IPv4 Subnet Calculator

Enter an IP with a CIDR prefix or a subnet mask to see its network, broadcast, host range, and host count. You can also split the network into smaller subnets.

Try:192.168.1.10/24 10.0.0.0/8 172.16.5.4/20 203.0.113.9/29

IPv6 calculator →

private IP (RFC 1918)10.3.72.0/21

network10.3.72.0/21

broadcast10.3.79.255

first host10.3.72.1

last host10.3.79.254

subnet mask255.255.248.0

wildcard0.0.7.255

addresses2,048

usable hosts2,046

classA

ipcalc 10.3.72.0/21

address00001010.00000011.01001000.00000000

subnet mask11111111.11111111.11111000.00000000

network00001010.00000011.01001000.00000000

broadcast00001010.00000011.01001111.11111111

green = network part, grey = host part

hex0x0a034800

decimal167987200

reverse dns0.72.3.10.in-addr.arpa

ipv4-mapped::ffff:a03:4800

/21 split into /29 · 256 subnets

close ×

#	network	host range	broadcast
1	10.3.72.0/29	10.3.72.1 – 10.3.72.6	10.3.72.7
2	10.3.72.8/29	10.3.72.9 – 10.3.72.14	10.3.72.15
3	10.3.72.16/29	10.3.72.17 – 10.3.72.22	10.3.72.23
4	10.3.72.24/29	10.3.72.25 – 10.3.72.30	10.3.72.31
5	10.3.72.32/29	10.3.72.33 – 10.3.72.38	10.3.72.39
6	10.3.72.40/29	10.3.72.41 – 10.3.72.46	10.3.72.47
7	10.3.72.48/29	10.3.72.49 – 10.3.72.54	10.3.72.55
8	10.3.72.56/29	10.3.72.57 – 10.3.72.62	10.3.72.63
9	10.3.72.64/29	10.3.72.65 – 10.3.72.70	10.3.72.71
10	10.3.72.72/29	10.3.72.73 – 10.3.72.78	10.3.72.79
11	10.3.72.80/29	10.3.72.81 – 10.3.72.86	10.3.72.87
12	10.3.72.88/29	10.3.72.89 – 10.3.72.94	10.3.72.95
13	10.3.72.96/29	10.3.72.97 – 10.3.72.102	10.3.72.103
14	10.3.72.104/29	10.3.72.105 – 10.3.72.110	10.3.72.111
15	10.3.72.112/29	10.3.72.113 – 10.3.72.118	10.3.72.119
16	10.3.72.120/29	10.3.72.121 – 10.3.72.126	10.3.72.127
17	10.3.72.128/29	10.3.72.129 – 10.3.72.134	10.3.72.135
18	10.3.72.136/29	10.3.72.137 – 10.3.72.142	10.3.72.143
19	10.3.72.144/29	10.3.72.145 – 10.3.72.150	10.3.72.151
20	10.3.72.152/29	10.3.72.153 – 10.3.72.158	10.3.72.159
21	10.3.72.160/29	10.3.72.161 – 10.3.72.166	10.3.72.167
22	10.3.72.168/29	10.3.72.169 – 10.3.72.174	10.3.72.175
23	10.3.72.176/29	10.3.72.177 – 10.3.72.182	10.3.72.183
24	10.3.72.184/29	10.3.72.185 – 10.3.72.190	10.3.72.191
25	10.3.72.192/29	10.3.72.193 – 10.3.72.198	10.3.72.199
26	10.3.72.200/29	10.3.72.201 – 10.3.72.206	10.3.72.207
27	10.3.72.208/29	10.3.72.209 – 10.3.72.214	10.3.72.215
28	10.3.72.216/29	10.3.72.217 – 10.3.72.222	10.3.72.223
29	10.3.72.224/29	10.3.72.225 – 10.3.72.230	10.3.72.231
30	10.3.72.232/29	10.3.72.233 – 10.3.72.238	10.3.72.239
