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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/16
Addresses2^112
/64 networks2^48
Network
fc3a::/16
First address
fc3a::
Last address
fc3a:ffff:ffff:ffff:ffff:ffff:ffff:ffff
Addresses
5,192,296,858,534,827,628,530,496,329,220,096 (2^112)
/64 networks (LANs)
281,474,976,710,656 (2^48)
Full form
fc3a:0000:0000:0000:0000:0000:0000:0000
Type
Unique local (ULA) fc00::/7
Private IPv6, like RFC 1918; usually fd00::/8
Reverse DNS zone
a.3.c.f.ip6.arpa
Split into smaller subnets/28
/17 (2)/18 (4)/19 (8)/20 (16)/24 (256)/28 (4,096)/32 (65,536)

fc3a::/16 makes 4,096 subnets of /28; the first 256 are listed.

Subnets
#SubnetLast address
1fc3a::/28fc3a:f:ffff:ffff:ffff:ffff:ffff:ffff
2fc3a:10::/28fc3a:1f:ffff:ffff:ffff:ffff:ffff:ffff
3fc3a:20::/28fc3a:2f:ffff:ffff:ffff:ffff:ffff:ffff
4fc3a:30::/28fc3a:3f:ffff:ffff:ffff:ffff:ffff:ffff
5fc3a:40::/28fc3a:4f:ffff:ffff:ffff:ffff:ffff:ffff
6fc3a:50::/28fc3a:5f:ffff:ffff:ffff:ffff:ffff:ffff
7fc3a:60::/28fc3a:6f:ffff:ffff:ffff:ffff:ffff:ffff
8fc3a:70::/28fc3a:7f:ffff:ffff:ffff:ffff:ffff:ffff
9fc3a:80::/28fc3a:8f:ffff:ffff:ffff:ffff:ffff:ffff
10fc3a:90::/28fc3a:9f:ffff:ffff:ffff:ffff:ffff:ffff
11fc3a:a0::/28fc3a:af:ffff:ffff:ffff:ffff:ffff:ffff
12fc3a:b0::/28fc3a:bf:ffff:ffff:ffff:ffff:ffff:ffff
13fc3a:c0::/28fc3a:cf:ffff:ffff:ffff:ffff:ffff:ffff
14fc3a:d0::/28fc3a:df:ffff:ffff:ffff:ffff:ffff:ffff
15fc3a:e0::/28fc3a:ef:ffff:ffff:ffff:ffff:ffff:ffff
16fc3a:f0::/28fc3a:ff:ffff:ffff:ffff:ffff:ffff:ffff
17fc3a:100::/28fc3a:10f:ffff:ffff:ffff:ffff:ffff:ffff
18fc3a:110::/28fc3a:11f:ffff:ffff:ffff:ffff:ffff:ffff
19fc3a:120::/28fc3a:12f:ffff:ffff:ffff:ffff:ffff:ffff
20fc3a:130::/28fc3a:13f:ffff:ffff:ffff:ffff:ffff:ffff
21fc3a:140::/28fc3a:14f:ffff:ffff:ffff:ffff:ffff:ffff
22fc3a:150::/28fc3a:15f:ffff:ffff:ffff:ffff:ffff:ffff
23fc3a:160::/28fc3a:16f:ffff:ffff:ffff:ffff:ffff:ffff
24fc3a:170::/28fc3a:17f:ffff:ffff:ffff:ffff:ffff:ffff
25fc3a:180::/28fc3a:18f:ffff:ffff:ffff:ffff:ffff:ffff
26fc3a:190::/28fc3a:19f:ffff:ffff:ffff:ffff:ffff:ffff
27fc3a:1a0::/28fc3a:1af:ffff:ffff:ffff:ffff:ffff:ffff
