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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.

Network249.167.0.0/17
Usable hosts32,766
Subnet mask255.255.128.0
Addresses32,768
Network address
249.167.0.0
Broadcast address
249.167.127.255
First usable
249.167.0.1
Last usable
249.167.127.254
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
Reserved 240.0.0.0/4
Future use; not usable on most systems
Old class
E (reserved)
As numbers
Hex F9A70000 · Integer 4188471296 to 4188504063
Reverse DNS zones
0.167.249.in-addr.arpa
1.167.249.in-addr.arpa
2.167.249.in-addr.arpa
3.167.249.in-addr.arpa
4.167.249.in-addr.arpa
5.167.249.in-addr.arpa
6.167.249.in-addr.arpa
7.167.249.in-addr.arpa
8.167.249.in-addr.arpa
9.167.249.in-addr.arpa
10.167.249.in-addr.arpa
11.167.249.in-addr.arpa
12.167.249.in-addr.arpa
13.167.249.in-addr.arpa
14.167.249.in-addr.arpa
15.167.249.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
Address11111001.10100111.00000000.00000000249.167.0.0
Subnet mask11111111.11111111.10000000.00000000255.255.128.0
Network11111001.10100111.00000000.00000000249.167.0.0
Broadcast11111001.10100111.01111111.11111111249.167.127.255
Split into smaller subnets/25
/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)

249.167.0.0/17 makes 256 subnets of /25.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1249.167.0.0/25249.167.0.1 to 249.167.0.126249.167.0.127126
2249.167.0.128/25249.167.0.129 to 249.167.0.254249.167.0.255126
3249.167.1.0/25249.167.1.1 to 249.167.1.126249.167.1.127126
4249.167.1.128/25249.167.1.129 to 249.167.1.254249.167.1.255126
5249.167.2.0/25249.167.2.1 to 249.167.2.126249.167.2.127126
6249.167.2.128/25249.167.2.129 to 249.167.2.254249.167.2.255126
7249.167.3.0/25249.167.3.1 to 249.167.3.126249.167.3.127126
8249.167.3.128/25249.167.3.129 to 249.167.3.254249.167.3.255126
9249.167.4.0/25249.167.4.1 to 249.167.4.126249.167.4.127126
10249.167.4.128/25249.167.4.129 to 249.167.4.254249.167.4.255126
11249.167.5.0/25249.167.5.1 to 249.167.5.126249.167.5.127126
12249.167.5.128/25249.167.5.129 to 249.167.5.254249.167.5.255126
13249.167.6.0/25249.167.6.1 to 249.167.6.126249.167.6.127126
14249.167.6.128/25249.167.6.129 to 249.167.6.254249.167.6.255126
15249.167.7.0/25249.167.7.1 to 249.167.7.126249.167.7.127126
16249.167.7.128/25249.167.7.129 to 249.167.7.254249.167.7.255126
17249.167.8.0/25249.167.8.1 to 249.167.8.126249.167.8.127126
18249.167.8.128/25249.167.8.129 to 249.167.8.254249.167.8.255126
19249.167.9.0/25249.167.9.1 to 249.167.9.126249.167.9.127126
20249.167.9.128/25249.167.9.129 to 249.167.9.254249.167.9.255126
21249.167.10.0/25249.167.10.1 to 249.167.10.126249.167.10.127126
22249.167.10.128/25249.167.10.129 to 249.167.10.254249.167.10.255126
23249.167.11.0/25249.167.11.1 to 249.167.11.126249.167.11.127126
24249.167.11.128/25249.167.11.129 to 249.167.11.254249.167.11.255126
25249.167.12.0/25249.167.12.1 to 249.167.12.126249.167.12.127126
26249.167.12.128/25249.167.12.129 to 249.167.12.254249.167.12.255126
27249.167.13.0/25249.167.13.1 to 249.167.13.126249.167.13.127126
28249.167.13.128/25249.167.13.129 to 249.167.13.254249.167.13.255126
