Free Sizing Calculators
Stop guessing. Get specific numbers for your system based on your actual usage. All calculators are free and work instantly in your browser.
Solar Panel Sizing Calculator
Enter your daily power usage and sun hours to find out exactly how many watts of solar panels you need.
Inputs
- → Daily energy use (Wh)
- → Peak sun hours
- → Efficiency losses
Output: Recommended panel wattage + number of panels
Battery Bank Sizing Calculator
Calculate how many amp-hours of battery storage you need based on your usage and desired days of autonomy.
Inputs
- → Daily energy use (Wh)
- → Days of autonomy
- → Depth of discharge
- → Battery voltage
Output: Total Ah needed + number of batteries
Generator Sizing Calculator
Find the right generator wattage by adding up your essential loads, including startup surge requirements.
Inputs
- → Running watts per appliance
- → Startup surge multipliers
Output: Minimum running watts + recommended generator size
Water Storage Tank Sizing
Calculate how many gallons of water storage you need based on household size, usage, and collection method.
Inputs
- → People in household
- → Gallons per person per day
- → Days without resupply
Output: Minimum gallons of storage needed
Need a custom calculation?
All calculators use standard engineering formulas. Each calculator page explains the math so you can verify the results and adjust for your specific situation.