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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.

Network149.2.0.0/15
Usable hosts131,070
Subnet mask255.254.0.0
Addresses131,072
Network address
149.2.0.0
Broadcast address
149.3.255.255
First usable
149.2.0.1
Last usable
149.3.255.254
Usable hosts
131,070 (131,072 less the network and broadcast addresses)
Subnet mask
255.254.0.0
Wildcard mask
0.1.255.255 (Cisco ACLs, OSPF)
Prefix length
/15
Type
Public public
Old class
B (default /16)
As numbers
Hex 95020000 · Integer 2499936256 to 2500067327
Reverse DNS zones
2.149.in-addr.arpa
3.149.in-addr.arpa
/15 is not on a 8-bit boundary, so it takes 2 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address10010101.00000010.00000000.00000000149.2.0.0
Subnet mask11111111.11111110.00000000.00000000255.254.0.0
Network10010101.00000010.00000000.00000000149.2.0.0
Broadcast10010101.00000011.11111111.11111111149.3.255.255
Split into smaller subnets/24
/16 (2)/17 (4)/18 (8)/19 (16)/20 (32)/21 (64)/22 (128)/23 (256)/24 (512)/25 (1,024)/26 (2,048)/27 (4,096)

149.2.0.0/15 makes 512 subnets of /24; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1149.2.0.0/24149.2.0.1 to 149.2.0.254149.2.0.255254
2149.2.1.0/24149.2.1.1 to 149.2.1.254149.2.1.255254
3149.2.2.0/24149.2.2.1 to 149.2.2.254149.2.2.255254
4149.2.3.0/24149.2.3.1 to 149.2.3.254149.2.3.255254
5149.2.4.0/24149.2.4.1 to 149.2.4.254149.2.4.255254
6149.2.5.0/24149.2.5.1 to 149.2.5.254149.2.5.255254
7149.2.6.0/24149.2.6.1 to 149.2.6.254149.2.6.255254
8149.2.7.0/24149.2.7.1 to 149.2.7.254149.2.7.255254
9149.2.8.0/24149.2.8.1 to 149.2.8.254149.2.8.255254
10149.2.9.0/24149.2.9.1 to 149.2.9.254149.2.9.255254
11149.2.10.0/24149.2.10.1 to 149.2.10.254149.2.10.255254
12149.2.11.0/24149.2.11.1 to 149.2.11.254149.2.11.255254
13149.2.12.0/24149.2.12.1 to 149.2.12.254149.2.12.255254
14149.2.13.0/24149.2.13.1 to 149.2.13.254149.2.13.255254
15149.2.14.0/24149.2.14.1 to 149.2.14.254149.2.14.255254
16149.2.15.0/24149.2.15.1 to 149.2.15.254149.2.15.255254
17149.2.16.0/24149.2.16.1 to 149.2.16.254149.2.16.255254
18149.2.17.0/24149.2.17.1 to 149.2.17.254149.2.17.255254
19149.2.18.0/24149.2.18.1 to 149.2.18.254149.2.18.255254
20149.2.19.0/24149.2.19.1 to 149.2.19.254149.2.19.255254
21149.2.20.0/24149.2.20.1 to 149.2.20.254149.2.20.255254
22149.2.21.0/24149.2.21.1 to 149.2.21.254149.2.21.255254
23149.2.22.0/24149.2.22.1 to 149.2.22.254149.2.22.255254
24149.2.23.0/24149.2.23.1 to 149.2.23.254149.2.23.255254
25149.2.24.0/24149.2.24.1 to 149.2.24.254149.2.24.255254
26149.2.25.0/24149.2.25.1 to 149.2.25.254149.2.25.255254
27149.2.26.0/24149.2.26.1 to 149.2.26.254149.2.26.255254
28149.2.27.0/24149.2.27.1 to 149.2.27.254149.2.27.255254
29149.2.28.0/24149.2.28.1 to 149.2.28.254149.2.28.255254
