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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.

Network121.35.0.0/17
Usable hosts32,766
Subnet mask255.255.128.0
Addresses32,768
Network address
121.35.0.0
Broadcast address
121.35.127.255
First usable
121.35.0.1
Last usable
121.35.127.254
Usable hosts
32,766 (32,768 less the network and broadcast addresses)
Subnet mask
255.255.128.0
Wildcard mask
0.0.127.255 (Cisco ACLs, OSPF)
Prefix length
/17
Type
Public public
Old class
A (default /8)
As numbers
Hex 79230000 · Integer 2032336896 to 2032369663
Reverse DNS zones
0.35.121.in-addr.arpa
1.35.121.in-addr.arpa
2.35.121.in-addr.arpa
3.35.121.in-addr.arpa
4.35.121.in-addr.arpa
5.35.121.in-addr.arpa
6.35.121.in-addr.arpa
7.35.121.in-addr.arpa
8.35.121.in-addr.arpa
9.35.121.in-addr.arpa
10.35.121.in-addr.arpa
11.35.121.in-addr.arpa
12.35.121.in-addr.arpa
13.35.121.in-addr.arpa
14.35.121.in-addr.arpa
15.35.121.in-addr.arpa
and 112 more
/17 is not on a 8-bit boundary, so it takes 128 /24 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address01111001.00100011.00000000.00000000121.35.0.0
Subnet mask11111111.11111111.10000000.00000000255.255.128.0
Network01111001.00100011.00000000.00000000121.35.0.0
Broadcast01111001.00100011.01111111.11111111121.35.127.255
Split into smaller subnets/28
/18 (2)/19 (4)/20 (8)/21 (16)/22 (32)/23 (64)/24 (128)/25 (256)/26 (512)/27 (1,024)/28 (2,048)/29 (4,096)

121.35.0.0/17 makes 2,048 subnets of /28; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1121.35.0.0/28121.35.0.1 to 121.35.0.14121.35.0.1514
2121.35.0.16/28121.35.0.17 to 121.35.0.30121.35.0.3114
3121.35.0.32/28121.35.0.33 to 121.35.0.46121.35.0.4714
4121.35.0.48/28121.35.0.49 to 121.35.0.62121.35.0.6314
5121.35.0.64/28121.35.0.65 to 121.35.0.78121.35.0.7914
6121.35.0.80/28121.35.0.81 to 121.35.0.94121.35.0.9514
7121.35.0.96/28121.35.0.97 to 121.35.0.110121.35.0.11114
8121.35.0.112/28121.35.0.113 to 121.35.0.126121.35.0.12714
9121.35.0.128/28121.35.0.129 to 121.35.0.142121.35.0.14314
10121.35.0.144/28121.35.0.145 to 121.35.0.158121.35.0.15914
11121.35.0.160/28121.35.0.161 to 121.35.0.174121.35.0.17514
12121.35.0.176/28121.35.0.177 to 121.35.0.190121.35.0.19114
13121.35.0.192/28121.35.0.193 to 121.35.0.206121.35.0.20714
14121.35.0.208/28121.35.0.209 to 121.35.0.222121.35.0.22314
15121.35.0.224/28121.35.0.225 to 121.35.0.238121.35.0.23914
16121.35.0.240/28121.35.0.241 to 121.35.0.254121.35.0.25514
17121.35.1.0/28121.35.1.1 to 121.35.1.14121.35.1.1514
18121.35.1.16/28121.35.1.17 to 121.35.1.30121.35.1.3114
19121.35.1.32/28121.35.1.33 to 121.35.1.46121.35.1.4714
20121.35.1.48/28121.35.1.49 to 121.35.1.62121.35.1.6314
21121.35.1.64/28121.35.1.65 to 121.35.1.78121.35.1.7914
22121.35.1.80/28121.35.1.81 to 121.35.1.94121.35.1.9514
23121.35.1.96/28121.35.1.97 to 121.35.1.110121.35.1.11114
