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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.

Network221.200.0.0/13
Usable hosts524,286
Subnet mask255.248.0.0
Addresses524,288
Network address
221.200.0.0
Broadcast address
221.207.255.255
First usable
221.200.0.1
Last usable
221.207.255.254
Usable hosts
524,286 (524,288 less the network and broadcast addresses)
Subnet mask
255.248.0.0
Wildcard mask
0.7.255.255 (Cisco ACLs, OSPF)
Prefix length
/13
Type
Public public
Old class
C (default /24)
As numbers
Hex DDC80000 · Integer 3720871936 to 3721396223
Reverse DNS zones
200.221.in-addr.arpa
201.221.in-addr.arpa
202.221.in-addr.arpa
203.221.in-addr.arpa
204.221.in-addr.arpa
205.221.in-addr.arpa
206.221.in-addr.arpa
207.221.in-addr.arpa
/13 is not on a 8-bit boundary, so it takes 8 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address11011101.11001000.00000000.00000000221.200.0.0
Subnet mask11111111.11111000.00000000.00000000255.248.0.0
Network11011101.11001000.00000000.00000000221.200.0.0
Broadcast11011101.11001111.11111111.11111111221.207.255.255
Split into smaller subnets/25
/14 (2)/15 (4)/16 (8)/17 (16)/18 (32)/19 (64)/20 (128)/21 (256)/22 (512)/23 (1,024)/24 (2,048)/25 (4,096)

221.200.0.0/13 makes 4,096 subnets of /25; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1221.200.0.0/25221.200.0.1 to 221.200.0.126221.200.0.127126
2221.200.0.128/25221.200.0.129 to 221.200.0.254221.200.0.255126
3221.200.1.0/25221.200.1.1 to 221.200.1.126221.200.1.127126
4221.200.1.128/25221.200.1.129 to 221.200.1.254221.200.1.255126
5221.200.2.0/25221.200.2.1 to 221.200.2.126221.200.2.127126
6221.200.2.128/25221.200.2.129 to 221.200.2.254221.200.2.255126
7221.200.3.0/25221.200.3.1 to 221.200.3.126221.200.3.127126
8221.200.3.128/25221.200.3.129 to 221.200.3.254221.200.3.255126
9221.200.4.0/25221.200.4.1 to 221.200.4.126221.200.4.127126
10221.200.4.128/25221.200.4.129 to 221.200.4.254221.200.4.255126
11221.200.5.0/25221.200.5.1 to 221.200.5.126221.200.5.127126
12221.200.5.128/25221.200.5.129 to 221.200.5.254221.200.5.255126
13221.200.6.0/25221.200.6.1 to 221.200.6.126221.200.6.127126
14221.200.6.128/25221.200.6.129 to 221.200.6.254221.200.6.255126
15221.200.7.0/25221.200.7.1 to 221.200.7.126221.200.7.127126
16221.200.7.128/25221.200.7.129 to 221.200.7.254221.200.7.255126
17221.200.8.0/25221.200.8.1 to 221.200.8.126221.200.8.127126
18221.200.8.128/25221.200.8.129 to 221.200.8.254221.200.8.255126
19221.200.9.0/25221.200.9.1 to 221.200.9.126221.200.9.127126
20221.200.9.128/25221.200.9.129 to 221.200.9.254221.200.9.255126
21221.200.10.0/25221.200.10.1 to 221.200.10.126221.200.10.127126
22221.200.10.128/25221.200.10.129 to 221.200.10.254221.200.10.255126
23221.200.11.0/25221.200.11.1 to 221.200.11.126221.200.11.127126
24221.200.11.128/25221.200.11.129 to 221.200.11.254221.200.11.255126
25221.200.12.0/25221.200.12.1 to 221.200.12.126221.200.12.127126
26221.200.12.128/25221.200.12.129 to 221.200.12.254221.200.12.255126
27221.200.13.0/25221.200.13.1 to 221.200.13.126221.200.13.127126
28221.200.13.128/25221.200.13.129 to 221.200.13.254221.200.13.255126
29221.200.14.0/25221.200.14.1 to 221.200.14.126221.200.14.127126
