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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
207c::/16
First address
207c::
Last address
207c: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
207c:0000:0000:0000:0000:0000:0000:0000
Type
Global unicast 2000::/3
Public internet addresses
Reverse DNS zone
c.7.0.2.ip6.arpa
Split into smaller subnets/28
/17 (2)/18 (4)/19 (8)/20 (16)/24 (256)/28 (4,096)/32 (65,536)

207c::/16 makes 4,096 subnets of /28; the first 256 are listed.

Subnets
#SubnetLast address
1207c::/28207c:f:ffff:ffff:ffff:ffff:ffff:ffff
2207c:10::/28207c:1f:ffff:ffff:ffff:ffff:ffff:ffff
3207c:20::/28207c:2f:ffff:ffff:ffff:ffff:ffff:ffff
4207c:30::/28207c:3f:ffff:ffff:ffff:ffff:ffff:ffff
5207c:40::/28207c:4f:ffff:ffff:ffff:ffff:ffff:ffff
6207c:50::/28207c:5f:ffff:ffff:ffff:ffff:ffff:ffff
7207c:60::/28207c:6f:ffff:ffff:ffff:ffff:ffff:ffff
8207c:70::/28207c:7f:ffff:ffff:ffff:ffff:ffff:ffff
9207c:80::/28207c:8f:ffff:ffff:ffff:ffff:ffff:ffff
10207c:90::/28207c:9f:ffff:ffff:ffff:ffff:ffff:ffff
11207c:a0::/28207c:af:ffff:ffff:ffff:ffff:ffff:ffff
12207c:b0::/28207c:bf:ffff:ffff:ffff:ffff:ffff:ffff
13207c:c0::/28207c:cf:ffff:ffff:ffff:ffff:ffff:ffff
14207c:d0::/28207c:df:ffff:ffff:ffff:ffff:ffff:ffff
15207c:e0::/28207c:ef:ffff:ffff:ffff:ffff:ffff:ffff
16207c:f0::/28207c:ff:ffff:ffff:ffff:ffff:ffff:ffff
17207c:100::/28207c:10f:ffff:ffff:ffff:ffff:ffff:ffff
18207c:110::/28207c:11f:ffff:ffff:ffff:ffff:ffff:ffff
19207c:120::/28207c:12f:ffff:ffff:ffff:ffff:ffff:ffff
20207c:130::/28207c:13f:ffff:ffff:ffff:ffff:ffff:ffff
21207c:140::/28207c:14f:ffff:ffff:ffff:ffff:ffff:ffff
22207c:150::/28207c:15f:ffff:ffff:ffff:ffff:ffff:ffff
23207c:160::/28207c:16f:ffff:ffff:ffff:ffff:ffff:ffff
24207c:170::/28207c:17f:ffff:ffff:ffff:ffff:ffff:ffff
25207c:180::/28207c:18f:ffff:ffff:ffff:ffff:ffff:ffff
26207c:190::/28207c:19f:ffff:ffff:ffff:ffff:ffff:ffff
27207c:1a0::/28207c:1af:ffff:ffff:ffff:ffff:ffff:ffff
28207c:1b0::/28207c:1bf:ffff:ffff:ffff:ffff:ffff:ffff
29207c:1c0::/28207c:1cf:ffff:ffff:ffff:ffff:ffff:ffff
30207c:1d0::/28207c:1df:ffff:ffff:ffff:ffff:ffff:ffff
31207c:1e0::/28207c:1ef:ffff:ffff:ffff:ffff:ffff:ffff
32207c:1f0::/28207c:1ff:ffff:ffff:ffff:ffff:ffff:ffff
33207c:200::/28207c:20f:ffff:ffff:ffff:ffff:ffff:ffff
34207c:210::/28207c:21f:ffff:ffff:ffff:ffff:ffff:ffff
35207c:220::/28207c:22f:ffff:ffff:ffff:ffff:ffff:ffff
36207c:230::/28207c:23f:ffff:ffff:ffff:ffff:ffff:ffff