28fc3a:1b0::/28fc3a:1bf:ffff:ffff:ffff:ffff:ffff:ffff
29fc3a:1c0::/28fc3a:1cf:ffff:ffff:ffff:ffff:ffff:ffff
30fc3a:1d0::/28fc3a:1df:ffff:ffff:ffff:ffff:ffff:ffff
31fc3a:1e0::/28fc3a:1ef:ffff:ffff:ffff:ffff:ffff:ffff
32fc3a:1f0::/28fc3a:1ff:ffff:ffff:ffff:ffff:ffff:ffff
33fc3a:200::/28fc3a:20f:ffff:ffff:ffff:ffff:ffff:ffff
34fc3a:210::/28fc3a:21f:ffff:ffff:ffff:ffff:ffff:ffff
35fc3a:220::/28fc3a:22f:ffff:ffff:ffff:ffff:ffff:ffff
36fc3a:230::/28fc3a:23f:ffff:ffff:ffff:ffff:ffff:ffff
37fc3a:240::/28fc3a:24f:ffff:ffff:ffff:ffff:ffff:ffff
38fc3a:250::/28fc3a:25f:ffff:ffff:ffff:ffff:ffff:ffff
39fc3a:260::/28fc3a:26f:ffff:ffff:ffff:ffff:ffff:ffff
40fc3a:270::/28fc3a:27f:ffff:ffff:ffff:ffff:ffff:ffff
41fc3a:280::/28fc3a:28f:ffff:ffff:ffff:ffff:ffff:ffff
42fc3a:290::/28fc3a:29f:ffff:ffff:ffff:ffff:ffff:ffff
43fc3a:2a0::/28fc3a:2af:ffff:ffff:ffff:ffff:ffff:ffff
44fc3a:2b0::/28fc3a:2bf:ffff:ffff:ffff:ffff:ffff:ffff
45fc3a:2c0::/28fc3a:2cf:ffff:ffff:ffff:ffff:ffff:ffff
46fc3a:2d0::/28fc3a:2df:ffff:ffff:ffff:ffff:ffff:ffff
47fc3a:2e0::/28fc3a:2ef:ffff:ffff:ffff:ffff:ffff:ffff
48fc3a:2f0::/28fc3a:2ff:ffff:ffff:ffff:ffff:ffff:ffff
49fc3a:300::/28fc3a:30f:ffff:ffff:ffff:ffff:ffff:ffff
50fc3a:310::/28fc3a:31f:ffff:ffff:ffff:ffff:ffff:ffff
51fc3a:320::/28fc3a:32f:ffff:ffff:ffff:ffff:ffff:ffff
52fc3a:330::/28fc3a:33f:ffff:ffff:ffff:ffff:ffff:ffff
53fc3a:340::/28fc3a:34f:ffff:ffff:ffff:ffff:ffff:ffff
54fc3a:350::/28fc3a:35f:ffff:ffff:ffff:ffff:ffff:ffff
55fc3a:360::/28fc3a:36f:ffff:ffff:ffff:ffff:ffff:ffff
56fc3a:370::/28fc3a:37f:ffff:ffff:ffff:ffff:ffff:ffff
57fc3a:380::/28fc3a:38f:ffff:ffff:ffff:ffff:ffff:ffff
58fc3a:390::/28fc3a:39f:ffff:ffff:ffff:ffff:ffff:ffff
59fc3a:3a0::/28fc3a:3af:ffff:ffff:ffff:ffff:ffff:ffff
60fc3a:3b0::/28fc3a:3bf:ffff:ffff:ffff:ffff:ffff:ffff
61fc3a:3c0::/28fc3a:3cf:ffff:ffff:ffff:ffff:ffff:ffff
62fc3a:3d0::/28fc3a:3df:ffff:ffff:ffff:ffff:ffff:ffff
63fc3a:3e0::/28fc3a:3ef:ffff:ffff:ffff:ffff:ffff:ffff
64fc3a:3f0::/28fc3a:3ff:ffff:ffff:ffff:ffff:ffff:ffff
65fc3a:400::/28fc3a:40f:ffff:ffff:ffff:ffff:ffff:ffff