30221.200.14.128/25221.200.14.129 to 221.200.14.254221.200.14.255126
31221.200.15.0/25221.200.15.1 to 221.200.15.126221.200.15.127126
32221.200.15.128/25221.200.15.129 to 221.200.15.254221.200.15.255126
33221.200.16.0/25221.200.16.1 to 221.200.16.126221.200.16.127126
34221.200.16.128/25221.200.16.129 to 221.200.16.254221.200.16.255126
35221.200.17.0/25221.200.17.1 to 221.200.17.126221.200.17.127126
36221.200.17.128/25221.200.17.129 to 221.200.17.254221.200.17.255126
37221.200.18.0/25221.200.18.1 to 221.200.18.126221.200.18.127126
38221.200.18.128/25221.200.18.129 to 221.200.18.254221.200.18.255126
39221.200.19.0/25221.200.19.1 to 221.200.19.126221.200.19.127126
40221.200.19.128/25221.200.19.129 to 221.200.19.254221.200.19.255126
41221.200.20.0/25221.200.20.1 to 221.200.20.126221.200.20.127126
42221.200.20.128/25221.200.20.129 to 221.200.20.254221.200.20.255126
43221.200.21.0/25221.200.21.1 to 221.200.21.126221.200.21.127126
44221.200.21.128/25221.200.21.129 to 221.200.21.254221.200.21.255126
45221.200.22.0/25221.200.22.1 to 221.200.22.126221.200.22.127126
46221.200.22.128/25221.200.22.129 to 221.200.22.254221.200.22.255126
47221.200.23.0/25221.200.23.1 to 221.200.23.126221.200.23.127126
48221.200.23.128/25221.200.23.129 to 221.200.23.254221.200.23.255126
49221.200.24.0/25221.200.24.1 to 221.200.24.126221.200.24.127126
50221.200.24.128/25221.200.24.129 to 221.200.24.254221.200.24.255126
51221.200.25.0/25221.200.25.1 to 221.200.25.126221.200.25.127126
52221.200.25.128/25221.200.25.129 to 221.200.25.254221.200.25.255126
53221.200.26.0/25221.200.26.1 to 221.200.26.126221.200.26.127126
54221.200.26.128/25221.200.26.129 to 221.200.26.254221.200.26.255126
55221.200.27.0/25221.200.27.1 to 221.200.27.126221.200.27.127126
56221.200.27.128/25221.200.27.129 to 221.200.27.254221.200.27.255126
57221.200.28.0/25221.200.28.1 to 221.200.28.126221.200.28.127126
58221.200.28.128/25221.200.28.129 to 221.200.28.254221.200.28.255126
59221.200.29.0/25221.200.29.1 to 221.200.29.126221.200.29.127126
60221.200.29.128/25221.200.29.129 to 221.200.29.254221.200.29.255126
61221.200.30.0/25221.200.30.1 to 221.200.30.126221.200.30.127126
62221.200.30.128/25221.200.30.129 to 221.200.30.254221.200.30.255126
63221.200.31.0/25221.200.31.1 to 221.200.31.126221.200.31.127126
64221.200.31.128/25221.200.31.129 to 221.200.31.254221.200.31.255126
65221.200.32.0/25221.200.32.1 to 221.200.32.126221.200.32.127126
66221.200.32.128/25221.200.32.129 to 221.200.32.254221.200.32.255126
67221.200.33.0/25221.200.33.1 to 221.200.33.126221.200.33.127126
68221.200.33.128/25221.200.33.129 to 221.200.33.254221.200.33.255126
69221.200.34.0/25221.200.34.1 to 221.200.34.126221.200.34.127126
70221.200.34.128/25221.200.34.129 to 221.200.34.254221.200.34.255126
71221.200.35.0/25221.200.35.1 to 221.200.35.126221.200.35.127126
72221.200.35.128/25221.200.35.129 to 221.200.35.254221.200.35.255126
73221.200.36.0/25221.200.36.1 to 221.200.36.126221.200.36.127126
74221.200.36.128/25221.200.36.129 to 221.200.36.254221.200.36.255126
75221.200.37.0/25221.200.37.1 to 221.200.37.126221.200.37.127126
