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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.

Network170.0.0.0/8
Usable hosts16,777,214
Subnet mask255.0.0.0
Addresses16,777,216
Network address
170.0.0.0
Broadcast address
170.255.255.255
First usable
170.0.0.1
Last usable
170.255.255.254
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 AA000000 · Integer 2852126720 to 2868903935
Reverse DNS zone
170.in-addr.arpa
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address10101010..00000000.00000000.00000000170.0.0.0
Subnet mask11111111..00000000.00000000.00000000255.0.0.0
Network10101010..00000000.00000000.00000000170.0.0.0
Broadcast10101010..11111111.11111111.11111111170.255.255.255
Split into smaller subnets/17
/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)

170.0.0.0/8 makes 512 subnets of /17; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1170.0.0.0/17170.0.0.1 to 170.0.127.254170.0.127.25532,766
2170.0.128.0/17170.0.128.1 to 170.0.255.254170.0.255.25532,766
3170.1.0.0/17170.1.0.1 to 170.1.127.254170.1.127.25532,766
4170.1.128.0/17170.1.128.1 to 170.1.255.254170.1.255.25532,766
5170.2.0.0/17170.2.0.1 to 170.2.127.254170.2.127.25532,766
6170.2.128.0/17170.2.128.1 to 170.2.255.254170.2.255.25532,766
7170.3.0.0/17170.3.0.1 to 170.3.127.254170.3.127.25532,766
8170.3.128.0/17170.3.128.1 to 170.3.255.254170.3.255.25532,766
9170.4.0.0/17170.4.0.1 to 170.4.127.254170.4.127.25532,766
10170.4.128.0/17170.4.128.1 to 170.4.255.254170.4.255.25532,766
11170.5.0.0/17170.5.0.1 to 170.5.127.254170.5.127.25532,766
12170.5.128.0/17170.5.128.1 to 170.5.255.254170.5.255.25532,766
13170.6.0.0/17170.6.0.1 to 170.6.127.254170.6.127.25532,766
14170.6.128.0/17170.6.128.1 to 170.6.255.254170.6.255.25532,766
15170.7.0.0/17170.7.0.1 to 170.7.127.254170.7.127.25532,766
16170.7.128.0/17170.7.128.1 to 170.7.255.254170.7.255.25532,766
17170.8.0.0/17170.8.0.1 to 170.8.127.254170.8.127.25532,766
18170.8.128.0/17170.8.128.1 to 170.8.255.254170.8.255.25532,766
19170.9.0.0/17170.9.0.1 to 170.9.127.254170.9.127.25532,766
20170.9.128.0/17170.9.128.1 to 170.9.255.254170.9.255.25532,766
21170.10.0.0/17170.10.0.1 to 170.10.127.254170.10.127.25532,766
22170.10.128.0/17170.10.128.1 to 170.10.255.254170.10.255.25532,766
23170.11.0.0/17170.11.0.1 to 170.11.127.254170.11.127.25532,766
24170.11.128.0/17170.11.128.1 to 170.11.255.254170.11.255.25532,766
25170.12.0.0/17170.12.0.1 to 170.12.127.254170.12.127.25532,766
26170.12.128.0/17170.12.128.1 to 170.12.255.254170.12.255.25532,766
27170.13.0.0/17170.13.0.1 to 170.13.127.254170.13.127.25532,766
28170.13.128.0/17170.13.128.1 to 170.13.255.254170.13.255.25532,766
29170.14.0.0/17170.14.0.1 to 170.14.127.254170.14.127.25532,766
30170.14.128.0/17170.14.128.1 to 170.14.255.254170.14.255.25532,766
31170.15.0.0/17170.15.0.1 to 170.15.127.254170.15.127.25532,766
32170.15.128.0/17170.15.128.1 to 170.15.255.254170.15.255.25532,766
33170.16.0.0/17170.16.0.1 to 170.16.127.254170.16.127.25532,766
34170.16.128.0/17170.16.128.1 to 170.16.255.254170.16.255.25532,766