29249.167.14.0/25249.167.14.1 to 249.167.14.126249.167.14.127126
30249.167.14.128/25249.167.14.129 to 249.167.14.254249.167.14.255126
31249.167.15.0/25249.167.15.1 to 249.167.15.126249.167.15.127126
32249.167.15.128/25249.167.15.129 to 249.167.15.254249.167.15.255126
33249.167.16.0/25249.167.16.1 to 249.167.16.126249.167.16.127126
34249.167.16.128/25249.167.16.129 to 249.167.16.254249.167.16.255126
35249.167.17.0/25249.167.17.1 to 249.167.17.126249.167.17.127126
36249.167.17.128/25249.167.17.129 to 249.167.17.254249.167.17.255126
37249.167.18.0/25249.167.18.1 to 249.167.18.126249.167.18.127126
38249.167.18.128/25249.167.18.129 to 249.167.18.254249.167.18.255126
39249.167.19.0/25249.167.19.1 to 249.167.19.126249.167.19.127126
40249.167.19.128/25249.167.19.129 to 249.167.19.254249.167.19.255126
41249.167.20.0/25249.167.20.1 to 249.167.20.126249.167.20.127126
42249.167.20.128/25249.167.20.129 to 249.167.20.254249.167.20.255126
43249.167.21.0/25249.167.21.1 to 249.167.21.126249.167.21.127126
44249.167.21.128/25249.167.21.129 to 249.167.21.254249.167.21.255126
45249.167.22.0/25249.167.22.1 to 249.167.22.126249.167.22.127126
46249.167.22.128/25249.167.22.129 to 249.167.22.254249.167.22.255126
47249.167.23.0/25249.167.23.1 to 249.167.23.126249.167.23.127126
48249.167.23.128/25249.167.23.129 to 249.167.23.254249.167.23.255126
49249.167.24.0/25249.167.24.1 to 249.167.24.126249.167.24.127126
50249.167.24.128/25249.167.24.129 to 249.167.24.254249.167.24.255126
51249.167.25.0/25249.167.25.1 to 249.167.25.126249.167.25.127126
52249.167.25.128/25249.167.25.129 to 249.167.25.254249.167.25.255126
53249.167.26.0/25249.167.26.1 to 249.167.26.126249.167.26.127126
54249.167.26.128/25249.167.26.129 to 249.167.26.254249.167.26.255126
55249.167.27.0/25249.167.27.1 to 249.167.27.126249.167.27.127126
56249.167.27.128/25249.167.27.129 to 249.167.27.254249.167.27.255126
57249.167.28.0/25249.167.28.1 to 249.167.28.126249.167.28.127126
58249.167.28.128/25249.167.28.129 to 249.167.28.254249.167.28.255126
59249.167.29.0/25249.167.29.1 to 249.167.29.126249.167.29.127126
60249.167.29.128/25249.167.29.129 to 249.167.29.254249.167.29.255126
61249.167.30.0/25249.167.30.1 to 249.167.30.126249.167.30.127126
62249.167.30.128/25249.167.30.129 to 249.167.30.254249.167.30.255126
63249.167.31.0/25249.167.31.1 to 249.167.31.126249.167.31.127126
64249.167.31.128/25249.167.31.129 to 249.167.31.254249.167.31.255126
65249.167.32.0/25249.167.32.1 to 249.167.32.126249.167.32.127126
66249.167.32.128/25249.167.32.129 to 249.167.32.254249.167.32.255126
67249.167.33.0/25249.167.33.1 to 249.167.33.126249.167.33.127126
68249.167.33.128/25249.167.33.129 to 249.167.33.254249.167.33.255126
69249.167.34.0/25249.167.34.1 to 249.167.34.126249.167.34.127126
70249.167.34.128/25249.167.34.129 to 249.167.34.254249.167.34.255126
71249.167.35.0/25249.167.35.1 to 249.167.35.126249.167.35.127126
72249.167.35.128/25249.167.35.129 to 249.167.35.254249.167.35.255126
73249.167.36.0/25249.167.36.1 to 249.167.36.126249.167.36.127126
74249.167.36.128/25249.167.36.129 to 249.167.36.254249.167.36.255126
75249.167.37.0/25249.167.37.1 to 249.167.37.126249.167.37.127126
