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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.

Network157.64.0.0/10
Usable hosts4,194,302
Subnet mask255.192.0.0
Addresses4,194,304
Network address
157.64.0.0
Broadcast address
157.127.255.255
First usable
157.64.0.1
Last usable
157.127.255.254
Usable hosts
4,194,302 (4,194,304 less the network and broadcast addresses)
Subnet mask
255.192.0.0
Wildcard mask
0.63.255.255 (Cisco ACLs, OSPF)
Prefix length
/10
Type
Public public
Old class
B (default /16)
As numbers
Hex 9D400000 · Integer 2638217216 to 2642411519
Reverse DNS zones
64.157.in-addr.arpa
65.157.in-addr.arpa
66.157.in-addr.arpa
67.157.in-addr.arpa
68.157.in-addr.arpa
69.157.in-addr.arpa
70.157.in-addr.arpa
71.157.in-addr.arpa
72.157.in-addr.arpa
73.157.in-addr.arpa
74.157.in-addr.arpa
75.157.in-addr.arpa
76.157.in-addr.arpa
77.157.in-addr.arpa
78.157.in-addr.arpa
79.157.in-addr.arpa
and 48 more
/10 is not on a 8-bit boundary, so it takes 64 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address10011101.01000000.00000000.00000000157.64.0.0
Subnet mask11111111.11000000.00000000.00000000255.192.0.0
Network10011101.01000000.00000000.00000000157.64.0.0
Broadcast10011101.01111111.11111111.11111111157.127.255.255
Split into smaller subnets/18
/11 (2)/12 (4)/13 (8)/14 (16)/15 (32)/16 (64)/17 (128)/18 (256)/19 (512)/20 (1,024)/21 (2,048)/22 (4,096)

157.64.0.0/10 makes 256 subnets of /18.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1157.64.0.0/18157.64.0.1 to 157.64.63.254157.64.63.25516,382
2157.64.64.0/18157.64.64.1 to 157.64.127.254157.64.127.25516,382
3157.64.128.0/18157.64.128.1 to 157.64.191.254157.64.191.25516,382
4157.64.192.0/18157.64.192.1 to 157.64.255.254157.64.255.25516,382
5157.65.0.0/18157.65.0.1 to 157.65.63.254157.65.63.25516,382
6157.65.64.0/18157.65.64.1 to 157.65.127.254157.65.127.25516,382
7157.65.128.0/18157.65.128.1 to 157.65.191.254157.65.191.25516,382
8157.65.192.0/18157.65.192.1 to 157.65.255.254157.65.255.25516,382
9157.66.0.0/18157.66.0.1 to 157.66.63.254157.66.63.25516,382
10157.66.64.0/18157.66.64.1 to 157.66.127.254157.66.127.25516,382
11157.66.128.0/18157.66.128.1 to 157.66.191.254157.66.191.25516,382
12157.66.192.0/18157.66.192.1 to 157.66.255.254157.66.255.25516,382
13157.67.0.0/18157.67.0.1 to 157.67.63.254157.67.63.25516,382
14157.67.64.0/18157.67.64.1 to 157.67.127.254157.67.127.25516,382
15157.67.128.0/18157.67.128.1 to 157.67.191.254157.67.191.25516,382
16157.67.192.0/18157.67.192.1 to 157.67.255.254157.67.255.25516,382
17157.68.0.0/18157.68.0.1 to 157.68.63.254157.68.63.25516,382
18157.68.64.0/18157.68.64.1 to 157.68.127.254157.68.127.25516,382
19157.68.128.0/18157.68.128.1 to 157.68.191.254157.68.191.25516,382
20157.68.192.0/18157.68.192.1 to 157.68.255.254157.68.255.25516,382
21157.69.0.0/18157.69.0.1 to 157.69.63.254157.69.63.25516,382
22157.69.64.0/18157.69.64.1 to 157.69.127.254157.69.127.25516,382
23157.69.128.0/18157.69.128.1 to 157.69.191.254157.69.191.25516,382
24157.69.192.0/18157.69.192.1 to 157.69.255.254157.69.255.25516,382
25157.70.0.0/18157.70.0.1 to 157.70.63.254157.70.63.25516,382
26157.70.64.0/18157.70.64.1 to 157.70.127.254157.70.127.25516,382
