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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.

Network157.158.0.0/15
Usable hosts131,070
Subnet mask255.254.0.0
Addresses131,072
Network address
157.158.0.0
Broadcast address
157.159.255.255
First usable
157.158.0.1
Last usable
157.159.255.254
Usable hosts
131,070 (131,072 less the network and broadcast addresses)
Subnet mask
255.254.0.0
Wildcard mask
0.1.255.255 (Cisco ACLs, OSPF)
Prefix length
/15
Type
Public public
Old class
B (default /16)
As numbers
Hex 9D9E0000 · Integer 2644377600 to 2644508671
Reverse DNS zones
158.157.in-addr.arpa
159.157.in-addr.arpa
/15 is not on a 8-bit boundary, so it takes 2 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address10011101.10011110.00000000.00000000157.158.0.0
Subnet mask11111111.11111110.00000000.00000000255.254.0.0
Network10011101.10011110.00000000.00000000157.158.0.0
Broadcast10011101.10011111.11111111.11111111157.159.255.255
Split into smaller subnets/25
/16 (2)/17 (4)/18 (8)/19 (16)/20 (32)/21 (64)/22 (128)/23 (256)/24 (512)/25 (1,024)/26 (2,048)/27 (4,096)

157.158.0.0/15 makes 1,024 subnets of /25; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1157.158.0.0/25157.158.0.1 to 157.158.0.126157.158.0.127126
2157.158.0.128/25157.158.0.129 to 157.158.0.254157.158.0.255126
3157.158.1.0/25157.158.1.1 to 157.158.1.126157.158.1.127126
4157.158.1.128/25157.158.1.129 to 157.158.1.254157.158.1.255126
5157.158.2.0/25157.158.2.1 to 157.158.2.126157.158.2.127126
6157.158.2.128/25157.158.2.129 to 157.158.2.254157.158.2.255126
7157.158.3.0/25157.158.3.1 to 157.158.3.126157.158.3.127126
8157.158.3.128/25157.158.3.129 to 157.158.3.254157.158.3.255126
9157.158.4.0/25157.158.4.1 to 157.158.4.126157.158.4.127126
10157.158.4.128/25157.158.4.129 to 157.158.4.254157.158.4.255126
11157.158.5.0/25157.158.5.1 to 157.158.5.126157.158.5.127126
12157.158.5.128/25157.158.5.129 to 157.158.5.254157.158.5.255126
13157.158.6.0/25157.158.6.1 to 157.158.6.126157.158.6.127126
14157.158.6.128/25157.158.6.129 to 157.158.6.254157.158.6.255126
15157.158.7.0/25157.158.7.1 to 157.158.7.126157.158.7.127126
16157.158.7.128/25157.158.7.129 to 157.158.7.254157.158.7.255126
17157.158.8.0/25157.158.8.1 to 157.158.8.126157.158.8.127126
18157.158.8.128/25157.158.8.129 to 157.158.8.254157.158.8.255126
19157.158.9.0/25157.158.9.1 to 157.158.9.126157.158.9.127126
20157.158.9.128/25157.158.9.129 to 157.158.9.254157.158.9.255126
21157.158.10.0/25157.158.10.1 to 157.158.10.126157.158.10.127126
22157.158.10.128/25157.158.10.129 to 157.158.10.254157.158.10.255126
23157.158.11.0/25157.158.11.1 to 157.158.11.126157.158.11.127126
24157.158.11.128/25157.158.11.129 to 157.158.11.254157.158.11.255126
25157.158.12.0/25157.158.12.1 to 157.158.12.126157.158.12.127126
26157.158.12.128/25157.158.12.129 to 157.158.12.254157.158.12.255126
27157.158.13.0/25157.158.13.1 to 157.158.13.126157.158.13.127126
28157.158.13.128/25157.158.13.129 to 157.158.13.254157.158.13.255126
29157.158.14.0/25157.158.14.1 to 157.158.14.126157.158.14.127126
30157.158.14.128/25157.158.14.129 to 157.158.14.254157.158.14.255126
