Pot odds tell you the price you are getting on a call. If there is $100 in the pot and the call costs $50, the final pot after calling is $150. You need 33.3% equity because $50 divided by $150 is 33.3%.
Outs are the unseen cards that will improve your hand to a likely winner. A flush draw has 9 outs, an open-ended straight draw has 8 outs, and a gutshot straight draw has 4 outs. Combo draws (flush + straight) can have 15 or more outs.
Implied odds go beyond pot odds by considering the additional money you can win on future streets when you hit your draw. If your opponent is likely to pay you off when you complete your hand, you can profitably call even when pot odds alone suggest a fold. This is especially relevant in deep-stacked crypto poker games.
The "Rule of 2 and 4" is a quick shortcut: multiply your outs by 2 for the chance of hitting on the next card, or by 4 for the chance of hitting on the turn or river combined. This calculator uses the exact formula for precision.
Note: The draw engine uses Texas Hold'em unseen-card counts and no opponent range. Omaha has different unseen-card counts, and actual equity depends on the cards and ranges in play.