30149.2.29.0/24149.2.29.1 to 149.2.29.254149.2.29.255254
31149.2.30.0/24149.2.30.1 to 149.2.30.254149.2.30.255254
32149.2.31.0/24149.2.31.1 to 149.2.31.254149.2.31.255254
33149.2.32.0/24149.2.32.1 to 149.2.32.254149.2.32.255254
34149.2.33.0/24149.2.33.1 to 149.2.33.254149.2.33.255254
35149.2.34.0/24149.2.34.1 to 149.2.34.254149.2.34.255254
36149.2.35.0/24149.2.35.1 to 149.2.35.254149.2.35.255254
37149.2.36.0/24149.2.36.1 to 149.2.36.254149.2.36.255254
38149.2.37.0/24149.2.37.1 to 149.2.37.254149.2.37.255254
39149.2.38.0/24149.2.38.1 to 149.2.38.254149.2.38.255254
40149.2.39.0/24149.2.39.1 to 149.2.39.254149.2.39.255254
41149.2.40.0/24149.2.40.1 to 149.2.40.254149.2.40.255254
42149.2.41.0/24149.2.41.1 to 149.2.41.254149.2.41.255254
43149.2.42.0/24149.2.42.1 to 149.2.42.254149.2.42.255254
44149.2.43.0/24149.2.43.1 to 149.2.43.254149.2.43.255254
45149.2.44.0/24149.2.44.1 to 149.2.44.254149.2.44.255254
46149.2.45.0/24149.2.45.1 to 149.2.45.254149.2.45.255254
47149.2.46.0/24149.2.46.1 to 149.2.46.254149.2.46.255254
48149.2.47.0/24149.2.47.1 to 149.2.47.254149.2.47.255254
49149.2.48.0/24149.2.48.1 to 149.2.48.254149.2.48.255254
50149.2.49.0/24149.2.49.1 to 149.2.49.254149.2.49.255254
51149.2.50.0/24149.2.50.1 to 149.2.50.254149.2.50.255254
52149.2.51.0/24149.2.51.1 to 149.2.51.254149.2.51.255254
53149.2.52.0/24149.2.52.1 to 149.2.52.254149.2.52.255254
54149.2.53.0/24149.2.53.1 to 149.2.53.254149.2.53.255254
55149.2.54.0/24149.2.54.1 to 149.2.54.254149.2.54.255254
56149.2.55.0/24149.2.55.1 to 149.2.55.254149.2.55.255254
57149.2.56.0/24149.2.56.1 to 149.2.56.254149.2.56.255254
58149.2.57.0/24149.2.57.1 to 149.2.57.254149.2.57.255254
59149.2.58.0/24149.2.58.1 to 149.2.58.254149.2.58.255254
60149.2.59.0/24149.2.59.1 to 149.2.59.254149.2.59.255254
61149.2.60.0/24149.2.60.1 to 149.2.60.254149.2.60.255254
62149.2.61.0/24149.2.61.1 to 149.2.61.254149.2.61.255254
63149.2.62.0/24149.2.62.1 to 149.2.62.254149.2.62.255254
64149.2.63.0/24149.2.63.1 to 149.2.63.254149.2.63.255254
65149.2.64.0/24149.2.64.1 to 149.2.64.254149.2.64.255254
66149.2.65.0/24149.2.65.1 to 149.2.65.254149.2.65.255254
67149.2.66.0/24149.2.66.1 to 149.2.66.254149.2.66.255254
68149.2.67.0/24149.2.67.1 to 149.2.67.254149.2.67.255254
69149.2.68.0/24149.2.68.1 to 149.2.68.254149.2.68.255254
70149.2.69.0/24149.2.69.1 to 149.2.69.254149.2.69.255254
71149.2.70.0/24149.2.70.1 to 149.2.70.254149.2.70.255254
72149.2.71.0/24149.2.71.1 to 149.2.71.254149.2.71.255254
73149.2.72.0/24149.2.72.1 to 149.2.72.254149.2.72.255254
74149.2.73.0/24149.2.73.1 to 149.2.73.254149.2.73.255254
75149.2.74.0/24149.2.74.1 to 149.2.74.254149.2.74.255254
76149.2.75.0/24149.2.75.1 to 149.2.75.254149.2.75.255254
77149.2.76.0/24149.2.76.1 to 149.2.76.254149.2.76.255254
