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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/7
Addresses2^121
/64 networks2^57
Network
3c00::/7
First address
3c00::
Last address
3dff:ffff:ffff:ffff:ffff:ffff:ffff:ffff
Addresses
2,658,455,991,569,831,745,807,614,120,560,689,152 (2^121)
/64 networks (LANs)
144,115,188,075,855,872 (2^57)
Full form
3c00:0000:0000:0000:0000:0000:0000:0000
Type
Global unicast 2000::/3
Public internet addresses
Reverse DNS zones
c.3.ip6.arpa
d.3.ip6.arpa
/7 is not on a 4-bit boundary, so it takes 2 /8 zones.
Split into smaller subnets/16
/8 (2)/9 (4)/10 (8)/11 (16)/12 (32)/16 (512)/20 (8,192)

3c00::/7 makes 512 subnets of /16; the first 256 are listed.

Subnets
#SubnetLast address
13c00::/163c00:ffff:ffff:ffff:ffff:ffff:ffff:ffff
23c01::/163c01:ffff:ffff:ffff:ffff:ffff:ffff:ffff
33c02::/163c02:ffff:ffff:ffff:ffff:ffff:ffff:ffff
43c03::/163c03:ffff:ffff:ffff:ffff:ffff:ffff:ffff
53c04::/163c04:ffff:ffff:ffff:ffff:ffff:ffff:ffff
63c05::/163c05:ffff:ffff:ffff:ffff:ffff:ffff:ffff
73c06::/163c06:ffff:ffff:ffff:ffff:ffff:ffff:ffff
83c07::/163c07:ffff:ffff:ffff:ffff:ffff:ffff:ffff
93c08::/163c08:ffff:ffff:ffff:ffff:ffff:ffff:ffff
103c09::/163c09:ffff:ffff:ffff:ffff:ffff:ffff:ffff
113c0a::/163c0a:ffff:ffff:ffff:ffff:ffff:ffff:ffff
123c0b::/163c0b:ffff:ffff:ffff:ffff:ffff:ffff:ffff
133c0c::/163c0c:ffff:ffff:ffff:ffff:ffff:ffff:ffff
143c0d::/163c0d:ffff:ffff:ffff:ffff:ffff:ffff:ffff
153c0e::/163c0e:ffff:ffff:ffff:ffff:ffff:ffff:ffff
163c0f::/163c0f:ffff:ffff:ffff:ffff:ffff:ffff:ffff
173c10::/163c10:ffff:ffff:ffff:ffff:ffff:ffff:ffff
183c11::/163c11:ffff:ffff:ffff:ffff:ffff:ffff:ffff
193c12::/163c12:ffff:ffff:ffff:ffff:ffff:ffff:ffff
203c13::/163c13:ffff:ffff:ffff:ffff:ffff:ffff:ffff
213c14::/163c14:ffff:ffff:ffff:ffff:ffff:ffff:ffff
223c15::/163c15:ffff:ffff:ffff:ffff:ffff:ffff:ffff
233c16::/163c16:ffff:ffff:ffff:ffff:ffff:ffff:ffff
243c17::/163c17:ffff:ffff:ffff:ffff:ffff:ffff:ffff
253c18::/163c18:ffff:ffff:ffff:ffff:ffff:ffff:ffff
263c19::/163c19:ffff:ffff:ffff:ffff:ffff:ffff:ffff
273c1a::/163c1a:ffff:ffff:ffff:ffff:ffff:ffff:ffff
283c1b::/163c1b:ffff:ffff:ffff:ffff:ffff:ffff:ffff
293c1c::/163c1c:ffff:ffff:ffff:ffff:ffff:ffff:ffff
303c1d::/163c1d:ffff:ffff:ffff:ffff:ffff:ffff:ffff
313c1e::/163c1e:ffff:ffff:ffff:ffff:ffff:ffff:ffff
323c1f::/163c1f:ffff:ffff:ffff:ffff:ffff:ffff:ffff
333c20::/163c20:ffff:ffff:ffff:ffff:ffff:ffff:ffff
343c21::/163c21:ffff:ffff:ffff:ffff:ffff:ffff:ffff
353c22::/163c22:ffff:ffff:ffff:ffff:ffff:ffff:ffff
363c23::/163c23:ffff:ffff:ffff:ffff:ffff:ffff:ffff
373c24::/163c24:ffff:ffff:ffff:ffff:ffff:ffff:ffff
383c25::/163c25:ffff:ffff:ffff:ffff:ffff:ffff:ffff
393c26::/163c26:ffff:ffff:ffff:ffff:ffff:ffff:ffff
403c27::/163c27:ffff:ffff:ffff:ffff:ffff:ffff:ffff
413c28::/163c28:ffff:ffff:ffff:ffff:ffff:ffff:ffff
423c29::/163c29:ffff:ffff:ffff:ffff:ffff:ffff:ffff
433c2a::/163c2a:ffff:ffff:ffff:ffff:ffff:ffff:ffff
443c2b::/163c2b:ffff:ffff:ffff:ffff:ffff:ffff:ffff
453c2c::/163c2c:ffff:ffff:ffff:ffff:ffff:ffff:ffff
463c2d::/163c2d:ffff:ffff:ffff:ffff:ffff:ffff:ffff
473c2e::/163c2e:ffff:ffff:ffff:ffff:ffff:ffff:ffff
483c2f::/163c2f:ffff:ffff:ffff:ffff:ffff:ffff:ffff
493c30::/163c30:ffff:ffff:ffff:ffff:ffff:ffff:ffff
503c31::/163c31:ffff:ffff:ffff:ffff:ffff:ffff:ffff
513c32::/163c32:ffff:ffff:ffff:ffff:ffff:ffff:ffff
523c33::/163c33:ffff:ffff:ffff:ffff:ffff:ffff:ffff
533c34::/163c34:ffff:ffff:ffff:ffff:ffff:ffff:ffff
543c35::/163c35:ffff:ffff:ffff:ffff:ffff:ffff:ffff
553c36::/163c36:ffff:ffff:ffff:ffff:ffff:ffff:ffff
563c37::/163c37:ffff:ffff:ffff:ffff:ffff:ffff:ffff
573c38::/163c38:ffff:ffff:ffff:ffff:ffff:ffff:ffff
583c39::/163c39:ffff:ffff:ffff:ffff:ffff:ffff:ffff
593c3a::/163c3a:ffff:ffff:ffff:ffff:ffff:ffff:ffff
603c3b::/163c3b:ffff:ffff:ffff:ffff:ffff:ffff:ffff
613c3c::/163c3c:ffff:ffff:ffff:ffff:ffff:ffff:ffff
623c3d::/163c3d:ffff:ffff:ffff:ffff:ffff:ffff:ffff
633c3e::/163c3e:ffff:ffff:ffff:ffff:ffff:ffff:ffff
