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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.

Network192.168.0.0/16
Usable hosts65,534
Subnet mask255.255.0.0
Addresses65,536
Network address
192.168.0.0
Broadcast address
192.168.255.255
First usable
192.168.0.1
Last usable
192.168.255.254
Usable hosts
65,534 (65,536 less the network and broadcast addresses)
Subnet mask
255.255.0.0
Wildcard mask
0.0.255.255 (Cisco ACLs, OSPF)
Prefix length
/16
Type
Private (RFC 1918) 192.168.0.0/16
Office and home networks; not routed on the internet
Old class
C (default /24)
As numbers
Hex C0A80000 · Integer 3232235520 to 3232301055
Reverse DNS zone
168.192.in-addr.arpa
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address11000000.10101000..00000000.00000000192.168.0.0
Subnet mask11111111.11111111..00000000.00000000255.255.0.0
Network11000000.10101000..00000000.00000000192.168.0.0
Broadcast11000000.10101000..11111111.11111111192.168.255.255
Split into smaller subnets/25
/17 (2)/18 (4)/19 (8)/20 (16)/21 (32)/22 (64)/23 (128)/24 (256)/25 (512)/26 (1,024)/27 (2,048)/28 (4,096)

192.168.0.0/16 makes 512 subnets of /25; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1192.168.0.0/25192.168.0.1 to 192.168.0.126192.168.0.127126
2192.168.0.128/25192.168.0.129 to 192.168.0.254192.168.0.255126
3192.168.1.0/25192.168.1.1 to 192.168.1.126192.168.1.127126
4192.168.1.128/25192.168.1.129 to 192.168.1.254192.168.1.255126
5192.168.2.0/25192.168.2.1 to 192.168.2.126192.168.2.127126
6192.168.2.128/25192.168.2.129 to 192.168.2.254192.168.2.255126
7192.168.3.0/25192.168.3.1 to 192.168.3.126192.168.3.127126
8192.168.3.128/25192.168.3.129 to 192.168.3.254192.168.3.255126
9192.168.4.0/25192.168.4.1 to 192.168.4.126192.168.4.127126
10192.168.4.128/25192.168.4.129 to 192.168.4.254192.168.4.255126
11192.168.5.0/25192.168.5.1 to 192.168.5.126192.168.5.127126
12192.168.5.128/25192.168.5.129 to 192.168.5.254192.168.5.255126
13192.168.6.0/25192.168.6.1 to 192.168.6.126192.168.6.127126
14192.168.6.128/25192.168.6.129 to 192.168.6.254192.168.6.255126
15192.168.7.0/25192.168.7.1 to 192.168.7.126192.168.7.127126
16192.168.7.128/25192.168.7.129 to 192.168.7.254192.168.7.255126
17192.168.8.0/25192.168.8.1 to 192.168.8.126192.168.8.127126
18192.168.8.128/25192.168.8.129 to 192.168.8.254192.168.8.255126
19192.168.9.0/25192.168.9.1 to 192.168.9.126192.168.9.127126
20192.168.9.128/25192.168.9.129 to 192.168.9.254192.168.9.255126
21192.168.10.0/25192.168.10.1 to 192.168.10.126192.168.10.127126
22192.168.10.128/25192.168.10.129 to 192.168.10.254192.168.10.255126
23192.168.11.0/25192.168.11.1 to 192.168.11.126192.168.11.127126
24192.168.11.128/25192.168.11.129 to 192.168.11.254192.168.11.255126
25192.168.12.0/25192.168.12.1 to 192.168.12.126192.168.12.127126
26192.168.12.128/25192.168.12.129 to 192.168.12.254192.168.12.255126
27192.168.13.0/25192.168.13.1 to 192.168.13.126192.168.13.127126
28192.168.13.128/25192.168.13.129 to 192.168.13.254192.168.13.255126
29192.168.14.0/25192.168.14.1 to 192.168.14.126192.168.14.127126
30192.168.14.128/25192.168.14.129 to 192.168.14.254192.168.14.255126
31192.168.15.0/25192.168.15.1 to 192.168.15.126192.168.15.127126
32192.168.15.128/25192.168.15.129 to 192.168.15.254192.168.15.255126
33192.168.16.0/25192.168.16.1 to 192.168.16.126192.168.16.127126
34192.168.16.128/25192.168.16.129 to 192.168.16.254192.168.16.255126
35192.168.17.0/25192.168.17.1 to 192.168.17.126192.168.17.127126
36192.168.17.128/25192.168.17.129 to 192.168.17.254192.168.17.255126
37192.168.18.0/25192.168.18.1 to 192.168.18.126192.168.18.127126
38192.168.18.128/25192.168.18.129 to 192.168.18.254192.168.18.255126
39192.168.19.0/25192.168.19.1 to 192.168.19.126192.168.19.127126
