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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.

Prefix/20
Addresses2^108
/64 networks2^44
Network
fc4a::/20
First address
fc4a::
Last address
fc4a:fff:ffff:ffff:ffff:ffff:ffff:ffff
Addresses
324,518,553,658,426,726,783,156,020,576,256 (2^108)
/64 networks (LANs)
17,592,186,044,416 (2^44)
Full form
fc4a:0000:0000:0000:0000:0000:0000:0000
Type
Unique local (ULA) fc00::/7
Private IPv6, like RFC 1918; usually fd00::/8
Reverse DNS zone
0.a.4.c.f.ip6.arpa
Split into smaller subnets/28
/21 (2)/22 (4)/23 (8)/24 (16)/28 (256)/32 (4,096)/36 (65,536)

fc4a::/20 makes 256 subnets of /28.

Subnets
#SubnetLast address
1fc4a::/28fc4a:f:ffff:ffff:ffff:ffff:ffff:ffff
2fc4a:10::/28fc4a:1f:ffff:ffff:ffff:ffff:ffff:ffff
3fc4a:20::/28fc4a:2f:ffff:ffff:ffff:ffff:ffff:ffff
4fc4a:30::/28fc4a:3f:ffff:ffff:ffff:ffff:ffff:ffff
5fc4a:40::/28fc4a:4f:ffff:ffff:ffff:ffff:ffff:ffff
6fc4a:50::/28fc4a:5f:ffff:ffff:ffff:ffff:ffff:ffff
7fc4a:60::/28fc4a:6f:ffff:ffff:ffff:ffff:ffff:ffff
8fc4a:70::/28fc4a:7f:ffff:ffff:ffff:ffff:ffff:ffff
9fc4a:80::/28fc4a:8f:ffff:ffff:ffff:ffff:ffff:ffff
10fc4a:90::/28fc4a:9f:ffff:ffff:ffff:ffff:ffff:ffff
11fc4a:a0::/28fc4a:af:ffff:ffff:ffff:ffff:ffff:ffff
12fc4a:b0::/28fc4a:bf:ffff:ffff:ffff:ffff:ffff:ffff
13fc4a:c0::/28fc4a:cf:ffff:ffff:ffff:ffff:ffff:ffff
14fc4a:d0::/28fc4a:df:ffff:ffff:ffff:ffff:ffff:ffff
15fc4a:e0::/28fc4a:ef:ffff:ffff:ffff:ffff:ffff:ffff
16fc4a:f0::/28fc4a:ff:ffff:ffff:ffff:ffff:ffff:ffff
17fc4a:100::/28fc4a:10f:ffff:ffff:ffff:ffff:ffff:ffff
18fc4a:110::/28fc4a:11f:ffff:ffff:ffff:ffff:ffff:ffff
19fc4a:120::/28fc4a:12f:ffff:ffff:ffff:ffff:ffff:ffff
20fc4a:130::/28fc4a:13f:ffff:ffff:ffff:ffff:ffff:ffff
21fc4a:140::/28fc4a:14f:ffff:ffff:ffff:ffff:ffff:ffff
22fc4a:150::/28fc4a:15f:ffff:ffff:ffff:ffff:ffff:ffff
23fc4a:160::/28fc4a:16f:ffff:ffff:ffff:ffff:ffff:ffff
24fc4a:170::/28fc4a:17f:ffff:ffff:ffff:ffff:ffff:ffff
25fc4a:180::/28fc4a:18f:ffff:ffff:ffff:ffff:ffff:ffff
26fc4a:190::/28fc4a:19f:ffff:ffff:ffff:ffff:ffff:ffff
27fc4a:1a0::/28fc4a:1af:ffff:ffff:ffff:ffff:ffff:ffff
