The cost to upgrade to Business Class on Eva Air can vary depending on several factors, including the route, availability, fare class of your original ticket, and specific travel dates. To get the most accurate and up-to-date information on the upgrade cost, it is recommended to contact Eva Air directly or visit their official website. By providing specific details such as your departure and arrival airports, booking class, and travel dates, Eva Air's customer service or online booking system will be able to provide you with the precise upgrade price for your particular flight. They will assist you in determining the upgrade availability and associated cost, ensuring a seamless and enjoyable travel experience in Eva Air Business Class Upgrade.