76249.167.37.128/25249.167.37.129 to 249.167.37.254249.167.37.255126
77249.167.38.0/25249.167.38.1 to 249.167.38.126249.167.38.127126
78249.167.38.128/25249.167.38.129 to 249.167.38.254249.167.38.255126
79249.167.39.0/25249.167.39.1 to 249.167.39.126249.167.39.127126
80249.167.39.128/25249.167.39.129 to 249.167.39.254249.167.39.255126
81249.167.40.0/25249.167.40.1 to 249.167.40.126249.167.40.127126
82249.167.40.128/25249.167.40.129 to 249.167.40.254249.167.40.255126
83249.167.41.0/25249.167.41.1 to 249.167.41.126249.167.41.127126
84249.167.41.128/25249.167.41.129 to 249.167.41.254249.167.41.255126
85249.167.42.0/25249.167.42.1 to 249.167.42.126249.167.42.127126
86249.167.42.128/25249.167.42.129 to 249.167.42.254249.167.42.255126
87249.167.43.0/25249.167.43.1 to 249.167.43.126249.167.43.127126
88249.167.43.128/25249.167.43.129 to 249.167.43.254249.167.43.255126
89249.167.44.0/25249.167.44.1 to 249.167.44.126249.167.44.127126
90249.167.44.128/25249.167.44.129 to 249.167.44.254249.167.44.255126
91249.167.45.0/25249.167.45.1 to 249.167.45.126249.167.45.127126
92249.167.45.128/25249.167.45.129 to 249.167.45.254249.167.45.255126
93249.167.46.0/25249.167.46.1 to 249.167.46.126249.167.46.127126
94249.167.46.128/25249.167.46.129 to 249.167.46.254249.167.46.255126
95249.167.47.0/25249.167.47.1 to 249.167.47.126249.167.47.127126
96249.167.47.128/25249.167.47.129 to 249.167.47.254249.167.47.255126
97249.167.48.0/25249.167.48.1 to 249.167.48.126249.167.48.127126
98249.167.48.128/25249.167.48.129 to 249.167.48.254249.167.48.255126
99249.167.49.0/25249.167.49.1 to 249.167.49.126249.167.49.127126
100249.167.49.128/25249.167.49.129 to 249.167.49.254249.167.49.255126
101249.167.50.0/25249.167.50.1 to 249.167.50.126249.167.50.127126
102249.167.50.128/25249.167.50.129 to 249.167.50.254249.167.50.255126
103249.167.51.0/25249.167.51.1 to 249.167.51.126249.167.51.127126
104249.167.51.128/25249.167.51.129 to 249.167.51.254249.167.51.255126
105249.167.52.0/25249.167.52.1 to 249.167.52.126249.167.52.127126
106249.167.52.128/25249.167.52.129 to 249.167.52.254249.167.52.255126
107249.167.53.0/25249.167.53.1 to 249.167.53.126249.167.53.127126
108249.167.53.128/25249.167.53.129 to 249.167.53.254249.167.53.255126
109249.167.54.0/25249.167.54.1 to 249.167.54.126249.167.54.127126
110249.167.54.128/25249.167.54.129 to 249.167.54.254249.167.54.255126
111249.167.55.0/25249.167.55.1 to 249.167.55.126249.167.55.127126
112249.167.55.128/25249.167.55.129 to 249.167.55.254249.167.55.255126
113249.167.56.0/25249.167.56.1 to 249.167.56.126249.167.56.127126
114249.167.56.128/25249.167.56.129 to 249.167.56.254249.167.56.255126
115249.167.57.0/25249.167.57.1 to 249.167.57.126249.167.57.127126
116249.167.57.128/25249.167.57.129 to 249.167.57.254249.167.57.255126
117249.167.58.0/25249.167.58.1 to 249.167.58.126249.167.58.127126
118249.167.58.128/25249.167.58.129 to 249.167.58.254249.167.58.255126
119249.167.59.0/25249.167.59.1 to 249.167.59.126249.167.59.127126
120249.167.59.128/25249.167.59.129 to 249.167.59.254249.167.59.255126
121249.167.60.0/25249.167.60.1 to 249.167.60.126249.167.60.127126
122249.167.60.128/25249.167.60.129 to 249.167.60.254249.167.60.255126