31157.158.15.0/25157.158.15.1 to 157.158.15.126157.158.15.127126
32157.158.15.128/25157.158.15.129 to 157.158.15.254157.158.15.255126
33157.158.16.0/25157.158.16.1 to 157.158.16.126157.158.16.127126
34157.158.16.128/25157.158.16.129 to 157.158.16.254157.158.16.255126
35157.158.17.0/25157.158.17.1 to 157.158.17.126157.158.17.127126
36157.158.17.128/25157.158.17.129 to 157.158.17.254157.158.17.255126
37157.158.18.0/25157.158.18.1 to 157.158.18.126157.158.18.127126
38157.158.18.128/25157.158.18.129 to 157.158.18.254157.158.18.255126
39157.158.19.0/25157.158.19.1 to 157.158.19.126157.158.19.127126
40157.158.19.128/25157.158.19.129 to 157.158.19.254157.158.19.255126
41157.158.20.0/25157.158.20.1 to 157.158.20.126157.158.20.127126
42157.158.20.128/25157.158.20.129 to 157.158.20.254157.158.20.255126
43157.158.21.0/25157.158.21.1 to 157.158.21.126157.158.21.127126
44157.158.21.128/25157.158.21.129 to 157.158.21.254157.158.21.255126
45157.158.22.0/25157.158.22.1 to 157.158.22.126157.158.22.127126
46157.158.22.128/25157.158.22.129 to 157.158.22.254157.158.22.255126
47157.158.23.0/25157.158.23.1 to 157.158.23.126157.158.23.127126
48157.158.23.128/25157.158.23.129 to 157.158.23.254157.158.23.255126
49157.158.24.0/25157.158.24.1 to 157.158.24.126157.158.24.127126
50157.158.24.128/25157.158.24.129 to 157.158.24.254157.158.24.255126
51157.158.25.0/25157.158.25.1 to 157.158.25.126157.158.25.127126
52157.158.25.128/25157.158.25.129 to 157.158.25.254157.158.25.255126
53157.158.26.0/25157.158.26.1 to 157.158.26.126157.158.26.127126
54157.158.26.128/25157.158.26.129 to 157.158.26.254157.158.26.255126
55157.158.27.0/25157.158.27.1 to 157.158.27.126157.158.27.127126
56157.158.27.128/25157.158.27.129 to 157.158.27.254157.158.27.255126
57157.158.28.0/25157.158.28.1 to 157.158.28.126157.158.28.127126
58157.158.28.128/25157.158.28.129 to 157.158.28.254157.158.28.255126
59157.158.29.0/25157.158.29.1 to 157.158.29.126157.158.29.127126
60157.158.29.128/25157.158.29.129 to 157.158.29.254157.158.29.255126
61157.158.30.0/25157.158.30.1 to 157.158.30.126157.158.30.127126
62157.158.30.128/25157.158.30.129 to 157.158.30.254157.158.30.255126
63157.158.31.0/25157.158.31.1 to 157.158.31.126157.158.31.127126
64157.158.31.128/25157.158.31.129 to 157.158.31.254157.158.31.255126
65157.158.32.0/25157.158.32.1 to 157.158.32.126157.158.32.127126
66157.158.32.128/25157.158.32.129 to 157.158.32.254157.158.32.255126
67157.158.33.0/25157.158.33.1 to 157.158.33.126157.158.33.127126
68157.158.33.128/25157.158.33.129 to 157.158.33.254157.158.33.255126
69157.158.34.0/25157.158.34.1 to 157.158.34.126157.158.34.127126
70157.158.34.128/25157.158.34.129 to 157.158.34.254157.158.34.255126
71157.158.35.0/25157.158.35.1 to 157.158.35.126157.158.35.127126
72157.158.35.128/25157.158.35.129 to 157.158.35.254157.158.35.255126
73157.158.36.0/25157.158.36.1 to 157.158.36.126157.158.36.127126
74157.158.36.128/25157.158.36.129 to 157.158.36.254157.158.36.255126
75157.158.37.0/25157.158.37.1 to 157.158.37.126157.158.37.127126
76157.158.37.128/25157.158.37.129 to 157.158.37.254157.158.37.255126
77157.158.38.0/25157.158.38.1 to 157.158.38.126157.158.38.127126
