About WattSizing

Our Mission

At WattSizing, our mission is to make off-grid solar and battery storage accessible, safe, and understandable for everyone. We believe that transitioning to independent renewable energy shouldn't require an electrical engineering degree. By providing simple, accurate, and free tools, we empower homeowners, RV enthusiasts, and off-grid adventurers to confidently plan their power systems.

Who We Are

WattSizing was founded by a team of renewable energy professionals, off-grid practitioners, and software engineers. We were frustrated by the complex, confusing, and often heavily biased information available online. Many calculators are hidden behind lead-generation forms or designed to upsell specific brands. We built WattSizing to be a 100% free, vendor-neutral platform that gives you the exact math you need to size your solar array, battery bank, and inverter—without the sales pitch.

Our Editorial & Engineering Standards

Trust and accuracy are the core of everything we build. Our calculators and editorial guides are developed using:

• Standard industry formulas based on National Electrical Code (NEC) and international solar guidelines.
• Data from authoritative bodies like the U.S. Department of Energy (DOE), the National Renewable Energy Laboratory (NREL), and the Australian Clean Energy Regulator (CER).
• Real-world testing and feedback from certified solar installers and experienced off-grid practitioners.

How We Calculate and Verify

Every watt-hour estimate and sizing recommendation starts with nameplate ratings, measured load data where available, and conservative buffers. We document assumptions (depth of discharge, inverter surge factors, solar loss margins) so you can trace the math. Guides are reviewed against primary sources—NREL solar data, NEC references, manufacturer specs, and CER rebate rules—and updated when standards or rebate factors change.

See our editorial and engineering standards

Equipment We Reference

• Plug-in power meters and whole-home monitors for real-world wattage validation
• Industry-standard solar sizing formulas aligned with NEC and international off-grid practice
• Battery chemistries we size for: LiFePO4, sodium-ion, and deep-cycle lead-acid (with chemistry-specific DoD)
• Typical appliance nameplate and duty-cycle data from DOE and manufacturer documentation

What We Don't Do

WattSizing is not a licensed electrical contractor, installer, or engineering firm. We do not sell solar equipment, accept paid rankings in our calculator, or provide site-specific permitting or interconnection advice. Our tools and articles are educational starting points—always confirm final designs with a qualified installer or engineer for your jurisdiction.

Our Commitment to Transparency

We are committed to keeping our core calculator free to use forever. We do not accept paid placements to skew our calculator results. When we publish guides, we rely on primary sources, transparent math, and realistic efficiency buffers (like factoring in 90% Depth of Discharge and 25% system losses) so you aren't left in the dark when the sun goes down.