Police custody or remand means that the physical custody of the accused is with the Police, and the accused is lodged in a lock-up of a police station. After an FIR is lodged for a cognizable offense (which provides a punishment of more than three years), the accused is arrested by the police to prevent the tampering of evidence or influencing the witnesses.

Judicial custody or remand is there in case of serious offenses, where the Court may accede to the request of the police to remand the accused in judicial custody after the police custody period expires, that is to prevent the tampering of evidence or witnesses.

Key Differences

1. Police custody means that the accused stays in the lock-up of a police station or in the custody of an investigating agency that is probing the concerned matter, whereas judicial custody means that the accused stays in the lock-up of a police station or in the custody of an investigating agency who is probing the concerned matter, whereas judicial custody means that the accused is lodged up in jail and is under the custody of the Magistrate.
    
2. A person lodged in police custody has to appear within 24 hours before the concerned Magistrate, whereas in judicial custody the person is kept in jail until there is an order from the Court for bail.
    
3. Police custody begins as soon as the suspect is arrested by a police officer after receiving a complaint or filing an FIR, whereas, judicial custody begins after the public prosecutor satisfies the court that the custody of the accused is necessary for the investigation purpose.
    
4. In police custody, the time period is 24 hours which can be extended to a period of 15 days as a whole by the appropriate Magistrate, whereas in Judicial Custody the maximum time period for detention is 90 days, in the cases where the investigation is related to offenses punishable with life imprisonment, death or imprisonment for a term of not less than ten years and detention is 60 days for crimes where the imprisonment is for less than ten years.