40192.168.19.128/25192.168.19.129 to 192.168.19.254192.168.19.255126
41192.168.20.0/25192.168.20.1 to 192.168.20.126192.168.20.127126
42192.168.20.128/25192.168.20.129 to 192.168.20.254192.168.20.255126
43192.168.21.0/25192.168.21.1 to 192.168.21.126192.168.21.127126
44192.168.21.128/25192.168.21.129 to 192.168.21.254192.168.21.255126
45192.168.22.0/25192.168.22.1 to 192.168.22.126192.168.22.127126
46192.168.22.128/25192.168.22.129 to 192.168.22.254192.168.22.255126
47192.168.23.0/25192.168.23.1 to 192.168.23.126192.168.23.127126
48192.168.23.128/25192.168.23.129 to 192.168.23.254192.168.23.255126
49192.168.24.0/25192.168.24.1 to 192.168.24.126192.168.24.127126
50192.168.24.128/25192.168.24.129 to 192.168.24.254192.168.24.255126
51192.168.25.0/25192.168.25.1 to 192.168.25.126192.168.25.127126
52192.168.25.128/25192.168.25.129 to 192.168.25.254192.168.25.255126
53192.168.26.0/25192.168.26.1 to 192.168.26.126192.168.26.127126
54192.168.26.128/25192.168.26.129 to 192.168.26.254192.168.26.255126
55192.168.27.0/25192.168.27.1 to 192.168.27.126192.168.27.127126
56192.168.27.128/25192.168.27.129 to 192.168.27.254192.168.27.255126
57192.168.28.0/25192.168.28.1 to 192.168.28.126192.168.28.127126
58192.168.28.128/25192.168.28.129 to 192.168.28.254192.168.28.255126
59192.168.29.0/25192.168.29.1 to 192.168.29.126192.168.29.127126
60192.168.29.128/25192.168.29.129 to 192.168.29.254192.168.29.255126
61192.168.30.0/25192.168.30.1 to 192.168.30.126192.168.30.127126
62192.168.30.128/25192.168.30.129 to 192.168.30.254192.168.30.255126
63192.168.31.0/25192.168.31.1 to 192.168.31.126192.168.31.127126
64192.168.31.128/25192.168.31.129 to 192.168.31.254192.168.31.255126
65192.168.32.0/25192.168.32.1 to 192.168.32.126192.168.32.127126
66192.168.32.128/25192.168.32.129 to 192.168.32.254192.168.32.255126
67192.168.33.0/25192.168.33.1 to 192.168.33.126192.168.33.127126
68192.168.33.128/25192.168.33.129 to 192.168.33.254192.168.33.255126
69192.168.34.0/25192.168.34.1 to 192.168.34.126192.168.34.127126
70192.168.34.128/25192.168.34.129 to 192.168.34.254192.168.34.255126
71192.168.35.0/25192.168.35.1 to 192.168.35.126192.168.35.127126
72192.168.35.128/25192.168.35.129 to 192.168.35.254192.168.35.255126
73192.168.36.0/25192.168.36.1 to 192.168.36.126192.168.36.127126
74192.168.36.128/25192.168.36.129 to 192.168.36.254192.168.36.255126
75192.168.37.0/25192.168.37.1 to 192.168.37.126192.168.37.127126
76192.168.37.128/25192.168.37.129 to 192.168.37.254192.168.37.255126
77192.168.38.0/25192.168.38.1 to 192.168.38.126192.168.38.127126
78192.168.38.128/25192.168.38.129 to 192.168.38.254192.168.38.255126
79192.168.39.0/25192.168.39.1 to 192.168.39.126192.168.39.127126
80192.168.39.128/25192.168.39.129 to 192.168.39.254192.168.39.255126
81192.168.40.0/25192.168.40.1 to 192.168.40.126192.168.40.127126
82192.168.40.128/25192.168.40.129 to 192.168.40.254192.168.40.255126
83192.168.41.0/25192.168.41.1 to 192.168.41.126192.168.41.127126
84192.168.41.128/25192.168.41.129 to 192.168.41.254192.168.41.255126
85192.168.42.0/25192.168.42.1 to 192.168.42.126192.168.42.127126
86192.168.42.128/25192.168.42.129 to 192.168.42.254192.168.42.255126
87192.168.43.0/25192.168.43.1 to 192.168.43.126192.168.43.127126
88192.168.43.128/25192.168.43.129 to 192.168.43.254192.168.43.255126
89192.168.44.0/25192.168.44.1 to 192.168.44.126192.168.44.127126
90192.168.44.128/25192.168.44.129 to 192.168.44.254192.168.44.255126
91192.168.45.0/25192.168.45.1 to 192.168.45.126192.168.45.127126
92192.168.45.128/25192.168.45.129 to 192.168.45.254192.168.45.255126
93192.168.46.0/25192.168.46.1 to 192.168.46.126192.168.46.127126
94192.168.46.128/25192.168.46.129 to 192.168.46.254192.168.46.255126
95192.168.47.0/25192.168.47.1 to 192.168.47.126192.168.47.127126
