Standard mortar typically takes 24 to 48 hours to dry and cure completely, but the drying time will depend on the type of mortar. Fast-drying mortars are specifically designed to cure quickly, so you can start grouting sooner. The humidity and temperature of the room will also influence the time it takes, so keep these factors in mind as you plan your project. Remember, the mortar should be completely dry before you start to grout, or it could start to crumble and damage your tile