66fc3a:410::/28fc3a:41f:ffff:ffff:ffff:ffff:ffff:ffff
67fc3a:420::/28fc3a:42f:ffff:ffff:ffff:ffff:ffff:ffff
68fc3a:430::/28fc3a:43f:ffff:ffff:ffff:ffff:ffff:ffff
69fc3a:440::/28fc3a:44f:ffff:ffff:ffff:ffff:ffff:ffff
70fc3a:450::/28fc3a:45f:ffff:ffff:ffff:ffff:ffff:ffff
71fc3a:460::/28fc3a:46f:ffff:ffff:ffff:ffff:ffff:ffff
72fc3a:470::/28fc3a:47f:ffff:ffff:ffff:ffff:ffff:ffff
73fc3a:480::/28fc3a:48f:ffff:ffff:ffff:ffff:ffff:ffff
74fc3a:490::/28fc3a:49f:ffff:ffff:ffff:ffff:ffff:ffff
75fc3a:4a0::/28fc3a:4af:ffff:ffff:ffff:ffff:ffff:ffff
76fc3a:4b0::/28fc3a:4bf:ffff:ffff:ffff:ffff:ffff:ffff
77fc3a:4c0::/28fc3a:4cf:ffff:ffff:ffff:ffff:ffff:ffff
78fc3a:4d0::/28fc3a:4df:ffff:ffff:ffff:ffff:ffff:ffff
79fc3a:4e0::/28fc3a:4ef:ffff:ffff:ffff:ffff:ffff:ffff
80fc3a:4f0::/28fc3a:4ff:ffff:ffff:ffff:ffff:ffff:ffff
81fc3a:500::/28fc3a:50f:ffff:ffff:ffff:ffff:ffff:ffff
82fc3a:510::/28fc3a:51f:ffff:ffff:ffff:ffff:ffff:ffff
83fc3a:520::/28fc3a:52f:ffff:ffff:ffff:ffff:ffff:ffff
84fc3a:530::/28fc3a:53f:ffff:ffff:ffff:ffff:ffff:ffff
85fc3a:540::/28fc3a:54f:ffff:ffff:ffff:ffff:ffff:ffff
86fc3a:550::/28fc3a:55f:ffff:ffff:ffff:ffff:ffff:ffff
87fc3a:560::/28fc3a:56f:ffff:ffff:ffff:ffff:ffff:ffff
88fc3a:570::/28fc3a:57f:ffff:ffff:ffff:ffff:ffff:ffff
89fc3a:580::/28fc3a:58f:ffff:ffff:ffff:ffff:ffff:ffff
90fc3a:590::/28fc3a:59f:ffff:ffff:ffff:ffff:ffff:ffff
91fc3a:5a0::/28fc3a:5af:ffff:ffff:ffff:ffff:ffff:ffff
92fc3a:5b0::/28fc3a:5bf:ffff:ffff:ffff:ffff:ffff:ffff
93fc3a:5c0::/28fc3a:5cf:ffff:ffff:ffff:ffff:ffff:ffff
94fc3a:5d0::/28fc3a:5df:ffff:ffff:ffff:ffff:ffff:ffff
95fc3a:5e0::/28fc3a:5ef:ffff:ffff:ffff:ffff:ffff:ffff
96fc3a:5f0::/28fc3a:5ff:ffff:ffff:ffff:ffff:ffff:ffff
97fc3a:600::/28fc3a:60f:ffff:ffff:ffff:ffff:ffff:ffff
98fc3a:610::/28fc3a:61f:ffff:ffff:ffff:ffff:ffff:ffff
99fc3a:620::/28fc3a:62f:ffff:ffff:ffff:ffff:ffff:ffff
100fc3a:630::/28fc3a:63f:ffff:ffff:ffff:ffff:ffff:ffff
101fc3a:640::/28fc3a:64f:ffff:ffff:ffff:ffff:ffff:ffff
102fc3a:650::/28fc3a:65f:ffff:ffff:ffff:ffff:ffff:ffff
103fc3a:660::/28fc3a:66f:ffff:ffff:ffff:ffff:ffff:ffff
104fc3a:670::/28fc3a:67f:ffff:ffff:ffff:ffff:ffff:ffff