31	10.3.72.240/29	10.3.72.241 – 10.3.72.246	10.3.72.247
32	10.3.72.248/29	10.3.72.249 – 10.3.72.254	10.3.72.255
33	10.3.73.0/29	10.3.73.1 – 10.3.73.6	10.3.73.7
34	10.3.73.8/29	10.3.73.9 – 10.3.73.14	10.3.73.15
35	10.3.73.16/29	10.3.73.17 – 10.3.73.22	10.3.73.23
36	10.3.73.24/29	10.3.73.25 – 10.3.73.30	10.3.73.31
37	10.3.73.32/29	10.3.73.33 – 10.3.73.38	10.3.73.39
38	10.3.73.40/29	10.3.73.41 – 10.3.73.46	10.3.73.47
39	10.3.73.48/29	10.3.73.49 – 10.3.73.54	10.3.73.55
40	10.3.73.56/29	10.3.73.57 – 10.3.73.62	10.3.73.63
41	10.3.73.64/29	10.3.73.65 – 10.3.73.70	10.3.73.71
42	10.3.73.72/29	10.3.73.73 – 10.3.73.78	10.3.73.79
43	10.3.73.80/29	10.3.73.81 – 10.3.73.86	10.3.73.87
44	10.3.73.88/29	10.3.73.89 – 10.3.73.94	10.3.73.95
45	10.3.73.96/29	10.3.73.97 – 10.3.73.102	10.3.73.103
46	10.3.73.104/29	10.3.73.105 – 10.3.73.110	10.3.73.111
47	10.3.73.112/29	10.3.73.113 – 10.3.73.118	10.3.73.119
48	10.3.73.120/29	10.3.73.121 – 10.3.73.126	10.3.73.127
49	10.3.73.128/29	10.3.73.129 – 10.3.73.134	10.3.73.135
50	10.3.73.136/29	10.3.73.137 – 10.3.73.142	10.3.73.143
51	10.3.73.144/29	10.3.73.145 – 10.3.73.150	10.3.73.151
52	10.3.73.152/29	10.3.73.153 – 10.3.73.158	10.3.73.159
53	10.3.73.160/29	10.3.73.161 – 10.3.73.166	10.3.73.167
54	10.3.73.168/29	10.3.73.169 – 10.3.73.174	10.3.73.175
55	10.3.73.176/29	10.3.73.177 – 10.3.73.182	10.3.73.183
56	10.3.73.184/29	10.3.73.185 – 10.3.73.190	10.3.73.191
57	10.3.73.192/29	10.3.73.193 – 10.3.73.198	10.3.73.199
58	10.3.73.200/29	10.3.73.201 – 10.3.73.206	10.3.73.207
59	10.3.73.208/29	10.3.73.209 – 10.3.73.214	10.3.73.215
60	10.3.73.216/29	10.3.73.217 – 10.3.73.222	10.3.73.223
61	10.3.73.224/29	10.3.73.225 – 10.3.73.230	10.3.73.231
62	10.3.73.232/29	10.3.73.233 – 10.3.73.238	10.3.73.239
63	10.3.73.240/29	10.3.73.241 – 10.3.73.246	10.3.73.247
64	10.3.73.248/29	10.3.73.249 – 10.3.73.254	10.3.73.255
65	10.3.74.0/29	10.3.74.1 – 10.3.74.6	10.3.74.7
66	10.3.74.8/29	10.3.74.9 – 10.3.74.14	10.3.74.15
67	10.3.74.16/29	10.3.74.17 – 10.3.74.22	10.3.74.23
68	10.3.74.24/29	10.3.74.25 – 10.3.74.30	10.3.74.31
69	10.3.74.32/29	10.3.74.33 – 10.3.74.38	10.3.74.39
70	10.3.74.40/29	10.3.74.41 – 10.3.74.46	10.3.74.47
71	10.3.74.48/29	10.3.74.49 – 10.3.74.54	10.3.74.55
72	10.3.74.56/29	10.3.74.57 – 10.3.74.62	10.3.74.63
73	10.3.74.64/29	10.3.74.65 – 10.3.74.70	10.3.74.71
74	10.3.74.72/29	10.3.74.73 – 10.3.74.78	10.3.74.79
75	10.3.74.80/29	10.3.74.81 – 10.3.74.86	10.3.74.87
76	10.3.74.88/29	10.3.74.89 – 10.3.74.94	10.3.74.95