27157.70.128.0/18157.70.128.1 to 157.70.191.254157.70.191.25516,382
28157.70.192.0/18157.70.192.1 to 157.70.255.254157.70.255.25516,382
29157.71.0.0/18157.71.0.1 to 157.71.63.254157.71.63.25516,382
30157.71.64.0/18157.71.64.1 to 157.71.127.254157.71.127.25516,382
31157.71.128.0/18157.71.128.1 to 157.71.191.254157.71.191.25516,382
32157.71.192.0/18157.71.192.1 to 157.71.255.254157.71.255.25516,382
33157.72.0.0/18157.72.0.1 to 157.72.63.254157.72.63.25516,382
34157.72.64.0/18157.72.64.1 to 157.72.127.254157.72.127.25516,382
35157.72.128.0/18157.72.128.1 to 157.72.191.254157.72.191.25516,382
36157.72.192.0/18157.72.192.1 to 157.72.255.254157.72.255.25516,382
37157.73.0.0/18157.73.0.1 to 157.73.63.254157.73.63.25516,382
38157.73.64.0/18157.73.64.1 to 157.73.127.254157.73.127.25516,382
39157.73.128.0/18157.73.128.1 to 157.73.191.254157.73.191.25516,382
40157.73.192.0/18157.73.192.1 to 157.73.255.254157.73.255.25516,382
41157.74.0.0/18157.74.0.1 to 157.74.63.254157.74.63.25516,382
42157.74.64.0/18157.74.64.1 to 157.74.127.254157.74.127.25516,382
43157.74.128.0/18157.74.128.1 to 157.74.191.254157.74.191.25516,382
44157.74.192.0/18157.74.192.1 to 157.74.255.254157.74.255.25516,382
45157.75.0.0/18157.75.0.1 to 157.75.63.254157.75.63.25516,382
46157.75.64.0/18157.75.64.1 to 157.75.127.254157.75.127.25516,382
47157.75.128.0/18157.75.128.1 to 157.75.191.254157.75.191.25516,382
48157.75.192.0/18157.75.192.1 to 157.75.255.254157.75.255.25516,382
49157.76.0.0/18157.76.0.1 to 157.76.63.254157.76.63.25516,382
50157.76.64.0/18157.76.64.1 to 157.76.127.254157.76.127.25516,382
51157.76.128.0/18157.76.128.1 to 157.76.191.254157.76.191.25516,382
52157.76.192.0/18157.76.192.1 to 157.76.255.254157.76.255.25516,382
53157.77.0.0/18157.77.0.1 to 157.77.63.254157.77.63.25516,382
54157.77.64.0/18157.77.64.1 to 157.77.127.254157.77.127.25516,382
55157.77.128.0/18157.77.128.1 to 157.77.191.254157.77.191.25516,382
56157.77.192.0/18157.77.192.1 to 157.77.255.254157.77.255.25516,382
57157.78.0.0/18157.78.0.1 to 157.78.63.254157.78.63.25516,382
58157.78.64.0/18157.78.64.1 to 157.78.127.254157.78.127.25516,382
59157.78.128.0/18157.78.128.1 to 157.78.191.254157.78.191.25516,382
60157.78.192.0/18157.78.192.1 to 157.78.255.254157.78.255.25516,382
61157.79.0.0/18157.79.0.1 to 157.79.63.254157.79.63.25516,382
62157.79.64.0/18157.79.64.1 to 157.79.127.254157.79.127.25516,382
63157.79.128.0/18157.79.128.1 to 157.79.191.254157.79.191.25516,382
64157.79.192.0/18157.79.192.1 to 157.79.255.254157.79.255.25516,382
65157.80.0.0/18157.80.0.1 to 157.80.63.254157.80.63.25516,382
66157.80.64.0/18157.80.64.1 to 157.80.127.254157.80.127.25516,382
67157.80.128.0/18157.80.128.1 to 157.80.191.254157.80.191.25516,382
68157.80.192.0/18157.80.192.1 to 157.80.255.254157.80.255.25516,382
69157.81.0.0/18157.81.0.1 to 157.81.63.254157.81.63.25516,382
70157.81.64.0/18157.81.64.1 to 157.81.127.254157.81.127.25516,382
71157.81.128.0/18157.81.128.1 to 157.81.191.254157.81.191.25516,382
72157.81.192.0/18157.81.192.1 to 157.81.255.254157.81.255.25516,382
73157.82.0.0/18157.82.0.1 to 157.82.63.254157.82.63.25516,382
74157.82.64.0/18157.82.64.1 to 157.82.127.254157.82.127.25516,382
