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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.

Network192.0.0.0/6
Usable hosts67,108,862
Subnet mask252.0.0.0
Addresses67,108,864
Network address
192.0.0.0
Broadcast address
195.255.255.255
First usable
192.0.0.1
Last usable
195.255.255.254
Usable hosts
67,108,862 (67,108,864 less the network and broadcast addresses)
Subnet mask
252.0.0.0
Wildcard mask
3.255.255.255 (Cisco ACLs, OSPF)
Prefix length
/6
Type
Public public
Old class
C (default /24)
As numbers
Hex C0000000 · Integer 3221225472 to 3288334335
Reverse DNS zones
192.in-addr.arpa
193.in-addr.arpa
194.in-addr.arpa
195.in-addr.arpa
/6 is not on a 8-bit boundary, so it takes 4 /8 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address11000000.00000000.00000000.00000000192.0.0.0
Subnet mask11111100.00000000.00000000.00000000252.0.0.0
Network11000000.00000000.00000000.00000000192.0.0.0
Broadcast11000011.11111111.11111111.11111111195.255.255.255
Split into smaller subnets/15
/7 (2)/8 (4)/9 (8)/10 (16)/11 (32)/12 (64)/13 (128)/14 (256)/15 (512)/16 (1,024)/17 (2,048)/18 (4,096)

192.0.0.0/6 makes 512 subnets of /15; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1192.0.0.0/15192.0.0.1 to 192.1.255.254192.1.255.255131,070
2192.2.0.0/15192.2.0.1 to 192.3.255.254192.3.255.255131,070
3192.4.0.0/15192.4.0.1 to 192.5.255.254192.5.255.255131,070
4192.6.0.0/15192.6.0.1 to 192.7.255.254192.7.255.255131,070
5192.8.0.0/15192.8.0.1 to 192.9.255.254192.9.255.255131,070
6192.10.0.0/15192.10.0.1 to 192.11.255.254192.11.255.255131,070
7192.12.0.0/15192.12.0.1 to 192.13.255.254192.13.255.255131,070
8192.14.0.0/15192.14.0.1 to 192.15.255.254192.15.255.255131,070
9192.16.0.0/15192.16.0.1 to 192.17.255.254192.17.255.255131,070
10192.18.0.0/15192.18.0.1 to 192.19.255.254192.19.255.255131,070
11192.20.0.0/15192.20.0.1 to 192.21.255.254192.21.255.255131,070
12192.22.0.0/15192.22.0.1 to 192.23.255.254192.23.255.255131,070
13192.24.0.0/15192.24.0.1 to 192.25.255.254192.25.255.255131,070
14192.26.0.0/15192.26.0.1 to 192.27.255.254192.27.255.255131,070
15192.28.0.0/15192.28.0.1 to 192.29.255.254192.29.255.255131,070
16192.30.0.0/15192.30.0.1 to 192.31.255.254192.31.255.255131,070
17192.32.0.0/15192.32.0.1 to 192.33.255.254192.33.255.255131,070
18192.34.0.0/15192.34.0.1 to 192.35.255.254192.35.255.255131,070
19192.36.0.0/15192.36.0.1 to 192.37.255.254192.37.255.255131,070
20192.38.0.0/15192.38.0.1 to 192.39.255.254192.39.255.255131,070
21192.40.0.0/15192.40.0.1 to 192.41.255.254192.41.255.255131,070
22192.42.0.0/15192.42.0.1 to 192.43.255.254192.43.255.255131,070
23192.44.0.0/15192.44.0.1 to 192.45.255.254192.45.255.255131,070
24192.46.0.0/15192.46.0.1 to 192.47.255.254192.47.255.255131,070
25192.48.0.0/15192.48.0.1 to 192.49.255.254192.49.255.255131,070
26192.50.0.0/15192.50.0.1 to 192.51.255.254192.51.255.255131,070
27192.52.0.0/15192.52.0.1 to 192.53.255.254192.53.255.255131,070
28192.54.0.0/15192.54.0.1 to 192.55.255.254192.55.255.255131,070
29192.56.0.0/15192.56.0.1 to 192.57.255.254192.57.255.255131,070
30192.58.0.0/15192.58.0.1 to 192.59.255.254192.59.255.255131,070