78157.158.38.128/25157.158.38.129 to 157.158.38.254157.158.38.255126
79157.158.39.0/25157.158.39.1 to 157.158.39.126157.158.39.127126
80157.158.39.128/25157.158.39.129 to 157.158.39.254157.158.39.255126
81157.158.40.0/25157.158.40.1 to 157.158.40.126157.158.40.127126
82157.158.40.128/25157.158.40.129 to 157.158.40.254157.158.40.255126
83157.158.41.0/25157.158.41.1 to 157.158.41.126157.158.41.127126
84157.158.41.128/25157.158.41.129 to 157.158.41.254157.158.41.255126
85157.158.42.0/25157.158.42.1 to 157.158.42.126157.158.42.127126
86157.158.42.128/25157.158.42.129 to 157.158.42.254157.158.42.255126
87157.158.43.0/25157.158.43.1 to 157.158.43.126157.158.43.127126
88157.158.43.128/25157.158.43.129 to 157.158.43.254157.158.43.255126
89157.158.44.0/25157.158.44.1 to 157.158.44.126157.158.44.127126
90157.158.44.128/25157.158.44.129 to 157.158.44.254157.158.44.255126
91157.158.45.0/25157.158.45.1 to 157.158.45.126157.158.45.127126
92157.158.45.128/25157.158.45.129 to 157.158.45.254157.158.45.255126
93157.158.46.0/25157.158.46.1 to 157.158.46.126157.158.46.127126
94157.158.46.128/25157.158.46.129 to 157.158.46.254157.158.46.255126
95157.158.47.0/25157.158.47.1 to 157.158.47.126157.158.47.127126
96157.158.47.128/25157.158.47.129 to 157.158.47.254157.158.47.255126
97157.158.48.0/25157.158.48.1 to 157.158.48.126157.158.48.127126
98157.158.48.128/25157.158.48.129 to 157.158.48.254157.158.48.255126
99157.158.49.0/25157.158.49.1 to 157.158.49.126157.158.49.127126
100157.158.49.128/25157.158.49.129 to 157.158.49.254157.158.49.255126
101157.158.50.0/25157.158.50.1 to 157.158.50.126157.158.50.127126
102157.158.50.128/25157.158.50.129 to 157.158.50.254157.158.50.255126
103157.158.51.0/25157.158.51.1 to 157.158.51.126157.158.51.127126
104157.158.51.128/25157.158.51.129 to 157.158.51.254157.158.51.255126
105157.158.52.0/25157.158.52.1 to 157.158.52.126157.158.52.127126
106157.158.52.128/25157.158.52.129 to 157.158.52.254157.158.52.255126
107157.158.53.0/25157.158.53.1 to 157.158.53.126157.158.53.127126
108157.158.53.128/25157.158.53.129 to 157.158.53.254157.158.53.255126
109157.158.54.0/25157.158.54.1 to 157.158.54.126157.158.54.127126
110157.158.54.128/25157.158.54.129 to 157.158.54.254157.158.54.255126
111157.158.55.0/25157.158.55.1 to 157.158.55.126157.158.55.127126
112157.158.55.128/25157.158.55.129 to 157.158.55.254157.158.55.255126
113157.158.56.0/25157.158.56.1 to 157.158.56.126157.158.56.127126
114157.158.56.128/25157.158.56.129 to 157.158.56.254157.158.56.255126
115157.158.57.0/25157.158.57.1 to 157.158.57.126157.158.57.127126
116157.158.57.128/25157.158.57.129 to 157.158.57.254157.158.57.255126
117157.158.58.0/25157.158.58.1 to 157.158.58.126157.158.58.127126
118157.158.58.128/25157.158.58.129 to 157.158.58.254157.158.58.255126
119157.158.59.0/25157.158.59.1 to 157.158.59.126157.158.59.127126
120157.158.59.128/25157.158.59.129 to 157.158.59.254157.158.59.255126
121157.158.60.0/25157.158.60.1 to 157.158.60.126157.158.60.127126
122157.158.60.128/25157.158.60.129 to 157.158.60.254157.158.60.255126
123157.158.61.0/25157.158.61.1 to 157.158.61.126157.158.61.127126
