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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.

Network151.0.0.0/8
Usable hosts16,777,214
Subnet mask255.0.0.0
Addresses16,777,216
Network address
151.0.0.0
Broadcast address
151.255.255.255
First usable
151.0.0.1
Last usable
151.255.255.254
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
B (default /16)
As numbers
Hex 97000000 · Integer 2533359616 to 2550136831
Reverse DNS zone
151.in-addr.arpa
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address10010111..00000000.00000000.00000000151.0.0.0
Subnet mask11111111..00000000.00000000.00000000255.0.0.0
Network10010111..00000000.00000000.00000000151.0.0.0
Broadcast10010111..11111111.11111111.11111111151.255.255.255
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)

151.0.0.0/8 makes 256 subnets of /16.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1151.0.0.0/16151.0.0.1 to 151.0.255.254151.0.255.25565,534
2151.1.0.0/16151.1.0.1 to 151.1.255.254151.1.255.25565,534
3151.2.0.0/16151.2.0.1 to 151.2.255.254151.2.255.25565,534
4151.3.0.0/16151.3.0.1 to 151.3.255.254151.3.255.25565,534
5151.4.0.0/16151.4.0.1 to 151.4.255.254151.4.255.25565,534
6151.5.0.0/16151.5.0.1 to 151.5.255.254151.5.255.25565,534
7151.6.0.0/16151.6.0.1 to 151.6.255.254151.6.255.25565,534
8151.7.0.0/16151.7.0.1 to 151.7.255.254151.7.255.25565,534
9151.8.0.0/16151.8.0.1 to 151.8.255.254151.8.255.25565,534
10151.9.0.0/16151.9.0.1 to 151.9.255.254151.9.255.25565,534
11151.10.0.0/16151.10.0.1 to 151.10.255.254151.10.255.25565,534
12151.11.0.0/16151.11.0.1 to 151.11.255.254151.11.255.25565,534
13151.12.0.0/16151.12.0.1 to 151.12.255.254151.12.255.25565,534
14151.13.0.0/16151.13.0.1 to 151.13.255.254151.13.255.25565,534
15151.14.0.0/16151.14.0.1 to 151.14.255.254151.14.255.25565,534
16151.15.0.0/16151.15.0.1 to 151.15.255.254151.15.255.25565,534
17151.16.0.0/16151.16.0.1 to 151.16.255.254151.16.255.25565,534
18151.17.0.0/16151.17.0.1 to 151.17.255.254151.17.255.25565,534
19151.18.0.0/16151.18.0.1 to 151.18.255.254151.18.255.25565,534
20151.19.0.0/16151.19.0.1 to 151.19.255.254151.19.255.25565,534
21151.20.0.0/16151.20.0.1 to 151.20.255.254151.20.255.25565,534
22151.21.0.0/16151.21.0.1 to 151.21.255.254151.21.255.25565,534
23151.22.0.0/16151.22.0.1 to 151.22.255.254151.22.255.25565,534
24151.23.0.0/16151.23.0.1 to 151.23.255.254151.23.255.25565,534
25151.24.0.0/16151.24.0.1 to 151.24.255.254151.24.255.25565,534
26151.25.0.0/16151.25.0.1 to 151.25.255.254151.25.255.25565,534
27151.26.0.0/16151.26.0.1 to 151.26.255.254151.26.255.25565,534
28151.27.0.0/16151.27.0.1 to 151.27.255.254151.27.255.25565,534
29151.28.0.0/16151.28.0.1 to 151.28.255.254151.28.255.25565,534
30151.29.0.0/16151.29.0.1 to 151.29.255.254151.29.255.25565,534
31151.30.0.0/16151.30.0.1 to 151.30.255.254151.30.255.25565,534
32151.31.0.0/16151.31.0.1 to 151.31.255.254151.31.255.25565,534
33151.32.0.0/16151.32.0.1 to 151.32.255.254151.32.255.25565,534
34151.33.0.0/16151.33.0.1 to 151.33.255.254151.33.255.25565,534