28fc4a:1b0::/28fc4a:1bf:ffff:ffff:ffff:ffff:ffff:ffff
29fc4a:1c0::/28fc4a:1cf:ffff:ffff:ffff:ffff:ffff:ffff
30fc4a:1d0::/28fc4a:1df:ffff:ffff:ffff:ffff:ffff:ffff
31fc4a:1e0::/28fc4a:1ef:ffff:ffff:ffff:ffff:ffff:ffff
32fc4a:1f0::/28fc4a:1ff:ffff:ffff:ffff:ffff:ffff:ffff
33fc4a:200::/28fc4a:20f:ffff:ffff:ffff:ffff:ffff:ffff
34fc4a:210::/28fc4a:21f:ffff:ffff:ffff:ffff:ffff:ffff
35fc4a:220::/28fc4a:22f:ffff:ffff:ffff:ffff:ffff:ffff
36fc4a:230::/28fc4a:23f:ffff:ffff:ffff:ffff:ffff:ffff
37fc4a:240::/28fc4a:24f:ffff:ffff:ffff:ffff:ffff:ffff
38fc4a:250::/28fc4a:25f:ffff:ffff:ffff:ffff:ffff:ffff
39fc4a:260::/28fc4a:26f:ffff:ffff:ffff:ffff:ffff:ffff
40fc4a:270::/28fc4a:27f:ffff:ffff:ffff:ffff:ffff:ffff
41fc4a:280::/28fc4a:28f:ffff:ffff:ffff:ffff:ffff:ffff
42fc4a:290::/28fc4a:29f:ffff:ffff:ffff:ffff:ffff:ffff
43fc4a:2a0::/28fc4a:2af:ffff:ffff:ffff:ffff:ffff:ffff
44fc4a:2b0::/28fc4a:2bf:ffff:ffff:ffff:ffff:ffff:ffff
45fc4a:2c0::/28fc4a:2cf:ffff:ffff:ffff:ffff:ffff:ffff
46fc4a:2d0::/28fc4a:2df:ffff:ffff:ffff:ffff:ffff:ffff
47fc4a:2e0::/28fc4a:2ef:ffff:ffff:ffff:ffff:ffff:ffff
48fc4a:2f0::/28fc4a:2ff:ffff:ffff:ffff:ffff:ffff:ffff
49fc4a:300::/28fc4a:30f:ffff:ffff:ffff:ffff:ffff:ffff
50fc4a:310::/28fc4a:31f:ffff:ffff:ffff:ffff:ffff:ffff
51fc4a:320::/28fc4a:32f:ffff:ffff:ffff:ffff:ffff:ffff
52fc4a:330::/28fc4a:33f:ffff:ffff:ffff:ffff:ffff:ffff
53fc4a:340::/28fc4a:34f:ffff:ffff:ffff:ffff:ffff:ffff
54fc4a:350::/28fc4a:35f:ffff:ffff:ffff:ffff:ffff:ffff
55fc4a:360::/28fc4a:36f:ffff:ffff:ffff:ffff:ffff:ffff
56fc4a:370::/28fc4a:37f:ffff:ffff:ffff:ffff:ffff:ffff
57fc4a:380::/28fc4a:38f:ffff:ffff:ffff:ffff:ffff:ffff
58fc4a:390::/28fc4a:39f:ffff:ffff:ffff:ffff:ffff:ffff
59fc4a:3a0::/28fc4a:3af:ffff:ffff:ffff:ffff:ffff:ffff
60fc4a:3b0::/28fc4a:3bf:ffff:ffff:ffff:ffff:ffff:ffff
61fc4a:3c0::/28fc4a:3cf:ffff:ffff:ffff:ffff:ffff:ffff
62fc4a:3d0::/28fc4a:3df:ffff:ffff:ffff:ffff:ffff:ffff
63fc4a:3e0::/28fc4a:3ef:ffff:ffff:ffff:ffff:ffff:ffff
64fc4a:3f0::/28fc4a:3ff:ffff:ffff:ffff:ffff:ffff:ffff
65fc4a:400::/28fc4a:40f:ffff:ffff:ffff:ffff:ffff:ffff
66fc4a:410::/28fc4a:41f:ffff:ffff:ffff:ffff:ffff:ffff