75157.82.128.0/18157.82.128.1 to 157.82.191.254157.82.191.25516,382
76157.82.192.0/18157.82.192.1 to 157.82.255.254157.82.255.25516,382
77157.83.0.0/18157.83.0.1 to 157.83.63.254157.83.63.25516,382
78157.83.64.0/18157.83.64.1 to 157.83.127.254157.83.127.25516,382
79157.83.128.0/18157.83.128.1 to 157.83.191.254157.83.191.25516,382
80157.83.192.0/18157.83.192.1 to 157.83.255.254157.83.255.25516,382
81157.84.0.0/18157.84.0.1 to 157.84.63.254157.84.63.25516,382
82157.84.64.0/18157.84.64.1 to 157.84.127.254157.84.127.25516,382
83157.84.128.0/18157.84.128.1 to 157.84.191.254157.84.191.25516,382
84157.84.192.0/18157.84.192.1 to 157.84.255.254157.84.255.25516,382
85157.85.0.0/18157.85.0.1 to 157.85.63.254157.85.63.25516,382
86157.85.64.0/18157.85.64.1 to 157.85.127.254157.85.127.25516,382
87157.85.128.0/18157.85.128.1 to 157.85.191.254157.85.191.25516,382
88157.85.192.0/18157.85.192.1 to 157.85.255.254157.85.255.25516,382
89157.86.0.0/18157.86.0.1 to 157.86.63.254157.86.63.25516,382
90157.86.64.0/18157.86.64.1 to 157.86.127.254157.86.127.25516,382
91157.86.128.0/18157.86.128.1 to 157.86.191.254157.86.191.25516,382
92157.86.192.0/18157.86.192.1 to 157.86.255.254157.86.255.25516,382
93157.87.0.0/18157.87.0.1 to 157.87.63.254157.87.63.25516,382
94157.87.64.0/18157.87.64.1 to 157.87.127.254157.87.127.25516,382
95157.87.128.0/18157.87.128.1 to 157.87.191.254157.87.191.25516,382
96157.87.192.0/18157.87.192.1 to 157.87.255.254157.87.255.25516,382
97157.88.0.0/18157.88.0.1 to 157.88.63.254157.88.63.25516,382
98157.88.64.0/18157.88.64.1 to 157.88.127.254157.88.127.25516,382
99157.88.128.0/18157.88.128.1 to 157.88.191.254157.88.191.25516,382
100157.88.192.0/18157.88.192.1 to 157.88.255.254157.88.255.25516,382
101157.89.0.0/18157.89.0.1 to 157.89.63.254157.89.63.25516,382
102157.89.64.0/18157.89.64.1 to 157.89.127.254157.89.127.25516,382
103157.89.128.0/18157.89.128.1 to 157.89.191.254157.89.191.25516,382
104157.89.192.0/18157.89.192.1 to 157.89.255.254157.89.255.25516,382
105157.90.0.0/18157.90.0.1 to 157.90.63.254157.90.63.25516,382
106157.90.64.0/18157.90.64.1 to 157.90.127.254157.90.127.25516,382
107157.90.128.0/18157.90.128.1 to 157.90.191.254157.90.191.25516,382
108157.90.192.0/18157.90.192.1 to 157.90.255.254157.90.255.25516,382
109157.91.0.0/18157.91.0.1 to 157.91.63.254157.91.63.25516,382
110157.91.64.0/18157.91.64.1 to 157.91.127.254157.91.127.25516,382
111157.91.128.0/18157.91.128.1 to 157.91.191.254157.91.191.25516,382
112157.91.192.0/18157.91.192.1 to 157.91.255.254157.91.255.25516,382
113157.92.0.0/18157.92.0.1 to 157.92.63.254157.92.63.25516,382
114157.92.64.0/18157.92.64.1 to 157.92.127.254157.92.127.25516,382
115157.92.128.0/18157.92.128.1 to 157.92.191.254157.92.191.25516,382
116157.92.192.0/18157.92.192.1 to 157.92.255.254157.92.255.25516,382
117157.93.0.0/18157.93.0.1 to 157.93.63.254157.93.63.25516,382
118157.93.64.0/18157.93.64.1 to 157.93.127.254157.93.127.25516,382
119157.93.128.0/18157.93.128.1 to 157.93.191.254157.93.191.25516,382
120157.93.192.0/18157.93.192.1 to 157.93.255.254157.93.255.25516,382
121157.94.0.0/18157.94.0.1 to 157.94.63.254157.94.63.25516,382
122157.94.64.0/18157.94.64.1 to 157.94.127.254157.94.127.25516,382