35151.34.0.0/16151.34.0.1 to 151.34.255.254151.34.255.25565,534
36151.35.0.0/16151.35.0.1 to 151.35.255.254151.35.255.25565,534
37151.36.0.0/16151.36.0.1 to 151.36.255.254151.36.255.25565,534
38151.37.0.0/16151.37.0.1 to 151.37.255.254151.37.255.25565,534
39151.38.0.0/16151.38.0.1 to 151.38.255.254151.38.255.25565,534
40151.39.0.0/16151.39.0.1 to 151.39.255.254151.39.255.25565,534
41151.40.0.0/16151.40.0.1 to 151.40.255.254151.40.255.25565,534
42151.41.0.0/16151.41.0.1 to 151.41.255.254151.41.255.25565,534
43151.42.0.0/16151.42.0.1 to 151.42.255.254151.42.255.25565,534
44151.43.0.0/16151.43.0.1 to 151.43.255.254151.43.255.25565,534
45151.44.0.0/16151.44.0.1 to 151.44.255.254151.44.255.25565,534
46151.45.0.0/16151.45.0.1 to 151.45.255.254151.45.255.25565,534
47151.46.0.0/16151.46.0.1 to 151.46.255.254151.46.255.25565,534
48151.47.0.0/16151.47.0.1 to 151.47.255.254151.47.255.25565,534
49151.48.0.0/16151.48.0.1 to 151.48.255.254151.48.255.25565,534
50151.49.0.0/16151.49.0.1 to 151.49.255.254151.49.255.25565,534
51151.50.0.0/16151.50.0.1 to 151.50.255.254151.50.255.25565,534
52151.51.0.0/16151.51.0.1 to 151.51.255.254151.51.255.25565,534
53151.52.0.0/16151.52.0.1 to 151.52.255.254151.52.255.25565,534
54151.53.0.0/16151.53.0.1 to 151.53.255.254151.53.255.25565,534
55151.54.0.0/16151.54.0.1 to 151.54.255.254151.54.255.25565,534
56151.55.0.0/16151.55.0.1 to 151.55.255.254151.55.255.25565,534
57151.56.0.0/16151.56.0.1 to 151.56.255.254151.56.255.25565,534
58151.57.0.0/16151.57.0.1 to 151.57.255.254151.57.255.25565,534
59151.58.0.0/16151.58.0.1 to 151.58.255.254151.58.255.25565,534
60151.59.0.0/16151.59.0.1 to 151.59.255.254151.59.255.25565,534
61151.60.0.0/16151.60.0.1 to 151.60.255.254151.60.255.25565,534
62151.61.0.0/16151.61.0.1 to 151.61.255.254151.61.255.25565,534
63151.62.0.0/16151.62.0.1 to 151.62.255.254151.62.255.25565,534
64151.63.0.0/16151.63.0.1 to 151.63.255.254151.63.255.25565,534
65151.64.0.0/16151.64.0.1 to 151.64.255.254151.64.255.25565,534
66151.65.0.0/16151.65.0.1 to 151.65.255.254151.65.255.25565,534
67151.66.0.0/16151.66.0.1 to 151.66.255.254151.66.255.25565,534
68151.67.0.0/16151.67.0.1 to 151.67.255.254151.67.255.25565,534
69151.68.0.0/16151.68.0.1 to 151.68.255.254151.68.255.25565,534
70151.69.0.0/16151.69.0.1 to 151.69.255.254151.69.255.25565,534
71151.70.0.0/16151.70.0.1 to 151.70.255.254151.70.255.25565,534
72151.71.0.0/16151.71.0.1 to 151.71.255.254151.71.255.25565,534
73151.72.0.0/16151.72.0.1 to 151.72.255.254151.72.255.25565,534
74151.73.0.0/16151.73.0.1 to 151.73.255.254151.73.255.25565,534
75151.74.0.0/16151.74.0.1 to 151.74.255.254151.74.255.25565,534
76151.75.0.0/16151.75.0.1 to 151.75.255.254151.75.255.25565,534
77151.76.0.0/16151.76.0.1 to 151.76.255.254151.76.255.25565,534
78151.77.0.0/16151.77.0.1 to 151.77.255.254151.77.255.25565,534
79151.78.0.0/16151.78.0.1 to 151.78.255.254151.78.255.25565,534
80151.79.0.0/16151.79.0.1 to 151.79.255.254151.79.255.25565,534
81151.80.0.0/16151.80.0.1 to 151.80.255.254151.80.255.25565,534