67fc4a:420::/28fc4a:42f:ffff:ffff:ffff:ffff:ffff:ffff
68fc4a:430::/28fc4a:43f:ffff:ffff:ffff:ffff:ffff:ffff
69fc4a:440::/28fc4a:44f:ffff:ffff:ffff:ffff:ffff:ffff
70fc4a:450::/28fc4a:45f:ffff:ffff:ffff:ffff:ffff:ffff
71fc4a:460::/28fc4a:46f:ffff:ffff:ffff:ffff:ffff:ffff
72fc4a:470::/28fc4a:47f:ffff:ffff:ffff:ffff:ffff:ffff
73fc4a:480::/28fc4a:48f:ffff:ffff:ffff:ffff:ffff:ffff
74fc4a:490::/28fc4a:49f:ffff:ffff:ffff:ffff:ffff:ffff
75fc4a:4a0::/28fc4a:4af:ffff:ffff:ffff:ffff:ffff:ffff
76fc4a:4b0::/28fc4a:4bf:ffff:ffff:ffff:ffff:ffff:ffff
77fc4a:4c0::/28fc4a:4cf:ffff:ffff:ffff:ffff:ffff:ffff
78fc4a:4d0::/28fc4a:4df:ffff:ffff:ffff:ffff:ffff:ffff
79fc4a:4e0::/28fc4a:4ef:ffff:ffff:ffff:ffff:ffff:ffff
80fc4a:4f0::/28fc4a:4ff:ffff:ffff:ffff:ffff:ffff:ffff
81fc4a:500::/28fc4a:50f:ffff:ffff:ffff:ffff:ffff:ffff
82fc4a:510::/28fc4a:51f:ffff:ffff:ffff:ffff:ffff:ffff
83fc4a:520::/28fc4a:52f:ffff:ffff:ffff:ffff:ffff:ffff
84fc4a:530::/28fc4a:53f:ffff:ffff:ffff:ffff:ffff:ffff
85fc4a:540::/28fc4a:54f:ffff:ffff:ffff:ffff:ffff:ffff
86fc4a:550::/28fc4a:55f:ffff:ffff:ffff:ffff:ffff:ffff
87fc4a:560::/28fc4a:56f:ffff:ffff:ffff:ffff:ffff:ffff
88fc4a:570::/28fc4a:57f:ffff:ffff:ffff:ffff:ffff:ffff
89fc4a:580::/28fc4a:58f:ffff:ffff:ffff:ffff:ffff:ffff
90fc4a:590::/28fc4a:59f:ffff:ffff:ffff:ffff:ffff:ffff
91fc4a:5a0::/28fc4a:5af:ffff:ffff:ffff:ffff:ffff:ffff
92fc4a:5b0::/28fc4a:5bf:ffff:ffff:ffff:ffff:ffff:ffff
93fc4a:5c0::/28fc4a:5cf:ffff:ffff:ffff:ffff:ffff:ffff
94fc4a:5d0::/28fc4a:5df:ffff:ffff:ffff:ffff:ffff:ffff
95fc4a:5e0::/28fc4a:5ef:ffff:ffff:ffff:ffff:ffff:ffff
96fc4a:5f0::/28fc4a:5ff:ffff:ffff:ffff:ffff:ffff:ffff
97fc4a:600::/28fc4a:60f:ffff:ffff:ffff:ffff:ffff:ffff
98fc4a:610::/28fc4a:61f:ffff:ffff:ffff:ffff:ffff:ffff
99fc4a:620::/28fc4a:62f:ffff:ffff:ffff:ffff:ffff:ffff
100fc4a:630::/28fc4a:63f:ffff:ffff:ffff:ffff:ffff:ffff
101fc4a:640::/28fc4a:64f:ffff:ffff:ffff:ffff:ffff:ffff
102fc4a:650::/28fc4a:65f:ffff:ffff:ffff:ffff:ffff:ffff
103fc4a:660::/28fc4a:66f:ffff:ffff:ffff:ffff:ffff:ffff
104fc4a:670::/28fc4a:67f:ffff:ffff:ffff:ffff:ffff:ffff
105fc4a:680::/28fc4a:68f:ffff:ffff:ffff:ffff:ffff:ffff