643c3f::/163c3f:ffff:ffff:ffff:ffff:ffff:ffff:ffff
653c40::/163c40:ffff:ffff:ffff:ffff:ffff:ffff:ffff
663c41::/163c41:ffff:ffff:ffff:ffff:ffff:ffff:ffff
673c42::/163c42:ffff:ffff:ffff:ffff:ffff:ffff:ffff
683c43::/163c43:ffff:ffff:ffff:ffff:ffff:ffff:ffff
693c44::/163c44:ffff:ffff:ffff:ffff:ffff:ffff:ffff
703c45::/163c45:ffff:ffff:ffff:ffff:ffff:ffff:ffff
713c46::/163c46:ffff:ffff:ffff:ffff:ffff:ffff:ffff
723c47::/163c47:ffff:ffff:ffff:ffff:ffff:ffff:ffff
733c48::/163c48:ffff:ffff:ffff:ffff:ffff:ffff:ffff
743c49::/163c49:ffff:ffff:ffff:ffff:ffff:ffff:ffff
753c4a::/163c4a:ffff:ffff:ffff:ffff:ffff:ffff:ffff
763c4b::/163c4b:ffff:ffff:ffff:ffff:ffff:ffff:ffff
773c4c::/163c4c:ffff:ffff:ffff:ffff:ffff:ffff:ffff
783c4d::/163c4d:ffff:ffff:ffff:ffff:ffff:ffff:ffff
793c4e::/163c4e:ffff:ffff:ffff:ffff:ffff:ffff:ffff
803c4f::/163c4f:ffff:ffff:ffff:ffff:ffff:ffff:ffff
813c50::/163c50:ffff:ffff:ffff:ffff:ffff:ffff:ffff
823c51::/163c51:ffff:ffff:ffff:ffff:ffff:ffff:ffff
833c52::/163c52:ffff:ffff:ffff:ffff:ffff:ffff:ffff
843c53::/163c53:ffff:ffff:ffff:ffff:ffff:ffff:ffff
853c54::/163c54:ffff:ffff:ffff:ffff:ffff:ffff:ffff
863c55::/163c55:ffff:ffff:ffff:ffff:ffff:ffff:ffff
873c56::/163c56:ffff:ffff:ffff:ffff:ffff:ffff:ffff
883c57::/163c57:ffff:ffff:ffff:ffff:ffff:ffff:ffff
893c58::/163c58:ffff:ffff:ffff:ffff:ffff:ffff:ffff
903c59::/163c59:ffff:ffff:ffff:ffff:ffff:ffff:ffff
913c5a::/163c5a:ffff:ffff:ffff:ffff:ffff:ffff:ffff
923c5b::/163c5b:ffff:ffff:ffff:ffff:ffff:ffff:ffff
933c5c::/163c5c:ffff:ffff:ffff:ffff:ffff:ffff:ffff
943c5d::/163c5d:ffff:ffff:ffff:ffff:ffff:ffff:ffff
953c5e::/163c5e:ffff:ffff:ffff:ffff:ffff:ffff:ffff
963c5f::/163c5f:ffff:ffff:ffff:ffff:ffff:ffff:ffff
973c60::/163c60:ffff:ffff:ffff:ffff:ffff:ffff:ffff
983c61::/163c61:ffff:ffff:ffff:ffff:ffff:ffff:ffff
993c62::/163c62:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1003c63::/163c63:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1013c64::/163c64:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1023c65::/163c65:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1033c66::/163c66:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1043c67::/163c67:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1053c68::/163c68:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1063c69::/163c69:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1073c6a::/163c6a:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1083c6b::/163c6b:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1093c6c::/163c6c:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1103c6d::/163c6d:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1113c6e::/163c6e:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1123c6f::/163c6f:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1133c70::/163c70:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1143c71::/163c71:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1153c72::/163c72:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1163c73::/163c73:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1173c74::/163c74:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1183c75::/163c75:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1193c76::/163c76:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1203c77::/163c77:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1213c78::/163c78:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1223c79::/163c79:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1233c7a::/163c7a:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1243c7b::/163c7b:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1253c7c::/163c7c:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1263c7d::/163c7d:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1273c7e::/163c7e:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1283c7f::/163c7f:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1293c80::/163c80:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