24121.35.1.112/28121.35.1.113 to 121.35.1.126121.35.1.12714
25121.35.1.128/28121.35.1.129 to 121.35.1.142121.35.1.14314
26121.35.1.144/28121.35.1.145 to 121.35.1.158121.35.1.15914
27121.35.1.160/28121.35.1.161 to 121.35.1.174121.35.1.17514
28121.35.1.176/28121.35.1.177 to 121.35.1.190121.35.1.19114
29121.35.1.192/28121.35.1.193 to 121.35.1.206121.35.1.20714
30121.35.1.208/28121.35.1.209 to 121.35.1.222121.35.1.22314
31121.35.1.224/28121.35.1.225 to 121.35.1.238121.35.1.23914
32121.35.1.240/28121.35.1.241 to 121.35.1.254121.35.1.25514
33121.35.2.0/28121.35.2.1 to 121.35.2.14121.35.2.1514
34121.35.2.16/28121.35.2.17 to 121.35.2.30121.35.2.3114
35121.35.2.32/28121.35.2.33 to 121.35.2.46121.35.2.4714
36121.35.2.48/28121.35.2.49 to 121.35.2.62121.35.2.6314
37121.35.2.64/28121.35.2.65 to 121.35.2.78121.35.2.7914
38121.35.2.80/28121.35.2.81 to 121.35.2.94121.35.2.9514
39121.35.2.96/28121.35.2.97 to 121.35.2.110121.35.2.11114
40121.35.2.112/28121.35.2.113 to 121.35.2.126121.35.2.12714
41121.35.2.128/28121.35.2.129 to 121.35.2.142121.35.2.14314
42121.35.2.144/28121.35.2.145 to 121.35.2.158121.35.2.15914
43121.35.2.160/28121.35.2.161 to 121.35.2.174121.35.2.17514
44121.35.2.176/28121.35.2.177 to 121.35.2.190121.35.2.19114
45121.35.2.192/28121.35.2.193 to 121.35.2.206121.35.2.20714
46121.35.2.208/28121.35.2.209 to 121.35.2.222121.35.2.22314
47121.35.2.224/28121.35.2.225 to 121.35.2.238121.35.2.23914
48121.35.2.240/28121.35.2.241 to 121.35.2.254121.35.2.25514
49121.35.3.0/28121.35.3.1 to 121.35.3.14121.35.3.1514
50121.35.3.16/28121.35.3.17 to 121.35.3.30121.35.3.3114
51121.35.3.32/28121.35.3.33 to 121.35.3.46121.35.3.4714
52121.35.3.48/28121.35.3.49 to 121.35.3.62121.35.3.6314
53121.35.3.64/28121.35.3.65 to 121.35.3.78121.35.3.7914
54121.35.3.80/28121.35.3.81 to 121.35.3.94121.35.3.9514
55121.35.3.96/28121.35.3.97 to 121.35.3.110121.35.3.11114
56121.35.3.112/28121.35.3.113 to 121.35.3.126121.35.3.12714
57121.35.3.128/28121.35.3.129 to 121.35.3.142121.35.3.14314
58121.35.3.144/28121.35.3.145 to 121.35.3.158121.35.3.15914
59121.35.3.160/28121.35.3.161 to 121.35.3.174121.35.3.17514
60121.35.3.176/28121.35.3.177 to 121.35.3.190121.35.3.19114
61121.35.3.192/28121.35.3.193 to 121.35.3.206121.35.3.20714
62121.35.3.208/28121.35.3.209 to 121.35.3.222121.35.3.22314
63121.35.3.224/28121.35.3.225 to 121.35.3.238121.35.3.23914
64121.35.3.240/28121.35.3.241 to 121.35.3.254121.35.3.25514
65121.35.4.0/28121.35.4.1 to 121.35.4.14121.35.4.1514
66121.35.4.16/28121.35.4.17 to 121.35.4.30121.35.4.3114
67121.35.4.32/28121.35.4.33 to 121.35.4.46121.35.4.4714
68121.35.4.48/28121.35.4.49 to 121.35.4.62121.35.4.6314
69121.35.4.64/28121.35.4.65 to 121.35.4.78121.35.4.7914
70121.35.4.80/28121.35.4.81 to 121.35.4.94121.35.4.9514
71121.35.4.96/28121.35.4.97 to 121.35.4.110121.35.4.11114
72121.35.4.112/28121.35.4.113 to 121.35.4.126121.35.4.12714