76221.200.37.128/25221.200.37.129 to 221.200.37.254221.200.37.255126
77221.200.38.0/25221.200.38.1 to 221.200.38.126221.200.38.127126
78221.200.38.128/25221.200.38.129 to 221.200.38.254221.200.38.255126
79221.200.39.0/25221.200.39.1 to 221.200.39.126221.200.39.127126
80221.200.39.128/25221.200.39.129 to 221.200.39.254221.200.39.255126
81221.200.40.0/25221.200.40.1 to 221.200.40.126221.200.40.127126
82221.200.40.128/25221.200.40.129 to 221.200.40.254221.200.40.255126
83221.200.41.0/25221.200.41.1 to 221.200.41.126221.200.41.127126
84221.200.41.128/25221.200.41.129 to 221.200.41.254221.200.41.255126
85221.200.42.0/25221.200.42.1 to 221.200.42.126221.200.42.127126
86221.200.42.128/25221.200.42.129 to 221.200.42.254221.200.42.255126
87221.200.43.0/25221.200.43.1 to 221.200.43.126221.200.43.127126
88221.200.43.128/25221.200.43.129 to 221.200.43.254221.200.43.255126
89221.200.44.0/25221.200.44.1 to 221.200.44.126221.200.44.127126
90221.200.44.128/25221.200.44.129 to 221.200.44.254221.200.44.255126
91221.200.45.0/25221.200.45.1 to 221.200.45.126221.200.45.127126
92221.200.45.128/25221.200.45.129 to 221.200.45.254221.200.45.255126
93221.200.46.0/25221.200.46.1 to 221.200.46.126221.200.46.127126
94221.200.46.128/25221.200.46.129 to 221.200.46.254221.200.46.255126
95221.200.47.0/25221.200.47.1 to 221.200.47.126221.200.47.127126
96221.200.47.128/25221.200.47.129 to 221.200.47.254221.200.47.255126
97221.200.48.0/25221.200.48.1 to 221.200.48.126221.200.48.127126
98221.200.48.128/25221.200.48.129 to 221.200.48.254221.200.48.255126
99221.200.49.0/25221.200.49.1 to 221.200.49.126221.200.49.127126
100221.200.49.128/25221.200.49.129 to 221.200.49.254221.200.49.255126
101221.200.50.0/25221.200.50.1 to 221.200.50.126221.200.50.127126
102221.200.50.128/25221.200.50.129 to 221.200.50.254221.200.50.255126
103221.200.51.0/25221.200.51.1 to 221.200.51.126221.200.51.127126
104221.200.51.128/25221.200.51.129 to 221.200.51.254221.200.51.255126
105221.200.52.0/25221.200.52.1 to 221.200.52.126221.200.52.127126
106221.200.52.128/25221.200.52.129 to 221.200.52.254221.200.52.255126
107221.200.53.0/25221.200.53.1 to 221.200.53.126221.200.53.127126
108221.200.53.128/25221.200.53.129 to 221.200.53.254221.200.53.255126
109221.200.54.0/25221.200.54.1 to 221.200.54.126221.200.54.127126
110221.200.54.128/25221.200.54.129 to 221.200.54.254221.200.54.255126
111221.200.55.0/25221.200.55.1 to 221.200.55.126221.200.55.127126
112221.200.55.128/25221.200.55.129 to 221.200.55.254221.200.55.255126
113221.200.56.0/25221.200.56.1 to 221.200.56.126221.200.56.127126
114221.200.56.128/25221.200.56.129 to 221.200.56.254221.200.56.255126
115221.200.57.0/25221.200.57.1 to 221.200.57.126221.200.57.127126
116221.200.57.128/25221.200.57.129 to 221.200.57.254221.200.57.255126
117221.200.58.0/25221.200.58.1 to 221.200.58.126221.200.58.127126
118221.200.58.128/25221.200.58.129 to 221.200.58.254221.200.58.255126
119221.200.59.0/25221.200.59.1 to 221.200.59.126221.200.59.127126
120221.200.59.128/25221.200.59.129 to 221.200.59.254221.200.59.255126
121221.200.60.0/25221.200.60.1 to 221.200.60.126221.200.60.127126
122221.200.60.128/25221.200.60.129 to 221.200.60.254221.200.60.255126