78149.2.77.0/24149.2.77.1 to 149.2.77.254149.2.77.255254
79149.2.78.0/24149.2.78.1 to 149.2.78.254149.2.78.255254
80149.2.79.0/24149.2.79.1 to 149.2.79.254149.2.79.255254
81149.2.80.0/24149.2.80.1 to 149.2.80.254149.2.80.255254
82149.2.81.0/24149.2.81.1 to 149.2.81.254149.2.81.255254
83149.2.82.0/24149.2.82.1 to 149.2.82.254149.2.82.255254
84149.2.83.0/24149.2.83.1 to 149.2.83.254149.2.83.255254
85149.2.84.0/24149.2.84.1 to 149.2.84.254149.2.84.255254
86149.2.85.0/24149.2.85.1 to 149.2.85.254149.2.85.255254
87149.2.86.0/24149.2.86.1 to 149.2.86.254149.2.86.255254
88149.2.87.0/24149.2.87.1 to 149.2.87.254149.2.87.255254
89149.2.88.0/24149.2.88.1 to 149.2.88.254149.2.88.255254
90149.2.89.0/24149.2.89.1 to 149.2.89.254149.2.89.255254
91149.2.90.0/24149.2.90.1 to 149.2.90.254149.2.90.255254
92149.2.91.0/24149.2.91.1 to 149.2.91.254149.2.91.255254
93149.2.92.0/24149.2.92.1 to 149.2.92.254149.2.92.255254
94149.2.93.0/24149.2.93.1 to 149.2.93.254149.2.93.255254
95149.2.94.0/24149.2.94.1 to 149.2.94.254149.2.94.255254
96149.2.95.0/24149.2.95.1 to 149.2.95.254149.2.95.255254
97149.2.96.0/24149.2.96.1 to 149.2.96.254149.2.96.255254
98149.2.97.0/24149.2.97.1 to 149.2.97.254149.2.97.255254
99149.2.98.0/24149.2.98.1 to 149.2.98.254149.2.98.255254
100149.2.99.0/24149.2.99.1 to 149.2.99.254149.2.99.255254
101149.2.100.0/24149.2.100.1 to 149.2.100.254149.2.100.255254
102149.2.101.0/24149.2.101.1 to 149.2.101.254149.2.101.255254
103149.2.102.0/24149.2.102.1 to 149.2.102.254149.2.102.255254
104149.2.103.0/24149.2.103.1 to 149.2.103.254149.2.103.255254
105149.2.104.0/24149.2.104.1 to 149.2.104.254149.2.104.255254
106149.2.105.0/24149.2.105.1 to 149.2.105.254149.2.105.255254
107149.2.106.0/24149.2.106.1 to 149.2.106.254149.2.106.255254
108149.2.107.0/24149.2.107.1 to 149.2.107.254149.2.107.255254
109149.2.108.0/24149.2.108.1 to 149.2.108.254149.2.108.255254
110149.2.109.0/24149.2.109.1 to 149.2.109.254149.2.109.255254
111149.2.110.0/24149.2.110.1 to 149.2.110.254149.2.110.255254
112149.2.111.0/24149.2.111.1 to 149.2.111.254149.2.111.255254
113149.2.112.0/24149.2.112.1 to 149.2.112.254149.2.112.255254
114149.2.113.0/24149.2.113.1 to 149.2.113.254149.2.113.255254
115149.2.114.0/24149.2.114.1 to 149.2.114.254149.2.114.255254
116149.2.115.0/24149.2.115.1 to 149.2.115.254149.2.115.255254
117149.2.116.0/24149.2.116.1 to 149.2.116.254149.2.116.255254
118149.2.117.0/24149.2.117.1 to 149.2.117.254149.2.117.255254
119149.2.118.0/24149.2.118.1 to 149.2.118.254149.2.118.255254
120149.2.119.0/24149.2.119.1 to 149.2.119.254149.2.119.255254
121149.2.120.0/24149.2.120.1 to 149.2.120.254149.2.120.255254
122149.2.121.0/24149.2.121.1 to 149.2.121.254149.2.121.255254
123149.2.122.0/24149.2.122.1 to 149.2.122.254149.2.122.255254