123249.167.61.0/25249.167.61.1 to 249.167.61.126249.167.61.127126
124249.167.61.128/25249.167.61.129 to 249.167.61.254249.167.61.255126
125249.167.62.0/25249.167.62.1 to 249.167.62.126249.167.62.127126
126249.167.62.128/25249.167.62.129 to 249.167.62.254249.167.62.255126
127249.167.63.0/25249.167.63.1 to 249.167.63.126249.167.63.127126
128249.167.63.128/25249.167.63.129 to 249.167.63.254249.167.63.255126
129249.167.64.0/25249.167.64.1 to 249.167.64.126249.167.64.127126
130249.167.64.128/25249.167.64.129 to 249.167.64.254249.167.64.255126
131249.167.65.0/25249.167.65.1 to 249.167.65.126249.167.65.127126
132249.167.65.128/25249.167.65.129 to 249.167.65.254249.167.65.255126
133249.167.66.0/25249.167.66.1 to 249.167.66.126249.167.66.127126
134249.167.66.128/25249.167.66.129 to 249.167.66.254249.167.66.255126
135249.167.67.0/25249.167.67.1 to 249.167.67.126249.167.67.127126
136249.167.67.128/25249.167.67.129 to 249.167.67.254249.167.67.255126
137249.167.68.0/25249.167.68.1 to 249.167.68.126249.167.68.127126
138249.167.68.128/25249.167.68.129 to 249.167.68.254249.167.68.255126
139249.167.69.0/25249.167.69.1 to 249.167.69.126249.167.69.127126
140249.167.69.128/25249.167.69.129 to 249.167.69.254249.167.69.255126
141249.167.70.0/25249.167.70.1 to 249.167.70.126249.167.70.127126
142249.167.70.128/25249.167.70.129 to 249.167.70.254249.167.70.255126
143249.167.71.0/25249.167.71.1 to 249.167.71.126249.167.71.127126
144249.167.71.128/25249.167.71.129 to 249.167.71.254249.167.71.255126
145249.167.72.0/25249.167.72.1 to 249.167.72.126249.167.72.127126
146249.167.72.128/25249.167.72.129 to 249.167.72.254249.167.72.255126
147249.167.73.0/25249.167.73.1 to 249.167.73.126249.167.73.127126
148249.167.73.128/25249.167.73.129 to 249.167.73.254249.167.73.255126
149249.167.74.0/25249.167.74.1 to 249.167.74.126249.167.74.127126
150249.167.74.128/25249.167.74.129 to 249.167.74.254249.167.74.255126
151249.167.75.0/25249.167.75.1 to 249.167.75.126249.167.75.127126
152249.167.75.128/25249.167.75.129 to 249.167.75.254249.167.75.255126
153249.167.76.0/25249.167.76.1 to 249.167.76.126249.167.76.127126
154249.167.76.128/25249.167.76.129 to 249.167.76.254249.167.76.255126
155249.167.77.0/25249.167.77.1 to 249.167.77.126249.167.77.127126
156249.167.77.128/25249.167.77.129 to 249.167.77.254249.167.77.255126
157249.167.78.0/25249.167.78.1 to 249.167.78.126249.167.78.127126
158249.167.78.128/25249.167.78.129 to 249.167.78.254249.167.78.255126
159249.167.79.0/25249.167.79.1 to 249.167.79.126249.167.79.127126
160249.167.79.128/25249.167.79.129 to 249.167.79.254249.167.79.255126
161249.167.80.0/25249.167.80.1 to 249.167.80.126249.167.80.127126
162249.167.80.128/25249.167.80.129 to 249.167.80.254249.167.80.255126
163249.167.81.0/25249.167.81.1 to 249.167.81.126249.167.81.127126
164249.167.81.128/25249.167.81.129 to 249.167.81.254249.167.81.255126
165249.167.82.0/25249.167.82.1 to 249.167.82.126249.167.82.127126
166249.167.82.128/25249.167.82.129 to 249.167.82.254249.167.82.255126
167249.167.83.0/25249.167.83.1 to 249.167.83.126249.167.83.127126
168249.167.83.128/25249.167.83.129 to 249.167.83.254249.167.83.255126