35170.17.0.0/17170.17.0.1 to 170.17.127.254170.17.127.25532,766
36170.17.128.0/17170.17.128.1 to 170.17.255.254170.17.255.25532,766
37170.18.0.0/17170.18.0.1 to 170.18.127.254170.18.127.25532,766
38170.18.128.0/17170.18.128.1 to 170.18.255.254170.18.255.25532,766
39170.19.0.0/17170.19.0.1 to 170.19.127.254170.19.127.25532,766
40170.19.128.0/17170.19.128.1 to 170.19.255.254170.19.255.25532,766
41170.20.0.0/17170.20.0.1 to 170.20.127.254170.20.127.25532,766
42170.20.128.0/17170.20.128.1 to 170.20.255.254170.20.255.25532,766
43170.21.0.0/17170.21.0.1 to 170.21.127.254170.21.127.25532,766
44170.21.128.0/17170.21.128.1 to 170.21.255.254170.21.255.25532,766
45170.22.0.0/17170.22.0.1 to 170.22.127.254170.22.127.25532,766
46170.22.128.0/17170.22.128.1 to 170.22.255.254170.22.255.25532,766
47170.23.0.0/17170.23.0.1 to 170.23.127.254170.23.127.25532,766
48170.23.128.0/17170.23.128.1 to 170.23.255.254170.23.255.25532,766
49170.24.0.0/17170.24.0.1 to 170.24.127.254170.24.127.25532,766
50170.24.128.0/17170.24.128.1 to 170.24.255.254170.24.255.25532,766
51170.25.0.0/17170.25.0.1 to 170.25.127.254170.25.127.25532,766
52170.25.128.0/17170.25.128.1 to 170.25.255.254170.25.255.25532,766
53170.26.0.0/17170.26.0.1 to 170.26.127.254170.26.127.25532,766
54170.26.128.0/17170.26.128.1 to 170.26.255.254170.26.255.25532,766
55170.27.0.0/17170.27.0.1 to 170.27.127.254170.27.127.25532,766
56170.27.128.0/17170.27.128.1 to 170.27.255.254170.27.255.25532,766
57170.28.0.0/17170.28.0.1 to 170.28.127.254170.28.127.25532,766
58170.28.128.0/17170.28.128.1 to 170.28.255.254170.28.255.25532,766
59170.29.0.0/17170.29.0.1 to 170.29.127.254170.29.127.25532,766
60170.29.128.0/17170.29.128.1 to 170.29.255.254170.29.255.25532,766
61170.30.0.0/17170.30.0.1 to 170.30.127.254170.30.127.25532,766
62170.30.128.0/17170.30.128.1 to 170.30.255.254170.30.255.25532,766
63170.31.0.0/17170.31.0.1 to 170.31.127.254170.31.127.25532,766
64170.31.128.0/17170.31.128.1 to 170.31.255.254170.31.255.25532,766
65170.32.0.0/17170.32.0.1 to 170.32.127.254170.32.127.25532,766
66170.32.128.0/17170.32.128.1 to 170.32.255.254170.32.255.25532,766
67170.33.0.0/17170.33.0.1 to 170.33.127.254170.33.127.25532,766
68170.33.128.0/17170.33.128.1 to 170.33.255.254170.33.255.25532,766
69170.34.0.0/17170.34.0.1 to 170.34.127.254170.34.127.25532,766
70170.34.128.0/17170.34.128.1 to 170.34.255.254170.34.255.25532,766
71170.35.0.0/17170.35.0.1 to 170.35.127.254170.35.127.25532,766
72170.35.128.0/17170.35.128.1 to 170.35.255.254170.35.255.25532,766
73170.36.0.0/17170.36.0.1 to 170.36.127.254170.36.127.25532,766
74170.36.128.0/17170.36.128.1 to 170.36.255.254170.36.255.25532,766
75170.37.0.0/17170.37.0.1 to 170.37.127.254170.37.127.25532,766
76170.37.128.0/17170.37.128.1 to 170.37.255.254170.37.255.25532,766
77170.38.0.0/17170.38.0.1 to 170.38.127.254170.38.127.25532,766
78170.38.128.0/17170.38.128.1 to 170.38.255.254170.38.255.25532,766
79170.39.0.0/17170.39.0.1 to 170.39.127.254170.39.127.25532,766