96192.168.47.128/25192.168.47.129 to 192.168.47.254192.168.47.255126
97192.168.48.0/25192.168.48.1 to 192.168.48.126192.168.48.127126
98192.168.48.128/25192.168.48.129 to 192.168.48.254192.168.48.255126
99192.168.49.0/25192.168.49.1 to 192.168.49.126192.168.49.127126
100192.168.49.128/25192.168.49.129 to 192.168.49.254192.168.49.255126
101192.168.50.0/25192.168.50.1 to 192.168.50.126192.168.50.127126
102192.168.50.128/25192.168.50.129 to 192.168.50.254192.168.50.255126
103192.168.51.0/25192.168.51.1 to 192.168.51.126192.168.51.127126
104192.168.51.128/25192.168.51.129 to 192.168.51.254192.168.51.255126
105192.168.52.0/25192.168.52.1 to 192.168.52.126192.168.52.127126
106192.168.52.128/25192.168.52.129 to 192.168.52.254192.168.52.255126
107192.168.53.0/25192.168.53.1 to 192.168.53.126192.168.53.127126
108192.168.53.128/25192.168.53.129 to 192.168.53.254192.168.53.255126
109192.168.54.0/25192.168.54.1 to 192.168.54.126192.168.54.127126
110192.168.54.128/25192.168.54.129 to 192.168.54.254192.168.54.255126
111192.168.55.0/25192.168.55.1 to 192.168.55.126192.168.55.127126
112192.168.55.128/25192.168.55.129 to 192.168.55.254192.168.55.255126
113192.168.56.0/25192.168.56.1 to 192.168.56.126192.168.56.127126
114192.168.56.128/25192.168.56.129 to 192.168.56.254192.168.56.255126
115192.168.57.0/25192.168.57.1 to 192.168.57.126192.168.57.127126
116192.168.57.128/25192.168.57.129 to 192.168.57.254192.168.57.255126
117192.168.58.0/25192.168.58.1 to 192.168.58.126192.168.58.127126
118192.168.58.128/25192.168.58.129 to 192.168.58.254192.168.58.255126
119192.168.59.0/25192.168.59.1 to 192.168.59.126192.168.59.127126
120192.168.59.128/25192.168.59.129 to 192.168.59.254192.168.59.255126
121192.168.60.0/25192.168.60.1 to 192.168.60.126192.168.60.127126
122192.168.60.128/25192.168.60.129 to 192.168.60.254192.168.60.255126
123192.168.61.0/25192.168.61.1 to 192.168.61.126192.168.61.127126
124192.168.61.128/25192.168.61.129 to 192.168.61.254192.168.61.255126
125192.168.62.0/25192.168.62.1 to 192.168.62.126192.168.62.127126
126192.168.62.128/25192.168.62.129 to 192.168.62.254192.168.62.255126
127192.168.63.0/25192.168.63.1 to 192.168.63.126192.168.63.127126
128192.168.63.128/25192.168.63.129 to 192.168.63.254192.168.63.255126
129192.168.64.0/25192.168.64.1 to 192.168.64.126192.168.64.127126
130192.168.64.128/25192.168.64.129 to 192.168.64.254192.168.64.255126
131192.168.65.0/25192.168.65.1 to 192.168.65.126192.168.65.127126
132192.168.65.128/25192.168.65.129 to 192.168.65.254192.168.65.255126
133192.168.66.0/25192.168.66.1 to 192.168.66.126192.168.66.127126
134192.168.66.128/25192.168.66.129 to 192.168.66.254192.168.66.255126
135192.168.67.0/25192.168.67.1 to 192.168.67.126192.168.67.127126
136192.168.67.128/25192.168.67.129 to 192.168.67.254192.168.67.255126
137192.168.68.0/25192.168.68.1 to 192.168.68.126192.168.68.127126
138192.168.68.128/25192.168.68.129 to 192.168.68.254192.168.68.255126
139192.168.69.0/25192.168.69.1 to 192.168.69.126192.168.69.127126
140192.168.69.128/25192.168.69.129 to 192.168.69.254192.168.69.255126
141192.168.70.0/25192.168.70.1 to 192.168.70.126192.168.70.127126
142192.168.70.128/25192.168.70.129 to 192.168.70.254192.168.70.255126
143192.168.71.0/25192.168.71.1 to 192.168.71.126192.168.71.127126
144192.168.71.128/25192.168.71.129 to 192.168.71.254192.168.71.255126
145192.168.72.0/25192.168.72.1 to 192.168.72.126192.168.72.127126
146192.168.72.128/25192.168.72.129 to 192.168.72.254192.168.72.255126
147192.168.73.0/25192.168.73.1 to 192.168.73.126192.168.73.127126
148192.168.73.128/25192.168.73.129 to 192.168.73.254192.168.73.255126
149192.168.74.0/25192.168.74.1 to 192.168.74.126192.168.74.127126
150192.168.74.128/25192.168.74.129 to 192.168.74.254192.168.74.255126