169249.167.84.0/25249.167.84.1 to 249.167.84.126249.167.84.127126
170249.167.84.128/25249.167.84.129 to 249.167.84.254249.167.84.255126
171249.167.85.0/25249.167.85.1 to 249.167.85.126249.167.85.127126
172249.167.85.128/25249.167.85.129 to 249.167.85.254249.167.85.255126
173249.167.86.0/25249.167.86.1 to 249.167.86.126249.167.86.127126
174249.167.86.128/25249.167.86.129 to 249.167.86.254249.167.86.255126
175249.167.87.0/25249.167.87.1 to 249.167.87.126249.167.87.127126
176249.167.87.128/25249.167.87.129 to 249.167.87.254249.167.87.255126
177249.167.88.0/25249.167.88.1 to 249.167.88.126249.167.88.127126
178249.167.88.128/25249.167.88.129 to 249.167.88.254249.167.88.255126
179249.167.89.0/25249.167.89.1 to 249.167.89.126249.167.89.127126
180249.167.89.128/25249.167.89.129 to 249.167.89.254249.167.89.255126
181249.167.90.0/25249.167.90.1 to 249.167.90.126249.167.90.127126
182249.167.90.128/25249.167.90.129 to 249.167.90.254249.167.90.255126
183249.167.91.0/25249.167.91.1 to 249.167.91.126249.167.91.127126
184249.167.91.128/25249.167.91.129 to 249.167.91.254249.167.91.255126
185249.167.92.0/25249.167.92.1 to 249.167.92.126249.167.92.127126
186249.167.92.128/25249.167.92.129 to 249.167.92.254249.167.92.255126
187249.167.93.0/25249.167.93.1 to 249.167.93.126249.167.93.127126
188249.167.93.128/25249.167.93.129 to 249.167.93.254249.167.93.255126
189249.167.94.0/25249.167.94.1 to 249.167.94.126249.167.94.127126
190249.167.94.128/25249.167.94.129 to 249.167.94.254249.167.94.255126
191249.167.95.0/25249.167.95.1 to 249.167.95.126249.167.95.127126
192249.167.95.128/25249.167.95.129 to 249.167.95.254249.167.95.255126
193249.167.96.0/25249.167.96.1 to 249.167.96.126249.167.96.127126
194249.167.96.128/25249.167.96.129 to 249.167.96.254249.167.96.255126
195249.167.97.0/25249.167.97.1 to 249.167.97.126249.167.97.127126
196249.167.97.128/25249.167.97.129 to 249.167.97.254249.167.97.255126
197249.167.98.0/25249.167.98.1 to 249.167.98.126249.167.98.127126
198249.167.98.128/25249.167.98.129 to 249.167.98.254249.167.98.255126
199249.167.99.0/25249.167.99.1 to 249.167.99.126249.167.99.127126
200249.167.99.128/25249.167.99.129 to 249.167.99.254249.167.99.255126
201249.167.100.0/25249.167.100.1 to 249.167.100.126249.167.100.127126
202249.167.100.128/25249.167.100.129 to 249.167.100.254249.167.100.255126
203249.167.101.0/25249.167.101.1 to 249.167.101.126249.167.101.127126
204249.167.101.128/25249.167.101.129 to 249.167.101.254249.167.101.255126
205249.167.102.0/25249.167.102.1 to 249.167.102.126249.167.102.127126
206249.167.102.128/25249.167.102.129 to 249.167.102.254249.167.102.255126
207249.167.103.0/25249.167.103.1 to 249.167.103.126249.167.103.127126
208249.167.103.128/25249.167.103.129 to 249.167.103.254249.167.103.255126
209249.167.104.0/25249.167.104.1 to 249.167.104.126249.167.104.127126
210249.167.104.128/25249.167.104.129 to 249.167.104.254249.167.104.255126
211249.167.105.0/25249.167.105.1 to 249.167.105.126249.167.105.127126
212249.167.105.128/25249.167.105.129 to 249.167.105.254249.167.105.255126
213249.167.106.0/25249.167.106.1 to 249.167.106.126249.167.106.127126