31192.60.0.0/15192.60.0.1 to 192.61.255.254192.61.255.255131,070
32192.62.0.0/15192.62.0.1 to 192.63.255.254192.63.255.255131,070
33192.64.0.0/15192.64.0.1 to 192.65.255.254192.65.255.255131,070
34192.66.0.0/15192.66.0.1 to 192.67.255.254192.67.255.255131,070
35192.68.0.0/15192.68.0.1 to 192.69.255.254192.69.255.255131,070
36192.70.0.0/15192.70.0.1 to 192.71.255.254192.71.255.255131,070
37192.72.0.0/15192.72.0.1 to 192.73.255.254192.73.255.255131,070
38192.74.0.0/15192.74.0.1 to 192.75.255.254192.75.255.255131,070
39192.76.0.0/15192.76.0.1 to 192.77.255.254192.77.255.255131,070
40192.78.0.0/15192.78.0.1 to 192.79.255.254192.79.255.255131,070
41192.80.0.0/15192.80.0.1 to 192.81.255.254192.81.255.255131,070
42192.82.0.0/15192.82.0.1 to 192.83.255.254192.83.255.255131,070
43192.84.0.0/15192.84.0.1 to 192.85.255.254192.85.255.255131,070
44192.86.0.0/15192.86.0.1 to 192.87.255.254192.87.255.255131,070
45192.88.0.0/15192.88.0.1 to 192.89.255.254192.89.255.255131,070
46192.90.0.0/15192.90.0.1 to 192.91.255.254192.91.255.255131,070
47192.92.0.0/15192.92.0.1 to 192.93.255.254192.93.255.255131,070
48192.94.0.0/15192.94.0.1 to 192.95.255.254192.95.255.255131,070
49192.96.0.0/15192.96.0.1 to 192.97.255.254192.97.255.255131,070
50192.98.0.0/15192.98.0.1 to 192.99.255.254192.99.255.255131,070
51192.100.0.0/15192.100.0.1 to 192.101.255.254192.101.255.255131,070
52192.102.0.0/15192.102.0.1 to 192.103.255.254192.103.255.255131,070
53192.104.0.0/15192.104.0.1 to 192.105.255.254192.105.255.255131,070
54192.106.0.0/15192.106.0.1 to 192.107.255.254192.107.255.255131,070
55192.108.0.0/15192.108.0.1 to 192.109.255.254192.109.255.255131,070
56192.110.0.0/15192.110.0.1 to 192.111.255.254192.111.255.255131,070
57192.112.0.0/15192.112.0.1 to 192.113.255.254192.113.255.255131,070
58192.114.0.0/15192.114.0.1 to 192.115.255.254192.115.255.255131,070
59192.116.0.0/15192.116.0.1 to 192.117.255.254192.117.255.255131,070
60192.118.0.0/15192.118.0.1 to 192.119.255.254192.119.255.255131,070
61192.120.0.0/15192.120.0.1 to 192.121.255.254192.121.255.255131,070
62192.122.0.0/15192.122.0.1 to 192.123.255.254192.123.255.255131,070
63192.124.0.0/15192.124.0.1 to 192.125.255.254192.125.255.255131,070
64192.126.0.0/15192.126.0.1 to 192.127.255.254192.127.255.255131,070
65192.128.0.0/15192.128.0.1 to 192.129.255.254192.129.255.255131,070
66192.130.0.0/15192.130.0.1 to 192.131.255.254192.131.255.255131,070
67192.132.0.0/15192.132.0.1 to 192.133.255.254192.133.255.255131,070
68192.134.0.0/15192.134.0.1 to 192.135.255.254192.135.255.255131,070
69192.136.0.0/15192.136.0.1 to 192.137.255.254192.137.255.255131,070
70192.138.0.0/15192.138.0.1 to 192.139.255.254192.139.255.255131,070
71192.140.0.0/15192.140.0.1 to 192.141.255.254192.141.255.255131,070
72192.142.0.0/15192.142.0.1 to 192.143.255.254192.143.255.255131,070
73192.144.0.0/15192.144.0.1 to 192.145.255.254192.145.255.255131,070
74192.146.0.0/15192.146.0.1 to 192.147.255.254192.147.255.255131,070
75192.148.0.0/15192.148.0.1 to 192.149.255.254192.149.255.255131,070
76192.150.0.0/15192.150.0.1 to 192.151.255.254192.151.255.255131,070
