• You’ll need to a llow about 24 hours for each 4 to 5 pounds of frozen turkey you plan to thaw in the fridge. Approximate times to defrost a whole turkey in the fridge: - 10 pounds — 2 days plus 12 hours - 15 pounds — 3 days plus 18 hours - 20 pounds — 5 days - 25 pounds — 6 days plus 6 hours.