123157.94.128.0/18157.94.128.1 to 157.94.191.254157.94.191.25516,382
124157.94.192.0/18157.94.192.1 to 157.94.255.254157.94.255.25516,382
125157.95.0.0/18157.95.0.1 to 157.95.63.254157.95.63.25516,382
126157.95.64.0/18157.95.64.1 to 157.95.127.254157.95.127.25516,382
127157.95.128.0/18157.95.128.1 to 157.95.191.254157.95.191.25516,382
128157.95.192.0/18157.95.192.1 to 157.95.255.254157.95.255.25516,382
129157.96.0.0/18157.96.0.1 to 157.96.63.254157.96.63.25516,382
130157.96.64.0/18157.96.64.1 to 157.96.127.254157.96.127.25516,382
131157.96.128.0/18157.96.128.1 to 157.96.191.254157.96.191.25516,382
132157.96.192.0/18157.96.192.1 to 157.96.255.254157.96.255.25516,382
133157.97.0.0/18157.97.0.1 to 157.97.63.254157.97.63.25516,382
134157.97.64.0/18157.97.64.1 to 157.97.127.254157.97.127.25516,382
135157.97.128.0/18157.97.128.1 to 157.97.191.254157.97.191.25516,382
136157.97.192.0/18157.97.192.1 to 157.97.255.254157.97.255.25516,382
137157.98.0.0/18157.98.0.1 to 157.98.63.254157.98.63.25516,382
138157.98.64.0/18157.98.64.1 to 157.98.127.254157.98.127.25516,382
139157.98.128.0/18157.98.128.1 to 157.98.191.254157.98.191.25516,382
140157.98.192.0/18157.98.192.1 to 157.98.255.254157.98.255.25516,382
141157.99.0.0/18157.99.0.1 to 157.99.63.254157.99.63.25516,382
142157.99.64.0/18157.99.64.1 to 157.99.127.254157.99.127.25516,382
143157.99.128.0/18157.99.128.1 to 157.99.191.254157.99.191.25516,382
144157.99.192.0/18157.99.192.1 to 157.99.255.254157.99.255.25516,382
145157.100.0.0/18157.100.0.1 to 157.100.63.254157.100.63.25516,382
146157.100.64.0/18157.100.64.1 to 157.100.127.254157.100.127.25516,382
147157.100.128.0/18157.100.128.1 to 157.100.191.254157.100.191.25516,382
148157.100.192.0/18157.100.192.1 to 157.100.255.254157.100.255.25516,382
149157.101.0.0/18157.101.0.1 to 157.101.63.254157.101.63.25516,382
150157.101.64.0/18157.101.64.1 to 157.101.127.254157.101.127.25516,382
151157.101.128.0/18157.101.128.1 to 157.101.191.254157.101.191.25516,382
152157.101.192.0/18157.101.192.1 to 157.101.255.254157.101.255.25516,382
153157.102.0.0/18157.102.0.1 to 157.102.63.254157.102.63.25516,382
154157.102.64.0/18157.102.64.1 to 157.102.127.254157.102.127.25516,382
155157.102.128.0/18157.102.128.1 to 157.102.191.254157.102.191.25516,382
156157.102.192.0/18157.102.192.1 to 157.102.255.254157.102.255.25516,382
157157.103.0.0/18157.103.0.1 to 157.103.63.254157.103.63.25516,382
158157.103.64.0/18157.103.64.1 to 157.103.127.254157.103.127.25516,382
159157.103.128.0/18157.103.128.1 to 157.103.191.254157.103.191.25516,382
160157.103.192.0/18157.103.192.1 to 157.103.255.254157.103.255.25516,382
161157.104.0.0/18157.104.0.1 to 157.104.63.254157.104.63.25516,382
162157.104.64.0/18157.104.64.1 to 157.104.127.254157.104.127.25516,382
163157.104.128.0/18157.104.128.1 to 157.104.191.254157.104.191.25516,382
164157.104.192.0/18157.104.192.1 to 157.104.255.254157.104.255.25516,382
165157.105.0.0/18157.105.0.1 to 157.105.63.254157.105.63.25516,382
166157.105.64.0/18157.105.64.1 to 157.105.127.254157.105.127.25516,382
167157.105.128.0/18157.105.128.1 to 157.105.191.254157.105.191.25516,382