73121.35.4.128/28121.35.4.129 to 121.35.4.142121.35.4.14314
74121.35.4.144/28121.35.4.145 to 121.35.4.158121.35.4.15914
75121.35.4.160/28121.35.4.161 to 121.35.4.174121.35.4.17514
76121.35.4.176/28121.35.4.177 to 121.35.4.190121.35.4.19114
77121.35.4.192/28121.35.4.193 to 121.35.4.206121.35.4.20714
78121.35.4.208/28121.35.4.209 to 121.35.4.222121.35.4.22314
79121.35.4.224/28121.35.4.225 to 121.35.4.238121.35.4.23914
80121.35.4.240/28121.35.4.241 to 121.35.4.254121.35.4.25514
81121.35.5.0/28121.35.5.1 to 121.35.5.14121.35.5.1514
82121.35.5.16/28121.35.5.17 to 121.35.5.30121.35.5.3114
83121.35.5.32/28121.35.5.33 to 121.35.5.46121.35.5.4714
84121.35.5.48/28121.35.5.49 to 121.35.5.62121.35.5.6314
85121.35.5.64/28121.35.5.65 to 121.35.5.78121.35.5.7914
86121.35.5.80/28121.35.5.81 to 121.35.5.94121.35.5.9514
87121.35.5.96/28121.35.5.97 to 121.35.5.110121.35.5.11114
88121.35.5.112/28121.35.5.113 to 121.35.5.126121.35.5.12714
89121.35.5.128/28121.35.5.129 to 121.35.5.142121.35.5.14314
90121.35.5.144/28121.35.5.145 to 121.35.5.158121.35.5.15914
91121.35.5.160/28121.35.5.161 to 121.35.5.174121.35.5.17514
92121.35.5.176/28121.35.5.177 to 121.35.5.190121.35.5.19114
93121.35.5.192/28121.35.5.193 to 121.35.5.206121.35.5.20714
94121.35.5.208/28121.35.5.209 to 121.35.5.222121.35.5.22314
95121.35.5.224/28121.35.5.225 to 121.35.5.238121.35.5.23914
96121.35.5.240/28121.35.5.241 to 121.35.5.254121.35.5.25514
97121.35.6.0/28121.35.6.1 to 121.35.6.14121.35.6.1514
98121.35.6.16/28121.35.6.17 to 121.35.6.30121.35.6.3114
99121.35.6.32/28121.35.6.33 to 121.35.6.46121.35.6.4714
100121.35.6.48/28121.35.6.49 to 121.35.6.62121.35.6.6314
101121.35.6.64/28121.35.6.65 to 121.35.6.78121.35.6.7914
102121.35.6.80/28121.35.6.81 to 121.35.6.94121.35.6.9514
103121.35.6.96/28121.35.6.97 to 121.35.6.110121.35.6.11114
104121.35.6.112/28121.35.6.113 to 121.35.6.126121.35.6.12714
105121.35.6.128/28121.35.6.129 to 121.35.6.142121.35.6.14314
106121.35.6.144/28121.35.6.145 to 121.35.6.158121.35.6.15914
107121.35.6.160/28121.35.6.161 to 121.35.6.174121.35.6.17514
108121.35.6.176/28121.35.6.177 to 121.35.6.190121.35.6.19114
109121.35.6.192/28121.35.6.193 to 121.35.6.206121.35.6.20714
110121.35.6.208/28121.35.6.209 to 121.35.6.222121.35.6.22314
111121.35.6.224/28121.35.6.225 to 121.35.6.238121.35.6.23914
112121.35.6.240/28121.35.6.241 to 121.35.6.254121.35.6.25514
113121.35.7.0/28121.35.7.1 to 121.35.7.14121.35.7.1514
114121.35.7.16/28121.35.7.17 to 121.35.7.30121.35.7.3114
115121.35.7.32/28121.35.7.33 to 121.35.7.46121.35.7.4714
116121.35.7.48/28121.35.7.49 to 121.35.7.62121.35.7.6314
117121.35.7.64/28121.35.7.65 to 121.35.7.78121.35.7.7914
118121.35.7.80/28121.35.7.81 to 121.35.7.94121.35.7.9514
119121.35.7.96/28121.35.7.97 to 121.35.7.110121.35.7.11114
120121.35.7.112/28121.35.7.113 to 121.35.7.126121.35.7.12714