123221.200.61.0/25221.200.61.1 to 221.200.61.126221.200.61.127126
124221.200.61.128/25221.200.61.129 to 221.200.61.254221.200.61.255126
125221.200.62.0/25221.200.62.1 to 221.200.62.126221.200.62.127126
126221.200.62.128/25221.200.62.129 to 221.200.62.254221.200.62.255126
127221.200.63.0/25221.200.63.1 to 221.200.63.126221.200.63.127126
128221.200.63.128/25221.200.63.129 to 221.200.63.254221.200.63.255126
129221.200.64.0/25221.200.64.1 to 221.200.64.126221.200.64.127126
130221.200.64.128/25221.200.64.129 to 221.200.64.254221.200.64.255126
131221.200.65.0/25221.200.65.1 to 221.200.65.126221.200.65.127126
132221.200.65.128/25221.200.65.129 to 221.200.65.254221.200.65.255126
133221.200.66.0/25221.200.66.1 to 221.200.66.126221.200.66.127126
134221.200.66.128/25221.200.66.129 to 221.200.66.254221.200.66.255126
135221.200.67.0/25221.200.67.1 to 221.200.67.126221.200.67.127126
136221.200.67.128/25221.200.67.129 to 221.200.67.254221.200.67.255126
137221.200.68.0/25221.200.68.1 to 221.200.68.126221.200.68.127126
138221.200.68.128/25221.200.68.129 to 221.200.68.254221.200.68.255126
139221.200.69.0/25221.200.69.1 to 221.200.69.126221.200.69.127126
140221.200.69.128/25221.200.69.129 to 221.200.69.254221.200.69.255126
141221.200.70.0/25221.200.70.1 to 221.200.70.126221.200.70.127126
142221.200.70.128/25221.200.70.129 to 221.200.70.254221.200.70.255126
143221.200.71.0/25221.200.71.1 to 221.200.71.126221.200.71.127126
144221.200.71.128/25221.200.71.129 to 221.200.71.254221.200.71.255126
145221.200.72.0/25221.200.72.1 to 221.200.72.126221.200.72.127126
146221.200.72.128/25221.200.72.129 to 221.200.72.254221.200.72.255126
147221.200.73.0/25221.200.73.1 to 221.200.73.126221.200.73.127126
148221.200.73.128/25221.200.73.129 to 221.200.73.254221.200.73.255126
149221.200.74.0/25221.200.74.1 to 221.200.74.126221.200.74.127126
150221.200.74.128/25221.200.74.129 to 221.200.74.254221.200.74.255126
151221.200.75.0/25221.200.75.1 to 221.200.75.126221.200.75.127126
152221.200.75.128/25221.200.75.129 to 221.200.75.254221.200.75.255126
153221.200.76.0/25221.200.76.1 to 221.200.76.126221.200.76.127126
154221.200.76.128/25221.200.76.129 to 221.200.76.254221.200.76.255126
155221.200.77.0/25221.200.77.1 to 221.200.77.126221.200.77.127126
156221.200.77.128/25221.200.77.129 to 221.200.77.254221.200.77.255126
157221.200.78.0/25221.200.78.1 to 221.200.78.126221.200.78.127126
158221.200.78.128/25221.200.78.129 to 221.200.78.254221.200.78.255126
159221.200.79.0/25221.200.79.1 to 221.200.79.126221.200.79.127126
160221.200.79.128/25221.200.79.129 to 221.200.79.254221.200.79.255126
161221.200.80.0/25221.200.80.1 to 221.200.80.126221.200.80.127126
162221.200.80.128/25221.200.80.129 to 221.200.80.254221.200.80.255126
163221.200.81.0/25221.200.81.1 to 221.200.81.126221.200.81.127126
164221.200.81.128/25221.200.81.129 to 221.200.81.254221.200.81.255126
165221.200.82.0/25221.200.82.1 to 221.200.82.126221.200.82.127126
166221.200.82.128/25221.200.82.129 to 221.200.82.254221.200.82.255126
167221.200.83.0/25221.200.83.1 to 221.200.83.126221.200.83.127126
168221.200.83.128/25221.200.83.129 to 221.200.83.254221.200.83.255126
