A warranty is a contract, not a vehicle record, so nothing you can type a number plate into will tell you whether one is in force. There are three separate things people mean by the question, they are held by three different parties, and only one of them expires on a date. Sorting out which one you are asking about is most of the work.
Is my car still under warranty from the manufacturer?
A new car warranty runs from the date of first registration for a stated period or mileage, whichever comes first, and it belongs to the car rather than to the first buyer, so it transfers on sale. The manufacturer holds it against the VIN and any franchised dealer for that make can confirm the remaining term, usually while you wait. Corrosion and paint cover often run for longer than the mechanical term, and some makes require servicing within the network for the cover to continue.
The dealer's own warranty, which is whatever it says
A used car sold with a warranty from the dealer or a third party administrator is covered by a policy document, and the document is the whole of the deal. Read what is excluded, what the claim limit is per repair and in total, whether wear and tear is covered, whether you have to use their garages, and whether servicing conditions apply. These products vary enormously and the name on the certificate tells you nothing; the schedule does.
Your legal rights, which are not a warranty at all
Buying from a trader gives you statutory rights that exist whether or not a warranty was sold: the vehicle must be of satisfactory quality, fit for purpose and as described. A fault that shows up shortly after purchase gives you a short right to reject, and after that a right to a repair or replacement before a price reduction or a final rejection. None of that applies to a private sale, where the only real duty on the seller is not to misdescribe the car.
How to check before you buy
Get the VIN, phone a franchised dealer for the make and ask for the remaining factory warranty and the service record in the same call. Ask the seller for the warranty policy document rather than a description of it. And check the recall position separately, because an outstanding safety recall is fixed free of charge by the manufacturer regardless of warranty status, and an unfixed one on a car you are about to buy is a free job somebody has not booked.
Questions people ask about what warranty does my car have
Can I check car warranty cover from the number plate?
No. Warranty status is held by the manufacturer or the administrator against the VIN or a policy number, and no public vehicle record carries it.
Is my car under warranty after I buy it second hand?
Usually yes, because it attaches to the vehicle rather than the buyer. Some makes require the servicing schedule to have been followed, so ask for the record at the same time.
Is a used car warranty the same as my consumer rights?
No. Rights against a trade seller exist by law and cannot be signed away. A warranty is an extra contract, often with exclusions, and it never replaces those rights.
What if the car has an outstanding recall?
The manufacturer fixes a safety recall free, whatever the warranty position. Check for one before you buy and get it booked, because an unrepaired recall is a fault somebody already knows about.