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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.

Network197.0.0.0/8
Usable hosts16,777,214
Subnet mask255.0.0.0
Addresses16,777,216
Network address
197.0.0.0
Broadcast address
197.255.255.255
First usable
197.0.0.1
Last usable
197.255.255.254
Usable hosts
16,777,214 (16,777,216 less the network and broadcast addresses)
Subnet mask
255.0.0.0
Wildcard mask
0.255.255.255 (Cisco ACLs, OSPF)
Prefix length
/8
Type
Public public
Old class
C (default /24)
As numbers
Hex C5000000 · Integer 3305111552 to 3321888767
Reverse DNS zone
197.in-addr.arpa
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address11000101..00000000.00000000.00000000197.0.0.0
Subnet mask11111111..00000000.00000000.00000000255.0.0.0
Network11000101..00000000.00000000.00000000197.0.0.0
Broadcast11000101..11111111.11111111.11111111197.255.255.255
Split into smaller subnets/16
/9 (2)/10 (4)/11 (8)/12 (16)/13 (32)/14 (64)/15 (128)/16 (256)/17 (512)/18 (1,024)/19 (2,048)/20 (4,096)

197.0.0.0/8 makes 256 subnets of /16.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1197.0.0.0/16197.0.0.1 to 197.0.255.254197.0.255.25565,534
2197.1.0.0/16197.1.0.1 to 197.1.255.254197.1.255.25565,534
3197.2.0.0/16197.2.0.1 to 197.2.255.254197.2.255.25565,534
4197.3.0.0/16197.3.0.1 to 197.3.255.254197.3.255.25565,534
5197.4.0.0/16197.4.0.1 to 197.4.255.254197.4.255.25565,534
6197.5.0.0/16197.5.0.1 to 197.5.255.254197.5.255.25565,534
7197.6.0.0/16197.6.0.1 to 197.6.255.254197.6.255.25565,534
8197.7.0.0/16197.7.0.1 to 197.7.255.254197.7.255.25565,534
9197.8.0.0/16197.8.0.1 to 197.8.255.254197.8.255.25565,534
10197.9.0.0/16197.9.0.1 to 197.9.255.254197.9.255.25565,534
11197.10.0.0/16197.10.0.1 to 197.10.255.254197.10.255.25565,534
12197.11.0.0/16197.11.0.1 to 197.11.255.254197.11.255.25565,534
13197.12.0.0/16197.12.0.1 to 197.12.255.254197.12.255.25565,534
14197.13.0.0/16197.13.0.1 to 197.13.255.254197.13.255.25565,534
15197.14.0.0/16197.14.0.1 to 197.14.255.254197.14.255.25565,534
16197.15.0.0/16197.15.0.1 to 197.15.255.254197.15.255.25565,534
17197.16.0.0/16197.16.0.1 to 197.16.255.254197.16.255.25565,534
18197.17.0.0/16197.17.0.1 to 197.17.255.254197.17.255.25565,534
19197.18.0.0/16197.18.0.1 to 197.18.255.254197.18.255.25565,534
20197.19.0.0/16197.19.0.1 to 197.19.255.254197.19.255.25565,534
21197.20.0.0/16197.20.0.1 to 197.20.255.254197.20.255.25565,534
22197.21.0.0/16197.21.0.1 to 197.21.255.254197.21.255.25565,534
23197.22.0.0/16197.22.0.1 to 197.22.255.254197.22.255.25565,534
24197.23.0.0/16197.23.0.1 to 197.23.255.254197.23.255.25565,534
25197.24.0.0/16197.24.0.1 to 197.24.255.254197.24.255.25565,534
26197.25.0.0/16197.25.0.1 to 197.25.255.254197.25.255.25565,534
27197.26.0.0/16197.26.0.1 to 197.26.255.254197.26.255.25565,534
28197.27.0.0/16197.27.0.1 to 197.27.255.254197.27.255.25565,534
29197.28.0.0/16197.28.0.1 to 197.28.255.254197.28.255.25565,534
30197.29.0.0/16197.29.0.1 to 197.29.255.254197.29.255.25565,534
31197.30.0.0/16197.30.0.1 to 197.30.255.254197.30.255.25565,534