105fc3a:680::/28fc3a:68f:ffff:ffff:ffff:ffff:ffff:ffff
106fc3a:690::/28fc3a:69f:ffff:ffff:ffff:ffff:ffff:ffff
107fc3a:6a0::/28fc3a:6af:ffff:ffff:ffff:ffff:ffff:ffff
108fc3a:6b0::/28fc3a:6bf:ffff:ffff:ffff:ffff:ffff:ffff
109fc3a:6c0::/28fc3a:6cf:ffff:ffff:ffff:ffff:ffff:ffff
110fc3a:6d0::/28fc3a:6df:ffff:ffff:ffff:ffff:ffff:ffff
111fc3a:6e0::/28fc3a:6ef:ffff:ffff:ffff:ffff:ffff:ffff
112fc3a:6f0::/28fc3a:6ff:ffff:ffff:ffff:ffff:ffff:ffff
113fc3a:700::/28fc3a:70f:ffff:ffff:ffff:ffff:ffff:ffff
114fc3a:710::/28fc3a:71f:ffff:ffff:ffff:ffff:ffff:ffff
115fc3a:720::/28fc3a:72f:ffff:ffff:ffff:ffff:ffff:ffff
116fc3a:730::/28fc3a:73f:ffff:ffff:ffff:ffff:ffff:ffff
117fc3a:740::/28fc3a:74f:ffff:ffff:ffff:ffff:ffff:ffff
118fc3a:750::/28fc3a:75f:ffff:ffff:ffff:ffff:ffff:ffff
119fc3a:760::/28fc3a:76f:ffff:ffff:ffff:ffff:ffff:ffff
120fc3a:770::/28fc3a:77f:ffff:ffff:ffff:ffff:ffff:ffff
121fc3a:780::/28fc3a:78f:ffff:ffff:ffff:ffff:ffff:ffff
122fc3a:790::/28fc3a:79f:ffff:ffff:ffff:ffff:ffff:ffff
123fc3a:7a0::/28fc3a:7af:ffff:ffff:ffff:ffff:ffff:ffff
124fc3a:7b0::/28fc3a:7bf:ffff:ffff:ffff:ffff:ffff:ffff
125fc3a:7c0::/28fc3a:7cf:ffff:ffff:ffff:ffff:ffff:ffff
126fc3a:7d0::/28fc3a:7df:ffff:ffff:ffff:ffff:ffff:ffff
127fc3a:7e0::/28fc3a:7ef:ffff:ffff:ffff:ffff:ffff:ffff
128fc3a:7f0::/28fc3a:7ff:ffff:ffff:ffff:ffff:ffff:ffff
129fc3a:800::/28fc3a:80f:ffff:ffff:ffff:ffff:ffff:ffff
130fc3a:810::/28fc3a:81f:ffff:ffff:ffff:ffff:ffff:ffff
131fc3a:820::/28fc3a:82f:ffff:ffff:ffff:ffff:ffff:ffff
132fc3a:830::/28fc3a:83f:ffff:ffff:ffff:ffff:ffff:ffff
133fc3a:840::/28fc3a:84f:ffff:ffff:ffff:ffff:ffff:ffff
134fc3a:850::/28fc3a:85f:ffff:ffff:ffff:ffff:ffff:ffff
135fc3a:860::/28fc3a:86f:ffff:ffff:ffff:ffff:ffff:ffff
136fc3a:870::/28fc3a:87f:ffff:ffff:ffff:ffff:ffff:ffff
137fc3a:880::/28fc3a:88f:ffff:ffff:ffff:ffff:ffff:ffff
138fc3a:890::/28fc3a:89f:ffff:ffff:ffff:ffff:ffff:ffff
139fc3a:8a0::/28fc3a:8af:ffff:ffff:ffff:ffff:ffff:ffff
140fc3a:8b0::/28fc3a:8bf:ffff:ffff:ffff:ffff:ffff:ffff
141fc3a:8c0::/28fc3a:8cf:ffff:ffff:ffff:ffff:ffff:ffff
142fc3a:8d0::/28fc3a:8df:ffff:ffff:ffff:ffff:ffff:ffff