82151.81.0.0/16151.81.0.1 to 151.81.255.254151.81.255.25565,534
83151.82.0.0/16151.82.0.1 to 151.82.255.254151.82.255.25565,534
84151.83.0.0/16151.83.0.1 to 151.83.255.254151.83.255.25565,534
85151.84.0.0/16151.84.0.1 to 151.84.255.254151.84.255.25565,534
86151.85.0.0/16151.85.0.1 to 151.85.255.254151.85.255.25565,534
87151.86.0.0/16151.86.0.1 to 151.86.255.254151.86.255.25565,534
88151.87.0.0/16151.87.0.1 to 151.87.255.254151.87.255.25565,534
89151.88.0.0/16151.88.0.1 to 151.88.255.254151.88.255.25565,534
90151.89.0.0/16151.89.0.1 to 151.89.255.254151.89.255.25565,534
91151.90.0.0/16151.90.0.1 to 151.90.255.254151.90.255.25565,534
92151.91.0.0/16151.91.0.1 to 151.91.255.254151.91.255.25565,534
93151.92.0.0/16151.92.0.1 to 151.92.255.254151.92.255.25565,534
94151.93.0.0/16151.93.0.1 to 151.93.255.254151.93.255.25565,534
95151.94.0.0/16151.94.0.1 to 151.94.255.254151.94.255.25565,534
96151.95.0.0/16151.95.0.1 to 151.95.255.254151.95.255.25565,534
97151.96.0.0/16151.96.0.1 to 151.96.255.254151.96.255.25565,534
98151.97.0.0/16151.97.0.1 to 151.97.255.254151.97.255.25565,534
99151.98.0.0/16151.98.0.1 to 151.98.255.254151.98.255.25565,534
100151.99.0.0/16151.99.0.1 to 151.99.255.254151.99.255.25565,534
101151.100.0.0/16151.100.0.1 to 151.100.255.254151.100.255.25565,534
102151.101.0.0/16151.101.0.1 to 151.101.255.254151.101.255.25565,534
103151.102.0.0/16151.102.0.1 to 151.102.255.254151.102.255.25565,534
104151.103.0.0/16151.103.0.1 to 151.103.255.254151.103.255.25565,534
105151.104.0.0/16151.104.0.1 to 151.104.255.254151.104.255.25565,534
106151.105.0.0/16151.105.0.1 to 151.105.255.254151.105.255.25565,534
107151.106.0.0/16151.106.0.1 to 151.106.255.254151.106.255.25565,534
108151.107.0.0/16151.107.0.1 to 151.107.255.254151.107.255.25565,534
109151.108.0.0/16151.108.0.1 to 151.108.255.254151.108.255.25565,534
110151.109.0.0/16151.109.0.1 to 151.109.255.254151.109.255.25565,534
111151.110.0.0/16151.110.0.1 to 151.110.255.254151.110.255.25565,534
112151.111.0.0/16151.111.0.1 to 151.111.255.254151.111.255.25565,534
113151.112.0.0/16151.112.0.1 to 151.112.255.254151.112.255.25565,534
114151.113.0.0/16151.113.0.1 to 151.113.255.254151.113.255.25565,534
115151.114.0.0/16151.114.0.1 to 151.114.255.254151.114.255.25565,534
116151.115.0.0/16151.115.0.1 to 151.115.255.254151.115.255.25565,534
117151.116.0.0/16151.116.0.1 to 151.116.255.254151.116.255.25565,534
118151.117.0.0/16151.117.0.1 to 151.117.255.254151.117.255.25565,534
119151.118.0.0/16151.118.0.1 to 151.118.255.254151.118.255.25565,534
120151.119.0.0/16151.119.0.1 to 151.119.255.254151.119.255.25565,534
121151.120.0.0/16151.120.0.1 to 151.120.255.254151.120.255.25565,534
122151.121.0.0/16151.121.0.1 to 151.121.255.254151.121.255.25565,534
123151.122.0.0/16151.122.0.1 to 151.122.255.254151.122.255.25565,534
124151.123.0.0/16151.123.0.1 to 151.123.255.254151.123.255.25565,534
125151.124.0.0/16151.124.0.1 to 151.124.255.254151.124.255.25565,534
126151.125.0.0/16151.125.0.1 to 151.125.255.254151.125.255.25565,534