37207c:240::/28207c:24f:ffff:ffff:ffff:ffff:ffff:ffff
38207c:250::/28207c:25f:ffff:ffff:ffff:ffff:ffff:ffff
39207c:260::/28207c:26f:ffff:ffff:ffff:ffff:ffff:ffff
40207c:270::/28207c:27f:ffff:ffff:ffff:ffff:ffff:ffff
41207c:280::/28207c:28f:ffff:ffff:ffff:ffff:ffff:ffff
42207c:290::/28207c:29f:ffff:ffff:ffff:ffff:ffff:ffff
43207c:2a0::/28207c:2af:ffff:ffff:ffff:ffff:ffff:ffff
44207c:2b0::/28207c:2bf:ffff:ffff:ffff:ffff:ffff:ffff
45207c:2c0::/28207c:2cf:ffff:ffff:ffff:ffff:ffff:ffff
46207c:2d0::/28207c:2df:ffff:ffff:ffff:ffff:ffff:ffff
47207c:2e0::/28207c:2ef:ffff:ffff:ffff:ffff:ffff:ffff
48207c:2f0::/28207c:2ff:ffff:ffff:ffff:ffff:ffff:ffff
49207c:300::/28207c:30f:ffff:ffff:ffff:ffff:ffff:ffff
50207c:310::/28207c:31f:ffff:ffff:ffff:ffff:ffff:ffff
51207c:320::/28207c:32f:ffff:ffff:ffff:ffff:ffff:ffff
52207c:330::/28207c:33f:ffff:ffff:ffff:ffff:ffff:ffff
53207c:340::/28207c:34f:ffff:ffff:ffff:ffff:ffff:ffff
54207c:350::/28207c:35f:ffff:ffff:ffff:ffff:ffff:ffff
55207c:360::/28207c:36f:ffff:ffff:ffff:ffff:ffff:ffff
56207c:370::/28207c:37f:ffff:ffff:ffff:ffff:ffff:ffff
57207c:380::/28207c:38f:ffff:ffff:ffff:ffff:ffff:ffff
58207c:390::/28207c:39f:ffff:ffff:ffff:ffff:ffff:ffff
59207c:3a0::/28207c:3af:ffff:ffff:ffff:ffff:ffff:ffff
60207c:3b0::/28207c:3bf:ffff:ffff:ffff:ffff:ffff:ffff
61207c:3c0::/28207c:3cf:ffff:ffff:ffff:ffff:ffff:ffff
62207c:3d0::/28207c:3df:ffff:ffff:ffff:ffff:ffff:ffff
63207c:3e0::/28207c:3ef:ffff:ffff:ffff:ffff:ffff:ffff
64207c:3f0::/28207c:3ff:ffff:ffff:ffff:ffff:ffff:ffff
65207c:400::/28207c:40f:ffff:ffff:ffff:ffff:ffff:ffff
66207c:410::/28207c:41f:ffff:ffff:ffff:ffff:ffff:ffff
67207c:420::/28207c:42f:ffff:ffff:ffff:ffff:ffff:ffff
68207c:430::/28207c:43f:ffff:ffff:ffff:ffff:ffff:ffff
69207c:440::/28207c:44f:ffff:ffff:ffff:ffff:ffff:ffff
70207c:450::/28207c:45f:ffff:ffff:ffff:ffff:ffff:ffff
71207c:460::/28207c:46f:ffff:ffff:ffff:ffff:ffff:ffff
72207c:470::/28207c:47f:ffff:ffff:ffff:ffff:ffff:ffff
73207c:480::/28207c:48f:ffff:ffff:ffff:ffff:ffff:ffff
74207c:490::/28207c:49f:ffff:ffff:ffff:ffff:ffff:ffff
75207c:4a0::/28207c:4af:ffff:ffff:ffff:ffff:ffff:ffff
76207c:4b0::/28207c:4bf:ffff:ffff:ffff:ffff:ffff:ffff
77207c:4c0::/28207c:4cf:ffff:ffff:ffff:ffff:ffff:ffff
78207c:4d0::/28207c:4df:ffff:ffff:ffff:ffff:ffff:ffff
79207c:4e0::/28207c:4ef:ffff:ffff:ffff:ffff:ffff:ffff
80207c:4f0::/28207c:4ff:ffff:ffff:ffff:ffff:ffff:ffff
