Clubs remaining in the competition still have to play their Fifth Round matches, which begin this week with Nottingham Forest hosting Burnley on Tuesday.
The remaining ties take place over the rest of this week before the north-east derby between Sunderland and Newcastle United next Wednesday completes the Fifth Round.
Sixth Round ties must be played by Saturday 21 February, with the first leg of the Semi-Final to be played by 7 March and the second leg by 21 March.
Dates for The Final will be scheduled once the competing clubs are confirmed.
The Sixth Round Proper draw
1 Leicester City v Birmingham City
2 Newcastle United v Chelsea
3 Manchester City v Crewe Alexandra
4 Nottingham Forest v Tottenham Hotspur
The Semi-Final draw
First leg
1 Manchester City v Leicester City
2 Tottenham Hotspur v Newcastle United or Chelsea
Second leg
1 Leicester City v Manchester City
2 Newcastle United or Chelsea v Tottenham Hotspur
The Final
First leg
Manchester City/Leicester City v Tottenham Hotspur/Newcastle United/Chelsea
Second leg
Tottenham Hotspur/Newcastle United/Chelsea v Manchester City/Leicester City