106fc4a:690::/28fc4a:69f:ffff:ffff:ffff:ffff:ffff:ffff
107fc4a:6a0::/28fc4a:6af:ffff:ffff:ffff:ffff:ffff:ffff
108fc4a:6b0::/28fc4a:6bf:ffff:ffff:ffff:ffff:ffff:ffff
109fc4a:6c0::/28fc4a:6cf:ffff:ffff:ffff:ffff:ffff:ffff
110fc4a:6d0::/28fc4a:6df:ffff:ffff:ffff:ffff:ffff:ffff
111fc4a:6e0::/28fc4a:6ef:ffff:ffff:ffff:ffff:ffff:ffff
112fc4a:6f0::/28fc4a:6ff:ffff:ffff:ffff:ffff:ffff:ffff
113fc4a:700::/28fc4a:70f:ffff:ffff:ffff:ffff:ffff:ffff
114fc4a:710::/28fc4a:71f:ffff:ffff:ffff:ffff:ffff:ffff
115fc4a:720::/28fc4a:72f:ffff:ffff:ffff:ffff:ffff:ffff
116fc4a:730::/28fc4a:73f:ffff:ffff:ffff:ffff:ffff:ffff
117fc4a:740::/28fc4a:74f:ffff:ffff:ffff:ffff:ffff:ffff
118fc4a:750::/28fc4a:75f:ffff:ffff:ffff:ffff:ffff:ffff
119fc4a:760::/28fc4a:76f:ffff:ffff:ffff:ffff:ffff:ffff
120fc4a:770::/28fc4a:77f:ffff:ffff:ffff:ffff:ffff:ffff
121fc4a:780::/28fc4a:78f:ffff:ffff:ffff:ffff:ffff:ffff
122fc4a:790::/28fc4a:79f:ffff:ffff:ffff:ffff:ffff:ffff
123fc4a:7a0::/28fc4a:7af:ffff:ffff:ffff:ffff:ffff:ffff
124fc4a:7b0::/28fc4a:7bf:ffff:ffff:ffff:ffff:ffff:ffff
125fc4a:7c0::/28fc4a:7cf:ffff:ffff:ffff:ffff:ffff:ffff
126fc4a:7d0::/28fc4a:7df:ffff:ffff:ffff:ffff:ffff:ffff
127fc4a:7e0::/28fc4a:7ef:ffff:ffff:ffff:ffff:ffff:ffff
128fc4a:7f0::/28fc4a:7ff:ffff:ffff:ffff:ffff:ffff:ffff
129fc4a:800::/28fc4a:80f:ffff:ffff:ffff:ffff:ffff:ffff
130fc4a:810::/28fc4a:81f:ffff:ffff:ffff:ffff:ffff:ffff
131fc4a:820::/28fc4a:82f:ffff:ffff:ffff:ffff:ffff:ffff
132fc4a:830::/28fc4a:83f:ffff:ffff:ffff:ffff:ffff:ffff
133fc4a:840::/28fc4a:84f:ffff:ffff:ffff:ffff:ffff:ffff
134fc4a:850::/28fc4a:85f:ffff:ffff:ffff:ffff:ffff:ffff
135fc4a:860::/28fc4a:86f:ffff:ffff:ffff:ffff:ffff:ffff
136fc4a:870::/28fc4a:87f:ffff:ffff:ffff:ffff:ffff:ffff
137fc4a:880::/28fc4a:88f:ffff:ffff:ffff:ffff:ffff:ffff
138fc4a:890::/28fc4a:89f:ffff:ffff:ffff:ffff:ffff:ffff
139fc4a:8a0::/28fc4a:8af:ffff:ffff:ffff:ffff:ffff:ffff
140fc4a:8b0::/28fc4a:8bf:ffff:ffff:ffff:ffff:ffff:ffff
141fc4a:8c0::/28fc4a:8cf:ffff:ffff:ffff:ffff:ffff:ffff
142fc4a:8d0::/28fc4a:8df:ffff:ffff:ffff:ffff:ffff:ffff
143fc4a:8e0::/28fc4a:8ef:ffff:ffff:ffff:ffff:ffff:ffff