127151.126.0.0/16151.126.0.1 to 151.126.255.254151.126.255.25565,534
128151.127.0.0/16151.127.0.1 to 151.127.255.254151.127.255.25565,534
129151.128.0.0/16151.128.0.1 to 151.128.255.254151.128.255.25565,534
130151.129.0.0/16151.129.0.1 to 151.129.255.254151.129.255.25565,534
131151.130.0.0/16151.130.0.1 to 151.130.255.254151.130.255.25565,534
132151.131.0.0/16151.131.0.1 to 151.131.255.254151.131.255.25565,534
133151.132.0.0/16151.132.0.1 to 151.132.255.254151.132.255.25565,534
134151.133.0.0/16151.133.0.1 to 151.133.255.254151.133.255.25565,534
135151.134.0.0/16151.134.0.1 to 151.134.255.254151.134.255.25565,534
136151.135.0.0/16151.135.0.1 to 151.135.255.254151.135.255.25565,534
137151.136.0.0/16151.136.0.1 to 151.136.255.254151.136.255.25565,534
138151.137.0.0/16151.137.0.1 to 151.137.255.254151.137.255.25565,534
139151.138.0.0/16151.138.0.1 to 151.138.255.254151.138.255.25565,534
140151.139.0.0/16151.139.0.1 to 151.139.255.254151.139.255.25565,534
141151.140.0.0/16151.140.0.1 to 151.140.255.254151.140.255.25565,534
142151.141.0.0/16151.141.0.1 to 151.141.255.254151.141.255.25565,534
143151.142.0.0/16151.142.0.1 to 151.142.255.254151.142.255.25565,534
144151.143.0.0/16151.143.0.1 to 151.143.255.254151.143.255.25565,534
145151.144.0.0/16151.144.0.1 to 151.144.255.254151.144.255.25565,534
146151.145.0.0/16151.145.0.1 to 151.145.255.254151.145.255.25565,534
147151.146.0.0/16151.146.0.1 to 151.146.255.254151.146.255.25565,534
148151.147.0.0/16151.147.0.1 to 151.147.255.254151.147.255.25565,534
149151.148.0.0/16151.148.0.1 to 151.148.255.254151.148.255.25565,534
150151.149.0.0/16151.149.0.1 to 151.149.255.254151.149.255.25565,534
151151.150.0.0/16151.150.0.1 to 151.150.255.254151.150.255.25565,534
152151.151.0.0/16151.151.0.1 to 151.151.255.254151.151.255.25565,534
153151.152.0.0/16151.152.0.1 to 151.152.255.254151.152.255.25565,534
154151.153.0.0/16151.153.0.1 to 151.153.255.254151.153.255.25565,534
155151.154.0.0/16151.154.0.1 to 151.154.255.254151.154.255.25565,534
156151.155.0.0/16151.155.0.1 to 151.155.255.254151.155.255.25565,534
157151.156.0.0/16151.156.0.1 to 151.156.255.254151.156.255.25565,534
158151.157.0.0/16151.157.0.1 to 151.157.255.254151.157.255.25565,534
159151.158.0.0/16151.158.0.1 to 151.158.255.254151.158.255.25565,534
160151.159.0.0/16151.159.0.1 to 151.159.255.254151.159.255.25565,534
161151.160.0.0/16151.160.0.1 to 151.160.255.254151.160.255.25565,534
162151.161.0.0/16151.161.0.1 to 151.161.255.254151.161.255.25565,534
163151.162.0.0/16151.162.0.1 to 151.162.255.254151.162.255.25565,534
164151.163.0.0/16151.163.0.1 to 151.163.255.254151.163.255.25565,534
165151.164.0.0/16151.164.0.1 to 151.164.255.254151.164.255.25565,534
166151.165.0.0/16151.165.0.1 to 151.165.255.254151.165.255.25565,534
167151.166.0.0/16151.166.0.1 to 151.166.255.254151.166.255.25565,534
168151.167.0.0/16151.167.0.1 to 151.167.255.254151.167.255.25565,534
169151.168.0.0/16151.168.0.1 to 151.168.255.254151.168.255.25565,534
170151.169.0.0/16151.169.0.1 to 151.169.255.254151.169.255.25565,534
