New laptop battery suddenly dropped from 50% to 0%—is that normal?

Give it one complete charge and monitor it for a day or two, but don’t ignore another sudden shutdown. A one-time inaccurate reading is possible, while repeated drops from around half charge to empty usually point to a defective battery or charging circuit. Since the laptop is new, returning it promptly is safer than trying to troubleshoot it extensively yourself.

That isn’t normal behavior for a brand-new laptop. Charge it fully and see whether the battery percentage behaves correctly through another use cycle. If it suddenly drops again, take it back to the store and request a replacement or warranty inspection.

The battery gauge may need calibration, especially if the laptop was just manufactured or has barely been used. Let it charge uninterrupted until it reports 100%, then use it normally and watch the percentage. You can also check the battery’s design capacity, current full-charge capacity, and cycle count through the manufacturer’s diagnostics or BIOS. Don’t repeatedly drain a lithium battery to 0%, though—once is enough for testing.