77	10.3.74.96/29	10.3.74.97 – 10.3.74.102	10.3.74.103
78	10.3.74.104/29	10.3.74.105 – 10.3.74.110	10.3.74.111
79	10.3.74.112/29	10.3.74.113 – 10.3.74.118	10.3.74.119
80	10.3.74.120/29	10.3.74.121 – 10.3.74.126	10.3.74.127
81	10.3.74.128/29	10.3.74.129 – 10.3.74.134	10.3.74.135
82	10.3.74.136/29	10.3.74.137 – 10.3.74.142	10.3.74.143
83	10.3.74.144/29	10.3.74.145 – 10.3.74.150	10.3.74.151
84	10.3.74.152/29	10.3.74.153 – 10.3.74.158	10.3.74.159
85	10.3.74.160/29	10.3.74.161 – 10.3.74.166	10.3.74.167
86	10.3.74.168/29	10.3.74.169 – 10.3.74.174	10.3.74.175
87	10.3.74.176/29	10.3.74.177 – 10.3.74.182	10.3.74.183
88	10.3.74.184/29	10.3.74.185 – 10.3.74.190	10.3.74.191
89	10.3.74.192/29	10.3.74.193 – 10.3.74.198	10.3.74.199
90	10.3.74.200/29	10.3.74.201 – 10.3.74.206	10.3.74.207
91	10.3.74.208/29	10.3.74.209 – 10.3.74.214	10.3.74.215
92	10.3.74.216/29	10.3.74.217 – 10.3.74.222	10.3.74.223
93	10.3.74.224/29	10.3.74.225 – 10.3.74.230	10.3.74.231
94	10.3.74.232/29	10.3.74.233 – 10.3.74.238	10.3.74.239
95	10.3.74.240/29	10.3.74.241 – 10.3.74.246	10.3.74.247
96	10.3.74.248/29	10.3.74.249 – 10.3.74.254	10.3.74.255
97	10.3.75.0/29	10.3.75.1 – 10.3.75.6	10.3.75.7
98	10.3.75.8/29	10.3.75.9 – 10.3.75.14	10.3.75.15
99	10.3.75.16/29	10.3.75.17 – 10.3.75.22	10.3.75.23
100	10.3.75.24/29	10.3.75.25 – 10.3.75.30	10.3.75.31
101	10.3.75.32/29	10.3.75.33 – 10.3.75.38	10.3.75.39
102	10.3.75.40/29	10.3.75.41 – 10.3.75.46	10.3.75.47
103	10.3.75.48/29	10.3.75.49 – 10.3.75.54	10.3.75.55
104	10.3.75.56/29	10.3.75.57 – 10.3.75.62	10.3.75.63
105	10.3.75.64/29	10.3.75.65 – 10.3.75.70	10.3.75.71
106	10.3.75.72/29	10.3.75.73 – 10.3.75.78	10.3.75.79
107	10.3.75.80/29	10.3.75.81 – 10.3.75.86	10.3.75.87
108	10.3.75.88/29	10.3.75.89 – 10.3.75.94	10.3.75.95
109	10.3.75.96/29	10.3.75.97 – 10.3.75.102	10.3.75.103
110	10.3.75.104/29	10.3.75.105 – 10.3.75.110	10.3.75.111
111	10.3.75.112/29	10.3.75.113 – 10.3.75.118	10.3.75.119
112	10.3.75.120/29	10.3.75.121 – 10.3.75.126	10.3.75.127
113	10.3.75.128/29	10.3.75.129 – 10.3.75.134	10.3.75.135
114	10.3.75.136/29	10.3.75.137 – 10.3.75.142	10.3.75.143
115	10.3.75.144/29	10.3.75.145 – 10.3.75.150	10.3.75.151
116	10.3.75.152/29	10.3.75.153 – 10.3.75.158	10.3.75.159
117	10.3.75.160/29	10.3.75.161 – 10.3.75.166	10.3.75.167
118	10.3.75.168/29	10.3.75.169 – 10.3.75.174	10.3.75.175
119	10.3.75.176/29	10.3.75.177 – 10.3.75.182	10.3.75.183
120	10.3.75.184/29	10.3.75.185 – 10.3.75.190	10.3.75.191
121	10.3.75.192/29	10.3.75.193 – 10.3.75.198	10.3.75.199
