The limit is free cells plus one, doubled for every empty column. With four empty cells and no empty column, you can move five cards.
You can move a run of cards onto a column in one go as long as the run is a valid sequence (descending, alternating colors) and there is room to shuffle it. The limit is:
(empty free cells + 1) × 2 for each empty column
An empty column that you are moving the cards to does not count.
Examples
- 4 empty cells, no empty column: 5 cards.
- 2 empty cells, no empty column: 3 cards.
- 2 empty cells and 1 empty column: 6 cards.
- No empty cells or columns: 1 card.
Why it matters
This is why empty cells and columns are worth keeping, and why clearing a column early is so strong (FreeCell strategy). The game works the move out for you, and it counts as a single move (how moves are counted). See also how free cells work and the full rules.