About the Solar Panel Output Calculator
A panel’s wattage is its output under standard test conditions. Real output depends on how many peak sun hours your site gets and a system derate factor covering inverter losses, temperature, wiring and dirt. Enter your own sun-hours figure — this calculator never guesses at your location.
Also known as: solar output calculator, pv generation calculator, how much power solar panels produce, solar kwh per day.
How to use this calculator
- Enter panel rating, number of panels, peak sun hours per day, system efficiency and the other fields.
- The result updates instantly as you type — press Calculate (or Enter) at any time.
- Review the breakdown shown under the main result.
- Use Copy result or Share to save the answer or send a link with your inputs.
Formula
daily kWh = array kWp × peak sun hours × derate factor
Worked example
Using the values pre-filled in the calculator above:
- Panel rating = 450 W
- Number of panels = 12
- Peak sun hours per day = 4
- System efficiency = 80 %
- Electricity rate per kWh = 0.28
the calculator returns:
- Daily generation: 17.28 kWh
- Annual generation: 6,307 kWh
- Monthly average: 525.6 kWh
- Array size: 5.4 kWp