124149.2.123.0/24149.2.123.1 to 149.2.123.254149.2.123.255254
125149.2.124.0/24149.2.124.1 to 149.2.124.254149.2.124.255254
126149.2.125.0/24149.2.125.1 to 149.2.125.254149.2.125.255254
127149.2.126.0/24149.2.126.1 to 149.2.126.254149.2.126.255254
128149.2.127.0/24149.2.127.1 to 149.2.127.254149.2.127.255254
129149.2.128.0/24149.2.128.1 to 149.2.128.254149.2.128.255254
130149.2.129.0/24149.2.129.1 to 149.2.129.254149.2.129.255254
131149.2.130.0/24149.2.130.1 to 149.2.130.254149.2.130.255254
132149.2.131.0/24149.2.131.1 to 149.2.131.254149.2.131.255254
133149.2.132.0/24149.2.132.1 to 149.2.132.254149.2.132.255254
134149.2.133.0/24149.2.133.1 to 149.2.133.254149.2.133.255254
135149.2.134.0/24149.2.134.1 to 149.2.134.254149.2.134.255254
136149.2.135.0/24149.2.135.1 to 149.2.135.254149.2.135.255254
137149.2.136.0/24149.2.136.1 to 149.2.136.254149.2.136.255254
138149.2.137.0/24149.2.137.1 to 149.2.137.254149.2.137.255254
139149.2.138.0/24149.2.138.1 to 149.2.138.254149.2.138.255254
140149.2.139.0/24149.2.139.1 to 149.2.139.254149.2.139.255254
141149.2.140.0/24149.2.140.1 to 149.2.140.254149.2.140.255254
142149.2.141.0/24149.2.141.1 to 149.2.141.254149.2.141.255254
143149.2.142.0/24149.2.142.1 to 149.2.142.254149.2.142.255254
144149.2.143.0/24149.2.143.1 to 149.2.143.254149.2.143.255254
145149.2.144.0/24149.2.144.1 to 149.2.144.254149.2.144.255254
146149.2.145.0/24149.2.145.1 to 149.2.145.254149.2.145.255254
147149.2.146.0/24149.2.146.1 to 149.2.146.254149.2.146.255254
148149.2.147.0/24149.2.147.1 to 149.2.147.254149.2.147.255254
149149.2.148.0/24149.2.148.1 to 149.2.148.254149.2.148.255254
150149.2.149.0/24149.2.149.1 to 149.2.149.254149.2.149.255254
151149.2.150.0/24149.2.150.1 to 149.2.150.254149.2.150.255254
152149.2.151.0/24149.2.151.1 to 149.2.151.254149.2.151.255254
153149.2.152.0/24149.2.152.1 to 149.2.152.254149.2.152.255254
154149.2.153.0/24149.2.153.1 to 149.2.153.254149.2.153.255254
155149.2.154.0/24149.2.154.1 to 149.2.154.254149.2.154.255254
156149.2.155.0/24149.2.155.1 to 149.2.155.254149.2.155.255254
157149.2.156.0/24149.2.156.1 to 149.2.156.254149.2.156.255254
158149.2.157.0/24149.2.157.1 to 149.2.157.254149.2.157.255254
159149.2.158.0/24149.2.158.1 to 149.2.158.254149.2.158.255254
160149.2.159.0/24149.2.159.1 to 149.2.159.254149.2.159.255254
161149.2.160.0/24149.2.160.1 to 149.2.160.254149.2.160.255254
162149.2.161.0/24149.2.161.1 to 149.2.161.254149.2.161.255254
163149.2.162.0/24149.2.162.1 to 149.2.162.254149.2.162.255254
164149.2.163.0/24149.2.163.1 to 149.2.163.254149.2.163.255254
165149.2.164.0/24149.2.164.1 to 149.2.164.254149.2.164.255254
166149.2.165.0/24149.2.165.1 to 149.2.165.254149.2.165.255254
167149.2.166.0/24149.2.166.1 to 149.2.166.254149.2.166.255254
168149.2.167.0/24149.2.167.1 to 149.2.167.254149.2.167.255254