80170.39.128.0/17170.39.128.1 to 170.39.255.254170.39.255.25532,766
81170.40.0.0/17170.40.0.1 to 170.40.127.254170.40.127.25532,766
82170.40.128.0/17170.40.128.1 to 170.40.255.254170.40.255.25532,766
83170.41.0.0/17170.41.0.1 to 170.41.127.254170.41.127.25532,766
84170.41.128.0/17170.41.128.1 to 170.41.255.254170.41.255.25532,766
85170.42.0.0/17170.42.0.1 to 170.42.127.254170.42.127.25532,766
86170.42.128.0/17170.42.128.1 to 170.42.255.254170.42.255.25532,766
87170.43.0.0/17170.43.0.1 to 170.43.127.254170.43.127.25532,766
88170.43.128.0/17170.43.128.1 to 170.43.255.254170.43.255.25532,766
89170.44.0.0/17170.44.0.1 to 170.44.127.254170.44.127.25532,766
90170.44.128.0/17170.44.128.1 to 170.44.255.254170.44.255.25532,766
91170.45.0.0/17170.45.0.1 to 170.45.127.254170.45.127.25532,766
92170.45.128.0/17170.45.128.1 to 170.45.255.254170.45.255.25532,766
93170.46.0.0/17170.46.0.1 to 170.46.127.254170.46.127.25532,766
94170.46.128.0/17170.46.128.1 to 170.46.255.254170.46.255.25532,766
95170.47.0.0/17170.47.0.1 to 170.47.127.254170.47.127.25532,766
96170.47.128.0/17170.47.128.1 to 170.47.255.254170.47.255.25532,766
97170.48.0.0/17170.48.0.1 to 170.48.127.254170.48.127.25532,766
98170.48.128.0/17170.48.128.1 to 170.48.255.254170.48.255.25532,766
99170.49.0.0/17170.49.0.1 to 170.49.127.254170.49.127.25532,766
100170.49.128.0/17170.49.128.1 to 170.49.255.254170.49.255.25532,766
101170.50.0.0/17170.50.0.1 to 170.50.127.254170.50.127.25532,766
102170.50.128.0/17170.50.128.1 to 170.50.255.254170.50.255.25532,766
103170.51.0.0/17170.51.0.1 to 170.51.127.254170.51.127.25532,766
104170.51.128.0/17170.51.128.1 to 170.51.255.254170.51.255.25532,766
105170.52.0.0/17170.52.0.1 to 170.52.127.254170.52.127.25532,766
106170.52.128.0/17170.52.128.1 to 170.52.255.254170.52.255.25532,766
107170.53.0.0/17170.53.0.1 to 170.53.127.254170.53.127.25532,766
108170.53.128.0/17170.53.128.1 to 170.53.255.254170.53.255.25532,766
109170.54.0.0/17170.54.0.1 to 170.54.127.254170.54.127.25532,766
110170.54.128.0/17170.54.128.1 to 170.54.255.254170.54.255.25532,766
111170.55.0.0/17170.55.0.1 to 170.55.127.254170.55.127.25532,766
112170.55.128.0/17170.55.128.1 to 170.55.255.254170.55.255.25532,766
113170.56.0.0/17170.56.0.1 to 170.56.127.254170.56.127.25532,766
114170.56.128.0/17170.56.128.1 to 170.56.255.254170.56.255.25532,766
115170.57.0.0/17170.57.0.1 to 170.57.127.254170.57.127.25532,766
116170.57.128.0/17170.57.128.1 to 170.57.255.254170.57.255.25532,766
117170.58.0.0/17170.58.0.1 to 170.58.127.254170.58.127.25532,766
118170.58.128.0/17170.58.128.1 to 170.58.255.254170.58.255.25532,766
119170.59.0.0/17170.59.0.1 to 170.59.127.254170.59.127.25532,766
120170.59.128.0/17170.59.128.1 to 170.59.255.254170.59.255.25532,766
121170.60.0.0/17170.60.0.1 to 170.60.127.254170.60.127.25532,766
122170.60.128.0/17170.60.128.1 to 170.60.255.254170.60.255.25532,766
123170.61.0.0/17170.61.0.1 to 170.61.127.254170.61.127.25532,766
124170.61.128.0/17170.61.128.1 to 170.61.255.254170.61.255.25532,766
125170.62.0.0/17170.62.0.1 to 170.62.127.254170.62.127.25532,766
