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)10.3.40.0/21

network10.3.40.0/21

broadcast10.3.47.255

first host10.3.40.1

last host10.3.47.254

subnet mask255.255.248.0

wildcard0.0.7.255

addresses2,048

usable hosts2,046

classA

ipcalc 10.3.40.0/21

address00001010.00000011.00101000.00000000

subnet mask11111111.11111111.11111000.00000000

network00001010.00000011.00101000.00000000

broadcast00001010.00000011.00101111.11111111

green = network part, grey = host part

hex0x0a032800

decimal167979008

reverse dns0.40.3.10.in-addr.arpa

ipv4-mapped::ffff:a03:2800

/21 split into /29 · 256 subnets

close ×

#	network	host range	broadcast
1	10.3.40.0/29	10.3.40.1 – 10.3.40.6	10.3.40.7
2	10.3.40.8/29	10.3.40.9 – 10.3.40.14	10.3.40.15
3	10.3.40.16/29	10.3.40.17 – 10.3.40.22	10.3.40.23
4	10.3.40.24/29	10.3.40.25 – 10.3.40.30	10.3.40.31
5	10.3.40.32/29	10.3.40.33 – 10.3.40.38	10.3.40.39
6	10.3.40.40/29	10.3.40.41 – 10.3.40.46	10.3.40.47
7	10.3.40.48/29	10.3.40.49 – 10.3.40.54	10.3.40.55
8	10.3.40.56/29	10.3.40.57 – 10.3.40.62	10.3.40.63
9	10.3.40.64/29	10.3.40.65 – 10.3.40.70	10.3.40.71
10	10.3.40.72/29	10.3.40.73 – 10.3.40.78	10.3.40.79
11	10.3.40.80/29	10.3.40.81 – 10.3.40.86	10.3.40.87
12	10.3.40.88/29	10.3.40.89 – 10.3.40.94	10.3.40.95
13	10.3.40.96/29	10.3.40.97 – 10.3.40.102	10.3.40.103
14	10.3.40.104/29	10.3.40.105 – 10.3.40.110	10.3.40.111
15	10.3.40.112/29	10.3.40.113 – 10.3.40.118	10.3.40.119
16	10.3.40.120/29	10.3.40.121 – 10.3.40.126	10.3.40.127
17	10.3.40.128/29	10.3.40.129 – 10.3.40.134	10.3.40.135
18	10.3.40.136/29	10.3.40.137 – 10.3.40.142	10.3.40.143
19	10.3.40.144/29	10.3.40.145 – 10.3.40.150	10.3.40.151
20	10.3.40.152/29	10.3.40.153 – 10.3.40.158	10.3.40.159
21	10.3.40.160/29	10.3.40.161 – 10.3.40.166	10.3.40.167
22	10.3.40.168/29	10.3.40.169 – 10.3.40.174	10.3.40.175
23	10.3.40.176/29	10.3.40.177 – 10.3.40.182	10.3.40.183
24	10.3.40.184/29	10.3.40.185 – 10.3.40.190	10.3.40.191
25	10.3.40.192/29	10.3.40.193 – 10.3.40.198	10.3.40.199
26	10.3.40.200/29	10.3.40.201 – 10.3.40.206	10.3.40.207
27	10.3.40.208/29	10.3.40.209 – 10.3.40.214	10.3.40.215
28	10.3.40.216/29	10.3.40.217 – 10.3.40.222	10.3.40.223
29	10.3.40.224/29	10.3.40.225 – 10.3.40.230	10.3.40.231
30	10.3.40.232/29	10.3.40.233 – 10.3.40.238	10.3.40.239
31	10.3.40.240/29	10.3.40.241 – 10.3.40.246	10.3.40.247
32	10.3.40.248/29	10.3.40.249 – 10.3.40.254	10.3.40.255
33	10.3.41.0/29	10.3.41.1 – 10.3.41.6	10.3.41.7
34	10.3.41.8/29	10.3.41.9 – 10.3.41.14	10.3.41.15