81207c:500::/28207c:50f:ffff:ffff:ffff:ffff:ffff:ffff
82207c:510::/28207c:51f:ffff:ffff:ffff:ffff:ffff:ffff
83207c:520::/28207c:52f:ffff:ffff:ffff:ffff:ffff:ffff
84207c:530::/28207c:53f:ffff:ffff:ffff:ffff:ffff:ffff
85207c:540::/28207c:54f:ffff:ffff:ffff:ffff:ffff:ffff
86207c:550::/28207c:55f:ffff:ffff:ffff:ffff:ffff:ffff
87207c:560::/28207c:56f:ffff:ffff:ffff:ffff:ffff:ffff
88207c:570::/28207c:57f:ffff:ffff:ffff:ffff:ffff:ffff
89207c:580::/28207c:58f:ffff:ffff:ffff:ffff:ffff:ffff
90207c:590::/28207c:59f:ffff:ffff:ffff:ffff:ffff:ffff
91207c:5a0::/28207c:5af:ffff:ffff:ffff:ffff:ffff:ffff
92207c:5b0::/28207c:5bf:ffff:ffff:ffff:ffff:ffff:ffff
93207c:5c0::/28207c:5cf:ffff:ffff:ffff:ffff:ffff:ffff
94207c:5d0::/28207c:5df:ffff:ffff:ffff:ffff:ffff:ffff
95207c:5e0::/28207c:5ef:ffff:ffff:ffff:ffff:ffff:ffff
96207c:5f0::/28207c:5ff:ffff:ffff:ffff:ffff:ffff:ffff
97207c:600::/28207c:60f:ffff:ffff:ffff:ffff:ffff:ffff
98207c:610::/28207c:61f:ffff:ffff:ffff:ffff:ffff:ffff
99207c:620::/28207c:62f:ffff:ffff:ffff:ffff:ffff:ffff
100207c:630::/28207c:63f:ffff:ffff:ffff:ffff:ffff:ffff
101207c:640::/28207c:64f:ffff:ffff:ffff:ffff:ffff:ffff
102207c:650::/28207c:65f:ffff:ffff:ffff:ffff:ffff:ffff
103207c:660::/28207c:66f:ffff:ffff:ffff:ffff:ffff:ffff
104207c:670::/28207c:67f:ffff:ffff:ffff:ffff:ffff:ffff
105207c:680::/28207c:68f:ffff:ffff:ffff:ffff:ffff:ffff
106207c:690::/28207c:69f:ffff:ffff:ffff:ffff:ffff:ffff
107207c:6a0::/28207c:6af:ffff:ffff:ffff:ffff:ffff:ffff
108207c:6b0::/28207c:6bf:ffff:ffff:ffff:ffff:ffff:ffff
109207c:6c0::/28207c:6cf:ffff:ffff:ffff:ffff:ffff:ffff
110207c:6d0::/28207c:6df:ffff:ffff:ffff:ffff:ffff:ffff
111207c:6e0::/28207c:6ef:ffff:ffff:ffff:ffff:ffff:ffff
112207c:6f0::/28207c:6ff:ffff:ffff:ffff:ffff:ffff:ffff
113207c:700::/28207c:70f:ffff:ffff:ffff:ffff:ffff:ffff
114207c:710::/28207c:71f:ffff:ffff:ffff:ffff:ffff:ffff
115207c:720::/28207c:72f:ffff:ffff:ffff:ffff:ffff:ffff
116207c:730::/28207c:73f:ffff:ffff:ffff:ffff:ffff:ffff
117207c:740::/28207c:74f:ffff:ffff:ffff:ffff:ffff:ffff
118207c:750::/28207c:75f:ffff:ffff:ffff:ffff:ffff:ffff
119207c:760::/28207c:76f:ffff:ffff:ffff:ffff:ffff:ffff
120207c:770::/28207c:77f:ffff:ffff:ffff:ffff:ffff:ffff
121207c:780::/28207c:78f:ffff:ffff:ffff:ffff:ffff:ffff
122207c:790::/28207c:79f:ffff:ffff:ffff:ffff:ffff:ffff
123207c:7a0::/28207c:7af:ffff:ffff:ffff:ffff:ffff:ffff
124207c:7b0::/28207c:7bf:ffff:ffff:ffff:ffff:ffff:ffff
125207c:7c0::/28207c:7cf:ffff:ffff:ffff:ffff:ffff:ffff