169149.2.168.0/24149.2.168.1 to 149.2.168.254149.2.168.255254
170149.2.169.0/24149.2.169.1 to 149.2.169.254149.2.169.255254
171149.2.170.0/24149.2.170.1 to 149.2.170.254149.2.170.255254
172149.2.171.0/24149.2.171.1 to 149.2.171.254149.2.171.255254
173149.2.172.0/24149.2.172.1 to 149.2.172.254149.2.172.255254
174149.2.173.0/24149.2.173.1 to 149.2.173.254149.2.173.255254
175149.2.174.0/24149.2.174.1 to 149.2.174.254149.2.174.255254
176149.2.175.0/24149.2.175.1 to 149.2.175.254149.2.175.255254
177149.2.176.0/24149.2.176.1 to 149.2.176.254149.2.176.255254
178149.2.177.0/24149.2.177.1 to 149.2.177.254149.2.177.255254
179149.2.178.0/24149.2.178.1 to 149.2.178.254149.2.178.255254
180149.2.179.0/24149.2.179.1 to 149.2.179.254149.2.179.255254
181149.2.180.0/24149.2.180.1 to 149.2.180.254149.2.180.255254
182149.2.181.0/24149.2.181.1 to 149.2.181.254149.2.181.255254
183149.2.182.0/24149.2.182.1 to 149.2.182.254149.2.182.255254
184149.2.183.0/24149.2.183.1 to 149.2.183.254149.2.183.255254
185149.2.184.0/24149.2.184.1 to 149.2.184.254149.2.184.255254
186149.2.185.0/24149.2.185.1 to 149.2.185.254149.2.185.255254
187149.2.186.0/24149.2.186.1 to 149.2.186.254149.2.186.255254
188149.2.187.0/24149.2.187.1 to 149.2.187.254149.2.187.255254
189149.2.188.0/24149.2.188.1 to 149.2.188.254149.2.188.255254
190149.2.189.0/24149.2.189.1 to 149.2.189.254149.2.189.255254
191149.2.190.0/24149.2.190.1 to 149.2.190.254149.2.190.255254
192149.2.191.0/24149.2.191.1 to 149.2.191.254149.2.191.255254
193149.2.192.0/24149.2.192.1 to 149.2.192.254149.2.192.255254
194149.2.193.0/24149.2.193.1 to 149.2.193.254149.2.193.255254
195149.2.194.0/24149.2.194.1 to 149.2.194.254149.2.194.255254
196149.2.195.0/24149.2.195.1 to 149.2.195.254149.2.195.255254
197149.2.196.0/24149.2.196.1 to 149.2.196.254149.2.196.255254
198149.2.197.0/24149.2.197.1 to 149.2.197.254149.2.197.255254
199149.2.198.0/24149.2.198.1 to 149.2.198.254149.2.198.255254
200149.2.199.0/24149.2.199.1 to 149.2.199.254149.2.199.255254
201149.2.200.0/24149.2.200.1 to 149.2.200.254149.2.200.255254
202149.2.201.0/24149.2.201.1 to 149.2.201.254149.2.201.255254
203149.2.202.0/24149.2.202.1 to 149.2.202.254149.2.202.255254
204149.2.203.0/24149.2.203.1 to 149.2.203.254149.2.203.255254
205149.2.204.0/24149.2.204.1 to 149.2.204.254149.2.204.255254
206149.2.205.0/24149.2.205.1 to 149.2.205.254149.2.205.255254
207149.2.206.0/24149.2.206.1 to 149.2.206.254149.2.206.255254
208149.2.207.0/24149.2.207.1 to 149.2.207.254149.2.207.255254
209149.2.208.0/24149.2.208.1 to 149.2.208.254149.2.208.255254
210149.2.209.0/24149.2.209.1 to 149.2.209.254149.2.209.255254
211149.2.210.0/24149.2.210.1 to 149.2.210.254149.2.210.255254
212149.2.211.0/24149.2.211.1 to 149.2.211.254149.2.211.255254