122	10.3.75.200/29	10.3.75.201 – 10.3.75.206	10.3.75.207
123	10.3.75.208/29	10.3.75.209 – 10.3.75.214	10.3.75.215
124	10.3.75.216/29	10.3.75.217 – 10.3.75.222	10.3.75.223
125	10.3.75.224/29	10.3.75.225 – 10.3.75.230	10.3.75.231
126	10.3.75.232/29	10.3.75.233 – 10.3.75.238	10.3.75.239
127	10.3.75.240/29	10.3.75.241 – 10.3.75.246	10.3.75.247
128	10.3.75.248/29	10.3.75.249 – 10.3.75.254	10.3.75.255
129	10.3.76.0/29	10.3.76.1 – 10.3.76.6	10.3.76.7
130	10.3.76.8/29	10.3.76.9 – 10.3.76.14	10.3.76.15
131	10.3.76.16/29	10.3.76.17 – 10.3.76.22	10.3.76.23
132	10.3.76.24/29	10.3.76.25 – 10.3.76.30	10.3.76.31
133	10.3.76.32/29	10.3.76.33 – 10.3.76.38	10.3.76.39
134	10.3.76.40/29	10.3.76.41 – 10.3.76.46	10.3.76.47
135	10.3.76.48/29	10.3.76.49 – 10.3.76.54	10.3.76.55
136	10.3.76.56/29	10.3.76.57 – 10.3.76.62	10.3.76.63
137	10.3.76.64/29	10.3.76.65 – 10.3.76.70	10.3.76.71
138	10.3.76.72/29	10.3.76.73 – 10.3.76.78	10.3.76.79
139	10.3.76.80/29	10.3.76.81 – 10.3.76.86	10.3.76.87
140	10.3.76.88/29	10.3.76.89 – 10.3.76.94	10.3.76.95
141	10.3.76.96/29	10.3.76.97 – 10.3.76.102	10.3.76.103
142	10.3.76.104/29	10.3.76.105 – 10.3.76.110	10.3.76.111
143	10.3.76.112/29	10.3.76.113 – 10.3.76.118	10.3.76.119
144	10.3.76.120/29	10.3.76.121 – 10.3.76.126	10.3.76.127
145	10.3.76.128/29	10.3.76.129 – 10.3.76.134	10.3.76.135
146	10.3.76.136/29	10.3.76.137 – 10.3.76.142	10.3.76.143
147	10.3.76.144/29	10.3.76.145 – 10.3.76.150	10.3.76.151
148	10.3.76.152/29	10.3.76.153 – 10.3.76.158	10.3.76.159
149	10.3.76.160/29	10.3.76.161 – 10.3.76.166	10.3.76.167
150	10.3.76.168/29	10.3.76.169 – 10.3.76.174	10.3.76.175
151	10.3.76.176/29	10.3.76.177 – 10.3.76.182	10.3.76.183
152	10.3.76.184/29	10.3.76.185 – 10.3.76.190	10.3.76.191
153	10.3.76.192/29	10.3.76.193 – 10.3.76.198	10.3.76.199
154	10.3.76.200/29	10.3.76.201 – 10.3.76.206	10.3.76.207
155	10.3.76.208/29	10.3.76.209 – 10.3.76.214	10.3.76.215
156	10.3.76.216/29	10.3.76.217 – 10.3.76.222	10.3.76.223
157	10.3.76.224/29	10.3.76.225 – 10.3.76.230	10.3.76.231
158	10.3.76.232/29	10.3.76.233 – 10.3.76.238	10.3.76.239
159	10.3.76.240/29	10.3.76.241 – 10.3.76.246	10.3.76.247
160	10.3.76.248/29	10.3.76.249 – 10.3.76.254	10.3.76.255
161	10.3.77.0/29	10.3.77.1 – 10.3.77.6	10.3.77.7
162	10.3.77.8/29	10.3.77.9 – 10.3.77.14	10.3.77.15
163	10.3.77.16/29	10.3.77.17 – 10.3.77.22	10.3.77.23
164	10.3.77.24/29	10.3.77.25 – 10.3.77.30	10.3.77.31
165	10.3.77.32/29	10.3.77.33 – 10.3.77.38	10.3.77.39
166	10.3.77.40/29	10.3.77.41 – 10.3.77.46	10.3.77.47