77192.152.0.0/15192.152.0.1 to 192.153.255.254192.153.255.255131,070
78192.154.0.0/15192.154.0.1 to 192.155.255.254192.155.255.255131,070
79192.156.0.0/15192.156.0.1 to 192.157.255.254192.157.255.255131,070
80192.158.0.0/15192.158.0.1 to 192.159.255.254192.159.255.255131,070
81192.160.0.0/15192.160.0.1 to 192.161.255.254192.161.255.255131,070
82192.162.0.0/15192.162.0.1 to 192.163.255.254192.163.255.255131,070
83192.164.0.0/15192.164.0.1 to 192.165.255.254192.165.255.255131,070
84192.166.0.0/15192.166.0.1 to 192.167.255.254192.167.255.255131,070
85192.168.0.0/15192.168.0.1 to 192.169.255.254192.169.255.255131,070
86192.170.0.0/15192.170.0.1 to 192.171.255.254192.171.255.255131,070
87192.172.0.0/15192.172.0.1 to 192.173.255.254192.173.255.255131,070
88192.174.0.0/15192.174.0.1 to 192.175.255.254192.175.255.255131,070
89192.176.0.0/15192.176.0.1 to 192.177.255.254192.177.255.255131,070
90192.178.0.0/15192.178.0.1 to 192.179.255.254192.179.255.255131,070
91192.180.0.0/15192.180.0.1 to 192.181.255.254192.181.255.255131,070
92192.182.0.0/15192.182.0.1 to 192.183.255.254192.183.255.255131,070
93192.184.0.0/15192.184.0.1 to 192.185.255.254192.185.255.255131,070
94192.186.0.0/15192.186.0.1 to 192.187.255.254192.187.255.255131,070
95192.188.0.0/15192.188.0.1 to 192.189.255.254192.189.255.255131,070
96192.190.0.0/15192.190.0.1 to 192.191.255.254192.191.255.255131,070
97192.192.0.0/15192.192.0.1 to 192.193.255.254192.193.255.255131,070
98192.194.0.0/15192.194.0.1 to 192.195.255.254192.195.255.255131,070
99192.196.0.0/15192.196.0.1 to 192.197.255.254192.197.255.255131,070
100192.198.0.0/15192.198.0.1 to 192.199.255.254192.199.255.255131,070
101192.200.0.0/15192.200.0.1 to 192.201.255.254192.201.255.255131,070
102192.202.0.0/15192.202.0.1 to 192.203.255.254192.203.255.255131,070
103192.204.0.0/15192.204.0.1 to 192.205.255.254192.205.255.255131,070
104192.206.0.0/15192.206.0.1 to 192.207.255.254192.207.255.255131,070
105192.208.0.0/15192.208.0.1 to 192.209.255.254192.209.255.255131,070
106192.210.0.0/15192.210.0.1 to 192.211.255.254192.211.255.255131,070
107192.212.0.0/15192.212.0.1 to 192.213.255.254192.213.255.255131,070
108192.214.0.0/15192.214.0.1 to 192.215.255.254192.215.255.255131,070
109192.216.0.0/15192.216.0.1 to 192.217.255.254192.217.255.255131,070
110192.218.0.0/15192.218.0.1 to 192.219.255.254192.219.255.255131,070
111192.220.0.0/15192.220.0.1 to 192.221.255.254192.221.255.255131,070
112192.222.0.0/15192.222.0.1 to 192.223.255.254192.223.255.255131,070
113192.224.0.0/15192.224.0.1 to 192.225.255.254192.225.255.255131,070
114192.226.0.0/15192.226.0.1 to 192.227.255.254192.227.255.255131,070
115192.228.0.0/15192.228.0.1 to 192.229.255.254192.229.255.255131,070
116192.230.0.0/15192.230.0.1 to 192.231.255.254192.231.255.255131,070
117192.232.0.0/15192.232.0.1 to 192.233.255.254192.233.255.255131,070
118192.234.0.0/15192.234.0.1 to 192.235.255.254192.235.255.255131,070
119192.236.0.0/15192.236.0.1 to 192.237.255.254192.237.255.255131,070
120192.238.0.0/15192.238.0.1 to 192.239.255.254192.239.255.255131,070
121192.240.0.0/15192.240.0.1 to 192.241.255.254192.241.255.255131,070