121121.35.7.128/28121.35.7.129 to 121.35.7.142121.35.7.14314
122121.35.7.144/28121.35.7.145 to 121.35.7.158121.35.7.15914
123121.35.7.160/28121.35.7.161 to 121.35.7.174121.35.7.17514
124121.35.7.176/28121.35.7.177 to 121.35.7.190121.35.7.19114
125121.35.7.192/28121.35.7.193 to 121.35.7.206121.35.7.20714
126121.35.7.208/28121.35.7.209 to 121.35.7.222121.35.7.22314
127121.35.7.224/28121.35.7.225 to 121.35.7.238121.35.7.23914
128121.35.7.240/28121.35.7.241 to 121.35.7.254121.35.7.25514
129121.35.8.0/28121.35.8.1 to 121.35.8.14121.35.8.1514
130121.35.8.16/28121.35.8.17 to 121.35.8.30121.35.8.3114
131121.35.8.32/28121.35.8.33 to 121.35.8.46121.35.8.4714
132121.35.8.48/28121.35.8.49 to 121.35.8.62121.35.8.6314
133121.35.8.64/28121.35.8.65 to 121.35.8.78121.35.8.7914
134121.35.8.80/28121.35.8.81 to 121.35.8.94121.35.8.9514
135121.35.8.96/28121.35.8.97 to 121.35.8.110121.35.8.11114
136121.35.8.112/28121.35.8.113 to 121.35.8.126121.35.8.12714
137121.35.8.128/28121.35.8.129 to 121.35.8.142121.35.8.14314
138121.35.8.144/28121.35.8.145 to 121.35.8.158121.35.8.15914
139121.35.8.160/28121.35.8.161 to 121.35.8.174121.35.8.17514
140121.35.8.176/28121.35.8.177 to 121.35.8.190121.35.8.19114
141121.35.8.192/28121.35.8.193 to 121.35.8.206121.35.8.20714
142121.35.8.208/28121.35.8.209 to 121.35.8.222121.35.8.22314
143121.35.8.224/28121.35.8.225 to 121.35.8.238121.35.8.23914
144121.35.8.240/28121.35.8.241 to 121.35.8.254121.35.8.25514
145121.35.9.0/28121.35.9.1 to 121.35.9.14121.35.9.1514
146121.35.9.16/28121.35.9.17 to 121.35.9.30121.35.9.3114
147121.35.9.32/28121.35.9.33 to 121.35.9.46121.35.9.4714
148121.35.9.48/28121.35.9.49 to 121.35.9.62121.35.9.6314
149121.35.9.64/28121.35.9.65 to 121.35.9.78121.35.9.7914
150121.35.9.80/28121.35.9.81 to 121.35.9.94121.35.9.9514
151121.35.9.96/28121.35.9.97 to 121.35.9.110121.35.9.11114
152121.35.9.112/28121.35.9.113 to 121.35.9.126121.35.9.12714
153121.35.9.128/28121.35.9.129 to 121.35.9.142121.35.9.14314
154121.35.9.144/28121.35.9.145 to 121.35.9.158121.35.9.15914
155121.35.9.160/28121.35.9.161 to 121.35.9.174121.35.9.17514
156121.35.9.176/28121.35.9.177 to 121.35.9.190121.35.9.19114
157121.35.9.192/28121.35.9.193 to 121.35.9.206121.35.9.20714
158121.35.9.208/28121.35.9.209 to 121.35.9.222121.35.9.22314
159121.35.9.224/28121.35.9.225 to 121.35.9.238121.35.9.23914
160121.35.9.240/28121.35.9.241 to 121.35.9.254121.35.9.25514
161121.35.10.0/28121.35.10.1 to 121.35.10.14121.35.10.1514
162121.35.10.16/28121.35.10.17 to 121.35.10.30121.35.10.3114
163121.35.10.32/28121.35.10.33 to 121.35.10.46121.35.10.4714
164121.35.10.48/28121.35.10.49 to 121.35.10.62121.35.10.6314
165121.35.10.64/28121.35.10.65 to 121.35.10.78121.35.10.7914
166121.35.10.80/28121.35.10.81 to 121.35.10.94121.35.10.9514
167121.35.10.96/28121.35.10.97 to 121.35.10.110121.35.10.11114