32197.31.0.0/16197.31.0.1 to 197.31.255.254197.31.255.25565,534
33197.32.0.0/16197.32.0.1 to 197.32.255.254197.32.255.25565,534
34197.33.0.0/16197.33.0.1 to 197.33.255.254197.33.255.25565,534
35197.34.0.0/16197.34.0.1 to 197.34.255.254197.34.255.25565,534
36197.35.0.0/16197.35.0.1 to 197.35.255.254197.35.255.25565,534
37197.36.0.0/16197.36.0.1 to 197.36.255.254197.36.255.25565,534
38197.37.0.0/16197.37.0.1 to 197.37.255.254197.37.255.25565,534
39197.38.0.0/16197.38.0.1 to 197.38.255.254197.38.255.25565,534
40197.39.0.0/16197.39.0.1 to 197.39.255.254197.39.255.25565,534
41197.40.0.0/16197.40.0.1 to 197.40.255.254197.40.255.25565,534
42197.41.0.0/16197.41.0.1 to 197.41.255.254197.41.255.25565,534
43197.42.0.0/16197.42.0.1 to 197.42.255.254197.42.255.25565,534
44197.43.0.0/16197.43.0.1 to 197.43.255.254197.43.255.25565,534
45197.44.0.0/16197.44.0.1 to 197.44.255.254197.44.255.25565,534
46197.45.0.0/16197.45.0.1 to 197.45.255.254197.45.255.25565,534
47197.46.0.0/16197.46.0.1 to 197.46.255.254197.46.255.25565,534
48197.47.0.0/16197.47.0.1 to 197.47.255.254197.47.255.25565,534
49197.48.0.0/16197.48.0.1 to 197.48.255.254197.48.255.25565,534
50197.49.0.0/16197.49.0.1 to 197.49.255.254197.49.255.25565,534
51197.50.0.0/16197.50.0.1 to 197.50.255.254197.50.255.25565,534
52197.51.0.0/16197.51.0.1 to 197.51.255.254197.51.255.25565,534
53197.52.0.0/16197.52.0.1 to 197.52.255.254197.52.255.25565,534
54197.53.0.0/16197.53.0.1 to 197.53.255.254197.53.255.25565,534
55197.54.0.0/16197.54.0.1 to 197.54.255.254197.54.255.25565,534
56197.55.0.0/16197.55.0.1 to 197.55.255.254197.55.255.25565,534
57197.56.0.0/16197.56.0.1 to 197.56.255.254197.56.255.25565,534
58197.57.0.0/16197.57.0.1 to 197.57.255.254197.57.255.25565,534
59197.58.0.0/16197.58.0.1 to 197.58.255.254197.58.255.25565,534
60197.59.0.0/16197.59.0.1 to 197.59.255.254197.59.255.25565,534
61197.60.0.0/16197.60.0.1 to 197.60.255.254197.60.255.25565,534
62197.61.0.0/16197.61.0.1 to 197.61.255.254197.61.255.25565,534
63197.62.0.0/16197.62.0.1 to 197.62.255.254197.62.255.25565,534
64197.63.0.0/16197.63.0.1 to 197.63.255.254197.63.255.25565,534
65197.64.0.0/16197.64.0.1 to 197.64.255.254197.64.255.25565,534
66197.65.0.0/16197.65.0.1 to 197.65.255.254197.65.255.25565,534
67197.66.0.0/16197.66.0.1 to 197.66.255.254197.66.255.25565,534
68197.67.0.0/16197.67.0.1 to 197.67.255.254197.67.255.25565,534
69197.68.0.0/16197.68.0.1 to 197.68.255.254197.68.255.25565,534
70197.69.0.0/16197.69.0.1 to 197.69.255.254197.69.255.25565,534
71197.70.0.0/16197.70.0.1 to 197.70.255.254197.70.255.25565,534
72197.71.0.0/16197.71.0.1 to 197.71.255.254197.71.255.25565,534
73197.72.0.0/16197.72.0.1 to 197.72.255.254197.72.255.25565,534
74197.73.0.0/16197.73.0.1 to 197.73.255.254197.73.255.25565,534
75197.74.0.0/16197.74.0.1 to 197.74.255.254197.74.255.25565,534
76197.75.0.0/16197.75.0.1 to 197.75.255.254197.75.255.25565,534
77197.76.0.0/16197.76.0.1 to 197.76.255.254197.76.255.25565,534
78197.77.0.0/16197.77.0.1 to 197.77.255.254197.77.255.25565,534
79197.78.0.0/16197.78.0.1 to 197.78.255.254197.78.255.25565,534