35	10.3.41.16/29	10.3.41.17 – 10.3.41.22	10.3.41.23
36	10.3.41.24/29	10.3.41.25 – 10.3.41.30	10.3.41.31
37	10.3.41.32/29	10.3.41.33 – 10.3.41.38	10.3.41.39
38	10.3.41.40/29	10.3.41.41 – 10.3.41.46	10.3.41.47
39	10.3.41.48/29	10.3.41.49 – 10.3.41.54	10.3.41.55
40	10.3.41.56/29	10.3.41.57 – 10.3.41.62	10.3.41.63
41	10.3.41.64/29	10.3.41.65 – 10.3.41.70	10.3.41.71
42	10.3.41.72/29	10.3.41.73 – 10.3.41.78	10.3.41.79
43	10.3.41.80/29	10.3.41.81 – 10.3.41.86	10.3.41.87
44	10.3.41.88/29	10.3.41.89 – 10.3.41.94	10.3.41.95
45	10.3.41.96/29	10.3.41.97 – 10.3.41.102	10.3.41.103
46	10.3.41.104/29	10.3.41.105 – 10.3.41.110	10.3.41.111
47	10.3.41.112/29	10.3.41.113 – 10.3.41.118	10.3.41.119
48	10.3.41.120/29	10.3.41.121 – 10.3.41.126	10.3.41.127
49	10.3.41.128/29	10.3.41.129 – 10.3.41.134	10.3.41.135
50	10.3.41.136/29	10.3.41.137 – 10.3.41.142	10.3.41.143
51	10.3.41.144/29	10.3.41.145 – 10.3.41.150	10.3.41.151
52	10.3.41.152/29	10.3.41.153 – 10.3.41.158	10.3.41.159
53	10.3.41.160/29	10.3.41.161 – 10.3.41.166	10.3.41.167
54	10.3.41.168/29	10.3.41.169 – 10.3.41.174	10.3.41.175
55	10.3.41.176/29	10.3.41.177 – 10.3.41.182	10.3.41.183
56	10.3.41.184/29	10.3.41.185 – 10.3.41.190	10.3.41.191
57	10.3.41.192/29	10.3.41.193 – 10.3.41.198	10.3.41.199
58	10.3.41.200/29	10.3.41.201 – 10.3.41.206	10.3.41.207
59	10.3.41.208/29	10.3.41.209 – 10.3.41.214	10.3.41.215
60	10.3.41.216/29	10.3.41.217 – 10.3.41.222	10.3.41.223
61	10.3.41.224/29	10.3.41.225 – 10.3.41.230	10.3.41.231
62	10.3.41.232/29	10.3.41.233 – 10.3.41.238	10.3.41.239
63	10.3.41.240/29	10.3.41.241 – 10.3.41.246	10.3.41.247
64	10.3.41.248/29	10.3.41.249 – 10.3.41.254	10.3.41.255
65	10.3.42.0/29	10.3.42.1 – 10.3.42.6	10.3.42.7
66	10.3.42.8/29	10.3.42.9 – 10.3.42.14	10.3.42.15
67	10.3.42.16/29	10.3.42.17 – 10.3.42.22	10.3.42.23
68	10.3.42.24/29	10.3.42.25 – 10.3.42.30	10.3.42.31
69	10.3.42.32/29	10.3.42.33 – 10.3.42.38	10.3.42.39
70	10.3.42.40/29	10.3.42.41 – 10.3.42.46	10.3.42.47
71	10.3.42.48/29	10.3.42.49 – 10.3.42.54	10.3.42.55
72	10.3.42.56/29	10.3.42.57 – 10.3.42.62	10.3.42.63
73	10.3.42.64/29	10.3.42.65 – 10.3.42.70	10.3.42.71
74	10.3.42.72/29	10.3.42.73 – 10.3.42.78	10.3.42.79
75	10.3.42.80/29	10.3.42.81 – 10.3.42.86	10.3.42.87
76	10.3.42.88/29	10.3.42.89 – 10.3.42.94	10.3.42.95
77	10.3.42.96/29	10.3.42.97 – 10.3.42.102	10.3.42.103
78	10.3.42.104/29	10.3.42.105 – 10.3.42.110	10.3.42.111
79	10.3.42.112/29	10.3.42.113 – 10.3.42.118	10.3.42.119
