.15.240/28166.167.15.241 to 166.167.15.254166.167.15.25514

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.