168157.105.192.0/18157.105.192.1 to 157.105.255.254157.105.255.25516,382
169157.106.0.0/18157.106.0.1 to 157.106.63.254157.106.63.25516,382
170157.106.64.0/18157.106.64.1 to 157.106.127.254157.106.127.25516,382
171157.106.128.0/18157.106.128.1 to 157.106.191.254157.106.191.25516,382
172157.106.192.0/18157.106.192.1 to 157.106.255.254157.106.255.25516,382
173157.107.0.0/18157.107.0.1 to 157.107.63.254157.107.63.25516,382
174157.107.64.0/18157.107.64.1 to 157.107.127.254157.107.127.25516,382
175157.107.128.0/18157.107.128.1 to 157.107.191.254157.107.191.25516,382
176157.107.192.0/18157.107.192.1 to 157.107.255.254157.107.255.25516,382
177157.108.0.0/18157.108.0.1 to 157.108.63.254157.108.63.25516,382
178157.108.64.0/18157.108.64.1 to 157.108.127.254157.108.127.25516,382
179157.108.128.0/18157.108.128.1 to 157.108.191.254157.108.191.25516,382
180157.108.192.0/18157.108.192.1 to 157.108.255.254157.108.255.25516,382
181157.109.0.0/18157.109.0.1 to 157.109.63.254157.109.63.25516,382
182157.109.64.0/18157.109.64.1 to 157.109.127.254157.109.127.25516,382
183157.109.128.0/18157.109.128.1 to 157.109.191.254157.109.191.25516,382
184157.109.192.0/18157.109.192.1 to 157.109.255.254157.109.255.25516,382
185157.110.0.0/18157.110.0.1 to 157.110.63.254157.110.63.25516,382
186157.110.64.0/18157.110.64.1 to 157.110.127.254157.110.127.25516,382
187157.110.128.0/18157.110.128.1 to 157.110.191.254157.110.191.25516,382
188157.110.192.0/18157.110.192.1 to 157.110.255.254157.110.255.25516,382
189157.111.0.0/18157.111.0.1 to 157.111.63.254157.111.63.25516,382
190157.111.64.0/18157.111.64.1 to 157.111.127.254157.111.127.25516,382
191157.111.128.0/18157.111.128.1 to 157.111.191.254157.111.191.25516,382
192157.111.192.0/18157.111.192.1 to 157.111.255.254157.111.255.25516,382
193157.112.0.0/18157.112.0.1 to 157.112.63.254157.112.63.25516,382
194157.112.64.0/18157.112.64.1 to 157.112.127.254157.112.127.25516,382
195157.112.128.0/18157.112.128.1 to 157.112.191.254157.112.191.25516,382
196157.112.192.0/18157.112.192.1 to 157.112.255.254157.112.255.25516,382
197157.113.0.0/18157.113.0.1 to 157.113.63.254157.113.63.25516,382
198157.113.64.0/18157.113.64.1 to 157.113.127.254157.113.127.25516,382
199157.113.128.0/18157.113.128.1 to 157.113.191.254157.113.191.25516,382
200157.113.192.0/18157.113.192.1 to 157.113.255.254157.113.255.25516,382
201157.114.0.0/18157.114.0.1 to 157.114.63.254157.114.63.25516,382
202157.114.64.0/18157.114.64.1 to 157.114.127.254157.114.127.25516,382
203157.114.128.0/18157.114.128.1 to 157.114.191.254157.114.191.25516,382
204157.114.192.0/18157.114.192.1 to 157.114.255.254157.114.255.25516,382
205157.115.0.0/18157.115.0.1 to 157.115.63.254157.115.63.25516,382
206157.115.64.0/18157.115.64.1 to 157.115.127.254157.115.127.25516,382
207157.115.128.0/18157.115.128.1 to 157.115.191.254157.115.191.25516,382
208157.115.192.0/18157.115.192.1 to 157.115.255.254157.115.255.25516,382
209157.116.0.0/18157.116.0.1 to 157.116.63.254157.116.63.25516,382
210157.116.64.0/18157.116.64.1 to 157.116.127.254157.116.127.25516,382
211157.116.128.0/18157.116.128.1 to 157.116.191.254157.116.191.25516,382
212157.116.192.0/18157.116.192.1 to 157.116.255.254157.116.255.25516,382