126170.62.128.0/17170.62.128.1 to 170.62.255.254170.62.255.25532,766
127170.63.0.0/17170.63.0.1 to 170.63.127.254170.63.127.25532,766
128170.63.128.0/17170.63.128.1 to 170.63.255.254170.63.255.25532,766
129170.64.0.0/17170.64.0.1 to 170.64.127.254170.64.127.25532,766
130170.64.128.0/17170.64.128.1 to 170.64.255.254170.64.255.25532,766
131170.65.0.0/17170.65.0.1 to 170.65.127.254170.65.127.25532,766
132170.65.128.0/17170.65.128.1 to 170.65.255.254170.65.255.25532,766
133170.66.0.0/17170.66.0.1 to 170.66.127.254170.66.127.25532,766
134170.66.128.0/17170.66.128.1 to 170.66.255.254170.66.255.25532,766
135170.67.0.0/17170.67.0.1 to 170.67.127.254170.67.127.25532,766
136170.67.128.0/17170.67.128.1 to 170.67.255.254170.67.255.25532,766
137170.68.0.0/17170.68.0.1 to 170.68.127.254170.68.127.25532,766
138170.68.128.0/17170.68.128.1 to 170.68.255.254170.68.255.25532,766
139170.69.0.0/17170.69.0.1 to 170.69.127.254170.69.127.25532,766
140170.69.128.0/17170.69.128.1 to 170.69.255.254170.69.255.25532,766
141170.70.0.0/17170.70.0.1 to 170.70.127.254170.70.127.25532,766
142170.70.128.0/17170.70.128.1 to 170.70.255.254170.70.255.25532,766
143170.71.0.0/17170.71.0.1 to 170.71.127.254170.71.127.25532,766
144170.71.128.0/17170.71.128.1 to 170.71.255.254170.71.255.25532,766
145170.72.0.0/17170.72.0.1 to 170.72.127.254170.72.127.25532,766
146170.72.128.0/17170.72.128.1 to 170.72.255.254170.72.255.25532,766
147170.73.0.0/17170.73.0.1 to 170.73.127.254170.73.127.25532,766
148170.73.128.0/17170.73.128.1 to 170.73.255.254170.73.255.25532,766
149170.74.0.0/17170.74.0.1 to 170.74.127.254170.74.127.25532,766
150170.74.128.0/17170.74.128.1 to 170.74.255.254170.74.255.25532,766
151170.75.0.0/17170.75.0.1 to 170.75.127.254170.75.127.25532,766
152170.75.128.0/17170.75.128.1 to 170.75.255.254170.75.255.25532,766
153170.76.0.0/17170.76.0.1 to 170.76.127.254170.76.127.25532,766
154170.76.128.0/17170.76.128.1 to 170.76.255.254170.76.255.25532,766
155170.77.0.0/17170.77.0.1 to 170.77.127.254170.77.127.25532,766
156170.77.128.0/17170.77.128.1 to 170.77.255.254170.77.255.25532,766
157170.78.0.0/17170.78.0.1 to 170.78.127.254170.78.127.25532,766
158170.78.128.0/17170.78.128.1 to 170.78.255.254170.78.255.25532,766
159170.79.0.0/17170.79.0.1 to 170.79.127.254170.79.127.25532,766
160170.79.128.0/17170.79.128.1 to 170.79.255.254170.79.255.25532,766
161170.80.0.0/17170.80.0.1 to 170.80.127.254170.80.127.25532,766
162170.80.128.0/17170.80.128.1 to 170.80.255.254170.80.255.25532,766
163170.81.0.0/17170.81.0.1 to 170.81.127.254170.81.127.25532,766
164170.81.128.0/17170.81.128.1 to 170.81.255.254170.81.255.25532,766
165170.82.0.0/17170.82.0.1 to 170.82.127.254170.82.127.25532,766
166170.82.128.0/17170.82.128.1 to 170.82.255.254170.82.255.25532,766
167170.83.0.0/17170.83.0.1 to 170.83.127.254170.83.127.25532,766
168170.83.128.0/17170.83.128.1 to 170.83.255.254170.83.255.25532,766
169170.84.0.0/17170.84.0.1 to 170.84.127.254170.84.127.25532,766
170170.84.128.0/17170.84.128.1 to 170.84.255.254170.84.255.25532,766