1303c81::/163c81:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1313c82::/163c82:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1323c83::/163c83:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1333c84::/163c84:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1343c85::/163c85:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1353c86::/163c86:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1363c87::/163c87:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1373c88::/163c88:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1383c89::/163c89:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1393c8a::/163c8a:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1403c8b::/163c8b:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1413c8c::/163c8c:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1423c8d::/163c8d:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1433c8e::/163c8e:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1443c8f::/163c8f:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1453c90::/163c90:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1463c91::/163c91:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1473c92::/163c92:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1483c93::/163c93:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1493c94::/163c94:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1503c95::/163c95:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1513c96::/163c96:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1523c97::/163c97:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1533c98::/163c98:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1543c99::/163c99:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1553c9a::/163c9a:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1563c9b::/163c9b:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1573c9c::/163c9c:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1583c9d::/163c9d:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1593c9e::/163c9e:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1603c9f::/163c9f:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1613ca0::/163ca0:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1623ca1::/163ca1:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1633ca2::/163ca2:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1643ca3::/163ca3:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1653ca4::/163ca4:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1663ca5::/163ca5:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1673ca6::/163ca6:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1683ca7::/163ca7:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1693ca8::/163ca8:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1703ca9::/163ca9:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1713caa::/163caa:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1723cab::/163cab:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1733cac::/163cac:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1743cad::/163cad:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1753cae::/163cae:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1763caf::/163caf:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1773cb0::/163cb0:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1783cb1::/163cb1:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1793cb2::/163cb2:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1803cb3::/163cb3:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1813cb4::/163cb4:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1823cb5::/163cb5:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1833cb6::/163cb6:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1843cb7::/163cb7:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1853cb8::/163cb8:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