169221.200.84.0/25221.200.84.1 to 221.200.84.126221.200.84.127126
170221.200.84.128/25221.200.84.129 to 221.200.84.254221.200.84.255126
171221.200.85.0/25221.200.85.1 to 221.200.85.126221.200.85.127126
172221.200.85.128/25221.200.85.129 to 221.200.85.254221.200.85.255126
173221.200.86.0/25221.200.86.1 to 221.200.86.126221.200.86.127126
174221.200.86.128/25221.200.86.129 to 221.200.86.254221.200.86.255126
175221.200.87.0/25221.200.87.1 to 221.200.87.126221.200.87.127126
176221.200.87.128/25221.200.87.129 to 221.200.87.254221.200.87.255126
177221.200.88.0/25221.200.88.1 to 221.200.88.126221.200.88.127126
178221.200.88.128/25221.200.88.129 to 221.200.88.254221.200.88.255126
179221.200.89.0/25221.200.89.1 to 221.200.89.126221.200.89.127126
180221.200.89.128/25221.200.89.129 to 221.200.89.254221.200.89.255126
181221.200.90.0/25221.200.90.1 to 221.200.90.126221.200.90.127126
182221.200.90.128/25221.200.90.129 to 221.200.90.254221.200.90.255126
183221.200.91.0/25221.200.91.1 to 221.200.91.126221.200.91.127126
184221.200.91.128/25221.200.91.129 to 221.200.91.254221.200.91.255126
185221.200.92.0/25221.200.92.1 to 221.200.92.126221.200.92.127126
186221.200.92.128/25221.200.92.129 to 221.200.92.254221.200.92.255126
187221.200.93.0/25221.200.93.1 to 221.200.93.126221.200.93.127126
188221.200.93.128/25221.200.93.129 to 221.200.93.254221.200.93.255126
189221.200.94.0/25221.200.94.1 to 221.200.94.126221.200.94.127126
190221.200.94.128/25221.200.94.129 to 221.200.94.254221.200.94.255126
191221.200.95.0/25221.200.95.1 to 221.200.95.126221.200.95.127126
192221.200.95.128/25221.200.95.129 to 221.200.95.254221.200.95.255126
193221.200.96.0/25221.200.96.1 to 221.200.96.126221.200.96.127126
194221.200.96.128/25221.200.96.129 to 221.200.96.254221.200.96.255126
195221.200.97.0/25221.200.97.1 to 221.200.97.126221.200.97.127126
196221.200.97.128/25221.200.97.129 to 221.200.97.254221.200.97.255126
197221.200.98.0/25221.200.98.1 to 221.200.98.126221.200.98.127126
198221.200.98.128/25221.200.98.129 to 221.200.98.254221.200.98.255126
199221.200.99.0/25221.200.99.1 to 221.200.99.126221.200.99.127126
200221.200.99.128/25221.200.99.129 to 221.200.99.254221.200.99.255126
201221.200.100.0/25221.200.100.1 to 221.200.100.126221.200.100.127126
202221.200.100.128/25221.200.100.129 to 221.200.100.254221.200.100.255126
203221.200.101.0/25221.200.101.1 to 221.200.101.126221.200.101.127126
204221.200.101.128/25221.200.101.129 to 221.200.101.254221.200.101.255126
205221.200.102.0/25221.200.102.1 to 221.200.102.126221.200.102.127126
206221.200.102.128/25221.200.102.129 to 221.200.102.254221.200.102.255126
207221.200.103.0/25221.200.103.1 to 221.200.103.126221.200.103.127126
208221.200.103.128/25221.200.103.129 to 221.200.103.254221.200.103.255126
209221.200.104.0/25221.200.104.1 to 221.200.104.126221.200.104.127126
210221.200.104.128/25221.200.104.129 to 221.200.104.254221.200.104.255126
211221.200.105.0/25221.200.105.1 to 221.200.105.126221.200.105.127126
212221.200.105.128/25221.200.105.129 to 221.200.105.254221.200.105.255126
213221.200.106.0/25221.200.106.1 to 221.200.106.126221.200.106.127126