144fc4a:8f0::/28fc4a:8ff:ffff:ffff:ffff:ffff:ffff:ffff
145fc4a:900::/28fc4a:90f:ffff:ffff:ffff:ffff:ffff:ffff
146fc4a:910::/28fc4a:91f:ffff:ffff:ffff:ffff:ffff:ffff
147fc4a:920::/28fc4a:92f:ffff:ffff:ffff:ffff:ffff:ffff
148fc4a:930::/28fc4a:93f:ffff:ffff:ffff:ffff:ffff:ffff
149fc4a:940::/28fc4a:94f:ffff:ffff:ffff:ffff:ffff:ffff
150fc4a:950::/28fc4a:95f:ffff:ffff:ffff:ffff:ffff:ffff
151fc4a:960::/28fc4a:96f:ffff:ffff:ffff:ffff:ffff:ffff
152fc4a:970::/28fc4a:97f:ffff:ffff:ffff:ffff:ffff:ffff
153fc4a:980::/28fc4a:98f:ffff:ffff:ffff:ffff:ffff:ffff
154fc4a:990::/28fc4a:99f:ffff:ffff:ffff:ffff:ffff:ffff
155fc4a:9a0::/28fc4a:9af:ffff:ffff:ffff:ffff:ffff:ffff
156fc4a:9b0::/28fc4a:9bf:ffff:ffff:ffff:ffff:ffff:ffff
157fc4a:9c0::/28fc4a:9cf:ffff:ffff:ffff:ffff:ffff:ffff
158fc4a:9d0::/28fc4a:9df:ffff:ffff:ffff:ffff:ffff:ffff
159fc4a:9e0::/28fc4a:9ef:ffff:ffff:ffff:ffff:ffff:ffff
160fc4a:9f0::/28fc4a:9ff:ffff:ffff:ffff:ffff:ffff:ffff
161fc4a:a00::/28fc4a:a0f:ffff:ffff:ffff:ffff:ffff:ffff
162fc4a:a10::/28fc4a:a1f:ffff:ffff:ffff:ffff:ffff:ffff
163fc4a:a20::/28fc4a:a2f:ffff:ffff:ffff:ffff:ffff:ffff
164fc4a:a30::/28fc4a:a3f:ffff:ffff:ffff:ffff:ffff:ffff
165fc4a:a40::/28fc4a:a4f:ffff:ffff:ffff:ffff:ffff:ffff
166fc4a:a50::/28fc4a:a5f:ffff:ffff:ffff:ffff:ffff:ffff
167fc4a:a60::/28fc4a:a6f:ffff:ffff:ffff:ffff:ffff:ffff
168fc4a:a70::/28fc4a:a7f:ffff:ffff:ffff:ffff:ffff:ffff
169fc4a:a80::/28fc4a:a8f:ffff:ffff:ffff:ffff:ffff:ffff
170fc4a:a90::/28fc4a:a9f:ffff:ffff:ffff:ffff:ffff:ffff
171fc4a:aa0::/28fc4a:aaf:ffff:ffff:ffff:ffff:ffff:ffff
172fc4a:ab0::/28fc4a:abf:ffff:ffff:ffff:ffff:ffff:ffff
173fc4a:ac0::/28fc4a:acf:ffff:ffff:ffff:ffff:ffff:ffff
174fc4a:ad0::/28fc4a:adf:ffff:ffff:ffff:ffff:ffff:ffff
175fc4a:ae0::/28fc4a:aef:ffff:ffff:ffff:ffff:ffff:ffff
176fc4a:af0::/28fc4a:aff:ffff:ffff:ffff:ffff:ffff:ffff
177fc4a:b00::/28fc4a:b0f:ffff:ffff:ffff:ffff:ffff:ffff
178fc4a:b10::/28fc4a:b1f:ffff:ffff:ffff:ffff:ffff:ffff
179fc4a:b20::/28fc4a:b2f:ffff:ffff:ffff:ffff:ffff:ffff
180fc4a:b30::/28fc4a:b3f:ffff:ffff:ffff:ffff:ffff:ffff
181fc4a:b40::/28fc4a:b4f:ffff:ffff:ffff:ffff:ffff:ffff