151192.168.75.0/25192.168.75.1 to 192.168.75.126192.168.75.127126
152192.168.75.128/25192.168.75.129 to 192.168.75.254192.168.75.255126
153192.168.76.0/25192.168.76.1 to 192.168.76.126192.168.76.127126
154192.168.76.128/25192.168.76.129 to 192.168.76.254192.168.76.255126
155192.168.77.0/25192.168.77.1 to 192.168.77.126192.168.77.127126
156192.168.77.128/25192.168.77.129 to 192.168.77.254192.168.77.255126
157192.168.78.0/25192.168.78.1 to 192.168.78.126192.168.78.127126
158192.168.78.128/25192.168.78.129 to 192.168.78.254192.168.78.255126
159192.168.79.0/25192.168.79.1 to 192.168.79.126192.168.79.127126
160192.168.79.128/25192.168.79.129 to 192.168.79.254192.168.79.255126
161192.168.80.0/25192.168.80.1 to 192.168.80.126192.168.80.127126
162192.168.80.128/25192.168.80.129 to 192.168.80.254192.168.80.255126
163192.168.81.0/25192.168.81.1 to 192.168.81.126192.168.81.127126
164192.168.81.128/25192.168.81.129 to 192.168.81.254192.168.81.255126
165192.168.82.0/25192.168.82.1 to 192.168.82.126192.168.82.127126
166192.168.82.128/25192.168.82.129 to 192.168.82.254192.168.82.255126
167192.168.83.0/25192.168.83.1 to 192.168.83.126192.168.83.127126
168192.168.83.128/25192.168.83.129 to 192.168.83.254192.168.83.255126
169192.168.84.0/25192.168.84.1 to 192.168.84.126192.168.84.127126
170192.168.84.128/25192.168.84.129 to 192.168.84.254192.168.84.255126
171192.168.85.0/25192.168.85.1 to 192.168.85.126192.168.85.127126
172192.168.85.128/25192.168.85.129 to 192.168.85.254192.168.85.255126
173192.168.86.0/25192.168.86.1 to 192.168.86.126192.168.86.127126
174192.168.86.128/25192.168.86.129 to 192.168.86.254192.168.86.255126
175192.168.87.0/25192.168.87.1 to 192.168.87.126192.168.87.127126
176192.168.87.128/25192.168.87.129 to 192.168.87.254192.168.87.255126
177192.168.88.0/25192.168.88.1 to 192.168.88.126192.168.88.127126
178192.168.88.128/25192.168.88.129 to 192.168.88.254192.168.88.255126
179192.168.89.0/25192.168.89.1 to 192.168.89.126192.168.89.127126
180192.168.89.128/25192.168.89.129 to 192.168.89.254192.168.89.255126
181192.168.90.0/25192.168.90.1 to 192.168.90.126192.168.90.127126
182192.168.90.128/25192.168.90.129 to 192.168.90.254192.168.90.255126
183192.168.91.0/25192.168.91.1 to 192.168.91.126192.168.91.127126
184192.168.91.128/25192.168.91.129 to 192.168.91.254192.168.91.255126
185192.168.92.0/25192.168.92.1 to 192.168.92.126192.168.92.127126
186192.168.92.128/25192.168.92.129 to 192.168.92.254192.168.92.255126
187192.168.93.0/25192.168.93.1 to 192.168.93.126192.168.93.127126
188192.168.93.128/25192.168.93.129 to 192.168.93.254192.168.93.255126
189192.168.94.0/25192.168.94.1 to 192.168.94.126192.168.94.127126
190192.168.94.128/25192.168.94.129 to 192.168.94.254192.168.94.255126
191192.168.95.0/25192.168.95.1 to 192.168.95.126192.168.95.127126
192192.168.95.128/25192.168.95.129 to 192.168.95.254192.168.95.255126
193192.168.96.0/25192.168.96.1 to 192.168.96.126192.168.96.127126
194192.168.96.128/25192.168.96.129 to 192.168.96.254192.168.96.255126
195192.168.97.0/25192.168.97.1 to 192.168.97.126192.168.97.127126
196192.168.97.128/25192.168.97.129 to 192.168.97.254192.168.97.255126
197192.168.98.0/25192.168.98.1 to 192.168.98.126192.168.98.127126
198192.168.98.128/25192.168.98.129 to 192.168.98.254192.168.98.255126
199192.168.99.0/25192.168.99.1 to 192.168.99.126192.168.99.127126
200192.168.99.128/25192.168.99.129 to 192.168.99.254192.168.99.255126
201192.168.100.0/25192.168.100.1 to 192.168.100.126192.168.100.127126
202192.168.100.128/25192.168.100.129 to 192.168.100.254192.168.100.255126
203192.168.101.0/25192.168.101.1 to 192.168.101.126192.168.101.127126
204192.168.101.128/25192.168.101.129 to 192.168.101.254192.168.101.255126