171151.170.0.0/16151.170.0.1 to 151.170.255.254151.170.255.25565,534
172151.171.0.0/16151.171.0.1 to 151.171.255.254151.171.255.25565,534
173151.172.0.0/16151.172.0.1 to 151.172.255.254151.172.255.25565,534
174151.173.0.0/16151.173.0.1 to 151.173.255.254151.173.255.25565,534
175151.174.0.0/16151.174.0.1 to 151.174.255.254151.174.255.25565,534
176151.175.0.0/16151.175.0.1 to 151.175.255.254151.175.255.25565,534
177151.176.0.0/16151.176.0.1 to 151.176.255.254151.176.255.25565,534
178151.177.0.0/16151.177.0.1 to 151.177.255.254151.177.255.25565,534
179151.178.0.0/16151.178.0.1 to 151.178.255.254151.178.255.25565,534
180151.179.0.0/16151.179.0.1 to 151.179.255.254151.179.255.25565,534
181151.180.0.0/16151.180.0.1 to 151.180.255.254151.180.255.25565,534
182151.181.0.0/16151.181.0.1 to 151.181.255.254151.181.255.25565,534
183151.182.0.0/16151.182.0.1 to 151.182.255.254151.182.255.25565,534
184151.183.0.0/16151.183.0.1 to 151.183.255.254151.183.255.25565,534
185151.184.0.0/16151.184.0.1 to 151.184.255.254151.184.255.25565,534
186151.185.0.0/16151.185.0.1 to 151.185.255.254151.185.255.25565,534
187151.186.0.0/16151.186.0.1 to 151.186.255.254151.186.255.25565,534
188151.187.0.0/16151.187.0.1 to 151.187.255.254151.187.255.25565,534
189151.188.0.0/16151.188.0.1 to 151.188.255.254151.188.255.25565,534
190151.189.0.0/16151.189.0.1 to 151.189.255.254151.189.255.25565,534
191151.190.0.0/16151.190.0.1 to 151.190.255.254151.190.255.25565,534
192151.191.0.0/16151.191.0.1 to 151.191.255.254151.191.255.25565,534
193151.192.0.0/16151.192.0.1 to 151.192.255.254151.192.255.25565,534
194151.193.0.0/16151.193.0.1 to 151.193.255.254151.193.255.25565,534
195151.194.0.0/16151.194.0.1 to 151.194.255.254151.194.255.25565,534
196151.195.0.0/16151.195.0.1 to 151.195.255.254151.195.255.25565,534
197151.196.0.0/16151.196.0.1 to 151.196.255.254151.196.255.25565,534
198151.197.0.0/16151.197.0.1 to 151.197.255.254151.197.255.25565,534
199151.198.0.0/16151.198.0.1 to 151.198.255.254151.198.255.25565,534
200151.199.0.0/16151.199.0.1 to 151.199.255.254151.199.255.25565,534
201151.200.0.0/16151.200.0.1 to 151.200.255.254151.200.255.25565,534
202151.201.0.0/16151.201.0.1 to 151.201.255.254151.201.255.25565,534
203151.202.0.0/16151.202.0.1 to 151.202.255.254151.202.255.25565,534
204151.203.0.0/16151.203.0.1 to 151.203.255.254151.203.255.25565,534
205151.204.0.0/16151.204.0.1 to 151.204.255.254151.204.255.25565,534
206151.205.0.0/16151.205.0.1 to 151.205.255.254151.205.255.25565,534
207151.206.0.0/16151.206.0.1 to 151.206.255.254151.206.255.25565,534
208151.207.0.0/16151.207.0.1 to 151.207.255.254151.207.255.25565,534
209151.208.0.0/16151.208.0.1 to 151.208.255.254151.208.255.25565,534
210151.209.0.0/16151.209.0.1 to 151.209.255.254151.209.255.25565,534
211151.210.0.0/16151.210.0.1 to 151.210.255.254151.210.255.25565,534
212151.211.0.0/16151.211.0.1 to 151.211.255.254151.211.255.25565,534
213151.212.0.0/16151.212.0.1 to 151.212.255.254151.212.255.25565,534
