How do you find out how old a car battery is?

Method 1: Look for the date code on the battery. This is usually a four-digit code that indicates the month and year the battery was manufactured. The first two digits represent the month, and the last two digits represent the year. For example, a date code of 1021 would indicate that the battery was manufactured in October 2021.

Method 2: Check the warranty information. Most car batteries come with a warranty that lasts for a certain number of years or months. The warranty information will usually be printed on the battery or in the owner's manual. If you know the date the battery was purchased, you can add the warranty period to that date to determine the battery's age.

Method 3: Have the battery tested. A professional can test the battery's capacity and voltage to determine its condition. This can give you an idea of how old the battery is and how much longer it is likely to last.