167	10.3.77.48/29	10.3.77.49 – 10.3.77.54	10.3.77.55
168	10.3.77.56/29	10.3.77.57 – 10.3.77.62	10.3.77.63
169	10.3.77.64/29	10.3.77.65 – 10.3.77.70	10.3.77.71
170	10.3.77.72/29	10.3.77.73 – 10.3.77.78	10.3.77.79
171	10.3.77.80/29	10.3.77.81 – 10.3.77.86	10.3.77.87
172	10.3.77.88/29	10.3.77.89 – 10.3.77.94	10.3.77.95
173	10.3.77.96/29	10.3.77.97 – 10.3.77.102	10.3.77.103
174	10.3.77.104/29	10.3.77.105 – 10.3.77.110	10.3.77.111
175	10.3.77.112/29	10.3.77.113 – 10.3.77.118	10.3.77.119
176	10.3.77.120/29	10.3.77.121 – 10.3.77.126	10.3.77.127
177	10.3.77.128/29	10.3.77.129 – 10.3.77.134	10.3.77.135
178	10.3.77.136/29	10.3.77.137 – 10.3.77.142	10.3.77.143
179	10.3.77.144/29	10.3.77.145 – 10.3.77.150	10.3.77.151
180	10.3.77.152/29	10.3.77.153 – 10.3.77.158	10.3.77.159
181	10.3.77.160/29	10.3.77.161 – 10.3.77.166	10.3.77.167
182	10.3.77.168/29	10.3.77.169 – 10.3.77.174	10.3.77.175
183	10.3.77.176/29	10.3.77.177 – 10.3.77.182	10.3.77.183
184	10.3.77.184/29	10.3.77.185 – 10.3.77.190	10.3.77.191
185	10.3.77.192/29	10.3.77.193 – 10.3.77.198	10.3.77.199
186	10.3.77.200/29	10.3.77.201 – 10.3.77.206	10.3.77.207
187	10.3.77.208/29	10.3.77.209 – 10.3.77.214	10.3.77.215
188	10.3.77.216/29	10.3.77.217 – 10.3.77.222	10.3.77.223
189	10.3.77.224/29	10.3.77.225 – 10.3.77.230	10.3.77.231
190	10.3.77.232/29	10.3.77.233 – 10.3.77.238	10.3.77.239
191	10.3.77.240/29	10.3.77.241 – 10.3.77.246	10.3.77.247
192	10.3.77.248/29	10.3.77.249 – 10.3.77.254	10.3.77.255
193	10.3.78.0/29	10.3.78.1 – 10.3.78.6	10.3.78.7
194	10.3.78.8/29	10.3.78.9 – 10.3.78.14	10.3.78.15
195	10.3.78.16/29	10.3.78.17 – 10.3.78.22	10.3.78.23
196	10.3.78.24/29	10.3.78.25 – 10.3.78.30	10.3.78.31
197	10.3.78.32/29	10.3.78.33 – 10.3.78.38	10.3.78.39
198	10.3.78.40/29	10.3.78.41 – 10.3.78.46	10.3.78.47
199	10.3.78.48/29	10.3.78.49 – 10.3.78.54	10.3.78.55
200	10.3.78.56/29	10.3.78.57 – 10.3.78.62	10.3.78.63
201	10.3.78.64/29	10.3.78.65 – 10.3.78.70	10.3.78.71
202	10.3.78.72/29	10.3.78.73 – 10.3.78.78	10.3.78.79
203	10.3.78.80/29	10.3.78.81 – 10.3.78.86	10.3.78.87
204	10.3.78.88/29	10.3.78.89 – 10.3.78.94	10.3.78.95
205	10.3.78.96/29	10.3.78.97 – 10.3.78.102	10.3.78.103
206	10.3.78.104/29	10.3.78.105 – 10.3.78.110	10.3.78.111
207	10.3.78.112/29	10.3.78.113 – 10.3.78.118	10.3.78.119
208	10.3.78.120/29	10.3.78.121 – 10.3.78.126	10.3.78.127
209	10.3.78.128/29	10.3.78.129 – 10.3.78.134	10.3.78.135
210	10.3.78.136/29	10.3.78.137 – 10.3.78.142	10.3.78.143
211	10.3.78.144/29	10.3.78.145 – 10.3.78.150	10.3.78.151