214249.167.106.128/25249.167.106.129 to 249.167.106.254249.167.106.255126
215249.167.107.0/25249.167.107.1 to 249.167.107.126249.167.107.127126
216249.167.107.128/25249.167.107.129 to 249.167.107.254249.167.107.255126
217249.167.108.0/25249.167.108.1 to 249.167.108.126249.167.108.127126
218249.167.108.128/25249.167.108.129 to 249.167.108.254249.167.108.255126
219249.167.109.0/25249.167.109.1 to 249.167.109.126249.167.109.127126
220249.167.109.128/25249.167.109.129 to 249.167.109.254249.167.109.255126
221249.167.110.0/25249.167.110.1 to 249.167.110.126249.167.110.127126
222249.167.110.128/25249.167.110.129 to 249.167.110.254249.167.110.255126
223249.167.111.0/25249.167.111.1 to 249.167.111.126249.167.111.127126
224249.167.111.128/25249.167.111.129 to 249.167.111.254249.167.111.255126
225249.167.112.0/25249.167.112.1 to 249.167.112.126249.167.112.127126
226249.167.112.128/25249.167.112.129 to 249.167.112.254249.167.112.255126
227249.167.113.0/25249.167.113.1 to 249.167.113.126249.167.113.127126
228249.167.113.128/25249.167.113.129 to 249.167.113.254249.167.113.255126
229249.167.114.0/25249.167.114.1 to 249.167.114.126249.167.114.127126
230249.167.114.128/25249.167.114.129 to 249.167.114.254249.167.114.255126
231249.167.115.0/25249.167.115.1 to 249.167.115.126249.167.115.127126
232249.167.115.128/25249.167.115.129 to 249.167.115.254249.167.115.255126
233249.167.116.0/25249.167.116.1 to 249.167.116.126249.167.116.127126
234249.167.116.128/25249.167.116.129 to 249.167.116.254249.167.116.255126
235249.167.117.0/25249.167.117.1 to 249.167.117.126249.167.117.127126
236249.167.117.128/25249.167.117.129 to 249.167.117.254249.167.117.255126
237249.167.118.0/25249.167.118.1 to 249.167.118.126249.167.118.127126
238249.167.118.128/25249.167.118.129 to 249.167.118.254249.167.118.255126
239249.167.119.0/25249.167.119.1 to 249.167.119.126249.167.119.127126
240249.167.119.128/25249.167.119.129 to 249.167.119.254249.167.119.255126
241249.167.120.0/25249.167.120.1 to 249.167.120.126249.167.120.127126
242249.167.120.128/25249.167.120.129 to 249.167.120.254249.167.120.255126
243249.167.121.0/25249.167.121.1 to 249.167.121.126249.167.121.127126
244249.167.121.128/25249.167.121.129 to 249.167.121.254249.167.121.255126
245249.167.122.0/25249.167.122.1 to 249.167.122.126249.167.122.127126
246249.167.122.128/25249.167.122.129 to 249.167.122.254249.167.122.255126
247249.167.123.0/25249.167.123.1 to 249.167.123.126249.167.123.127126
248249.167.123.128/25249.167.123.129 to 249.167.123.254249.167.123.255126
249249.167.124.0/25249.167.124.1 to 249.167.124.126249.167.124.127126
250249.167.124.128/25249.167.124.129 to 249.167.124.254249.167.124.255126
251249.167.125.0/25249.167.125.1 to 249.167.125.126249.167.125.127126
252249.167.125.128/25249.167.125.129 to 249.167.125.254249.167.125.255126
253249.167.126.0/25249.167.126.1 to 249.167.126.126249.167.126.127126
254249.167.126.128/25249.167.126.129 to 249.167.126.254249.167.126.255126
255249.167.127.0/25249.167.127.1 to 249.167.127.126249.167.127.127126
256249.167.127.128/25249.167.127.129 to 249.167.127.254249.167.127.255126

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.