122192.242.0.0/15192.242.0.1 to 192.243.255.254192.243.255.255131,070
123192.244.0.0/15192.244.0.1 to 192.245.255.254192.245.255.255131,070
124192.246.0.0/15192.246.0.1 to 192.247.255.254192.247.255.255131,070
125192.248.0.0/15192.248.0.1 to 192.249.255.254192.249.255.255131,070
126192.250.0.0/15192.250.0.1 to 192.251.255.254192.251.255.255131,070
127192.252.0.0/15192.252.0.1 to 192.253.255.254192.253.255.255131,070
128192.254.0.0/15192.254.0.1 to 192.255.255.254192.255.255.255131,070
129193.0.0.0/15193.0.0.1 to 193.1.255.254193.1.255.255131,070
130193.2.0.0/15193.2.0.1 to 193.3.255.254193.3.255.255131,070
131193.4.0.0/15193.4.0.1 to 193.5.255.254193.5.255.255131,070
132193.6.0.0/15193.6.0.1 to 193.7.255.254193.7.255.255131,070
133193.8.0.0/15193.8.0.1 to 193.9.255.254193.9.255.255131,070
134193.10.0.0/15193.10.0.1 to 193.11.255.254193.11.255.255131,070
135193.12.0.0/15193.12.0.1 to 193.13.255.254193.13.255.255131,070
136193.14.0.0/15193.14.0.1 to 193.15.255.254193.15.255.255131,070
137193.16.0.0/15193.16.0.1 to 193.17.255.254193.17.255.255131,070
138193.18.0.0/15193.18.0.1 to 193.19.255.254193.19.255.255131,070
139193.20.0.0/15193.20.0.1 to 193.21.255.254193.21.255.255131,070
140193.22.0.0/15193.22.0.1 to 193.23.255.254193.23.255.255131,070
141193.24.0.0/15193.24.0.1 to 193.25.255.254193.25.255.255131,070
142193.26.0.0/15193.26.0.1 to 193.27.255.254193.27.255.255131,070
143193.28.0.0/15193.28.0.1 to 193.29.255.254193.29.255.255131,070
144193.30.0.0/15193.30.0.1 to 193.31.255.254193.31.255.255131,070
145193.32.0.0/15193.32.0.1 to 193.33.255.254193.33.255.255131,070
146193.34.0.0/15193.34.0.1 to 193.35.255.254193.35.255.255131,070
147193.36.0.0/15193.36.0.1 to 193.37.255.254193.37.255.255131,070
148193.38.0.0/15193.38.0.1 to 193.39.255.254193.39.255.255131,070
149193.40.0.0/15193.40.0.1 to 193.41.255.254193.41.255.255131,070
150193.42.0.0/15193.42.0.1 to 193.43.255.254193.43.255.255131,070
151193.44.0.0/15193.44.0.1 to 193.45.255.254193.45.255.255131,070
152193.46.0.0/15193.46.0.1 to 193.47.255.254193.47.255.255131,070
153193.48.0.0/15193.48.0.1 to 193.49.255.254193.49.255.255131,070
154193.50.0.0/15193.50.0.1 to 193.51.255.254193.51.255.255131,070
155193.52.0.0/15193.52.0.1 to 193.53.255.254193.53.255.255131,070
156193.54.0.0/15193.54.0.1 to 193.55.255.254193.55.255.255131,070
157193.56.0.0/15193.56.0.1 to 193.57.255.254193.57.255.255131,070
158193.58.0.0/15193.58.0.1 to 193.59.255.254193.59.255.255131,070
159193.60.0.0/15193.60.0.1 to 193.61.255.254193.61.255.255131,070
160193.62.0.0/15193.62.0.1 to 193.63.255.254193.63.255.255131,070
161193.64.0.0/15193.64.0.1 to 193.65.255.254193.65.255.255131,070
162193.66.0.0/15193.66.0.1 to 193.67.255.254193.67.255.255131,070
163193.68.0.0/15193.68.0.1 to 193.69.255.254193.69.255.255131,070
164193.70.0.0/15193.70.0.1 to 193.71.255.254193.71.255.255131,070
165193.72.0.0/15193.72.0.1 to 193.73.255.254193.73.255.255131,070
166193.74.0.0/15193.74.0.1 to 193.75.255.254193.75.255.255131,070
167193.76.0.0/15193.76.0.1 to 193.77.255.254193.77.255.255131,070