182fc4a:b50::/28fc4a:b5f:ffff:ffff:ffff:ffff:ffff:ffff
183fc4a:b60::/28fc4a:b6f:ffff:ffff:ffff:ffff:ffff:ffff
184fc4a:b70::/28fc4a:b7f:ffff:ffff:ffff:ffff:ffff:ffff
185fc4a:b80::/28fc4a:b8f:ffff:ffff:ffff:ffff:ffff:ffff
186fc4a:b90::/28fc4a:b9f:ffff:ffff:ffff:ffff:ffff:ffff
187fc4a:ba0::/28fc4a:baf:ffff:ffff:ffff:ffff:ffff:ffff
188fc4a:bb0::/28fc4a:bbf:ffff:ffff:ffff:ffff:ffff:ffff
189fc4a:bc0::/28fc4a:bcf:ffff:ffff:ffff:ffff:ffff:ffff
190fc4a:bd0::/28fc4a:bdf:ffff:ffff:ffff:ffff:ffff:ffff
191fc4a:be0::/28fc4a:bef:ffff:ffff:ffff:ffff:ffff:ffff
192fc4a:bf0::/28fc4a:bff:ffff:ffff:ffff:ffff:ffff:ffff
193fc4a:c00::/28fc4a:c0f:ffff:ffff:ffff:ffff:ffff:ffff
194fc4a:c10::/28fc4a:c1f:ffff:ffff:ffff:ffff:ffff:ffff
195fc4a:c20::/28fc4a:c2f:ffff:ffff:ffff:ffff:ffff:ffff
196fc4a:c30::/28fc4a:c3f:ffff:ffff:ffff:ffff:ffff:ffff
197fc4a:c40::/28fc4a:c4f:ffff:ffff:ffff:ffff:ffff:ffff
198fc4a:c50::/28fc4a:c5f:ffff:ffff:ffff:ffff:ffff:ffff
199fc4a:c60::/28fc4a:c6f:ffff:ffff:ffff:ffff:ffff:ffff
200fc4a:c70::/28fc4a:c7f:ffff:ffff:ffff:ffff:ffff:ffff
201fc4a:c80::/28fc4a:c8f:ffff:ffff:ffff:ffff:ffff:ffff
202fc4a:c90::/28fc4a:c9f:ffff:ffff:ffff:ffff:ffff:ffff
203fc4a:ca0::/28fc4a:caf:ffff:ffff:ffff:ffff:ffff:ffff
204fc4a:cb0::/28fc4a:cbf:ffff:ffff:ffff:ffff:ffff:ffff
205fc4a:cc0::/28fc4a:ccf:ffff:ffff:ffff:ffff:ffff:ffff
206fc4a:cd0::/28fc4a:cdf:ffff:ffff:ffff:ffff:ffff:ffff
207fc4a:ce0::/28fc4a:cef:ffff:ffff:ffff:ffff:ffff:ffff
208fc4a:cf0::/28fc4a:cff:ffff:ffff:ffff:ffff:ffff:ffff
209fc4a:d00::/28fc4a:d0f:ffff:ffff:ffff:ffff:ffff:ffff
210fc4a:d10::/28fc4a:d1f:ffff:ffff:ffff:ffff:ffff:ffff
211fc4a:d20::/28fc4a:d2f:ffff:ffff:ffff:ffff:ffff:ffff
212fc4a:d30::/28fc4a:d3f:ffff:ffff:ffff:ffff:ffff:ffff
213fc4a:d40::/28fc4a:d4f:ffff:ffff:ffff:ffff:ffff:ffff
214fc4a:d50::/28fc4a:d5f:ffff:ffff:ffff:ffff:ffff:ffff
215fc4a:d60::/28fc4a:d6f:ffff:ffff:ffff:ffff:ffff:ffff
216fc4a:d70::/28fc4a:d7f:ffff:ffff:ffff:ffff:ffff:ffff
217fc4a:d80::/28fc4a:d8f:ffff:ffff:ffff:ffff:ffff:ffff
218fc4a:d90::/28fc4a:d9f:ffff:ffff:ffff:ffff:ffff:ffff
219fc4a:da0::/28fc4a:daf:ffff:ffff:ffff:ffff:ffff:ffff