80197.79.0.0/16197.79.0.1 to 197.79.255.254197.79.255.25565,534
81197.80.0.0/16197.80.0.1 to 197.80.255.254197.80.255.25565,534
82197.81.0.0/16197.81.0.1 to 197.81.255.254197.81.255.25565,534
83197.82.0.0/16197.82.0.1 to 197.82.255.254197.82.255.25565,534
84197.83.0.0/16197.83.0.1 to 197.83.255.254197.83.255.25565,534
85197.84.0.0/16197.84.0.1 to 197.84.255.254197.84.255.25565,534
86197.85.0.0/16197.85.0.1 to 197.85.255.254197.85.255.25565,534
87197.86.0.0/16197.86.0.1 to 197.86.255.254197.86.255.25565,534
88197.87.0.0/16197.87.0.1 to 197.87.255.254197.87.255.25565,534
89197.88.0.0/16197.88.0.1 to 197.88.255.254197.88.255.25565,534
90197.89.0.0/16197.89.0.1 to 197.89.255.254197.89.255.25565,534
91197.90.0.0/16197.90.0.1 to 197.90.255.254197.90.255.25565,534
92197.91.0.0/16197.91.0.1 to 197.91.255.254197.91.255.25565,534
93197.92.0.0/16197.92.0.1 to 197.92.255.254197.92.255.25565,534
94197.93.0.0/16197.93.0.1 to 197.93.255.254197.93.255.25565,534
95197.94.0.0/16197.94.0.1 to 197.94.255.254197.94.255.25565,534
96197.95.0.0/16197.95.0.1 to 197.95.255.254197.95.255.25565,534
97197.96.0.0/16197.96.0.1 to 197.96.255.254197.96.255.25565,534
98197.97.0.0/16197.97.0.1 to 197.97.255.254197.97.255.25565,534
99197.98.0.0/16197.98.0.1 to 197.98.255.254197.98.255.25565,534
100197.99.0.0/16197.99.0.1 to 197.99.255.254197.99.255.25565,534
101197.100.0.0/16197.100.0.1 to 197.100.255.254197.100.255.25565,534
102197.101.0.0/16197.101.0.1 to 197.101.255.254197.101.255.25565,534
103197.102.0.0/16197.102.0.1 to 197.102.255.254197.102.255.25565,534
104197.103.0.0/16197.103.0.1 to 197.103.255.254197.103.255.25565,534
105197.104.0.0/16197.104.0.1 to 197.104.255.254197.104.255.25565,534
106197.105.0.0/16197.105.0.1 to 197.105.255.254197.105.255.25565,534
107197.106.0.0/16197.106.0.1 to 197.106.255.254197.106.255.25565,534
108197.107.0.0/16197.107.0.1 to 197.107.255.254197.107.255.25565,534
109197.108.0.0/16197.108.0.1 to 197.108.255.254197.108.255.25565,534
110197.109.0.0/16197.109.0.1 to 197.109.255.254197.109.255.25565,534
111197.110.0.0/16197.110.0.1 to 197.110.255.254197.110.255.25565,534
112197.111.0.0/16197.111.0.1 to 197.111.255.254197.111.255.25565,534
113197.112.0.0/16197.112.0.1 to 197.112.255.254197.112.255.25565,534
114197.113.0.0/16197.113.0.1 to 197.113.255.254197.113.255.25565,534
115197.114.0.0/16197.114.0.1 to 197.114.255.254197.114.255.25565,534
116197.115.0.0/16197.115.0.1 to 197.115.255.254197.115.255.25565,534
117197.116.0.0/16197.116.0.1 to 197.116.255.254197.116.255.25565,534
118197.117.0.0/16197.117.0.1 to 197.117.255.254197.117.255.25565,534
119197.118.0.0/16197.118.0.1 to 197.118.255.254197.118.255.25565,534
120197.119.0.0/16197.119.0.1 to 197.119.255.254197.119.255.25565,534
121197.120.0.0/16197.120.0.1 to 197.120.255.254197.120.255.25565,534
122197.121.0.0/16197.121.0.1 to 197.121.255.254197.121.255.25565,534
123197.122.0.0/16197.122.0.1 to 197.122.255.254197.122.255.25565,534
124197.123.0.0/16197.123.0.1 to 197.123.255.254197.123.255.25565,534