143fc3a:8e0::/28fc3a:8ef:ffff:ffff:ffff:ffff:ffff:ffff
144fc3a:8f0::/28fc3a:8ff:ffff:ffff:ffff:ffff:ffff:ffff
145fc3a:900::/28fc3a:90f:ffff:ffff:ffff:ffff:ffff:ffff
146fc3a:910::/28fc3a:91f:ffff:ffff:ffff:ffff:ffff:ffff
147fc3a:920::/28fc3a:92f:ffff:ffff:ffff:ffff:ffff:ffff
148fc3a:930::/28fc3a:93f:ffff:ffff:ffff:ffff:ffff:ffff
149fc3a:940::/28fc3a:94f:ffff:ffff:ffff:ffff:ffff:ffff
150fc3a:950::/28fc3a:95f:ffff:ffff:ffff:ffff:ffff:ffff
151fc3a:960::/28fc3a:96f:ffff:ffff:ffff:ffff:ffff:ffff
152fc3a:970::/28fc3a:97f:ffff:ffff:ffff:ffff:ffff:ffff
153fc3a:980::/28fc3a:98f:ffff:ffff:ffff:ffff:ffff:ffff
154fc3a:990::/28fc3a:99f:ffff:ffff:ffff:ffff:ffff:ffff
155fc3a:9a0::/28fc3a:9af:ffff:ffff:ffff:ffff:ffff:ffff
156fc3a:9b0::/28fc3a:9bf:ffff:ffff:ffff:ffff:ffff:ffff
157fc3a:9c0::/28fc3a:9cf:ffff:ffff:ffff:ffff:ffff:ffff
158fc3a:9d0::/28fc3a:9df:ffff:ffff:ffff:ffff:ffff:ffff
159fc3a:9e0::/28fc3a:9ef:ffff:ffff:ffff:ffff:ffff:ffff
160fc3a:9f0::/28fc3a:9ff:ffff:ffff:ffff:ffff:ffff:ffff
161fc3a:a00::/28fc3a:a0f:ffff:ffff:ffff:ffff:ffff:ffff
162fc3a:a10::/28fc3a:a1f:ffff:ffff:ffff:ffff:ffff:ffff
163fc3a:a20::/28fc3a:a2f:ffff:ffff:ffff:ffff:ffff:ffff
164fc3a:a30::/28fc3a:a3f:ffff:ffff:ffff:ffff:ffff:ffff
165fc3a:a40::/28fc3a:a4f:ffff:ffff:ffff:ffff:ffff:ffff
166fc3a:a50::/28fc3a:a5f:ffff:ffff:ffff:ffff:ffff:ffff
167fc3a:a60::/28fc3a:a6f:ffff:ffff:ffff:ffff:ffff:ffff
168fc3a:a70::/28fc3a:a7f:ffff:ffff:ffff:ffff:ffff:ffff
169fc3a:a80::/28fc3a:a8f:ffff:ffff:ffff:ffff:ffff:ffff
170fc3a:a90::/28fc3a:a9f:ffff:ffff:ffff:ffff:ffff:ffff
171fc3a:aa0::/28fc3a:aaf:ffff:ffff:ffff:ffff:ffff:ffff
172fc3a:ab0::/28fc3a:abf:ffff:ffff:ffff:ffff:ffff:ffff
173fc3a:ac0::/28fc3a:acf:ffff:ffff:ffff:ffff:ffff:ffff
174fc3a:ad0::/28fc3a:adf:ffff:ffff:ffff:ffff:ffff:ffff
175fc3a:ae0::/28fc3a:aef:ffff:ffff:ffff:ffff:ffff:ffff
176fc3a:af0::/28fc3a:aff:ffff:ffff:ffff:ffff:ffff:ffff
177fc3a:b00::/28fc3a:b0f:ffff:ffff:ffff:ffff:ffff:ffff
178fc3a:b10::/28fc3a:b1f:ffff:ffff:ffff:ffff:ffff:ffff
179fc3a:b20::/28fc3a:b2f:ffff:ffff:ffff:ffff:ffff:ffff
180fc3a:b30::/28fc3a:b3f:ffff:ffff:ffff:ffff:ffff:ffff