80	10.3.42.120/29	10.3.42.121 – 10.3.42.126	10.3.42.127
81	10.3.42.128/29	10.3.42.129 – 10.3.42.134	10.3.42.135
82	10.3.42.136/29	10.3.42.137 – 10.3.42.142	10.3.42.143
83	10.3.42.144/29	10.3.42.145 – 10.3.42.150	10.3.42.151
84	10.3.42.152/29	10.3.42.153 – 10.3.42.158	10.3.42.159
85	10.3.42.160/29	10.3.42.161 – 10.3.42.166	10.3.42.167
86	10.3.42.168/29	10.3.42.169 – 10.3.42.174	10.3.42.175
87	10.3.42.176/29	10.3.42.177 – 10.3.42.182	10.3.42.183
88	10.3.42.184/29	10.3.42.185 – 10.3.42.190	10.3.42.191
89	10.3.42.192/29	10.3.42.193 – 10.3.42.198	10.3.42.199
90	10.3.42.200/29	10.3.42.201 – 10.3.42.206	10.3.42.207
91	10.3.42.208/29	10.3.42.209 – 10.3.42.214	10.3.42.215
92	10.3.42.216/29	10.3.42.217 – 10.3.42.222	10.3.42.223
93	10.3.42.224/29	10.3.42.225 – 10.3.42.230	10.3.42.231
94	10.3.42.232/29	10.3.42.233 – 10.3.42.238	10.3.42.239
95	10.3.42.240/29	10.3.42.241 – 10.3.42.246	10.3.42.247
96	10.3.42.248/29	10.3.42.249 – 10.3.42.254	10.3.42.255
97	10.3.43.0/29	10.3.43.1 – 10.3.43.6	10.3.43.7
98	10.3.43.8/29	10.3.43.9 – 10.3.43.14	10.3.43.15
99	10.3.43.16/29	10.3.43.17 – 10.3.43.22	10.3.43.23
100	10.3.43.24/29	10.3.43.25 – 10.3.43.30	10.3.43.31
101	10.3.43.32/29	10.3.43.33 – 10.3.43.38	10.3.43.39
102	10.3.43.40/29	10.3.43.41 – 10.3.43.46	10.3.43.47
103	10.3.43.48/29	10.3.43.49 – 10.3.43.54	10.3.43.55
104	10.3.43.56/29	10.3.43.57 – 10.3.43.62	10.3.43.63
105	10.3.43.64/29	10.3.43.65 – 10.3.43.70	10.3.43.71
106	10.3.43.72/29	10.3.43.73 – 10.3.43.78	10.3.43.79
107	10.3.43.80/29	10.3.43.81 – 10.3.43.86	10.3.43.87
108	10.3.43.88/29	10.3.43.89 – 10.3.43.94	10.3.43.95
109	10.3.43.96/29	10.3.43.97 – 10.3.43.102	10.3.43.103
110	10.3.43.104/29	10.3.43.105 – 10.3.43.110	10.3.43.111
111	10.3.43.112/29	10.3.43.113 – 10.3.43.118	10.3.43.119
112	10.3.43.120/29	10.3.43.121 – 10.3.43.126	10.3.43.127
113	10.3.43.128/29	10.3.43.129 – 10.3.43.134	10.3.43.135
114	10.3.43.136/29	10.3.43.137 – 10.3.43.142	10.3.43.143
115	10.3.43.144/29	10.3.43.145 – 10.3.43.150	10.3.43.151
116	10.3.43.152/29	10.3.43.153 – 10.3.43.158	10.3.43.159
117	10.3.43.160/29	10.3.43.161 – 10.3.43.166	10.3.43.167
118	10.3.43.168/29	10.3.43.169 – 10.3.43.174	10.3.43.175
119	10.3.43.176/29	10.3.43.177 – 10.3.43.182	10.3.43.183
120	10.3.43.184/29	10.3.43.185 – 10.3.43.190	10.3.43.191
121	10.3.43.192/29	10.3.43.193 – 10.3.43.198	10.3.43.199
122	10.3.43.200/29	10.3.43.201 – 10.3.43.206	10.3.43.207
123	10.3.43.208/29	10.3.43.209 – 10.3.43.214	10.3.43.215
124	10.3.43.216/29	10.3.43.217 – 10.3.43.222	10.3.43.223