124157.158.61.128/25157.158.61.129 to 157.158.61.254157.158.61.255126
125157.158.62.0/25157.158.62.1 to 157.158.62.126157.158.62.127126
126157.158.62.128/25157.158.62.129 to 157.158.62.254157.158.62.255126
127157.158.63.0/25157.158.63.1 to 157.158.63.126157.158.63.127126
128157.158.63.128/25157.158.63.129 to 157.158.63.254157.158.63.255126
129157.158.64.0/25157.158.64.1 to 157.158.64.126157.158.64.127126
130157.158.64.128/25157.158.64.129 to 157.158.64.254157.158.64.255126
131157.158.65.0/25157.158.65.1 to 157.158.65.126157.158.65.127126
132157.158.65.128/25157.158.65.129 to 157.158.65.254157.158.65.255126
133157.158.66.0/25157.158.66.1 to 157.158.66.126157.158.66.127126
134157.158.66.128/25157.158.66.129 to 157.158.66.254157.158.66.255126
135157.158.67.0/25157.158.67.1 to 157.158.67.126157.158.67.127126
136157.158.67.128/25157.158.67.129 to 157.158.67.254157.158.67.255126
137157.158.68.0/25157.158.68.1 to 157.158.68.126157.158.68.127126
138157.158.68.128/25157.158.68.129 to 157.158.68.254157.158.68.255126
139157.158.69.0/25157.158.69.1 to 157.158.69.126157.158.69.127126
140157.158.69.128/25157.158.69.129 to 157.158.69.254157.158.69.255126
141157.158.70.0/25157.158.70.1 to 157.158.70.126157.158.70.127126
142157.158.70.128/25157.158.70.129 to 157.158.70.254157.158.70.255126
143157.158.71.0/25157.158.71.1 to 157.158.71.126157.158.71.127126
144157.158.71.128/25157.158.71.129 to 157.158.71.254157.158.71.255126
145157.158.72.0/25157.158.72.1 to 157.158.72.126157.158.72.127126
146157.158.72.128/25157.158.72.129 to 157.158.72.254157.158.72.255126
147157.158.73.0/25157.158.73.1 to 157.158.73.126157.158.73.127126
148157.158.73.128/25157.158.73.129 to 157.158.73.254157.158.73.255126
149157.158.74.0/25157.158.74.1 to 157.158.74.126157.158.74.127126
150157.158.74.128/25157.158.74.129 to 157.158.74.254157.158.74.255126
151157.158.75.0/25157.158.75.1 to 157.158.75.126157.158.75.127126
152157.158.75.128/25157.158.75.129 to 157.158.75.254157.158.75.255126
153157.158.76.0/25157.158.76.1 to 157.158.76.126157.158.76.127126
154157.158.76.128/25157.158.76.129 to 157.158.76.254157.158.76.255126
155157.158.77.0/25157.158.77.1 to 157.158.77.126157.158.77.127126
156157.158.77.128/25157.158.77.129 to 157.158.77.254157.158.77.255126
157157.158.78.0/25157.158.78.1 to 157.158.78.126157.158.78.127126
158157.158.78.128/25157.158.78.129 to 157.158.78.254157.158.78.255126
159157.158.79.0/25157.158.79.1 to 157.158.79.126157.158.79.127126
160157.158.79.128/25157.158.79.129 to 157.158.79.254157.158.79.255126
161157.158.80.0/25157.158.80.1 to 157.158.80.126157.158.80.127126
162157.158.80.128/25157.158.80.129 to 157.158.80.254157.158.80.255126
163157.158.81.0/25157.158.81.1 to 157.158.81.126157.158.81.127126
164157.158.81.128/25157.158.81.129 to 157.158.81.254157.158.81.255126
165157.158.82.0/25157.158.82.1 to 157.158.82.126157.158.82.127126
166157.158.82.128/25157.158.82.129 to 157.158.82.254157.158.82.255126
167157.158.83.0/25157.158.83.1 to 157.158.83.126157.158.83.127126
168157.158.83.128/25157.158.83.129 to 157.158.83.254157.158.83.255126
169157.158.84.0/25157.158.84.1 to 157.158.84.126157.158.84.127126