205192.168.102.0/25192.168.102.1 to 192.168.102.126192.168.102.127126
206192.168.102.128/25192.168.102.129 to 192.168.102.254192.168.102.255126
207192.168.103.0/25192.168.103.1 to 192.168.103.126192.168.103.127126
208192.168.103.128/25192.168.103.129 to 192.168.103.254192.168.103.255126
209192.168.104.0/25192.168.104.1 to 192.168.104.126192.168.104.127126
210192.168.104.128/25192.168.104.129 to 192.168.104.254192.168.104.255126
211192.168.105.0/25192.168.105.1 to 192.168.105.126192.168.105.127126
212192.168.105.128/25192.168.105.129 to 192.168.105.254192.168.105.255126
213192.168.106.0/25192.168.106.1 to 192.168.106.126192.168.106.127126
214192.168.106.128/25192.168.106.129 to 192.168.106.254192.168.106.255126
215192.168.107.0/25192.168.107.1 to 192.168.107.126192.168.107.127126
216192.168.107.128/25192.168.107.129 to 192.168.107.254192.168.107.255126
217192.168.108.0/25192.168.108.1 to 192.168.108.126192.168.108.127126
218192.168.108.128/25192.168.108.129 to 192.168.108.254192.168.108.255126
219192.168.109.0/25192.168.109.1 to 192.168.109.126192.168.109.127126
220192.168.109.128/25192.168.109.129 to 192.168.109.254192.168.109.255126
221192.168.110.0/25192.168.110.1 to 192.168.110.126192.168.110.127126
222192.168.110.128/25192.168.110.129 to 192.168.110.254192.168.110.255126
223192.168.111.0/25192.168.111.1 to 192.168.111.126192.168.111.127126
224192.168.111.128/25192.168.111.129 to 192.168.111.254192.168.111.255126
225192.168.112.0/25192.168.112.1 to 192.168.112.126192.168.112.127126
226192.168.112.128/25192.168.112.129 to 192.168.112.254192.168.112.255126
227192.168.113.0/25192.168.113.1 to 192.168.113.126192.168.113.127126
228192.168.113.128/25192.168.113.129 to 192.168.113.254192.168.113.255126
229192.168.114.0/25192.168.114.1 to 192.168.114.126192.168.114.127126
230192.168.114.128/25192.168.114.129 to 192.168.114.254192.168.114.255126
231192.168.115.0/25192.168.115.1 to 192.168.115.126192.168.115.127126
232192.168.115.128/25192.168.115.129 to 192.168.115.254192.168.115.255126
233192.168.116.0/25192.168.116.1 to 192.168.116.126192.168.116.127126
234192.168.116.128/25192.168.116.129 to 192.168.116.254192.168.116.255126
235192.168.117.0/25192.168.117.1 to 192.168.117.126192.168.117.127126
236192.168.117.128/25192.168.117.129 to 192.168.117.254192.168.117.255126
237192.168.118.0/25192.168.118.1 to 192.168.118.126192.168.118.127126
238192.168.118.128/25192.168.118.129 to 192.168.118.254192.168.118.255126
239192.168.119.0/25192.168.119.1 to 192.168.119.126192.168.119.127126
240192.168.119.128/25192.168.119.129 to 192.168.119.254192.168.119.255126
241192.168.120.0/25192.168.120.1 to 192.168.120.126192.168.120.127126
242192.168.120.128/25192.168.120.129 to 192.168.120.254192.168.120.255126
243192.168.121.0/25192.168.121.1 to 192.168.121.126192.168.121.127126
244192.168.121.128/25192.168.121.129 to 192.168.121.254192.168.121.255126
245192.168.122.0/25192.168.122.1 to 192.168.122.126192.168.122.127126
246192.168.122.128/25192.168.122.129 to 192.168.122.254192.168.122.255126
247192.168.123.0/25192.168.123.1 to 192.168.123.126192.168.123.127126
248192.168.123.128/25192.168.123.129 to 192.168.123.254192.168.123.255126
249192.168.124.0/25192.168.124.1 to 192.168.124.126192.168.124.127126
250192.168.124.128/25192.168.124.129 to 192.168.124.254192.168.124.255126
251192.168.125.0/25192.168.125.1 to 192.168.125.126192.168.125.127126
252192.168.125.128/25192.168.125.129 to 192.168.125.254192.168.125.255126
253192.168.126.0/25192.168.126.1 to 192.168.126.126192.168.126.127126
254192.168.126.128/25192.168.126.129 to 192.168.126.254192.168.126.255126
255192.168.127.0/25192.168.127.1 to 192.168.127.126192.168.127.127126
256192.168.127.128/25192.168.127.129 to 192.168.127.254192.168.127.255126