220fc4a:db0::/28fc4a:dbf:ffff:ffff:ffff:ffff:ffff:ffff
221fc4a:dc0::/28fc4a:dcf:ffff:ffff:ffff:ffff:ffff:ffff
222fc4a:dd0::/28fc4a:ddf:ffff:ffff:ffff:ffff:ffff:ffff
223fc4a:de0::/28fc4a:def:ffff:ffff:ffff:ffff:ffff:ffff
224fc4a:df0::/28fc4a:dff:ffff:ffff:ffff:ffff:ffff:ffff
225fc4a:e00::/28fc4a:e0f:ffff:ffff:ffff:ffff:ffff:ffff
226fc4a:e10::/28fc4a:e1f:ffff:ffff:ffff:ffff:ffff:ffff
227fc4a:e20::/28fc4a:e2f:ffff:ffff:ffff:ffff:ffff:ffff
228fc4a:e30::/28fc4a:e3f:ffff:ffff:ffff:ffff:ffff:ffff
229fc4a:e40::/28fc4a:e4f:ffff:ffff:ffff:ffff:ffff:ffff
230fc4a:e50::/28fc4a:e5f:ffff:ffff:ffff:ffff:ffff:ffff
231fc4a:e60::/28fc4a:e6f:ffff:ffff:ffff:ffff:ffff:ffff
232fc4a:e70::/28fc4a:e7f:ffff:ffff:ffff:ffff:ffff:ffff
233fc4a:e80::/28fc4a:e8f:ffff:ffff:ffff:ffff:ffff:ffff
234fc4a:e90::/28fc4a:e9f:ffff:ffff:ffff:ffff:ffff:ffff
235fc4a:ea0::/28fc4a:eaf:ffff:ffff:ffff:ffff:ffff:ffff
236fc4a:eb0::/28fc4a:ebf:ffff:ffff:ffff:ffff:ffff:ffff
237fc4a:ec0::/28fc4a:ecf:ffff:ffff:ffff:ffff:ffff:ffff
238fc4a:ed0::/28fc4a:edf:ffff:ffff:ffff:ffff:ffff:ffff
239fc4a:ee0::/28fc4a:eef:ffff:ffff:ffff:ffff:ffff:ffff
240fc4a:ef0::/28fc4a:eff:ffff:ffff:ffff:ffff:ffff:ffff
241fc4a:f00::/28fc4a:f0f:ffff:ffff:ffff:ffff:ffff:ffff
242fc4a:f10::/28fc4a:f1f:ffff:ffff:ffff:ffff:ffff:ffff
243fc4a:f20::/28fc4a:f2f:ffff:ffff:ffff:ffff:ffff:ffff
244fc4a:f30::/28fc4a:f3f:ffff:ffff:ffff:ffff:ffff:ffff
245fc4a:f40::/28fc4a:f4f:ffff:ffff:ffff:ffff:ffff:ffff
246fc4a:f50::/28fc4a:f5f:ffff:ffff:ffff:ffff:ffff:ffff
247fc4a:f60::/28fc4a:f6f:ffff:ffff:ffff:ffff:ffff:ffff
248fc4a:f70::/28fc4a:f7f:ffff:ffff:ffff:ffff:ffff:ffff
249fc4a:f80::/28fc4a:f8f:ffff:ffff:ffff:ffff:ffff:ffff
250fc4a:f90::/28fc4a:f9f:ffff:ffff:ffff:ffff:ffff:ffff
251fc4a:fa0::/28fc4a:faf:ffff:ffff:ffff:ffff:ffff:ffff
252fc4a:fb0::/28fc4a:fbf:ffff:ffff:ffff:ffff:ffff:ffff
253fc4a:fc0::/28fc4a:fcf:ffff:ffff:ffff:ffff:ffff:ffff
254fc4a:fd0::/28fc4a:fdf:ffff:ffff:ffff:ffff:ffff:ffff
255fc4a:fe0::/28fc4a:fef:ffff:ffff:ffff:ffff:ffff:ffff
256fc4a:ff0::/28fc4a:fff:ffff:ffff:ffff:ffff:ffff:ffff

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.