- Solar panel calculatorSize a solar PV array from your daily electricity use, local peak sun hours, system losses, and panel wattage. Also estimates roof area and an off-grid battery bank using depth-of-discharge and round-trip efficiency.
- Solar payback calculatorApply the 30% federal ITC, model 0.5%/year panel degradation and 3%/year rate inflation, and see year-by-year cumulative savings until the system breaks even.
- Net metering calculatorCompare a solar bill under traditional 1:1 net metering vs export-only credits (e.g. CA NEM 3.0). Get monthly net cost, exported kWh, self-consumption ratio, and annualized totals.
- Solar panel tilt calculatorGet the year-round optimal tilt (≈ latitude), summer tilt (latitude − 15°) and winter tilt (latitude + 15°), plus expected production gain from seasonal adjustment.
- Solar inverter sizing calculatorNREL and SEIA recommend a DC:AC ratio of 1.15–1.30. Higher ratios cost less per AC watt but cause midday clipping. Find the sweet spot for your location.
Calculator directory
Solar Panel & PV System Calculators
Size and finance your residential PV system with tools based on NREL PVWatts irradiance data, NEC 2023 inverter sizing rules, and current US net-metering tariffs. Project payback and IRR under SREC and federal ITC scenarios, estimate net-metering savings, optimize fixed tilt by latitude, and right-size inverter AC output against panel DC capacity for each major module chemistry.
Formula notes
Formulas used in this calculator group
Compare the core equations behind each calculator in this hub before opening a detailed tool.
Solar panel calculator
- P_pv = kWh_d / (PSH × (1 − L))
- N = ⌈P_pv × 1000 / W_p⌉
Solar payback calculator
- C_n = C_s × (1 − R_i)
- N = min(n: ΣS_n ≥ C_n)
Net metering calculator
- C = kWh_i × R_i − kWh_e × R_e + F
Solar panel tilt calculator
- θy ≈ φ
- θs ≈ φ − 15°
- θw ≈ φ + 15°
Solar inverter sizing calculator
- P_ac = P_dc / R
- L_c ≈ max(0, (R − 1.15)^2 × 18%)
FAQ
Common questions for this calculator group
Review the most common planning questions from the calculators in this hub, with links back to each detailed page.
Which calculator in this group should I open first?
Start with the calculator whose title matches the decision you are making. The hub formulas help you compare what each tool actually models before you open the detailed page.
Why are the formulas shown as compact equations?
The hub view is a quick map. Each detailed calculator still explains the assumptions, inputs, examples, and caveats behind the equation.
Can I use these results before requesting a quote or buying equipment?
Yes, use them for early planning and comparison. Before purchase or installation, confirm the assumptions with equipment manuals, installers, utility rules, and local codes.