125197.124.0.0/16197.124.0.1 to 197.124.255.254197.124.255.25565,534
126197.125.0.0/16197.125.0.1 to 197.125.255.254197.125.255.25565,534
127197.126.0.0/16197.126.0.1 to 197.126.255.254197.126.255.25565,534
128197.127.0.0/16197.127.0.1 to 197.127.255.254197.127.255.25565,534
129197.128.0.0/16197.128.0.1 to 197.128.255.254197.128.255.25565,534
130197.129.0.0/16197.129.0.1 to 197.129.255.254197.129.255.25565,534
131197.130.0.0/16197.130.0.1 to 197.130.255.254197.130.255.25565,534
132197.131.0.0/16197.131.0.1 to 197.131.255.254197.131.255.25565,534
133197.132.0.0/16197.132.0.1 to 197.132.255.254197.132.255.25565,534
134197.133.0.0/16197.133.0.1 to 197.133.255.254197.133.255.25565,534
135197.134.0.0/16197.134.0.1 to 197.134.255.254197.134.255.25565,534
136197.135.0.0/16197.135.0.1 to 197.135.255.254197.135.255.25565,534
137197.136.0.0/16197.136.0.1 to 197.136.255.254197.136.255.25565,534
138197.137.0.0/16197.137.0.1 to 197.137.255.254197.137.255.25565,534
139197.138.0.0/16197.138.0.1 to 197.138.255.254197.138.255.25565,534
140197.139.0.0/16197.139.0.1 to 197.139.255.254197.139.255.25565,534
141197.140.0.0/16197.140.0.1 to 197.140.255.254197.140.255.25565,534
142197.141.0.0/16197.141.0.1 to 197.141.255.254197.141.255.25565,534
143197.142.0.0/16197.142.0.1 to 197.142.255.254197.142.255.25565,534
144197.143.0.0/16197.143.0.1 to 197.143.255.254197.143.255.25565,534
145197.144.0.0/16197.144.0.1 to 197.144.255.254197.144.255.25565,534
146197.145.0.0/16197.145.0.1 to 197.145.255.254197.145.255.25565,534
147197.146.0.0/16197.146.0.1 to 197.146.255.254197.146.255.25565,534
148197.147.0.0/16197.147.0.1 to 197.147.255.254197.147.255.25565,534
149197.148.0.0/16197.148.0.1 to 197.148.255.254197.148.255.25565,534
150197.149.0.0/16197.149.0.1 to 197.149.255.254197.149.255.25565,534
151197.150.0.0/16197.150.0.1 to 197.150.255.254197.150.255.25565,534
152197.151.0.0/16197.151.0.1 to 197.151.255.254197.151.255.25565,534
153197.152.0.0/16197.152.0.1 to 197.152.255.254197.152.255.25565,534
154197.153.0.0/16197.153.0.1 to 197.153.255.254197.153.255.25565,534
155197.154.0.0/16197.154.0.1 to 197.154.255.254197.154.255.25565,534
156197.155.0.0/16197.155.0.1 to 197.155.255.254197.155.255.25565,534
157197.156.0.0/16197.156.0.1 to 197.156.255.254197.156.255.25565,534
158197.157.0.0/16197.157.0.1 to 197.157.255.254197.157.255.25565,534
159197.158.0.0/16197.158.0.1 to 197.158.255.254197.158.255.25565,534
160197.159.0.0/16197.159.0.1 to 197.159.255.254197.159.255.25565,534
161197.160.0.0/16197.160.0.1 to 197.160.255.254197.160.255.25565,534
162197.161.0.0/16197.161.0.1 to 197.161.255.254197.161.255.25565,534
163197.162.0.0/16197.162.0.1 to 197.162.255.254197.162.255.25565,534
164197.163.0.0/16197.163.0.1 to 197.163.255.254197.163.255.25565,534
165197.164.0.0/16197.164.0.1 to 197.164.255.254197.164.255.25565,534
166197.165.0.0/16197.165.0.1 to 197.165.255.254197.165.255.25565,534
167197.166.0.0/16197.166.0.1 to 197.166.255.254197.166.255.25565,534
168197.167.0.0/16197.167.0.1 to 197.167.255.254197.167.255.25565,534