171170.85.0.0/17170.85.0.1 to 170.85.127.254170.85.127.25532,766
172170.85.128.0/17170.85.128.1 to 170.85.255.254170.85.255.25532,766
173170.86.0.0/17170.86.0.1 to 170.86.127.254170.86.127.25532,766
174170.86.128.0/17170.86.128.1 to 170.86.255.254170.86.255.25532,766
175170.87.0.0/17170.87.0.1 to 170.87.127.254170.87.127.25532,766
176170.87.128.0/17170.87.128.1 to 170.87.255.254170.87.255.25532,766
177170.88.0.0/17170.88.0.1 to 170.88.127.254170.88.127.25532,766
178170.88.128.0/17170.88.128.1 to 170.88.255.254170.88.255.25532,766
179170.89.0.0/17170.89.0.1 to 170.89.127.254170.89.127.25532,766
180170.89.128.0/17170.89.128.1 to 170.89.255.254170.89.255.25532,766
181170.90.0.0/17170.90.0.1 to 170.90.127.254170.90.127.25532,766
182170.90.128.0/17170.90.128.1 to 170.90.255.254170.90.255.25532,766
183170.91.0.0/17170.91.0.1 to 170.91.127.254170.91.127.25532,766
184170.91.128.0/17170.91.128.1 to 170.91.255.254170.91.255.25532,766
185170.92.0.0/17170.92.0.1 to 170.92.127.254170.92.127.25532,766
186170.92.128.0/17170.92.128.1 to 170.92.255.254170.92.255.25532,766
187170.93.0.0/17170.93.0.1 to 170.93.127.254170.93.127.25532,766
188170.93.128.0/17170.93.128.1 to 170.93.255.254170.93.255.25532,766
189170.94.0.0/17170.94.0.1 to 170.94.127.254170.94.127.25532,766
190170.94.128.0/17170.94.128.1 to 170.94.255.254170.94.255.25532,766
191170.95.0.0/17170.95.0.1 to 170.95.127.254170.95.127.25532,766
192170.95.128.0/17170.95.128.1 to 170.95.255.254170.95.255.25532,766
193170.96.0.0/17170.96.0.1 to 170.96.127.254170.96.127.25532,766
194170.96.128.0/17170.96.128.1 to 170.96.255.254170.96.255.25532,766
195170.97.0.0/17170.97.0.1 to 170.97.127.254170.97.127.25532,766
196170.97.128.0/17170.97.128.1 to 170.97.255.254170.97.255.25532,766
197170.98.0.0/17170.98.0.1 to 170.98.127.254170.98.127.25532,766
198170.98.128.0/17170.98.128.1 to 170.98.255.254170.98.255.25532,766
199170.99.0.0/17170.99.0.1 to 170.99.127.254170.99.127.25532,766
200170.99.128.0/17170.99.128.1 to 170.99.255.254170.99.255.25532,766
201170.100.0.0/17170.100.0.1 to 170.100.127.254170.100.127.25532,766
202170.100.128.0/17170.100.128.1 to 170.100.255.254170.100.255.25532,766
203170.101.0.0/17170.101.0.1 to 170.101.127.254170.101.127.25532,766
204170.101.128.0/17170.101.128.1 to 170.101.255.254170.101.255.25532,766
205170.102.0.0/17170.102.0.1 to 170.102.127.254170.102.127.25532,766
206170.102.128.0/17170.102.128.1 to 170.102.255.254170.102.255.25532,766
207170.103.0.0/17170.103.0.1 to 170.103.127.254170.103.127.25532,766
208170.103.128.0/17170.103.128.1 to 170.103.255.254170.103.255.25532,766
209170.104.0.0/17170.104.0.1 to 170.104.127.254170.104.127.25532,766
210170.104.128.0/17170.104.128.1 to 170.104.255.254170.104.255.25532,766
211170.105.0.0/17170.105.0.1 to 170.105.127.254170.105.127.25532,766
212170.105.128.0/17170.105.128.1 to 170.105.255.254170.105.255.25532,766
213170.106.0.0/17170.106.0.1 to 170.106.127.254170.106.127.25532,766
214170.106.128.0/17170.106.128.1 to 170.106.255.254170.106.255.25532,766
