Solar PV Calculator — FarmTracker Design Group

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Location — Click Map to Auto-Fill Solar Resource Data

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Annual solar resource: >7.0 kWh/m²/d (Excellent) 5.5–7.0 (Good) 4.0–5.5 (Moderate) <4.0 (Low)

☝ Click anywhere or click a station to set your solar resource data.

Selected Location

— No location selected —

☀ Solar data applied to calculator

Auto-fills: summer & winter peak sun hours, annual average — used to calculate array size and annual output.

Energy Usage & System Type

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Yellow = your inputsBlue = calculated

System Type

Grid-tied systems sell excess power back to the utility. No battery storage is required, though it can be added. Power goes out when the grid goes out (unless you have a backup system).

Daily Energy Consumption

Enter your average daily usage, or estimate from your monthly bill.

Daily Usage (kWh/day)

Monthly Bill ($) — optional estimator

Electricity Rate ($/kWh)

Peak / Surge Load (W)

Monthly kWh (estimated)

Annual Usage (kWh)

Minimum Inverter Size (W)

Solar Array Sizing

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Green = your inputsBlue = calculated

Use the Location map above to auto-fill peak sun hours. Standard residential panels are 390–430W. Derate factor accounts for heat, wiring losses, inverter efficiency (default 0.77 is conservative).

Solar Resource

Summer Peak Sun Hours (kWh/m²/day)

Winter Peak Sun Hours (kWh/m²/day)

Annual Average Peak Sun Hours

System Derate Factor (0.70–0.85)

Panel Specifications

Panel Wattage (W)

Panel Length (ft)

Panel Width (ft)

Panel Efficiency (%)

Array Results

System Size Needed (kW DC)

Panels Needed

Actual Array Size (kW DC)

Roof Area Required (sq ft)

Annual Production (kWh)

Summer Daily Output (kWh)

Winter Daily Output (kWh)

Annual Production vs. Usage

Battery Storage

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Green = your inputsBlue = calculated

For a grid-tied system, batteries are optional but provide backup power. For off-grid/hybrid, they are required. Set days of autonomy to 0 to skip batteries.

Days of Autonomy (backup days)

Battery Chemistry

Depth of Discharge (%)

Round-Trip Efficiency (%)

Battery Voltage (V)

Battery Ah per Unit

kWh per Battery

Battery Cost per kWh ($)

Total Capacity Needed (kWh)

Batteries Required

Actual Bank Capacity (kWh)

Total Battery Cost

System Costs & Incentives

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Green = your inputsBlue = calculated

The federal Investment Tax Credit (ITC) is currently 30% through 2032. Many states offer additional incentives.

Equipment & Installation

Installed Cost per Watt ($/W)

Solar Array + Install Cost

Inverter Cost ($)

Mounting / BOS / Permits ($)

Incentives

Federal ITC (30% of gross)

State Incentive / Rebate (%)

State Incentive Amount

Other Rebates / Credits ($)

Gross System Cost

Total Incentives

Net Cost After Incentives

Financial Returns

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Green = your inputsBlue = calculated

Net Metering Credit Rate ($/kWh)

Annual Electricity Rate Escalation (%)

System Degradation per Year (%)

System Lifetime (years)

Year 1 Savings

Payback Period

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Lifetime Savings

Net Profit (lifetime - net cost)

Cumulative Savings Over System Lifetime

Year paid off Payback year Still paying off

Year-by-Year Summary

Year 5 Cumulative Savings

Year 10 Cumulative Savings

Year 15 Cumulative Savings

Year 20 Cumulative Savings

Environmental Impact

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Values based on EPA U.S. average grid emissions factor of 0.386 kg CO₂ per kWh (2023). Your actual offset may vary by region.

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Metric tons CO₂ offset per year

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Equivalent trees planted per year

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Cars removed from road (equivalent)

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Gallons of gasoline offset per year

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Average homes powered equivalent

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Lifetime CO₂ offset (metric tons)