Run the numbers

Solar Tools

Fast, transparent calculators that work entirely in your browser. Every formula is shown, nothing is stored, and no email is required.

Sizing Tool

Solar System Size Calculator

Turn your daily energy use, sun hours and system losses into a recommended array size, panel count and inverter rating.

Array kW · panel count · roof area · inverter size

Financial Tool

Solar Payback Calculator

Estimate annual savings and payback period from system cost, generation, self-consumption, electricity rate and feed-in tariff.

Annual savings · payback years · 10 & 25-year net

Engineering Tool

Solar Panel Power Density Calculator

From rated power and module dimensions, compute power density in W/m², module efficiency and panels needed per kilowatt.

W/m² · module efficiency · panels per kW

Decision Tool

Single or Three-Phase Power?

Answer a few questions about your supply and system size to see whether single or three-phase is the right fit — and why it matters for solar.

Phase recommendation · reasoning · what to check

Sizing Tool

Solar Battery Size Calculator

Size a home battery from your overnight energy use, days of autonomy, depth of discharge and round-trip efficiency.

Usable kWh · nominal kWh · nightly load covered

Rebate Tool

Solar STC Rebate Calculator (Australia)

Estimate the federal STC incentive on an Australian solar install from system size, your zone rating, deeming years and the STC price.

STC count · estimated rebate value

Engineering Tool

Solar Cable Voltage Drop Calculator

Work out voltage drop on a DC string or single-phase AC run from length, current, conductor size and material — checked against AS/NZS guidance.

Voltage drop (V) · drop % · pass/flag vs limits

Design Tool

Tilt & Orientation Yield Estimator

Get an indicative annual-yield figure for a roof from its direction and pitch, relative to an optimally-oriented array.

Indicative relative yield % · rating · guidance

Engineering Tool

Solar String Sizing Calculator

Work out how many panels can go in series on a string — within the inverter's MPPT window and under the maximum system voltage — using temperature-corrected module voltages.

Min/max modules per string · cold Voc · voltage headroom

Design Tool

DC:AC Ratio (Inverter Load Ratio) Calculator

Check the ratio of array DC capacity to inverter AC rating — the inverter load ratio — and see whether it sits in the typical range or risks clipping.

DC:AC ratio · sizing verdict · clipping watch
About the tools

Using the calculators

Where do the calculations happen?
Entirely in your browser. The tools run on your device, store nothing, and require no email or sign-up.
Are the results a formal quote?
No. Every tool gives an estimate to help you reason about a system — not a quote or an engineering specification. Each calculator shows the formula it uses so you can check the working.
Is the site tied to any manufacturer?
No. Solar Analytica is independent and manufacturer-neutral — not affiliated with any brand — and the tools are free to use. Content was last reviewed in June 2026.