215170.107.0.0/17170.107.0.1 to 170.107.127.254170.107.127.25532,766
216170.107.128.0/17170.107.128.1 to 170.107.255.254170.107.255.25532,766
217170.108.0.0/17170.108.0.1 to 170.108.127.254170.108.127.25532,766
218170.108.128.0/17170.108.128.1 to 170.108.255.254170.108.255.25532,766
219170.109.0.0/17170.109.0.1 to 170.109.127.254170.109.127.25532,766
220170.109.128.0/17170.109.128.1 to 170.109.255.254170.109.255.25532,766
221170.110.0.0/17170.110.0.1 to 170.110.127.254170.110.127.25532,766
222170.110.128.0/17170.110.128.1 to 170.110.255.254170.110.255.25532,766
223170.111.0.0/17170.111.0.1 to 170.111.127.254170.111.127.25532,766
224170.111.128.0/17170.111.128.1 to 170.111.255.254170.111.255.25532,766
225170.112.0.0/17170.112.0.1 to 170.112.127.254170.112.127.25532,766
226170.112.128.0/17170.112.128.1 to 170.112.255.254170.112.255.25532,766
227170.113.0.0/17170.113.0.1 to 170.113.127.254170.113.127.25532,766
228170.113.128.0/17170.113.128.1 to 170.113.255.254170.113.255.25532,766
229170.114.0.0/17170.114.0.1 to 170.114.127.254170.114.127.25532,766
230170.114.128.0/17170.114.128.1 to 170.114.255.254170.114.255.25532,766
231170.115.0.0/17170.115.0.1 to 170.115.127.254170.115.127.25532,766
232170.115.128.0/17170.115.128.1 to 170.115.255.254170.115.255.25532,766
233170.116.0.0/17170.116.0.1 to 170.116.127.254170.116.127.25532,766
234170.116.128.0/17170.116.128.1 to 170.116.255.254170.116.255.25532,766
235170.117.0.0/17170.117.0.1 to 170.117.127.254170.117.127.25532,766
236170.117.128.0/17170.117.128.1 to 170.117.255.254170.117.255.25532,766
237170.118.0.0/17170.118.0.1 to 170.118.127.254170.118.127.25532,766
238170.118.128.0/17170.118.128.1 to 170.118.255.254170.118.255.25532,766
239170.119.0.0/17170.119.0.1 to 170.119.127.254170.119.127.25532,766
240170.119.128.0/17170.119.128.1 to 170.119.255.254170.119.255.25532,766
241170.120.0.0/17170.120.0.1 to 170.120.127.254170.120.127.25532,766
242170.120.128.0/17170.120.128.1 to 170.120.255.254170.120.255.25532,766
243170.121.0.0/17170.121.0.1 to 170.121.127.254170.121.127.25532,766
244170.121.128.0/17170.121.128.1 to 170.121.255.254170.121.255.25532,766
245170.122.0.0/17170.122.0.1 to 170.122.127.254170.122.127.25532,766
246170.122.128.0/17170.122.128.1 to 170.122.255.254170.122.255.25532,766
247170.123.0.0/17170.123.0.1 to 170.123.127.254170.123.127.25532,766
248170.123.128.0/17170.123.128.1 to 170.123.255.254170.123.255.25532,766
249170.124.0.0/17170.124.0.1 to 170.124.127.254170.124.127.25532,766
250170.124.128.0/17170.124.128.1 to 170.124.255.254170.124.255.25532,766
251170.125.0.0/17170.125.0.1 to 170.125.127.254170.125.127.25532,766
252170.125.128.0/17170.125.128.1 to 170.125.255.254170.125.255.25532,766
253170.126.0.0/17170.126.0.1 to 170.126.127.254170.126.127.25532,766
254170.126.128.0/17170.126.128.1 to 170.126.255.254170.126.255.25532,766
255170.127.0.0/17170.127.0.1 to 170.127.127.254170.127.127.25532,766
256170.127.128.0/17170.127.128.1 to 170.127.255.254170.127.255.25532,766

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.