BifacialPanels

Free tool

Bifacial solar panel calculator

A rough planning guide — not an accurate forecast. Estimate your daily and monthly energy and a conservative range for how much extra a bifacial panel's rear side adds in your setup. Everything runs in your browser.

Your setup

Total rated wattage of all panels combined.

Picking a state fills in an approximate peak-sun-hours figure. You can override it if you know your local value.

Estimated output

Daily energy

2.98–3.22

kWh / day

Monthly energy

91–98

kWh / month

Estimated bifacial gain

7.7%–16%

over an equivalent monofacial system (~2.77 kWh/day baseline).

Tilted panels with open sky behind them — where bifacial is at its strongest.

A rough planning guide, not a quote or forecast.

Actual performance depends on installation angle, rear-side exposure and clearance, ground reflectivity (albedo), shading, row spacing, temperature, and your specific hardware. We show a range on purpose — treat the numbers as a ballpark and confirm with a qualified installer.

Where the rear-side gain comes from

The rear face only generates from light that reaches it — light reflected up from the ground or a nearby surface. That's why the mounting type and the surface behind your panels drive most of the estimate above: a tilted, elevated panel over bright ground sees far more reflected light than one flush against a roof.

How bifacial panels collect lightDirect sunlightReflected lightFront faceRear faceBright ground reflects more light upward
Diagram showing direct sunlight reaching a panel's front face and reflected ground light reaching its rear face.

Apply it

See what your result means for your setup

Your mounting type drives most of the gain. These guides go deeper on the scenarios in the calculator.

Ground mount

Bifacial's strongest case — tilted and elevated over bright ground.

Read the guide

RV & portable

Why flat roof mounting usually limits the rear-side gain.

Read the guide

Off-grid cabin

Good on a tilted ground array, weaker flush on the roof.

Read the guide

Still deciding? Compare bifacial vs monofacial or browse the buyer's guide.

Good to know

Calculator FAQ

How accurate is this calculator?
It produces a conservative estimate, not an engineering result. Real output depends on tilt, rear-side clearance, ground reflectivity, shading, row spacing, temperature, and hardware. We show a range rather than a single number on purpose.
Why is my bifacial gain so low on a roof or RV mount?
A flush roof or flat RV mount sits directly behind the panel and blocks most light from reaching the rear face. That's physics, not a flaw — bifacial pays off most on tilted ground mounts with open sky and a bright surface behind the array.
What are 'peak sun hours'?
Peak sun hours are the equivalent number of hours per day at full-strength sunlight (1,000 W/m²). Selecting your state fills in an approximate annual average; your local value can differ with climate and season.
Does the calculator estimate cost savings or payback?
No. We don't show dollar savings or payback in this tool because that requires local electricity rates, install costs, and incentives we can't verify for you. We keep the calculator to energy estimates only.