170157.158.84.128/25157.158.84.129 to 157.158.84.254157.158.84.255126
171157.158.85.0/25157.158.85.1 to 157.158.85.126157.158.85.127126
172157.158.85.128/25157.158.85.129 to 157.158.85.254157.158.85.255126
173157.158.86.0/25157.158.86.1 to 157.158.86.126157.158.86.127126
174157.158.86.128/25157.158.86.129 to 157.158.86.254157.158.86.255126
175157.158.87.0/25157.158.87.1 to 157.158.87.126157.158.87.127126
176157.158.87.128/25157.158.87.129 to 157.158.87.254157.158.87.255126
177157.158.88.0/25157.158.88.1 to 157.158.88.126157.158.88.127126
178157.158.88.128/25157.158.88.129 to 157.158.88.254157.158.88.255126
179157.158.89.0/25157.158.89.1 to 157.158.89.126157.158.89.127126
180157.158.89.128/25157.158.89.129 to 157.158.89.254157.158.89.255126
181157.158.90.0/25157.158.90.1 to 157.158.90.126157.158.90.127126
182157.158.90.128/25157.158.90.129 to 157.158.90.254157.158.90.255126
183157.158.91.0/25157.158.91.1 to 157.158.91.126157.158.91.127126
184157.158.91.128/25157.158.91.129 to 157.158.91.254157.158.91.255126
185157.158.92.0/25157.158.92.1 to 157.158.92.126157.158.92.127126
186157.158.92.128/25157.158.92.129 to 157.158.92.254157.158.92.255126
187157.158.93.0/25157.158.93.1 to 157.158.93.126157.158.93.127126
188157.158.93.128/25157.158.93.129 to 157.158.93.254157.158.93.255126
189157.158.94.0/25157.158.94.1 to 157.158.94.126157.158.94.127126
190157.158.94.128/25157.158.94.129 to 157.158.94.254157.158.94.255126
191157.158.95.0/25157.158.95.1 to 157.158.95.126157.158.95.127126
192157.158.95.128/25157.158.95.129 to 157.158.95.254157.158.95.255126
193157.158.96.0/25157.158.96.1 to 157.158.96.126157.158.96.127126
194157.158.96.128/25157.158.96.129 to 157.158.96.254157.158.96.255126
195157.158.97.0/25157.158.97.1 to 157.158.97.126157.158.97.127126
196157.158.97.128/25157.158.97.129 to 157.158.97.254157.158.97.255126
197157.158.98.0/25157.158.98.1 to 157.158.98.126157.158.98.127126
198157.158.98.128/25157.158.98.129 to 157.158.98.254157.158.98.255126
199157.158.99.0/25157.158.99.1 to 157.158.99.126157.158.99.127126
200157.158.99.128/25157.158.99.129 to 157.158.99.254157.158.99.255126
201157.158.100.0/25157.158.100.1 to 157.158.100.126157.158.100.127126
202157.158.100.128/25157.158.100.129 to 157.158.100.254157.158.100.255126
203157.158.101.0/25157.158.101.1 to 157.158.101.126157.158.101.127126
204157.158.101.128/25157.158.101.129 to 157.158.101.254157.158.101.255126
205157.158.102.0/25157.158.102.1 to 157.158.102.126157.158.102.127126
206157.158.102.128/25157.158.102.129 to 157.158.102.254157.158.102.255126
207157.158.103.0/25157.158.103.1 to 157.158.103.126157.158.103.127126
208157.158.103.128/25157.158.103.129 to 157.158.103.254157.158.103.255126
209157.158.104.0/25157.158.104.1 to 157.158.104.126157.158.104.127126
210157.158.104.128/25157.158.104.129 to 157.158.104.254157.158.104.255126
211157.158.105.0/25157.158.105.1 to 157.158.105.126157.158.105.127126
212157.158.105.128/25157.158.105.129 to 157.158.105.254157.158.105.255126
213157.158.106.0/25157.158.106.1 to 157.158.106.126157.158.106.127126
214157.158.106.128/25157.158.106.129 to 157.158.106.254157.158.106.255126