181fc3a:b40::/28fc3a:b4f:ffff:ffff:ffff:ffff:ffff:ffff
182fc3a:b50::/28fc3a:b5f:ffff:ffff:ffff:ffff:ffff:ffff
183fc3a:b60::/28fc3a:b6f:ffff:ffff:ffff:ffff:ffff:ffff
184fc3a:b70::/28fc3a:b7f:ffff:ffff:ffff:ffff:ffff:ffff
185fc3a:b80::/28fc3a:b8f:ffff:ffff:ffff:ffff:ffff:ffff
186fc3a:b90::/28fc3a:b9f:ffff:ffff:ffff:ffff:ffff:ffff
187fc3a:ba0::/28fc3a:baf:ffff:ffff:ffff:ffff:ffff:ffff
188fc3a:bb0::/28fc3a:bbf:ffff:ffff:ffff:ffff:ffff:ffff
189fc3a:bc0::/28fc3a:bcf:ffff:ffff:ffff:ffff:ffff:ffff
190fc3a:bd0::/28fc3a:bdf:ffff:ffff:ffff:ffff:ffff:ffff
191fc3a:be0::/28fc3a:bef:ffff:ffff:ffff:ffff:ffff:ffff
192fc3a:bf0::/28fc3a:bff:ffff:ffff:ffff:ffff:ffff:ffff
193fc3a:c00::/28fc3a:c0f:ffff:ffff:ffff:ffff:ffff:ffff
194fc3a:c10::/28fc3a:c1f:ffff:ffff:ffff:ffff:ffff:ffff
195fc3a:c20::/28fc3a:c2f:ffff:ffff:ffff:ffff:ffff:ffff
196fc3a:c30::/28fc3a:c3f:ffff:ffff:ffff:ffff:ffff:ffff
197fc3a:c40::/28fc3a:c4f:ffff:ffff:ffff:ffff:ffff:ffff
198fc3a:c50::/28fc3a:c5f:ffff:ffff:ffff:ffff:ffff:ffff
199fc3a:c60::/28fc3a:c6f:ffff:ffff:ffff:ffff:ffff:ffff
200fc3a:c70::/28fc3a:c7f:ffff:ffff:ffff:ffff:ffff:ffff
201fc3a:c80::/28fc3a:c8f:ffff:ffff:ffff:ffff:ffff:ffff
202fc3a:c90::/28fc3a:c9f:ffff:ffff:ffff:ffff:ffff:ffff
203fc3a:ca0::/28fc3a:caf:ffff:ffff:ffff:ffff:ffff:ffff
204fc3a:cb0::/28fc3a:cbf:ffff:ffff:ffff:ffff:ffff:ffff
205fc3a:cc0::/28fc3a:ccf:ffff:ffff:ffff:ffff:ffff:ffff
206fc3a:cd0::/28fc3a:cdf:ffff:ffff:ffff:ffff:ffff:ffff
207fc3a:ce0::/28fc3a:cef:ffff:ffff:ffff:ffff:ffff:ffff
208fc3a:cf0::/28fc3a:cff:ffff:ffff:ffff:ffff:ffff:ffff
209fc3a:d00::/28fc3a:d0f:ffff:ffff:ffff:ffff:ffff:ffff
210fc3a:d10::/28fc3a:d1f:ffff:ffff:ffff:ffff:ffff:ffff
211fc3a:d20::/28fc3a:d2f:ffff:ffff:ffff:ffff:ffff:ffff
212fc3a:d30::/28fc3a:d3f:ffff:ffff:ffff:ffff:ffff:ffff
213fc3a:d40::/28fc3a:d4f:ffff:ffff:ffff:ffff:ffff:ffff
214fc3a:d50::/28fc3a:d5f:ffff:ffff:ffff:ffff:ffff:ffff
215fc3a:d60::/28fc3a:d6f:ffff:ffff:ffff:ffff:ffff:ffff
216fc3a:d70::/28fc3a:d7f:ffff:ffff:ffff:ffff:ffff:ffff
217fc3a:d80::/28fc3a:d8f:ffff:ffff:ffff:ffff:ffff:ffff
218fc3a:d90::/28fc3a:d9f:ffff:ffff:ffff:ffff:ffff:ffff