IPv4 CIDR reference (/0 to /32)

IPv4 prefix lengths
PrefixSubnet maskWildcardAddressesUsable hostsSizeTypical use
/00.0.0.0255.255.255.2554,294,967,2964,294,967,29416,777,216 × /24
/1128.0.0.0127.255.255.2552,147,483,6482,147,483,6468,388,608 × /24
/2192.0.0.063.255.255.2551,073,741,8241,073,741,8224,194,304 × /24
/3224.0.0.031.255.255.255536,870,912536,870,9102,097,152 × /24
/4240.0.0.015.255.255.255268,435,456268,435,4541,048,576 × /24
/5248.0.0.07.255.255.255134,217,728134,217,726524,288 × /24
/6252.0.0.03.255.255.25567,108,86467,108,862262,144 × /24
/7254.0.0.01.255.255.25533,554,43233,554,430131,072 × /24
/8255.0.0.00.255.255.25516,777,21616,777,21465,536 × /24Old class A; 10.0.0.0/8
/9255.128.0.00.127.255.2558,388,6088,388,60632,768 × /24
/10255.192.0.00.63.255.2554,194,3044,194,30216,384 × /24
/11255.224.0.00.31.255.2552,097,1522,097,1508,192 × /24
/12255.240.0.00.15.255.2551,048,5761,048,5744,096 × /24172.16.0.0/12
/13255.248.0.00.7.255.255524,288524,2862,048 × /24
/14255.252.0.00.3.255.255262,144262,1421,024 × /24
/15255.254.0.00.1.255.255131,072131,070512 × /24
/16255.255.0.00.0.255.25565,53665,534256 × /24Old class B; 192.168.0.0/16
/17255.255.128.00.0.127.25532,76832,766128 × /24
/18255.255.192.00.0.63.25516,38416,38264 × /24
/19255.255.224.00.0.31.2558,1928,19032 × /24
/20255.255.240.00.0.15.2554,0964,09416 × /24
/21255.255.248.00.0.7.2552,0482,0468 × /24
/22255.255.252.00.0.3.2551,0241,0224 × /24Large office or guest Wi-Fi (1,022 hosts)
/23255.255.254.00.0.1.2555125102 × /24Larger office LAN (510 hosts)
/24255.255.255.00.0.0.2552562541 × /24Typical office LAN (old class C)
/25255.255.255.1280.0.0.1271281261/2 of a /24Smaller LAN or VLAN
/26255.255.255.1920.0.0.6364621/4 of a /24Smaller LAN or VLAN
/27255.255.255.2240.0.0.3132301/8 of a /24Small VLAN, phones, cameras
/28255.255.255.2400.0.0.1516141/16 of a /24Small VLAN, phones, cameras
/29255.255.255.2480.0.0.7861/32 of a /24Small fixed public block (5 usable)
/30255.255.255.2520.0.0.3421/64 of a /24Point-to-point (old style)
/31255.255.255.2540.0.0.1221/128 of a /24Point-to-point link (RFC 3021)
/32255.255.255.2550.0.0.0111/256 of a /24One host