213157.117.0.0/18157.117.0.1 to 157.117.63.254157.117.63.25516,382
214157.117.64.0/18157.117.64.1 to 157.117.127.254157.117.127.25516,382
215157.117.128.0/18157.117.128.1 to 157.117.191.254157.117.191.25516,382
216157.117.192.0/18157.117.192.1 to 157.117.255.254157.117.255.25516,382
217157.118.0.0/18157.118.0.1 to 157.118.63.254157.118.63.25516,382
218157.118.64.0/18157.118.64.1 to 157.118.127.254157.118.127.25516,382
219157.118.128.0/18157.118.128.1 to 157.118.191.254157.118.191.25516,382
220157.118.192.0/18157.118.192.1 to 157.118.255.254157.118.255.25516,382
221157.119.0.0/18157.119.0.1 to 157.119.63.254157.119.63.25516,382
222157.119.64.0/18157.119.64.1 to 157.119.127.254157.119.127.25516,382
223157.119.128.0/18157.119.128.1 to 157.119.191.254157.119.191.25516,382
224157.119.192.0/18157.119.192.1 to 157.119.255.254157.119.255.25516,382
225157.120.0.0/18157.120.0.1 to 157.120.63.254157.120.63.25516,382
226157.120.64.0/18157.120.64.1 to 157.120.127.254157.120.127.25516,382
227157.120.128.0/18157.120.128.1 to 157.120.191.254157.120.191.25516,382
228157.120.192.0/18157.120.192.1 to 157.120.255.254157.120.255.25516,382
229157.121.0.0/18157.121.0.1 to 157.121.63.254157.121.63.25516,382
230157.121.64.0/18157.121.64.1 to 157.121.127.254157.121.127.25516,382
231157.121.128.0/18157.121.128.1 to 157.121.191.254157.121.191.25516,382
232157.121.192.0/18157.121.192.1 to 157.121.255.254157.121.255.25516,382
233157.122.0.0/18157.122.0.1 to 157.122.63.254157.122.63.25516,382
234157.122.64.0/18157.122.64.1 to 157.122.127.254157.122.127.25516,382
235157.122.128.0/18157.122.128.1 to 157.122.191.254157.122.191.25516,382
236157.122.192.0/18157.122.192.1 to 157.122.255.254157.122.255.25516,382
237157.123.0.0/18157.123.0.1 to 157.123.63.254157.123.63.25516,382
238157.123.64.0/18157.123.64.1 to 157.123.127.254157.123.127.25516,382
239157.123.128.0/18157.123.128.1 to 157.123.191.254157.123.191.25516,382
240157.123.192.0/18157.123.192.1 to 157.123.255.254157.123.255.25516,382
241157.124.0.0/18157.124.0.1 to 157.124.63.254157.124.63.25516,382
242157.124.64.0/18157.124.64.1 to 157.124.127.254157.124.127.25516,382
243157.124.128.0/18157.124.128.1 to 157.124.191.254157.124.191.25516,382
244157.124.192.0/18157.124.192.1 to 157.124.255.254157.124.255.25516,382
245157.125.0.0/18157.125.0.1 to 157.125.63.254157.125.63.25516,382
246157.125.64.0/18157.125.64.1 to 157.125.127.254157.125.127.25516,382
247157.125.128.0/18157.125.128.1 to 157.125.191.254157.125.191.25516,382
248157.125.192.0/18157.125.192.1 to 157.125.255.254157.125.255.25516,382
249157.126.0.0/18157.126.0.1 to 157.126.63.254157.126.63.25516,382
250157.126.64.0/18157.126.64.1 to 157.126.127.254157.126.127.25516,382
251157.126.128.0/18157.126.128.1 to 157.126.191.254157.126.191.25516,382
252157.126.192.0/18157.126.192.1 to 157.126.255.254157.126.255.25516,382
253157.127.0.0/18157.127.0.1 to 157.127.63.254157.127.63.25516,382
254157.127.64.0/18157.127.64.1 to 157.127.127.254157.127.127.25516,382
255157.127.128.0/18157.127.128.1 to 157.127.191.254157.127.191.25516,382
256157.127.192.0/18157.127.192.1 to 157.127.255.254157.127.255.25516,382

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.