Work out rainbow table size instantly with clear inputs, formula shown and shareable results.
A rainbow table trades storage for time by storing only the endpoints of hash-reduction chains, so storage falls by the chain length while lookup cost rises proportionally. Covering all passwords up to length 8 over 62 characters means about 2.2 x 10^14 candidates — feasible in the 2000s for unsalted MD5, and completely defeated by per-password salts, which force a separate table per salt value.
Rainbow table storage
keyspace = sum of C^k for k = 1..L; chains = keyspace / chain length; storage = chains x bytes per chain
Only against unsalted hashes. Every modern password hash includes a random salt, which is precisely the mitigation that makes precomputed tables worthless.
The attacker must build a separate table per salt value. With a 128-bit salt there are 2^128 variants, so no table can be prepared in advance.