212	10.3.78.152/29	10.3.78.153 – 10.3.78.158	10.3.78.159
213	10.3.78.160/29	10.3.78.161 – 10.3.78.166	10.3.78.167
214	10.3.78.168/29	10.3.78.169 – 10.3.78.174	10.3.78.175
215	10.3.78.176/29	10.3.78.177 – 10.3.78.182	10.3.78.183
216	10.3.78.184/29	10.3.78.185 – 10.3.78.190	10.3.78.191
217	10.3.78.192/29	10.3.78.193 – 10.3.78.198	10.3.78.199
218	10.3.78.200/29	10.3.78.201 – 10.3.78.206	10.3.78.207
219	10.3.78.208/29	10.3.78.209 – 10.3.78.214	10.3.78.215
220	10.3.78.216/29	10.3.78.217 – 10.3.78.222	10.3.78.223
221	10.3.78.224/29	10.3.78.225 – 10.3.78.230	10.3.78.231
222	10.3.78.232/29	10.3.78.233 – 10.3.78.238	10.3.78.239
223	10.3.78.240/29	10.3.78.241 – 10.3.78.246	10.3.78.247
224	10.3.78.248/29	10.3.78.249 – 10.3.78.254	10.3.78.255
225	10.3.79.0/29	10.3.79.1 – 10.3.79.6	10.3.79.7
226	10.3.79.8/29	10.3.79.9 – 10.3.79.14	10.3.79.15
227	10.3.79.16/29	10.3.79.17 – 10.3.79.22	10.3.79.23
228	10.3.79.24/29	10.3.79.25 – 10.3.79.30	10.3.79.31
229	10.3.79.32/29	10.3.79.33 – 10.3.79.38	10.3.79.39
230	10.3.79.40/29	10.3.79.41 – 10.3.79.46	10.3.79.47
231	10.3.79.48/29	10.3.79.49 – 10.3.79.54	10.3.79.55
232	10.3.79.56/29	10.3.79.57 – 10.3.79.62	10.3.79.63
233	10.3.79.64/29	10.3.79.65 – 10.3.79.70	10.3.79.71
234	10.3.79.72/29	10.3.79.73 – 10.3.79.78	10.3.79.79
235	10.3.79.80/29	10.3.79.81 – 10.3.79.86	10.3.79.87
236	10.3.79.88/29	10.3.79.89 – 10.3.79.94	10.3.79.95
237	10.3.79.96/29	10.3.79.97 – 10.3.79.102	10.3.79.103
238	10.3.79.104/29	10.3.79.105 – 10.3.79.110	10.3.79.111
239	10.3.79.112/29	10.3.79.113 – 10.3.79.118	10.3.79.119
240	10.3.79.120/29	10.3.79.121 – 10.3.79.126	10.3.79.127
241	10.3.79.128/29	10.3.79.129 – 10.3.79.134	10.3.79.135
242	10.3.79.136/29	10.3.79.137 – 10.3.79.142	10.3.79.143
243	10.3.79.144/29	10.3.79.145 – 10.3.79.150	10.3.79.151
244	10.3.79.152/29	10.3.79.153 – 10.3.79.158	10.3.79.159
245	10.3.79.160/29	10.3.79.161 – 10.3.79.166	10.3.79.167
246	10.3.79.168/29	10.3.79.169 – 10.3.79.174	10.3.79.175
247	10.3.79.176/29	10.3.79.177 – 10.3.79.182	10.3.79.183
248	10.3.79.184/29	10.3.79.185 – 10.3.79.190	10.3.79.191
249	10.3.79.192/29	10.3.79.193 – 10.3.79.198	10.3.79.199
250	10.3.79.200/29	10.3.79.201 – 10.3.79.206	10.3.79.207
251	10.3.79.208/29	10.3.79.209 – 10.3.79.214	10.3.79.215
252	10.3.79.216/29	10.3.79.217 – 10.3.79.222	10.3.79.223
253	10.3.79.224/29	10.3.79.225 – 10.3.79.230	10.3.79.231
254	10.3.79.232/29	10.3.79.233 – 10.3.79.238	10.3.79.239
255	10.3.79.240/29	10.3.79.241 – 10.3.79.246	10.3.79.247
256	10.3.79.248/29	10.3.79.249 – 10.3.79.254	10.3.79.255