125	10.3.43.224/29	10.3.43.225 – 10.3.43.230	10.3.43.231
126	10.3.43.232/29	10.3.43.233 – 10.3.43.238	10.3.43.239
127	10.3.43.240/29	10.3.43.241 – 10.3.43.246	10.3.43.247
128	10.3.43.248/29	10.3.43.249 – 10.3.43.254	10.3.43.255
129	10.3.44.0/29	10.3.44.1 – 10.3.44.6	10.3.44.7
130	10.3.44.8/29	10.3.44.9 – 10.3.44.14	10.3.44.15
131	10.3.44.16/29	10.3.44.17 – 10.3.44.22	10.3.44.23
132	10.3.44.24/29	10.3.44.25 – 10.3.44.30	10.3.44.31
133	10.3.44.32/29	10.3.44.33 – 10.3.44.38	10.3.44.39
134	10.3.44.40/29	10.3.44.41 – 10.3.44.46	10.3.44.47
135	10.3.44.48/29	10.3.44.49 – 10.3.44.54	10.3.44.55
136	10.3.44.56/29	10.3.44.57 – 10.3.44.62	10.3.44.63
137	10.3.44.64/29	10.3.44.65 – 10.3.44.70	10.3.44.71
138	10.3.44.72/29	10.3.44.73 – 10.3.44.78	10.3.44.79
139	10.3.44.80/29	10.3.44.81 – 10.3.44.86	10.3.44.87
140	10.3.44.88/29	10.3.44.89 – 10.3.44.94	10.3.44.95
141	10.3.44.96/29	10.3.44.97 – 10.3.44.102	10.3.44.103
142	10.3.44.104/29	10.3.44.105 – 10.3.44.110	10.3.44.111
143	10.3.44.112/29	10.3.44.113 – 10.3.44.118	10.3.44.119
144	10.3.44.120/29	10.3.44.121 – 10.3.44.126	10.3.44.127
145	10.3.44.128/29	10.3.44.129 – 10.3.44.134	10.3.44.135
146	10.3.44.136/29	10.3.44.137 – 10.3.44.142	10.3.44.143
147	10.3.44.144/29	10.3.44.145 – 10.3.44.150	10.3.44.151
148	10.3.44.152/29	10.3.44.153 – 10.3.44.158	10.3.44.159
149	10.3.44.160/29	10.3.44.161 – 10.3.44.166	10.3.44.167
150	10.3.44.168/29	10.3.44.169 – 10.3.44.174	10.3.44.175
151	10.3.44.176/29	10.3.44.177 – 10.3.44.182	10.3.44.183
152	10.3.44.184/29	10.3.44.185 – 10.3.44.190	10.3.44.191
153	10.3.44.192/29	10.3.44.193 – 10.3.44.198	10.3.44.199
154	10.3.44.200/29	10.3.44.201 – 10.3.44.206	10.3.44.207
155	10.3.44.208/29	10.3.44.209 – 10.3.44.214	10.3.44.215
156	10.3.44.216/29	10.3.44.217 – 10.3.44.222	10.3.44.223
157	10.3.44.224/29	10.3.44.225 – 10.3.44.230	10.3.44.231
158	10.3.44.232/29	10.3.44.233 – 10.3.44.238	10.3.44.239
159	10.3.44.240/29	10.3.44.241 – 10.3.44.246	10.3.44.247
160	10.3.44.248/29	10.3.44.249 – 10.3.44.254	10.3.44.255
161	10.3.45.0/29	10.3.45.1 – 10.3.45.6	10.3.45.7
162	10.3.45.8/29	10.3.45.9 – 10.3.45.14	10.3.45.15
163	10.3.45.16/29	10.3.45.17 – 10.3.45.22	10.3.45.23
164	10.3.45.24/29	10.3.45.25 – 10.3.45.30	10.3.45.31
165	10.3.45.32/29	10.3.45.33 – 10.3.45.38	10.3.45.39
166	10.3.45.40/29	10.3.45.41 – 10.3.45.46	10.3.45.47
167	10.3.45.48/29	10.3.45.49 – 10.3.45.54	10.3.45.55
168	10.3.45.56/29	10.3.45.57 – 10.3.45.62	10.3.45.63
