Solar Production Calculator: annual & monthly kWh
Instant solar panel kWh / production calculator: enter array kW, peak sun hours, and system loss → planning annual and monthly energy. For industrial screens—not PVWatts weather-year simulation or residential shopping.
Quick answer
How much energy will my array produce? Annual kWh ≈ Array kW × Peak sun hours × 365 × (1 − Loss). Example: 10 kW, 5.0 PSH, 15% loss → about 15,513 kWh/yr (~1,293 kWh/month flat). Need panel count first? Use the solar panel calculator. Confirm PSH in peak sun hours. Hub: Solar calculator.
Quick PV Energy Production Calculator
Defaults: 10 kW array · 5.0 PSH · 15% system loss.
10 kW × 5.0 × 365 × 0.85.
Advanced PV Energy Production Calculator
Presets
PV Energy Production Results
Engineering disclaimer
Simplified estimate—not NREL PVWatts. Real yield varies with weather year, tilt, shading, and OEM curves. Use for planning screens only.
Results
~15,513 kWh/yr — default example.
Annual kWh by peak sun hours
| PSH | kWh/yr | kWh/month |
|---|
People also ask
- How do I estimate solar kWh? Array kW × PSH × days × (1 − loss).
- Is this PVWatts? No—simplified planning formula with explicit loss %.
- Monthly vs annual? Monthly ≈ annual ÷ 12 for a flat screen; seasonality needs site data.
Planning guidance
This page estimates yield from a known array. If you still need array kW, start with panel sizing. Treat results as a linear planning screen—not a weather-year bid.
- Size first: Get array kW from the solar panel sizing calculator.
- PSH: Confirm with peak sun hours / irradiance guides.
- Loss band: 12–20% is common for commercial rooftops before weather uncertainty—see losses & derating.
- Cost link: Carry kWh into the energy estimator.
- Hub: Solar calculator.
Last updated: 2026-08-07. Simplified estimate—not NREL PVWatts.
Typical scenarios
- 10 kW office roof: ~12–18 MWh/yr depending on PSH and soiling.
- 50 kW warehouse: Scales linearly here—confirm inverter clipping separately.
- High-loss site: Dusty / long DC runs—raise loss % before quoting savings.
Daily, monthly, and annual yield
Daily kWh ≈ Array kW × PSH × (1 − loss). Annual multiplies by days/year. Monthly on this page is annual ÷ 12 (flat)—useful for bill screens, not seasonal design.
| Example (10 kW · 5.0 PSH · 15% loss) | Energy |
|---|---|
| Daily | 10 × 5 × 0.85 = 42.5 kWh/day |
| Monthly (flat) | ≈ 1,293 kWh/month |
| Annual | ≈ 15,513 kWh/year |
This calculator vs NREL PVWatts
- This tool: Explicit kW × PSH × days × (1 − loss)—fast, transparent, linear.
- PVWatts / SAM: Weather-year irradiance, tilt/azimuth, temperature, and inverter models.
- Use this page for screening; confirm bids with NREL PVWatts or SAM.
Formula (quick reference)
Annual kWh = Array kW × Peak sun hours × Days × (1 − Loss fraction)
Monthly ≈ Annual ÷ 12 (flat average). How to choose loss %: solar system losses & derating.
Formula and sources
Not equivalent to PVWatts. Use for planning screens; confirm with site irradiance and OEM software.
Frequently Asked Questions
How do I calculate solar panel kWh production?
Multiply array kW by peak sun hours, days per year, and (1 − system loss). Example: 10 × 5 × 365 × 0.85 ≈ 15,513 kWh/yr.
How many kWh does a 10 kW solar system produce?
At 5.0 PSH and 15% loss ≈ 15,513 kWh/year (~1,293 kWh/month flat). Raise or lower PSH/loss in the calculator for your site.
Is this the same as NREL PVWatts?
No. This is a simplified planning estimate with an explicit loss percentage—not a weather-year simulation. Use PVWatts/SAM for deeper studies.
What loss percentage should I use?
Often 12–20% for commercial systems covering inverter, wiring, soiling, and mismatch. See solar system losses & derating.
How does this differ from solar panel sizing?
This page = production (kWh) from a known array. The solar panel calculator finds how many panels / array kW from daily load. Do not use production to size panel count.
Why is monthly just annual divided by 12?
Flat average for quick bill screens. Real seasonality needs monthly PSH or a weather-year model—start with peak sun hours.
What is the next step?
Size MPPT controllers for string current, or screen energy cost with the energy estimator.
How it works
Daily full-sun equivalent hours are scaled across the year and reduced by a combined system loss fraction. The model is linear in array kW—clipping, seasonal PSH, and tilt are out of scope here.
Worked examples
- 10 kW · 5.0 PSH · 15% loss
10 × 5 × 365 × 0.85 = 15,512.5 kWh/yr (~1,293 kWh/month).
- 50 kW · 4.5 PSH · 18% loss
50 × 4.5 × 365 × 0.82 ≈ 67,342 kWh/yr.