168193.78.0.0/15193.78.0.1 to 193.79.255.254193.79.255.255131,070
169193.80.0.0/15193.80.0.1 to 193.81.255.254193.81.255.255131,070
170193.82.0.0/15193.82.0.1 to 193.83.255.254193.83.255.255131,070
171193.84.0.0/15193.84.0.1 to 193.85.255.254193.85.255.255131,070
172193.86.0.0/15193.86.0.1 to 193.87.255.254193.87.255.255131,070
173193.88.0.0/15193.88.0.1 to 193.89.255.254193.89.255.255131,070
174193.90.0.0/15193.90.0.1 to 193.91.255.254193.91.255.255131,070
175193.92.0.0/15193.92.0.1 to 193.93.255.254193.93.255.255131,070
176193.94.0.0/15193.94.0.1 to 193.95.255.254193.95.255.255131,070
177193.96.0.0/15193.96.0.1 to 193.97.255.254193.97.255.255131,070
178193.98.0.0/15193.98.0.1 to 193.99.255.254193.99.255.255131,070
179193.100.0.0/15193.100.0.1 to 193.101.255.254193.101.255.255131,070
180193.102.0.0/15193.102.0.1 to 193.103.255.254193.103.255.255131,070
181193.104.0.0/15193.104.0.1 to 193.105.255.254193.105.255.255131,070
182193.106.0.0/15193.106.0.1 to 193.107.255.254193.107.255.255131,070
183193.108.0.0/15193.108.0.1 to 193.109.255.254193.109.255.255131,070
184193.110.0.0/15193.110.0.1 to 193.111.255.254193.111.255.255131,070
185193.112.0.0/15193.112.0.1 to 193.113.255.254193.113.255.255131,070
186193.114.0.0/15193.114.0.1 to 193.115.255.254193.115.255.255131,070
187193.116.0.0/15193.116.0.1 to 193.117.255.254193.117.255.255131,070
188193.118.0.0/15193.118.0.1 to 193.119.255.254193.119.255.255131,070
189193.120.0.0/15193.120.0.1 to 193.121.255.254193.121.255.255131,070
190193.122.0.0/15193.122.0.1 to 193.123.255.254193.123.255.255131,070
191193.124.0.0/15193.124.0.1 to 193.125.255.254193.125.255.255131,070
192193.126.0.0/15193.126.0.1 to 193.127.255.254193.127.255.255131,070
193193.128.0.0/15193.128.0.1 to 193.129.255.254193.129.255.255131,070
194193.130.0.0/15193.130.0.1 to 193.131.255.254193.131.255.255131,070
195193.132.0.0/15193.132.0.1 to 193.133.255.254193.133.255.255131,070
196193.134.0.0/15193.134.0.1 to 193.135.255.254193.135.255.255131,070
197193.136.0.0/15193.136.0.1 to 193.137.255.254193.137.255.255131,070
198193.138.0.0/15193.138.0.1 to 193.139.255.254193.139.255.255131,070
199193.140.0.0/15193.140.0.1 to 193.141.255.254193.141.255.255131,070
200193.142.0.0/15193.142.0.1 to 193.143.255.254193.143.255.255131,070
201193.144.0.0/15193.144.0.1 to 193.145.255.254193.145.255.255131,070
202193.146.0.0/15193.146.0.1 to 193.147.255.254193.147.255.255131,070
203193.148.0.0/15193.148.0.1 to 193.149.255.254193.149.255.255131,070
204193.150.0.0/15193.150.0.1 to 193.151.255.254193.151.255.255131,070
205193.152.0.0/15193.152.0.1 to 193.153.255.254193.153.255.255131,070
206193.154.0.0/15193.154.0.1 to 193.155.255.254193.155.255.255131,070
207193.156.0.0/15193.156.0.1 to 193.157.255.254193.157.255.255131,070
208193.158.0.0/15193.158.0.1 to 193.159.255.254193.159.255.255131,070
209193.160.0.0/15193.160.0.1 to 193.161.255.254193.161.255.255131,070
210193.162.0.0/15193.162.0.1 to 193.163.255.254193.163.255.255131,070
211193.164.0.0/15193.164.0.1 to 193.165.255.254193.165.255.255131,070
212193.166.0.0/15193.166.0.1 to 193.167.255.254193.167.255.255131,070