169	10.3.45.64/29	10.3.45.65 – 10.3.45.70	10.3.45.71
170	10.3.45.72/29	10.3.45.73 – 10.3.45.78	10.3.45.79
171	10.3.45.80/29	10.3.45.81 – 10.3.45.86	10.3.45.87
172	10.3.45.88/29	10.3.45.89 – 10.3.45.94	10.3.45.95
173	10.3.45.96/29	10.3.45.97 – 10.3.45.102	10.3.45.103
174	10.3.45.104/29	10.3.45.105 – 10.3.45.110	10.3.45.111
175	10.3.45.112/29	10.3.45.113 – 10.3.45.118	10.3.45.119
176	10.3.45.120/29	10.3.45.121 – 10.3.45.126	10.3.45.127
177	10.3.45.128/29	10.3.45.129 – 10.3.45.134	10.3.45.135
178	10.3.45.136/29	10.3.45.137 – 10.3.45.142	10.3.45.143
179	10.3.45.144/29	10.3.45.145 – 10.3.45.150	10.3.45.151
180	10.3.45.152/29	10.3.45.153 – 10.3.45.158	10.3.45.159
181	10.3.45.160/29	10.3.45.161 – 10.3.45.166	10.3.45.167
182	10.3.45.168/29	10.3.45.169 – 10.3.45.174	10.3.45.175
183	10.3.45.176/29	10.3.45.177 – 10.3.45.182	10.3.45.183
184	10.3.45.184/29	10.3.45.185 – 10.3.45.190	10.3.45.191
185	10.3.45.192/29	10.3.45.193 – 10.3.45.198	10.3.45.199
186	10.3.45.200/29	10.3.45.201 – 10.3.45.206	10.3.45.207
187	10.3.45.208/29	10.3.45.209 – 10.3.45.214	10.3.45.215
188	10.3.45.216/29	10.3.45.217 – 10.3.45.222	10.3.45.223
189	10.3.45.224/29	10.3.45.225 – 10.3.45.230	10.3.45.231
190	10.3.45.232/29	10.3.45.233 – 10.3.45.238	10.3.45.239
191	10.3.45.240/29	10.3.45.241 – 10.3.45.246	10.3.45.247
192	10.3.45.248/29	10.3.45.249 – 10.3.45.254	10.3.45.255
193	10.3.46.0/29	10.3.46.1 – 10.3.46.6	10.3.46.7
194	10.3.46.8/29	10.3.46.9 – 10.3.46.14	10.3.46.15
195	10.3.46.16/29	10.3.46.17 – 10.3.46.22	10.3.46.23
196	10.3.46.24/29	10.3.46.25 – 10.3.46.30	10.3.46.31
197	10.3.46.32/29	10.3.46.33 – 10.3.46.38	10.3.46.39
198	10.3.46.40/29	10.3.46.41 – 10.3.46.46	10.3.46.47
199	10.3.46.48/29	10.3.46.49 – 10.3.46.54	10.3.46.55
200	10.3.46.56/29	10.3.46.57 – 10.3.46.62	10.3.46.63
201	10.3.46.64/29	10.3.46.65 – 10.3.46.70	10.3.46.71
202	10.3.46.72/29	10.3.46.73 – 10.3.46.78	10.3.46.79
203	10.3.46.80/29	10.3.46.81 – 10.3.46.86	10.3.46.87
204	10.3.46.88/29	10.3.46.89 – 10.3.46.94	10.3.46.95
205	10.3.46.96/29	10.3.46.97 – 10.3.46.102	10.3.46.103
206	10.3.46.104/29	10.3.46.105 – 10.3.46.110	10.3.46.111
207	10.3.46.112/29	10.3.46.113 – 10.3.46.118	10.3.46.119
208	10.3.46.120/29	10.3.46.121 – 10.3.46.126	10.3.46.127
209	10.3.46.128/29	10.3.46.129 – 10.3.46.134	10.3.46.135
210	10.3.46.136/29	10.3.46.137 – 10.3.46.142	10.3.46.143
211	10.3.46.144/29	10.3.46.145 – 10.3.46.150	10.3.46.151
212	10.3.46.152/29	10.3.46.153 – 10.3.46.158	10.3.46.159
213	10.3.46.160/29	10.3.46.161 – 10.3.46.166	10.3.46.167
