How does extending a 60-day Tourist Visa work in Thailand?

When extending a 60-day Tourist Visa in Thailand, the extension generally starts from the current expiration date. Most immigration offices allow you to apply for an extension up to 30 days before the expiration, and they typically add the new extension period onto the existing visa duration. However, there can be variations, and some offices, like in Jontiem, may require you to wait until the last week before applying. It is also noted that during the Covid pandemic, extensions were often granted based on the date the application was made.