213193.168.0.0/15193.168.0.1 to 193.169.255.254193.169.255.255131,070
214193.170.0.0/15193.170.0.1 to 193.171.255.254193.171.255.255131,070
215193.172.0.0/15193.172.0.1 to 193.173.255.254193.173.255.255131,070
216193.174.0.0/15193.174.0.1 to 193.175.255.254193.175.255.255131,070
217193.176.0.0/15193.176.0.1 to 193.177.255.254193.177.255.255131,070
218193.178.0.0/15193.178.0.1 to 193.179.255.254193.179.255.255131,070
219193.180.0.0/15193.180.0.1 to 193.181.255.254193.181.255.255131,070
220193.182.0.0/15193.182.0.1 to 193.183.255.254193.183.255.255131,070
221193.184.0.0/15193.184.0.1 to 193.185.255.254193.185.255.255131,070
222193.186.0.0/15193.186.0.1 to 193.187.255.254193.187.255.255131,070
223193.188.0.0/15193.188.0.1 to 193.189.255.254193.189.255.255131,070
224193.190.0.0/15193.190.0.1 to 193.191.255.254193.191.255.255131,070
225193.192.0.0/15193.192.0.1 to 193.193.255.254193.193.255.255131,070
226193.194.0.0/15193.194.0.1 to 193.195.255.254193.195.255.255131,070
227193.196.0.0/15193.196.0.1 to 193.197.255.254193.197.255.255131,070
228193.198.0.0/15193.198.0.1 to 193.199.255.254193.199.255.255131,070
229193.200.0.0/15193.200.0.1 to 193.201.255.254193.201.255.255131,070
230193.202.0.0/15193.202.0.1 to 193.203.255.254193.203.255.255131,070
231193.204.0.0/15193.204.0.1 to 193.205.255.254193.205.255.255131,070
232193.206.0.0/15193.206.0.1 to 193.207.255.254193.207.255.255131,070
233193.208.0.0/15193.208.0.1 to 193.209.255.254193.209.255.255131,070
234193.210.0.0/15193.210.0.1 to 193.211.255.254193.211.255.255131,070
235193.212.0.0/15193.212.0.1 to 193.213.255.254193.213.255.255131,070
236193.214.0.0/15193.214.0.1 to 193.215.255.254193.215.255.255131,070
237193.216.0.0/15193.216.0.1 to 193.217.255.254193.217.255.255131,070
238193.218.0.0/15193.218.0.1 to 193.219.255.254193.219.255.255131,070
239193.220.0.0/15193.220.0.1 to 193.221.255.254193.221.255.255131,070
240193.222.0.0/15193.222.0.1 to 193.223.255.254193.223.255.255131,070
241193.224.0.0/15193.224.0.1 to 193.225.255.254193.225.255.255131,070
242193.226.0.0/15193.226.0.1 to 193.227.255.254193.227.255.255131,070
243193.228.0.0/15193.228.0.1 to 193.229.255.254193.229.255.255131,070
244193.230.0.0/15193.230.0.1 to 193.231.255.254193.231.255.255131,070
245193.232.0.0/15193.232.0.1 to 193.233.255.254193.233.255.255131,070
246193.234.0.0/15193.234.0.1 to 193.235.255.254193.235.255.255131,070
247193.236.0.0/15193.236.0.1 to 193.237.255.254193.237.255.255131,070
248193.238.0.0/15193.238.0.1 to 193.239.255.254193.239.255.255131,070
249193.240.0.0/15193.240.0.1 to 193.241.255.254193.241.255.255131,070
250193.242.0.0/15193.242.0.1 to 193.243.255.254193.243.255.255131,070
251193.244.0.0/15193.244.0.1 to 193.245.255.254193.245.255.255131,070
252193.246.0.0/15193.246.0.1 to 193.247.255.254193.247.255.255131,070
253193.248.0.0/15193.248.0.1 to 193.249.255.254193.249.255.255131,070
254193.250.0.0/15193.250.0.1 to 193.251.255.254193.251.255.255131,070
255193.252.0.0/15193.252.0.1 to 193.253.255.254193.253.255.255131,070
256193.254.0.0/15193.254.0.1 to 193.255.255.254193.255.255.255131,070

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.