1863cb9::/163cb9:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1873cba::/163cba:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1883cbb::/163cbb:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1893cbc::/163cbc:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1903cbd::/163cbd:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1913cbe::/163cbe:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1923cbf::/163cbf:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1933cc0::/163cc0:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1943cc1::/163cc1:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1953cc2::/163cc2:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1963cc3::/163cc3:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1973cc4::/163cc4:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1983cc5::/163cc5:ffff:ffff:ffff:ffff:ffff:ffff:ffff
1993cc6::/163cc6:ffff:ffff:ffff:ffff:ffff:ffff:ffff
2003cc7::/163cc7:ffff:ffff:ffff:ffff:ffff:ffff:ffff
2013cc8::/163cc8:ffff:ffff:ffff:ffff:ffff:ffff:ffff
2023cc9::/163cc9:ffff:ffff:ffff:ffff:ffff:ffff:ffff
2033cca::/163cca:ffff:ffff:ffff:ffff:ffff:ffff:ffff
2043ccb::/163ccb:ffff:ffff:ffff:ffff:ffff:ffff:ffff
2053ccc::/163ccc:ffff:ffff:ffff:ffff:ffff:ffff:ffff
2063ccd::/163ccd:ffff:ffff:ffff:ffff:ffff:ffff:ffff
2073cce::/163cce:ffff:ffff:ffff:ffff:ffff:ffff:ffff
2083ccf::/163ccf:ffff:ffff:ffff:ffff:ffff:ffff:ffff
2093cd0::/163cd0:ffff:ffff:ffff:ffff:ffff:ffff:ffff
2103cd1::/163cd1:ffff:ffff:ffff:ffff:ffff:ffff:ffff
2113cd2::/163cd2:ffff:ffff:ffff:ffff:ffff:ffff:ffff
2123cd3::/163cd3:ffff:ffff:ffff:ffff:ffff:ffff:ffff
2133cd4::/163cd4:ffff:ffff:ffff:ffff:ffff:ffff:ffff
2143cd5::/163cd5:ffff:ffff:ffff:ffff:ffff:ffff:ffff
2153cd6::/163cd6:ffff:ffff:ffff:ffff:ffff:ffff:ffff
2163cd7::/163cd7:ffff:ffff:ffff:ffff:ffff:ffff:ffff
2173cd8::/163cd8:ffff:ffff:ffff:ffff:ffff:ffff:ffff
2183cd9::/163cd9:ffff:ffff:ffff:ffff:ffff:ffff:ffff
2193cda::/163cda:ffff:ffff:ffff:ffff:ffff:ffff:ffff
2203cdb::/163cdb:ffff:ffff:ffff:ffff:ffff:ffff:ffff
2213cdc::/163cdc:ffff:ffff:ffff:ffff:ffff:ffff:ffff
2223cdd::/163cdd:ffff:ffff:ffff:ffff:ffff:ffff:ffff
2233cde::/163cde:ffff:ffff:ffff:ffff:ffff:ffff:ffff
2243cdf::/163cdf:ffff:ffff:ffff:ffff:ffff:ffff:ffff
2253ce0::/163ce0:ffff:ffff:ffff:ffff:ffff:ffff:ffff
2263ce1::/163ce1:ffff:ffff:ffff:ffff:ffff:ffff:ffff
2273ce2::/163ce2:ffff:ffff:ffff:ffff:ffff:ffff:ffff
2283ce3::/163ce3:ffff:ffff:ffff:ffff:ffff:ffff:ffff
2293ce4::/163ce4:ffff:ffff:ffff:ffff:ffff:ffff:ffff
2303ce5::/163ce5:ffff:ffff:ffff:ffff:ffff:ffff:ffff
2313ce6::/163ce6:ffff:ffff:ffff:ffff:ffff:ffff:ffff
2323ce7::/163ce7:ffff:ffff:ffff:ffff:ffff:ffff:ffff
2333ce8::/163ce8:ffff:ffff:ffff:ffff:ffff:ffff:ffff
2343ce9::/163ce9:ffff:ffff:ffff:ffff:ffff:ffff:ffff
2353cea::/163cea:ffff:ffff:ffff:ffff:ffff:ffff:ffff
2363ceb::/163ceb:ffff:ffff:ffff:ffff:ffff:ffff:ffff
2373cec::/163cec:ffff:ffff:ffff:ffff:ffff:ffff:ffff
2383ced::/163ced:ffff:ffff:ffff:ffff:ffff:ffff:ffff
2393cee::/163cee:ffff:ffff:ffff:ffff:ffff:ffff:ffff
2403cef::/163cef:ffff:ffff:ffff:ffff:ffff:ffff:ffff
2413cf0::/163cf0:ffff:ffff:ffff:ffff:ffff:ffff:ffff
2423cf1::/163cf1:ffff:ffff:ffff:ffff:ffff:ffff:ffff
2433cf2::/163cf2:ffff:ffff:ffff:ffff:ffff:ffff:ffff
2443cf3::/163cf3:ffff:ffff:ffff:ffff:ffff:ffff:ffff
2453cf4::/163cf4:ffff:ffff:ffff:ffff:ffff:ffff:ffff
2463cf5::/163cf5:ffff:ffff:ffff:ffff:ffff:ffff:ffff
2473cf6::/163cf6:ffff:ffff:ffff:ffff:ffff:ffff:ffff
2483cf7::/163cf7:ffff:ffff:ffff:ffff:ffff:ffff:ffff
2493cf8::/163cf8:ffff:ffff:ffff:ffff:ffff:ffff:ffff
2503cf9::/163cf9:ffff:ffff:ffff:ffff:ffff:ffff:ffff
2513cfa::/163cfa:ffff:ffff:ffff:ffff:ffff:ffff:ffff
2523cfb::/163cfb:ffff:ffff:ffff:ffff:ffff:ffff:ffff
2533cfc::/163cfc:ffff:ffff:ffff:ffff:ffff:ffff:ffff
2543cfd::/163cfd:ffff:ffff:ffff:ffff:ffff:ffff:ffff
2553cfe::/163cfe:ffff:ffff:ffff:ffff:ffff:ffff:ffff
2563cff::/163cff:ffff: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.