169197.168.0.0/16197.168.0.1 to 197.168.255.254197.168.255.25565,534
170197.169.0.0/16197.169.0.1 to 197.169.255.254197.169.255.25565,534
171197.170.0.0/16197.170.0.1 to 197.170.255.254197.170.255.25565,534
172197.171.0.0/16197.171.0.1 to 197.171.255.254197.171.255.25565,534
173197.172.0.0/16197.172.0.1 to 197.172.255.254197.172.255.25565,534
174197.173.0.0/16197.173.0.1 to 197.173.255.254197.173.255.25565,534
175197.174.0.0/16197.174.0.1 to 197.174.255.254197.174.255.25565,534
176197.175.0.0/16197.175.0.1 to 197.175.255.254197.175.255.25565,534
177197.176.0.0/16197.176.0.1 to 197.176.255.254197.176.255.25565,534
178197.177.0.0/16197.177.0.1 to 197.177.255.254197.177.255.25565,534
179197.178.0.0/16197.178.0.1 to 197.178.255.254197.178.255.25565,534
180197.179.0.0/16197.179.0.1 to 197.179.255.254197.179.255.25565,534
181197.180.0.0/16197.180.0.1 to 197.180.255.254197.180.255.25565,534
182197.181.0.0/16197.181.0.1 to 197.181.255.254197.181.255.25565,534
183197.182.0.0/16197.182.0.1 to 197.182.255.254197.182.255.25565,534
184197.183.0.0/16197.183.0.1 to 197.183.255.254197.183.255.25565,534
185197.184.0.0/16197.184.0.1 to 197.184.255.254197.184.255.25565,534
186197.185.0.0/16197.185.0.1 to 197.185.255.254197.185.255.25565,534
187197.186.0.0/16197.186.0.1 to 197.186.255.254197.186.255.25565,534
188197.187.0.0/16197.187.0.1 to 197.187.255.254197.187.255.25565,534
189197.188.0.0/16197.188.0.1 to 197.188.255.254197.188.255.25565,534
190197.189.0.0/16197.189.0.1 to 197.189.255.254197.189.255.25565,534
191197.190.0.0/16197.190.0.1 to 197.190.255.254197.190.255.25565,534
192197.191.0.0/16197.191.0.1 to 197.191.255.254197.191.255.25565,534
193197.192.0.0/16197.192.0.1 to 197.192.255.254197.192.255.25565,534
194197.193.0.0/16197.193.0.1 to 197.193.255.254197.193.255.25565,534
195197.194.0.0/16197.194.0.1 to 197.194.255.254197.194.255.25565,534
196197.195.0.0/16197.195.0.1 to 197.195.255.254197.195.255.25565,534
197197.196.0.0/16197.196.0.1 to 197.196.255.254197.196.255.25565,534
198197.197.0.0/16197.197.0.1 to 197.197.255.254197.197.255.25565,534
199197.198.0.0/16197.198.0.1 to 197.198.255.254197.198.255.25565,534
200197.199.0.0/16197.199.0.1 to 197.199.255.254197.199.255.25565,534
201197.200.0.0/16197.200.0.1 to 197.200.255.254197.200.255.25565,534
202197.201.0.0/16197.201.0.1 to 197.201.255.254197.201.255.25565,534
203197.202.0.0/16197.202.0.1 to 197.202.255.254197.202.255.25565,534
204197.203.0.0/16197.203.0.1 to 197.203.255.254197.203.255.25565,534
205197.204.0.0/16197.204.0.1 to 197.204.255.254197.204.255.25565,534
206197.205.0.0/16197.205.0.1 to 197.205.255.254197.205.255.25565,534
207197.206.0.0/16197.206.0.1 to 197.206.255.254197.206.255.25565,534
208197.207.0.0/16197.207.0.1 to 197.207.255.254197.207.255.25565,534
209197.208.0.0/16197.208.0.1 to 197.208.255.254197.208.255.25565,534
210197.209.0.0/16197.209.0.1 to 197.209.255.254197.209.255.25565,534
211197.210.0.0/16197.210.0.1 to 197.210.255.254197.210.255.25565,534
212197.211.0.0/16197.211.0.1 to 197.211.255.254197.211.255.25565,534
213197.212.0.0/16197.212.0.1 to 197.212.255.254197.212.255.25565,534