126207c:7d0::/28207c:7df:ffff:ffff:ffff:ffff:ffff:ffff
127207c:7e0::/28207c:7ef:ffff:ffff:ffff:ffff:ffff:ffff
128207c:7f0::/28207c:7ff:ffff:ffff:ffff:ffff:ffff:ffff
129207c:800::/28207c:80f:ffff:ffff:ffff:ffff:ffff:ffff
130207c:810::/28207c:81f:ffff:ffff:ffff:ffff:ffff:ffff
131207c:820::/28207c:82f:ffff:ffff:ffff:ffff:ffff:ffff
132207c:830::/28207c:83f:ffff:ffff:ffff:ffff:ffff:ffff
133207c:840::/28207c:84f:ffff:ffff:ffff:ffff:ffff:ffff
134207c:850::/28207c:85f:ffff:ffff:ffff:ffff:ffff:ffff
135207c:860::/28207c:86f:ffff:ffff:ffff:ffff:ffff:ffff
136207c:870::/28207c:87f:ffff:ffff:ffff:ffff:ffff:ffff
137207c:880::/28207c:88f:ffff:ffff:ffff:ffff:ffff:ffff
138207c:890::/28207c:89f:ffff:ffff:ffff:ffff:ffff:ffff
139207c:8a0::/28207c:8af:ffff:ffff:ffff:ffff:ffff:ffff
140207c:8b0::/28207c:8bf:ffff:ffff:ffff:ffff:ffff:ffff
141207c:8c0::/28207c:8cf:ffff:ffff:ffff:ffff:ffff:ffff
142207c:8d0::/28207c:8df:ffff:ffff:ffff:ffff:ffff:ffff
143207c:8e0::/28207c:8ef:ffff:ffff:ffff:ffff:ffff:ffff
144207c:8f0::/28207c:8ff:ffff:ffff:ffff:ffff:ffff:ffff
145207c:900::/28207c:90f:ffff:ffff:ffff:ffff:ffff:ffff
146207c:910::/28207c:91f:ffff:ffff:ffff:ffff:ffff:ffff
147207c:920::/28207c:92f:ffff:ffff:ffff:ffff:ffff:ffff
148207c:930::/28207c:93f:ffff:ffff:ffff:ffff:ffff:ffff
149207c:940::/28207c:94f:ffff:ffff:ffff:ffff:ffff:ffff
150207c:950::/28207c:95f:ffff:ffff:ffff:ffff:ffff:ffff
151207c:960::/28207c:96f:ffff:ffff:ffff:ffff:ffff:ffff
152207c:970::/28207c:97f:ffff:ffff:ffff:ffff:ffff:ffff
153207c:980::/28207c:98f:ffff:ffff:ffff:ffff:ffff:ffff
154207c:990::/28207c:99f:ffff:ffff:ffff:ffff:ffff:ffff
155207c:9a0::/28207c:9af:ffff:ffff:ffff:ffff:ffff:ffff
156207c:9b0::/28207c:9bf:ffff:ffff:ffff:ffff:ffff:ffff
157207c:9c0::/28207c:9cf:ffff:ffff:ffff:ffff:ffff:ffff
158207c:9d0::/28207c:9df:ffff:ffff:ffff:ffff:ffff:ffff
159207c:9e0::/28207c:9ef:ffff:ffff:ffff:ffff:ffff:ffff
160207c:9f0::/28207c:9ff:ffff:ffff:ffff:ffff:ffff:ffff
161207c:a00::/28207c:a0f:ffff:ffff:ffff:ffff:ffff:ffff
162207c:a10::/28207c:a1f:ffff:ffff:ffff:ffff:ffff:ffff
163207c:a20::/28207c:a2f:ffff:ffff:ffff:ffff:ffff:ffff
164207c:a30::/28207c:a3f:ffff:ffff:ffff:ffff:ffff:ffff
165207c:a40::/28207c:a4f:ffff:ffff:ffff:ffff:ffff:ffff
166207c:a50::/28207c:a5f:ffff:ffff:ffff:ffff:ffff:ffff
167207c:a60::/28207c:a6f:ffff:ffff:ffff:ffff:ffff:ffff
168207c:a70::/28207c:a7f:ffff:ffff:ffff:ffff:ffff:ffff
169207c:a80::/28207c:a8f:ffff:ffff:ffff:ffff:ffff:ffff