IPv6 prefix reference

IPv6 prefix lengths
PrefixAddresses/64 LANs/48 sitesNibbleTypical use
/342,535,295,865,117,307,932,921,825,928,971,026,432 (2^125)2,305,843,009,213,693,95235,184,372,088,832NoAll global unicast (2000::/3)
/165,192,296,858,534,827,628,530,496,329,220,096 (2^112)281,474,976,710,6564,294,967,296Yes
/20324,518,553,658,426,726,783,156,020,576,256 (2^108)17,592,186,044,416268,435,456YesLarge provider allocation (RIPE minimum for some)
/29633,825,300,114,114,700,748,351,602,688 (2^99)34,359,738,368524,288NoRIPE allocation to a provider (often)
/3279,228,162,514,264,337,593,543,950,336 (2^96)4,294,967,29665,536YesProvider allocation (RIPE default)
/364,951,760,157,141,521,099,596,496,896 (2^92)268,435,4564,096Yes
/40309,485,009,821,345,068,724,781,056 (2^88)16,777,216256Yes
/4419,342,813,113,834,066,795,298,816 (2^84)1,048,57616Yes
/481,208,925,819,614,629,174,706,176 (2^80)65,5361YesOne site or organisation (RIPE PI / assignment)
/5275,557,863,725,914,323,419,136 (2^76)4,096Yes
/564,722,366,482,869,645,213,696 (2^72)256YesSmall site or home (common provider assignment)
/60295,147,905,179,352,825,856 (2^68)16YesSome home broadband (16 LANs)
/6418,446,744,073,709,551,616 (2^64)1YesOne LAN or VLAN (needed for SLAAC)
/7272,057,594,037,927,936 (2^56)1/256 of a /64Yes
/80281,474,976,710,656 (2^48)1/65,536 of a /64Yes
/964,294,967,2961/4,294,967,296 of a /64YesEmbeds an IPv4 address (NAT64)
/11265,5361/281,474,976,710,656 of a /64Yes
/1202561/72,057,594,037,927,936 of a /64Yes
/124161/1,152,921,504,606,846,976 of a /64Yes
/12641/4,611,686,018,427,387,904 of a /64No
/12721/9,223,372,036,854,775,808 of a /64NoPoint-to-point link (RFC 6164)
/12811/18,446,744,073,709,551,616 of a /64YesOne host or loopback