214151.213.0.0/16151.213.0.1 to 151.213.255.254151.213.255.25565,534
215151.214.0.0/16151.214.0.1 to 151.214.255.254151.214.255.25565,534
216151.215.0.0/16151.215.0.1 to 151.215.255.254151.215.255.25565,534
217151.216.0.0/16151.216.0.1 to 151.216.255.254151.216.255.25565,534
218151.217.0.0/16151.217.0.1 to 151.217.255.254151.217.255.25565,534
219151.218.0.0/16151.218.0.1 to 151.218.255.254151.218.255.25565,534
220151.219.0.0/16151.219.0.1 to 151.219.255.254151.219.255.25565,534
221151.220.0.0/16151.220.0.1 to 151.220.255.254151.220.255.25565,534
222151.221.0.0/16151.221.0.1 to 151.221.255.254151.221.255.25565,534
223151.222.0.0/16151.222.0.1 to 151.222.255.254151.222.255.25565,534
224151.223.0.0/16151.223.0.1 to 151.223.255.254151.223.255.25565,534
225151.224.0.0/16151.224.0.1 to 151.224.255.254151.224.255.25565,534
226151.225.0.0/16151.225.0.1 to 151.225.255.254151.225.255.25565,534
227151.226.0.0/16151.226.0.1 to 151.226.255.254151.226.255.25565,534
228151.227.0.0/16151.227.0.1 to 151.227.255.254151.227.255.25565,534
229151.228.0.0/16151.228.0.1 to 151.228.255.254151.228.255.25565,534
230151.229.0.0/16151.229.0.1 to 151.229.255.254151.229.255.25565,534
231151.230.0.0/16151.230.0.1 to 151.230.255.254151.230.255.25565,534
232151.231.0.0/16151.231.0.1 to 151.231.255.254151.231.255.25565,534
233151.232.0.0/16151.232.0.1 to 151.232.255.254151.232.255.25565,534
234151.233.0.0/16151.233.0.1 to 151.233.255.254151.233.255.25565,534
235151.234.0.0/16151.234.0.1 to 151.234.255.254151.234.255.25565,534
236151.235.0.0/16151.235.0.1 to 151.235.255.254151.235.255.25565,534
237151.236.0.0/16151.236.0.1 to 151.236.255.254151.236.255.25565,534
238151.237.0.0/16151.237.0.1 to 151.237.255.254151.237.255.25565,534
239151.238.0.0/16151.238.0.1 to 151.238.255.254151.238.255.25565,534
240151.239.0.0/16151.239.0.1 to 151.239.255.254151.239.255.25565,534
241151.240.0.0/16151.240.0.1 to 151.240.255.254151.240.255.25565,534
242151.241.0.0/16151.241.0.1 to 151.241.255.254151.241.255.25565,534
243151.242.0.0/16151.242.0.1 to 151.242.255.254151.242.255.25565,534
244151.243.0.0/16151.243.0.1 to 151.243.255.254151.243.255.25565,534
245151.244.0.0/16151.244.0.1 to 151.244.255.254151.244.255.25565,534
246151.245.0.0/16151.245.0.1 to 151.245.255.254151.245.255.25565,534
247151.246.0.0/16151.246.0.1 to 151.246.255.254151.246.255.25565,534
248151.247.0.0/16151.247.0.1 to 151.247.255.254151.247.255.25565,534
249151.248.0.0/16151.248.0.1 to 151.248.255.254151.248.255.25565,534
250151.249.0.0/16151.249.0.1 to 151.249.255.254151.249.255.25565,534
251151.250.0.0/16151.250.0.1 to 151.250.255.254151.250.255.25565,534
252151.251.0.0/16151.251.0.1 to 151.251.255.254151.251.255.25565,534
253151.252.0.0/16151.252.0.1 to 151.252.255.254151.252.255.25565,534
254151.253.0.0/16151.253.0.1 to 151.253.255.254151.253.255.25565,534
255151.254.0.0/16151.254.0.1 to 151.254.255.254151.254.255.25565,534
256151.255.0.0/16151.255.0.1 to 151.255.255.254151.255.255.25565,534

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.