01 / table

IPv4 CIDR prefix table.

Click a prefix longer than your network to split it into subnets.

prefix	subnet mask	addresses	hosts	in your /21
/0	0.0.0.0	4,294,967,296	4,294,967,294	-
/1	128.0.0.0	2,147,483,648	2,147,483,646	-
/2	192.0.0.0	1,073,741,824	1,073,741,822	-
/3	224.0.0.0	536,870,912	536,870,910	-
/4	240.0.0.0	268,435,456	268,435,454	-
/5	248.0.0.0	134,217,728	134,217,726	-
/6	252.0.0.0	67,108,864	67,108,862	-
/7	254.0.0.0	33,554,432	33,554,430	-
/8	255.0.0.0	16,777,216	16,777,214	-
/9	255.128.0.0	8,388,608	8,388,606	-
/10	255.192.0.0	4,194,304	4,194,302	-
/11	255.224.0.0	2,097,152	2,097,150	-
/12	255.240.0.0	1,048,576	1,048,574	-
/13	255.248.0.0	524,288	524,286	-
/14	255.252.0.0	262,144	262,142	-
/15	255.254.0.0	131,072	131,070	-
/16	255.255.0.0	65,536	65,534	-
/17	255.255.128.0	32,768	32,766	-
/18	255.255.192.0	16,384	16,382	-
/19	255.255.224.0	8,192	8,190	-
/20	255.255.240.0	4,096	4,094	-
/21	255.255.248.0	2,048	2,046	1
/22	255.255.252.0	1,024	1,022	2 split →
/23	255.255.254.0	512	510	4 split →
/24	255.255.255.0	256	254	8 split →
/25	255.255.255.128	128	126	16 split →
/26	255.255.255.192	64	62	32 split →
/27	255.255.255.224	32	30	64 split →
/28	255.255.255.240	16	14	128 split →
/29	255.255.255.248	8	6	256 split →
/30	255.255.255.252	4	2	512 split →
/31	255.255.255.254	2	2	1,024 split →
/32	255.255.255.255	1	1	2,048 split →

02 / faq

About this calculator.

How do I use this subnet calculator?

▼

Type an IP address followed by a prefix, like 192.168.1.10/24, or by a subnet mask, like 192.168.1.10 255.255.255.0. Without a prefix it uses /24. Click a row in the table to split the network into smaller subnets.

Why are usable hosts always 2 fewer?

▼

The first address in a subnet is the network address and the last is the broadcast address, so neither can go to a device. The exceptions are /31 (point-to-point links, RFC 3021) and /32 (a single address), which use every address.

Can I use it from a terminal?

▼

Yes. curl 'ipku.in/en/tools/ipv4-subnet-calculator?q=192.168.1.10/24' returns the result as plain text.

Learn how to work it out →