Solar Calculator

Solar Calculator Sri Lanka

Enter your solar system size in watts or kW to estimate monthly and yearly electricity generation, then optionally turn on a savings estimate.

Estimated savings option

System size in kW5.0 kW
Estimated kWh per 1 kW / month108 kWh
Daily generation18 kWh
Monthly generation540 kWh
Yearly generation6,480 kWh
About this calculatorSolar Calculator Sri Lanka

Estimate how many kWh a solar setup can generate each month and year from the panel size in watts or kW, with an optional electricity-savings estimate.

Best used for

Quick planning, rough comparisons, and checking whether your assumptions are in the right range before you rely on final quotes or advice.

Before you rely on the result

Review the assumptions below, then compare with related calculators if your decision depends on rates, eligibility, or provider-specific rules.

How this calculator works

  • Enter the solar system size in watts or kW.
  • Adjust the estimated monthly kWh generated per 1 kW of solar capacity using the default value or your own planning assumption.
  • The calculator estimates daily, monthly, and yearly energy generation, and can optionally estimate bill savings using your chosen electricity rate.

Worked example

A 5 kW system using a default estimate of 108 kWh per month for each 1 kW of solar capacity produces about 540 kWh per month.

Important assumptions

  • The default monthly generation estimate is editable so you can use your own solar-yield assumption.
  • Daily generation is derived by dividing the monthly estimate by 30 for a quick planning view.
  • Yearly generation is estimated as 12 times the monthly generation.
  • The optional savings estimate assumes every generated kWh offsets electricity at the selected rate, which is a simplification.

Methodology and review

Last updatedMarch 2026

Shared calculator template reviewed for formula clarity and on-page transparency.

Reviewed byLankacalculator editorial team

Editorial review focuses on practical accuracy, assumptions, and user-facing clarity.

Editorial note

Lankacalculator publishes these tools for practical planning, with the expectation that users will validate important decisions against primary sources.

How this calculation is produced

  • This calculator uses the formula and assumptions defined for the page to turn your inputs into a practical planning estimate.
  • Results are designed to be quick, transparent, and useful for first-pass decisions rather than provider-specific final quotes.
  • The output should be treated as a directional estimate until you check the relevant rates, rules, or assumptions behind your case.

What to verify before relying on it

  • Check that your units, assumptions, and scenario match the real decision you are trying to make.
  • Compare the output with a second trusted source if the result affects money, health, or compliance.
  • Use official provider, government, or expert information whenever the estimate needs to become a final decision.

When this tool is useful

  • Use this for quick planning, early comparisons, and first-pass estimates.
  • Use it when you need a decision baseline before opening a spreadsheet or asking for quotes.
  • Use it again whenever the main assumptions behind the calculation change.

How to read the result

  • Treat the primary result as an estimate that depends on the inputs and formula assumptions.
  • Compare supporting metrics, not just the headline number, before making a decision.
  • If the output affects spending or health decisions, validate it with a second source.

Common mistakes

  • Entering optimistic assumptions and reading the result as certain.
  • Comparing results from different tools without aligning units or definitions.
  • Using one scenario only instead of testing a few realistic alternatives.

Good next steps

  • Run a second scenario with stricter assumptions.
  • Compare the output with related calculators or guide pages in the same topic.
  • Use the result to narrow options, then confirm details with real provider or expert information.

FAQ

Are these calculators free?

Yes. lankacalculator tools are free to use and designed to be quick to access without sign-up.

How accurate are the results?

The calculators use clear assumptions and formulas, but results are estimates and should be checked against official documents or provider terms.

Can I use this on mobile?

Yes. The layout is built to work cleanly on phones, tablets, and desktops.

Do you store my inputs?

No account is required for these tools, and calculator inputs are not stored as user profiles in this v1 setup.

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