170207c:a90::/28207c:a9f:ffff:ffff:ffff:ffff:ffff:ffff
171207c:aa0::/28207c:aaf:ffff:ffff:ffff:ffff:ffff:ffff
172207c:ab0::/28207c:abf:ffff:ffff:ffff:ffff:ffff:ffff
173207c:ac0::/28207c:acf:ffff:ffff:ffff:ffff:ffff:ffff
174207c:ad0::/28207c:adf:ffff:ffff:ffff:ffff:ffff:ffff
175207c:ae0::/28207c:aef:ffff:ffff:ffff:ffff:ffff:ffff
176207c:af0::/28207c:aff:ffff:ffff:ffff:ffff:ffff:ffff
177207c:b00::/28207c:b0f:ffff:ffff:ffff:ffff:ffff:ffff
178207c:b10::/28207c:b1f:ffff:ffff:ffff:ffff:ffff:ffff
179207c:b20::/28207c:b2f:ffff:ffff:ffff:ffff:ffff:ffff
180207c:b30::/28207c:b3f:ffff:ffff:ffff:ffff:ffff:ffff
181207c:b40::/28207c:b4f:ffff:ffff:ffff:ffff:ffff:ffff
182207c:b50::/28207c:b5f:ffff:ffff:ffff:ffff:ffff:ffff
183207c:b60::/28207c:b6f:ffff:ffff:ffff:ffff:ffff:ffff
184207c:b70::/28207c:b7f:ffff:ffff:ffff:ffff:ffff:ffff
185207c:b80::/28207c:b8f:ffff:ffff:ffff:ffff:ffff:ffff
186207c:b90::/28207c:b9f:ffff:ffff:ffff:ffff:ffff:ffff
187207c:ba0::/28207c:baf:ffff:ffff:ffff:ffff:ffff:ffff
188207c:bb0::/28207c:bbf:ffff:ffff:ffff:ffff:ffff:ffff
189207c:bc0::/28207c:bcf:ffff:ffff:ffff:ffff:ffff:ffff
190207c:bd0::/28207c:bdf:ffff:ffff:ffff:ffff:ffff:ffff
191207c:be0::/28207c:bef:ffff:ffff:ffff:ffff:ffff:ffff
192207c:bf0::/28207c:bff:ffff:ffff:ffff:ffff:ffff:ffff
193207c:c00::/28207c:c0f:ffff:ffff:ffff:ffff:ffff:ffff
194207c:c10::/28207c:c1f:ffff:ffff:ffff:ffff:ffff:ffff
195207c:c20::/28207c:c2f:ffff:ffff:ffff:ffff:ffff:ffff
196207c:c30::/28207c:c3f:ffff:ffff:ffff:ffff:ffff:ffff
197207c:c40::/28207c:c4f:ffff:ffff:ffff:ffff:ffff:ffff
198207c:c50::/28207c:c5f:ffff:ffff:ffff:ffff:ffff:ffff
199207c:c60::/28207c:c6f:ffff:ffff:ffff:ffff:ffff:ffff
200207c:c70::/28207c:c7f:ffff:ffff:ffff:ffff:ffff:ffff
201207c:c80::/28207c:c8f:ffff:ffff:ffff:ffff:ffff:ffff
202207c:c90::/28207c:c9f:ffff:ffff:ffff:ffff:ffff:ffff
203207c:ca0::/28207c:caf:ffff:ffff:ffff:ffff:ffff:ffff
204207c:cb0::/28207c:cbf:ffff:ffff:ffff:ffff:ffff:ffff
205207c:cc0::/28207c:ccf:ffff:ffff:ffff:ffff:ffff:ffff
206207c:cd0::/28207c:cdf:ffff:ffff:ffff:ffff:ffff:ffff
207207c:ce0::/28207c:cef:ffff:ffff:ffff:ffff:ffff:ffff
208207c:cf0::/28207c:cff:ffff:ffff:ffff:ffff:ffff:ffff
209207c:d00::/28207c:d0f:ffff:ffff:ffff:ffff:ffff:ffff
210207c:d10::/28207c:d1f:ffff:ffff:ffff:ffff:ffff:ffff
211207c:d20::/28207c:d2f:ffff:ffff:ffff:ffff:ffff:ffff
212207c:d30::/28207c:d3f:ffff:ffff:ffff:ffff:ffff:ffff