Private and special ranges

IPv4

Special-purpose ranges
RangeNameWhat it is
255.255.255.255/32Limited broadcastEvery host on the local network
0.0.0.0/8This networkNot routed; 0.0.0.0 means "any address" in settings
10.0.0.0/8Private (RFC 1918)Office and home networks; not routed on the internet
100.64.0.0/10Shared address space (CGNAT)Used by providers behind carrier-grade NAT (RFC 6598)
127.0.0.0/8LoopbackThis computer
169.254.0.0/16Link-local (APIPA)Self-assigned when no DHCP server answers
172.16.0.0/12Private (RFC 1918)Office and home networks; not routed on the internet
192.0.0.0/24IETF protocol assignmentsSpecial uses such as DS-Lite
192.0.2.0/24Documentation (TEST-NET-1)For examples; never used on a network
192.88.99.0/246to4 relay (deprecated)Formerly anycast for 6to4
192.168.0.0/16Private (RFC 1918)Office and home networks; not routed on the internet
198.18.0.0/15BenchmarkingNetwork equipment testing (RFC 2544)
198.51.100.0/24Documentation (TEST-NET-2)For examples; never used on a network
203.0.113.0/24Documentation (TEST-NET-3)For examples; never used on a network
224.0.0.0/4MulticastOne-to-many traffic, such as IPTV and routing protocols
240.0.0.0/4ReservedFuture use; not usable on most systems

IPv6

Special-purpose ranges
RangeNameWhat it is
::/128UnspecifiedNo address; :: means "any address" in settings
::1/128LoopbackThis computer
::ffff:0:0/96IPv4-mappedAn IPv4 address written as IPv6
64:ff9b::/96NAT64IPv4 addresses reached through a NAT64 gateway
100::/64Discard onlyTraffic sent here is dropped (RFC 6666)
2001:db8::/32DocumentationFor examples; never used on a network
2001::/32TeredoIPv6 tunnelled over IPv4 UDP
2002::/166to4IPv6 tunnelled over IPv4 (largely retired)
3fff::/20DocumentationFor examples (RFC 9637)
fc00::/7Unique local (ULA)Private IPv6, like RFC 1918; usually fd00::/8
fe80::/10Link-localEvery IPv6 interface has one; not routed
ff00::/8MulticastOne-to-many traffic; replaces broadcast
2000::/3Global unicastPublic internet addresses

About this tool

A network is written as an address and a prefix length, such as 192.168.1.0/24: the first 24 bits name the network and the rest number the devices on it. The calculator works out where the network starts and ends, how many devices it holds, its subnet and wildcard masks, and the reverse DNS zone to ask your provider for.

It also splits a network into equal smaller ones (one per VLAN or site), turns a range of addresses into the fewest CIDR blocks for a firewall rule, and lists every IPv4 prefix length and the common IPv6 ones in reference tables.

Common questions

Why are two addresses lost in every IPv4 subnet?

The first address names the network and the last is the broadcast address, so a /24 has 256 addresses but 254 for devices. A /31 (a link between two routers) and a /32 (one host) are the exceptions.

What size of IPv6 network should a LAN use?

Always /64. Devices pick their own address within it (SLAAC), which needs the full 64 bits. A site usually gets a /48 or /56 from its provider, which holds 65,536 or 256 LANs.

What is a wildcard mask?

The subnet mask turned inside out: 255.255.255.0 becomes 0.0.0.255. Cisco access lists and OSPF use it to say which bits must match.

Which ranges can I use inside an office?

IPv4: 10.0.0.0/8, 172.16.0.0/12 and 192.168.0.0/16. IPv6: unique local addresses from fd00::/8, though most networks use the public prefix from their provider.