214	10.3.46.168/29	10.3.46.169 – 10.3.46.174	10.3.46.175
215	10.3.46.176/29	10.3.46.177 – 10.3.46.182	10.3.46.183
216	10.3.46.184/29	10.3.46.185 – 10.3.46.190	10.3.46.191
217	10.3.46.192/29	10.3.46.193 – 10.3.46.198	10.3.46.199
218	10.3.46.200/29	10.3.46.201 – 10.3.46.206	10.3.46.207
219	10.3.46.208/29	10.3.46.209 – 10.3.46.214	10.3.46.215
220	10.3.46.216/29	10.3.46.217 – 10.3.46.222	10.3.46.223
221	10.3.46.224/29	10.3.46.225 – 10.3.46.230	10.3.46.231
222	10.3.46.232/29	10.3.46.233 – 10.3.46.238	10.3.46.239
223	10.3.46.240/29	10.3.46.241 – 10.3.46.246	10.3.46.247
224	10.3.46.248/29	10.3.46.249 – 10.3.46.254	10.3.46.255
225	10.3.47.0/29	10.3.47.1 – 10.3.47.6	10.3.47.7
226	10.3.47.8/29	10.3.47.9 – 10.3.47.14	10.3.47.15
227	10.3.47.16/29	10.3.47.17 – 10.3.47.22	10.3.47.23
228	10.3.47.24/29	10.3.47.25 – 10.3.47.30	10.3.47.31
229	10.3.47.32/29	10.3.47.33 – 10.3.47.38	10.3.47.39
230	10.3.47.40/29	10.3.47.41 – 10.3.47.46	10.3.47.47
231	10.3.47.48/29	10.3.47.49 – 10.3.47.54	10.3.47.55
232	10.3.47.56/29	10.3.47.57 – 10.3.47.62	10.3.47.63
233	10.3.47.64/29	10.3.47.65 – 10.3.47.70	10.3.47.71
234	10.3.47.72/29	10.3.47.73 – 10.3.47.78	10.3.47.79
235	10.3.47.80/29	10.3.47.81 – 10.3.47.86	10.3.47.87
236	10.3.47.88/29	10.3.47.89 – 10.3.47.94	10.3.47.95
237	10.3.47.96/29	10.3.47.97 – 10.3.47.102	10.3.47.103
238	10.3.47.104/29	10.3.47.105 – 10.3.47.110	10.3.47.111
239	10.3.47.112/29	10.3.47.113 – 10.3.47.118	10.3.47.119
240	10.3.47.120/29	10.3.47.121 – 10.3.47.126	10.3.47.127
241	10.3.47.128/29	10.3.47.129 – 10.3.47.134	10.3.47.135
242	10.3.47.136/29	10.3.47.137 – 10.3.47.142	10.3.47.143
243	10.3.47.144/29	10.3.47.145 – 10.3.47.150	10.3.47.151
244	10.3.47.152/29	10.3.47.153 – 10.3.47.158	10.3.47.159
245	10.3.47.160/29	10.3.47.161 – 10.3.47.166	10.3.47.167
246	10.3.47.168/29	10.3.47.169 – 10.3.47.174	10.3.47.175
247	10.3.47.176/29	10.3.47.177 – 10.3.47.182	10.3.47.183
248	10.3.47.184/29	10.3.47.185 – 10.3.47.190	10.3.47.191
249	10.3.47.192/29	10.3.47.193 – 10.3.47.198	10.3.47.199
250	10.3.47.200/29	10.3.47.201 – 10.3.47.206	10.3.47.207
251	10.3.47.208/29	10.3.47.209 – 10.3.47.214	10.3.47.215
252	10.3.47.216/29	10.3.47.217 – 10.3.47.222	10.3.47.223
253	10.3.47.224/29	10.3.47.225 – 10.3.47.230	10.3.47.231
254	10.3.47.232/29	10.3.47.233 – 10.3.47.238	10.3.47.239
255	10.3.47.240/29	10.3.47.241 – 10.3.47.246	10.3.47.247
256	10.3.47.248/29	10.3.47.249 – 10.3.47.254	10.3.47.255

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 →