213207c:d40::/28207c:d4f:ffff:ffff:ffff:ffff:ffff:ffff
214207c:d50::/28207c:d5f:ffff:ffff:ffff:ffff:ffff:ffff
215207c:d60::/28207c:d6f:ffff:ffff:ffff:ffff:ffff:ffff
216207c:d70::/28207c:d7f:ffff:ffff:ffff:ffff:ffff:ffff
217207c:d80::/28207c:d8f:ffff:ffff:ffff:ffff:ffff:ffff
218207c:d90::/28207c:d9f:ffff:ffff:ffff:ffff:ffff:ffff
219207c:da0::/28207c:daf:ffff:ffff:ffff:ffff:ffff:ffff
220207c:db0::/28207c:dbf:ffff:ffff:ffff:ffff:ffff:ffff
221207c:dc0::/28207c:dcf:ffff:ffff:ffff:ffff:ffff:ffff
222207c:dd0::/28207c:ddf:ffff:ffff:ffff:ffff:ffff:ffff
223207c:de0::/28207c:def:ffff:ffff:ffff:ffff:ffff:ffff
224207c:df0::/28207c:dff:ffff:ffff:ffff:ffff:ffff:ffff
225207c:e00::/28207c:e0f:ffff:ffff:ffff:ffff:ffff:ffff
226207c:e10::/28207c:e1f:ffff:ffff:ffff:ffff:ffff:ffff
227207c:e20::/28207c:e2f:ffff:ffff:ffff:ffff:ffff:ffff
228207c:e30::/28207c:e3f:ffff:ffff:ffff:ffff:ffff:ffff
229207c:e40::/28207c:e4f:ffff:ffff:ffff:ffff:ffff:ffff
230207c:e50::/28207c:e5f:ffff:ffff:ffff:ffff:ffff:ffff
231207c:e60::/28207c:e6f:ffff:ffff:ffff:ffff:ffff:ffff
232207c:e70::/28207c:e7f:ffff:ffff:ffff:ffff:ffff:ffff
233207c:e80::/28207c:e8f:ffff:ffff:ffff:ffff:ffff:ffff
234207c:e90::/28207c:e9f:ffff:ffff:ffff:ffff:ffff:ffff
235207c:ea0::/28207c:eaf:ffff:ffff:ffff:ffff:ffff:ffff
236207c:eb0::/28207c:ebf:ffff:ffff:ffff:ffff:ffff:ffff
237207c:ec0::/28207c:ecf:ffff:ffff:ffff:ffff:ffff:ffff
238207c:ed0::/28207c:edf:ffff:ffff:ffff:ffff:ffff:ffff
239207c:ee0::/28207c:eef:ffff:ffff:ffff:ffff:ffff:ffff
240207c:ef0::/28207c:eff:ffff:ffff:ffff:ffff:ffff:ffff
241207c:f00::/28207c:f0f:ffff:ffff:ffff:ffff:ffff:ffff
242207c:f10::/28207c:f1f:ffff:ffff:ffff:ffff:ffff:ffff
243207c:f20::/28207c:f2f:ffff:ffff:ffff:ffff:ffff:ffff
244207c:f30::/28207c:f3f:ffff:ffff:ffff:ffff:ffff:ffff
245207c:f40::/28207c:f4f:ffff:ffff:ffff:ffff:ffff:ffff
246207c:f50::/28207c:f5f:ffff:ffff:ffff:ffff:ffff:ffff
247207c:f60::/28207c:f6f:ffff:ffff:ffff:ffff:ffff:ffff
248207c:f70::/28207c:f7f:ffff:ffff:ffff:ffff:ffff:ffff
249207c:f80::/28207c:f8f:ffff:ffff:ffff:ffff:ffff:ffff
250207c:f90::/28207c:f9f:ffff:ffff:ffff:ffff:ffff:ffff
251207c:fa0::/28207c:faf:ffff:ffff:ffff:ffff:ffff:ffff
252207c:fb0::/28207c:fbf:ffff:ffff:ffff:ffff:ffff:ffff
253207c:fc0::/28207c:fcf:ffff:ffff:ffff:ffff:ffff:ffff
254207c:fd0::/28207c:fdf:ffff:ffff:ffff:ffff:ffff:ffff
255207c:fe0::/28207c:fef:ffff:ffff:ffff:ffff:ffff:ffff
256207c:ff0::/28207c: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.