215157.158.107.0/25157.158.107.1 to 157.158.107.126157.158.107.127126
216157.158.107.128/25157.158.107.129 to 157.158.107.254157.158.107.255126
217157.158.108.0/25157.158.108.1 to 157.158.108.126157.158.108.127126
218157.158.108.128/25157.158.108.129 to 157.158.108.254157.158.108.255126
219157.158.109.0/25157.158.109.1 to 157.158.109.126157.158.109.127126
220157.158.109.128/25157.158.109.129 to 157.158.109.254157.158.109.255126
221157.158.110.0/25157.158.110.1 to 157.158.110.126157.158.110.127126
222157.158.110.128/25157.158.110.129 to 157.158.110.254157.158.110.255126
223157.158.111.0/25157.158.111.1 to 157.158.111.126157.158.111.127126
224157.158.111.128/25157.158.111.129 to 157.158.111.254157.158.111.255126
225157.158.112.0/25157.158.112.1 to 157.158.112.126157.158.112.127126
226157.158.112.128/25157.158.112.129 to 157.158.112.254157.158.112.255126
227157.158.113.0/25157.158.113.1 to 157.158.113.126157.158.113.127126
228157.158.113.128/25157.158.113.129 to 157.158.113.254157.158.113.255126
229157.158.114.0/25157.158.114.1 to 157.158.114.126157.158.114.127126
230157.158.114.128/25157.158.114.129 to 157.158.114.254157.158.114.255126
231157.158.115.0/25157.158.115.1 to 157.158.115.126157.158.115.127126
232157.158.115.128/25157.158.115.129 to 157.158.115.254157.158.115.255126
233157.158.116.0/25157.158.116.1 to 157.158.116.126157.158.116.127126
234157.158.116.128/25157.158.116.129 to 157.158.116.254157.158.116.255126
235157.158.117.0/25157.158.117.1 to 157.158.117.126157.158.117.127126
236157.158.117.128/25157.158.117.129 to 157.158.117.254157.158.117.255126
237157.158.118.0/25157.158.118.1 to 157.158.118.126157.158.118.127126
238157.158.118.128/25157.158.118.129 to 157.158.118.254157.158.118.255126
239157.158.119.0/25157.158.119.1 to 157.158.119.126157.158.119.127126
240157.158.119.128/25157.158.119.129 to 157.158.119.254157.158.119.255126
241157.158.120.0/25157.158.120.1 to 157.158.120.126157.158.120.127126
242157.158.120.128/25157.158.120.129 to 157.158.120.254157.158.120.255126
243157.158.121.0/25157.158.121.1 to 157.158.121.126157.158.121.127126
244157.158.121.128/25157.158.121.129 to 157.158.121.254157.158.121.255126
245157.158.122.0/25157.158.122.1 to 157.158.122.126157.158.122.127126
246157.158.122.128/25157.158.122.129 to 157.158.122.254157.158.122.255126
247157.158.123.0/25157.158.123.1 to 157.158.123.126157.158.123.127126
248157.158.123.128/25157.158.123.129 to 157.158.123.254157.158.123.255126
249157.158.124.0/25157.158.124.1 to 157.158.124.126157.158.124.127126
250157.158.124.128/25157.158.124.129 to 157.158.124.254157.158.124.255126
251157.158.125.0/25157.158.125.1 to 157.158.125.126157.158.125.127126
252157.158.125.128/25157.158.125.129 to 157.158.125.254157.158.125.255126
253157.158.126.0/25157.158.126.1 to 157.158.126.126157.158.126.127126
254157.158.126.128/25157.158.126.129 to 157.158.126.254157.158.126.255126
255157.158.127.0/25157.158.127.1 to 157.158.127.126157.158.127.127126
256157.158.127.128/25157.158.127.129 to 157.158.127.254157.158.127.255126

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.