The answer to 'what size electrical panel do I need' is that the size of your electrical panel depends on the total electrical load of your home. Most modern homes require a 200-amp electrical panel to handle the power needs of appliances, lighting, and other electrical devices. Larger homes or homes with high-power electrical equipment may need a 400-amp or even larger panel.
To determine the right size electrical panel for your home, you should consider factors like the square footage of your home, the number and types of appliances and devices you have, and any plans for future electrical upgrades or additions. It's best to consult with a licensed electrician who can assess your specific power requirements and recommend the appropriate electrical panel size.