168121.35.10.112/28121.35.10.113 to 121.35.10.126121.35.10.12714
169121.35.10.128/28121.35.10.129 to 121.35.10.142121.35.10.14314
170121.35.10.144/28121.35.10.145 to 121.35.10.158121.35.10.15914
171121.35.10.160/28121.35.10.161 to 121.35.10.174121.35.10.17514
172121.35.10.176/28121.35.10.177 to 121.35.10.190121.35.10.19114
173121.35.10.192/28121.35.10.193 to 121.35.10.206121.35.10.20714
174121.35.10.208/28121.35.10.209 to 121.35.10.222121.35.10.22314
175121.35.10.224/28121.35.10.225 to 121.35.10.238121.35.10.23914
176121.35.10.240/28121.35.10.241 to 121.35.10.254121.35.10.25514
177121.35.11.0/28121.35.11.1 to 121.35.11.14121.35.11.1514
178121.35.11.16/28121.35.11.17 to 121.35.11.30121.35.11.3114
179121.35.11.32/28121.35.11.33 to 121.35.11.46121.35.11.4714
180121.35.11.48/28121.35.11.49 to 121.35.11.62121.35.11.6314
181121.35.11.64/28121.35.11.65 to 121.35.11.78121.35.11.7914
182121.35.11.80/28121.35.11.81 to 121.35.11.94121.35.11.9514
183121.35.11.96/28121.35.11.97 to 121.35.11.110121.35.11.11114
184121.35.11.112/28121.35.11.113 to 121.35.11.126121.35.11.12714
185121.35.11.128/28121.35.11.129 to 121.35.11.142121.35.11.14314
186121.35.11.144/28121.35.11.145 to 121.35.11.158121.35.11.15914
187121.35.11.160/28121.35.11.161 to 121.35.11.174121.35.11.17514
188121.35.11.176/28121.35.11.177 to 121.35.11.190121.35.11.19114
189121.35.11.192/28121.35.11.193 to 121.35.11.206121.35.11.20714
190121.35.11.208/28121.35.11.209 to 121.35.11.222121.35.11.22314
191121.35.11.224/28121.35.11.225 to 121.35.11.238121.35.11.23914
192121.35.11.240/28121.35.11.241 to 121.35.11.254121.35.11.25514
193121.35.12.0/28121.35.12.1 to 121.35.12.14121.35.12.1514
194121.35.12.16/28121.35.12.17 to 121.35.12.30121.35.12.3114
195121.35.12.32/28121.35.12.33 to 121.35.12.46121.35.12.4714
196121.35.12.48/28121.35.12.49 to 121.35.12.62121.35.12.6314
197121.35.12.64/28121.35.12.65 to 121.35.12.78121.35.12.7914
198121.35.12.80/28121.35.12.81 to 121.35.12.94121.35.12.9514
199121.35.12.96/28121.35.12.97 to 121.35.12.110121.35.12.11114
200121.35.12.112/28121.35.12.113 to 121.35.12.126121.35.12.12714
201121.35.12.128/28121.35.12.129 to 121.35.12.142121.35.12.14314
202121.35.12.144/28121.35.12.145 to 121.35.12.158121.35.12.15914
203121.35.12.160/28121.35.12.161 to 121.35.12.174121.35.12.17514
204121.35.12.176/28121.35.12.177 to 121.35.12.190121.35.12.19114
205121.35.12.192/28121.35.12.193 to 121.35.12.206121.35.12.20714
206121.35.12.208/28121.35.12.209 to 121.35.12.222121.35.12.22314
207121.35.12.224/28121.35.12.225 to 121.35.12.238121.35.12.23914
208121.35.12.240/28121.35.12.241 to 121.35.12.254121.35.12.25514
209121.35.13.0/28121.35.13.1 to 121.35.13.14121.35.13.1514
210121.35.13.16/28121.35.13.17 to 121.35.13.30121.35.13.3114
211121.35.13.32/28121.35.13.33 to 121.35.13.46121.35.13.4714
212121.35.13.48/28121.35.13.49 to 121.35.13.62121.35.13.6314