214221.200.106.128/25221.200.106.129 to 221.200.106.254221.200.106.255126
215221.200.107.0/25221.200.107.1 to 221.200.107.126221.200.107.127126
216221.200.107.128/25221.200.107.129 to 221.200.107.254221.200.107.255126
217221.200.108.0/25221.200.108.1 to 221.200.108.126221.200.108.127126
218221.200.108.128/25221.200.108.129 to 221.200.108.254221.200.108.255126
219221.200.109.0/25221.200.109.1 to 221.200.109.126221.200.109.127126
220221.200.109.128/25221.200.109.129 to 221.200.109.254221.200.109.255126
221221.200.110.0/25221.200.110.1 to 221.200.110.126221.200.110.127126
222221.200.110.128/25221.200.110.129 to 221.200.110.254221.200.110.255126
223221.200.111.0/25221.200.111.1 to 221.200.111.126221.200.111.127126
224221.200.111.128/25221.200.111.129 to 221.200.111.254221.200.111.255126
225221.200.112.0/25221.200.112.1 to 221.200.112.126221.200.112.127126
226221.200.112.128/25221.200.112.129 to 221.200.112.254221.200.112.255126
227221.200.113.0/25221.200.113.1 to 221.200.113.126221.200.113.127126
228221.200.113.128/25221.200.113.129 to 221.200.113.254221.200.113.255126
229221.200.114.0/25221.200.114.1 to 221.200.114.126221.200.114.127126
230221.200.114.128/25221.200.114.129 to 221.200.114.254221.200.114.255126
231221.200.115.0/25221.200.115.1 to 221.200.115.126221.200.115.127126
232221.200.115.128/25221.200.115.129 to 221.200.115.254221.200.115.255126
233221.200.116.0/25221.200.116.1 to 221.200.116.126221.200.116.127126
234221.200.116.128/25221.200.116.129 to 221.200.116.254221.200.116.255126
235221.200.117.0/25221.200.117.1 to 221.200.117.126221.200.117.127126
236221.200.117.128/25221.200.117.129 to 221.200.117.254221.200.117.255126
237221.200.118.0/25221.200.118.1 to 221.200.118.126221.200.118.127126
238221.200.118.128/25221.200.118.129 to 221.200.118.254221.200.118.255126
239221.200.119.0/25221.200.119.1 to 221.200.119.126221.200.119.127126
240221.200.119.128/25221.200.119.129 to 221.200.119.254221.200.119.255126
241221.200.120.0/25221.200.120.1 to 221.200.120.126221.200.120.127126
242221.200.120.128/25221.200.120.129 to 221.200.120.254221.200.120.255126
243221.200.121.0/25221.200.121.1 to 221.200.121.126221.200.121.127126
244221.200.121.128/25221.200.121.129 to 221.200.121.254221.200.121.255126
245221.200.122.0/25221.200.122.1 to 221.200.122.126221.200.122.127126
246221.200.122.128/25221.200.122.129 to 221.200.122.254221.200.122.255126
247221.200.123.0/25221.200.123.1 to 221.200.123.126221.200.123.127126
248221.200.123.128/25221.200.123.129 to 221.200.123.254221.200.123.255126
249221.200.124.0/25221.200.124.1 to 221.200.124.126221.200.124.127126
250221.200.124.128/25221.200.124.129 to 221.200.124.254221.200.124.255126
251221.200.125.0/25221.200.125.1 to 221.200.125.126221.200.125.127126
252221.200.125.128/25221.200.125.129 to 221.200.125.254221.200.125.255126
253221.200.126.0/25221.200.126.1 to 221.200.126.126221.200.126.127126
254221.200.126.128/25221.200.126.129 to 221.200.126.254221.200.126.255126
255221.200.127.0/25221.200.127.1 to 221.200.127.126221.200.127.127126
256221.200.127.128/25221.200.127.129 to 221.200.127.254221.200.127.255126

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.