213149.2.212.0/24149.2.212.1 to 149.2.212.254149.2.212.255254
214149.2.213.0/24149.2.213.1 to 149.2.213.254149.2.213.255254
215149.2.214.0/24149.2.214.1 to 149.2.214.254149.2.214.255254
216149.2.215.0/24149.2.215.1 to 149.2.215.254149.2.215.255254
217149.2.216.0/24149.2.216.1 to 149.2.216.254149.2.216.255254
218149.2.217.0/24149.2.217.1 to 149.2.217.254149.2.217.255254
219149.2.218.0/24149.2.218.1 to 149.2.218.254149.2.218.255254
220149.2.219.0/24149.2.219.1 to 149.2.219.254149.2.219.255254
221149.2.220.0/24149.2.220.1 to 149.2.220.254149.2.220.255254
222149.2.221.0/24149.2.221.1 to 149.2.221.254149.2.221.255254
223149.2.222.0/24149.2.222.1 to 149.2.222.254149.2.222.255254
224149.2.223.0/24149.2.223.1 to 149.2.223.254149.2.223.255254
225149.2.224.0/24149.2.224.1 to 149.2.224.254149.2.224.255254
226149.2.225.0/24149.2.225.1 to 149.2.225.254149.2.225.255254
227149.2.226.0/24149.2.226.1 to 149.2.226.254149.2.226.255254
228149.2.227.0/24149.2.227.1 to 149.2.227.254149.2.227.255254
229149.2.228.0/24149.2.228.1 to 149.2.228.254149.2.228.255254
230149.2.229.0/24149.2.229.1 to 149.2.229.254149.2.229.255254
231149.2.230.0/24149.2.230.1 to 149.2.230.254149.2.230.255254
232149.2.231.0/24149.2.231.1 to 149.2.231.254149.2.231.255254
233149.2.232.0/24149.2.232.1 to 149.2.232.254149.2.232.255254
234149.2.233.0/24149.2.233.1 to 149.2.233.254149.2.233.255254
235149.2.234.0/24149.2.234.1 to 149.2.234.254149.2.234.255254
236149.2.235.0/24149.2.235.1 to 149.2.235.254149.2.235.255254
237149.2.236.0/24149.2.236.1 to 149.2.236.254149.2.236.255254
238149.2.237.0/24149.2.237.1 to 149.2.237.254149.2.237.255254
239149.2.238.0/24149.2.238.1 to 149.2.238.254149.2.238.255254
240149.2.239.0/24149.2.239.1 to 149.2.239.254149.2.239.255254
241149.2.240.0/24149.2.240.1 to 149.2.240.254149.2.240.255254
242149.2.241.0/24149.2.241.1 to 149.2.241.254149.2.241.255254
243149.2.242.0/24149.2.242.1 to 149.2.242.254149.2.242.255254
244149.2.243.0/24149.2.243.1 to 149.2.243.254149.2.243.255254
245149.2.244.0/24149.2.244.1 to 149.2.244.254149.2.244.255254
246149.2.245.0/24149.2.245.1 to 149.2.245.254149.2.245.255254
247149.2.246.0/24149.2.246.1 to 149.2.246.254149.2.246.255254
248149.2.247.0/24149.2.247.1 to 149.2.247.254149.2.247.255254
249149.2.248.0/24149.2.248.1 to 149.2.248.254149.2.248.255254
250149.2.249.0/24149.2.249.1 to 149.2.249.254149.2.249.255254
251149.2.250.0/24149.2.250.1 to 149.2.250.254149.2.250.255254
252149.2.251.0/24149.2.251.1 to 149.2.251.254149.2.251.255254
253149.2.252.0/24149.2.252.1 to 149.2.252.254149.2.252.255254
254149.2.253.0/24149.2.253.1 to 149.2.253.254149.2.253.255254
255149.2.254.0/24149.2.254.1 to 149.2.254.254149.2.254.255254
256149.2.255.0/24149.2.255.1 to 149.2.255.254149.2.255.255254

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.