213121.35.13.64/28121.35.13.65 to 121.35.13.78121.35.13.7914
214121.35.13.80/28121.35.13.81 to 121.35.13.94121.35.13.9514
215121.35.13.96/28121.35.13.97 to 121.35.13.110121.35.13.11114
216121.35.13.112/28121.35.13.113 to 121.35.13.126121.35.13.12714
217121.35.13.128/28121.35.13.129 to 121.35.13.142121.35.13.14314
218121.35.13.144/28121.35.13.145 to 121.35.13.158121.35.13.15914
219121.35.13.160/28121.35.13.161 to 121.35.13.174121.35.13.17514
220121.35.13.176/28121.35.13.177 to 121.35.13.190121.35.13.19114
221121.35.13.192/28121.35.13.193 to 121.35.13.206121.35.13.20714
222121.35.13.208/28121.35.13.209 to 121.35.13.222121.35.13.22314
223121.35.13.224/28121.35.13.225 to 121.35.13.238121.35.13.23914
224121.35.13.240/28121.35.13.241 to 121.35.13.254121.35.13.25514
225121.35.14.0/28121.35.14.1 to 121.35.14.14121.35.14.1514
226121.35.14.16/28121.35.14.17 to 121.35.14.30121.35.14.3114
227121.35.14.32/28121.35.14.33 to 121.35.14.46121.35.14.4714
228121.35.14.48/28121.35.14.49 to 121.35.14.62121.35.14.6314
229121.35.14.64/28121.35.14.65 to 121.35.14.78121.35.14.7914
230121.35.14.80/28121.35.14.81 to 121.35.14.94121.35.14.9514
231121.35.14.96/28121.35.14.97 to 121.35.14.110121.35.14.11114
232121.35.14.112/28121.35.14.113 to 121.35.14.126121.35.14.12714
233121.35.14.128/28121.35.14.129 to 121.35.14.142121.35.14.14314
234121.35.14.144/28121.35.14.145 to 121.35.14.158121.35.14.15914
235121.35.14.160/28121.35.14.161 to 121.35.14.174121.35.14.17514
236121.35.14.176/28121.35.14.177 to 121.35.14.190121.35.14.19114
237121.35.14.192/28121.35.14.193 to 121.35.14.206121.35.14.20714
238121.35.14.208/28121.35.14.209 to 121.35.14.222121.35.14.22314
239121.35.14.224/28121.35.14.225 to 121.35.14.238121.35.14.23914
240121.35.14.240/28121.35.14.241 to 121.35.14.254121.35.14.25514
241121.35.15.0/28121.35.15.1 to 121.35.15.14121.35.15.1514
242121.35.15.16/28121.35.15.17 to 121.35.15.30121.35.15.3114
243121.35.15.32/28121.35.15.33 to 121.35.15.46121.35.15.4714
244121.35.15.48/28121.35.15.49 to 121.35.15.62121.35.15.6314
245121.35.15.64/28121.35.15.65 to 121.35.15.78121.35.15.7914
246121.35.15.80/28121.35.15.81 to 121.35.15.94121.35.15.9514
247121.35.15.96/28121.35.15.97 to 121.35.15.110121.35.15.11114
248121.35.15.112/28121.35.15.113 to 121.35.15.126121.35.15.12714
249121.35.15.128/28121.35.15.129 to 121.35.15.142121.35.15.14314
250121.35.15.144/28121.35.15.145 to 121.35.15.158121.35.15.15914
251121.35.15.160/28121.35.15.161 to 121.35.15.174121.35.15.17514
252121.35.15.176/28121.35.15.177 to 121.35.15.190121.35.15.19114
253121.35.15.192/28121.35.15.193 to 121.35.15.206121.35.15.20714
254121.35.15.208/28121.35.15.209 to 121.35.15.222121.35.15.22314
255121.35.15.224/28121.35.15.225 to 121.35.15.238121.35.15.23914
256121.35.15.240/28121.35.15.241 to 121.35.15.254121.35.15.25514

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.