Most residential panels in 2025 are rated 250–550 watts, with 400-watt models becoming the new standard. A 400-watt panel can generate roughly 1. 5 kWh of energy per day, depending on local sunlight. household's 900 kWh/month consumption, you typically. . The Solar Panel Output Calculator is a highly useful tool so you can understand the total output, production, or power generation from your solar panels per day, month, or year. Input your solar panel system's total size and the peak sun hours specific to your location, this calculator simplifies. . A 300-watt solar panel will produce anywhere from 0. It's easy to use, requires just a few inputs, and provides accurate projections that can help you make informed decisions about your energy needs and return on investment (ROI). 2-3 kWh or 1,200-3,000 Wh of direct current (DC).