219fc3a:da0::/28fc3a:daf:ffff:ffff:ffff:ffff:ffff:ffff
220fc3a:db0::/28fc3a:dbf:ffff:ffff:ffff:ffff:ffff:ffff
221fc3a:dc0::/28fc3a:dcf:ffff:ffff:ffff:ffff:ffff:ffff
222fc3a:dd0::/28fc3a:ddf:ffff:ffff:ffff:ffff:ffff:ffff
223fc3a:de0::/28fc3a:def:ffff:ffff:ffff:ffff:ffff:ffff
224fc3a:df0::/28fc3a:dff:ffff:ffff:ffff:ffff:ffff:ffff
225fc3a:e00::/28fc3a:e0f:ffff:ffff:ffff:ffff:ffff:ffff
226fc3a:e10::/28fc3a:e1f:ffff:ffff:ffff:ffff:ffff:ffff
227fc3a:e20::/28fc3a:e2f:ffff:ffff:ffff:ffff:ffff:ffff
228fc3a:e30::/28fc3a:e3f:ffff:ffff:ffff:ffff:ffff:ffff
229fc3a:e40::/28fc3a:e4f:ffff:ffff:ffff:ffff:ffff:ffff
230fc3a:e50::/28fc3a:e5f:ffff:ffff:ffff:ffff:ffff:ffff
231fc3a:e60::/28fc3a:e6f:ffff:ffff:ffff:ffff:ffff:ffff
232fc3a:e70::/28fc3a:e7f:ffff:ffff:ffff:ffff:ffff:ffff
233fc3a:e80::/28fc3a:e8f:ffff:ffff:ffff:ffff:ffff:ffff
234fc3a:e90::/28fc3a:e9f:ffff:ffff:ffff:ffff:ffff:ffff
235fc3a:ea0::/28fc3a:eaf:ffff:ffff:ffff:ffff:ffff:ffff
236fc3a:eb0::/28fc3a:ebf:ffff:ffff:ffff:ffff:ffff:ffff
237fc3a:ec0::/28fc3a:ecf:ffff:ffff:ffff:ffff:ffff:ffff
238fc3a:ed0::/28fc3a:edf:ffff:ffff:ffff:ffff:ffff:ffff
239fc3a:ee0::/28fc3a:eef:ffff:ffff:ffff:ffff:ffff:ffff
240fc3a:ef0::/28fc3a:eff:ffff:ffff:ffff:ffff:ffff:ffff
241fc3a:f00::/28fc3a:f0f:ffff:ffff:ffff:ffff:ffff:ffff
242fc3a:f10::/28fc3a:f1f:ffff:ffff:ffff:ffff:ffff:ffff
243fc3a:f20::/28fc3a:f2f:ffff:ffff:ffff:ffff:ffff:ffff
244fc3a:f30::/28fc3a:f3f:ffff:ffff:ffff:ffff:ffff:ffff
245fc3a:f40::/28fc3a:f4f:ffff:ffff:ffff:ffff:ffff:ffff
246fc3a:f50::/28fc3a:f5f:ffff:ffff:ffff:ffff:ffff:ffff
247fc3a:f60::/28fc3a:f6f:ffff:ffff:ffff:ffff:ffff:ffff
248fc3a:f70::/28fc3a:f7f:ffff:ffff:ffff:ffff:ffff:ffff
249fc3a:f80::/28fc3a:f8f:ffff:ffff:ffff:ffff:ffff:ffff
250fc3a:f90::/28fc3a:f9f:ffff:ffff:ffff:ffff:ffff:ffff
251fc3a:fa0::/28fc3a:faf:ffff:ffff:ffff:ffff:ffff:ffff
252fc3a:fb0::/28fc3a:fbf:ffff:ffff:ffff:ffff:ffff:ffff
253fc3a:fc0::/28fc3a:fcf:ffff:ffff:ffff:ffff:ffff:ffff
254fc3a:fd0::/28fc3a:fdf:ffff:ffff:ffff:ffff:ffff:ffff
255fc3a:fe0::/28fc3a:fef:ffff:ffff:ffff:ffff:ffff:ffff
256fc3a:ff0::/28fc3a: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.