214197.213.0.0/16197.213.0.1 to 197.213.255.254197.213.255.25565,534
215197.214.0.0/16197.214.0.1 to 197.214.255.254197.214.255.25565,534
216197.215.0.0/16197.215.0.1 to 197.215.255.254197.215.255.25565,534
217197.216.0.0/16197.216.0.1 to 197.216.255.254197.216.255.25565,534
218197.217.0.0/16197.217.0.1 to 197.217.255.254197.217.255.25565,534
219197.218.0.0/16197.218.0.1 to 197.218.255.254197.218.255.25565,534
220197.219.0.0/16197.219.0.1 to 197.219.255.254197.219.255.25565,534
221197.220.0.0/16197.220.0.1 to 197.220.255.254197.220.255.25565,534
222197.221.0.0/16197.221.0.1 to 197.221.255.254197.221.255.25565,534
223197.222.0.0/16197.222.0.1 to 197.222.255.254197.222.255.25565,534
224197.223.0.0/16197.223.0.1 to 197.223.255.254197.223.255.25565,534
225197.224.0.0/16197.224.0.1 to 197.224.255.254197.224.255.25565,534
226197.225.0.0/16197.225.0.1 to 197.225.255.254197.225.255.25565,534
227197.226.0.0/16197.226.0.1 to 197.226.255.254197.226.255.25565,534
228197.227.0.0/16197.227.0.1 to 197.227.255.254197.227.255.25565,534
229197.228.0.0/16197.228.0.1 to 197.228.255.254197.228.255.25565,534
230197.229.0.0/16197.229.0.1 to 197.229.255.254197.229.255.25565,534
231197.230.0.0/16197.230.0.1 to 197.230.255.254197.230.255.25565,534
232197.231.0.0/16197.231.0.1 to 197.231.255.254197.231.255.25565,534
233197.232.0.0/16197.232.0.1 to 197.232.255.254197.232.255.25565,534
234197.233.0.0/16197.233.0.1 to 197.233.255.254197.233.255.25565,534
235197.234.0.0/16197.234.0.1 to 197.234.255.254197.234.255.25565,534
236197.235.0.0/16197.235.0.1 to 197.235.255.254197.235.255.25565,534
237197.236.0.0/16197.236.0.1 to 197.236.255.254197.236.255.25565,534
238197.237.0.0/16197.237.0.1 to 197.237.255.254197.237.255.25565,534
239197.238.0.0/16197.238.0.1 to 197.238.255.254197.238.255.25565,534
240197.239.0.0/16197.239.0.1 to 197.239.255.254197.239.255.25565,534
241197.240.0.0/16197.240.0.1 to 197.240.255.254197.240.255.25565,534
242197.241.0.0/16197.241.0.1 to 197.241.255.254197.241.255.25565,534
243197.242.0.0/16197.242.0.1 to 197.242.255.254197.242.255.25565,534
244197.243.0.0/16197.243.0.1 to 197.243.255.254197.243.255.25565,534
245197.244.0.0/16197.244.0.1 to 197.244.255.254197.244.255.25565,534
246197.245.0.0/16197.245.0.1 to 197.245.255.254197.245.255.25565,534
247197.246.0.0/16197.246.0.1 to 197.246.255.254197.246.255.25565,534
248197.247.0.0/16197.247.0.1 to 197.247.255.254197.247.255.25565,534
249197.248.0.0/16197.248.0.1 to 197.248.255.254197.248.255.25565,534
250197.249.0.0/16197.249.0.1 to 197.249.255.254197.249.255.25565,534
251197.250.0.0/16197.250.0.1 to 197.250.255.254197.250.255.25565,534
252197.251.0.0/16197.251.0.1 to 197.251.255.254197.251.255.25565,534
253197.252.0.0/16197.252.0.1 to 197.252.255.254197.252.255.25565,534
254197.253.0.0/16197.253.0.1 to 197.253.255.254197.253.255.25565,534
255197.254.0.0/16197.254.0.1 to 197.254.255.254197.254.255.25565,534
256197.255.0.0/16197.255.0.1 to 197.255.255.254197.255.255.25565,534

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.