What size solar system could fit your electricity use?

Enter your monthly bill and estimated daytime use to see an illustrative installation cost and savings range.

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Start with two inputs

Enter your details

Use an average of several bills if available, or start with the example values and adjust them. The default avoided rate of 4.20 baht/kWh is an assumption, not the tariff for every home.

Monthly electricity bill bahtUse an average of several bills if available.

Daytime electricity use 50%Roughly 08:00–17:00. Choose a lower value if you mainly use electricity in the evening; start at 50% if unsure.

Have a bill? Refine the estimate

Monthly electricity use kWh · if knownUse the kWh on your bill instead of estimating it from the amount paid.

Avoided electricity rate baht/kWhUsed for savings and to derive kWh when not entered; the actual rate depends on your tariff and usage tier.

Assumed installation cost per kWp bahtStarting assumption from our guide. Adjust it if you have a quote.

How it works

Where do these numbers come from?

1. Estimate daytime demand

Monthly kWh × daytime use share, then assume 70% of that demand overlaps with solar generation.

2. Estimate system size

Assume 4–5 peak sun hours per day, or 120–150 kWh per kWp each month, to show a range.

3. Estimate payback

Multiply expected self-used solar electricity by the avoided rate, then divide the assumed cost by annual savings.

This estimate assumes less self-consumption than examples that use 100% of solar output. It excludes income from exported electricity, panel degradation, maintenance, tax, roof work, and equipment replacement. It does not use actual sunlight or shading data for your location. It is not a guarantee or a quotation.

Want an assessment for your actual site?

Read about checking your roof and electrical system, or speak with our team about sizing a system from your bills and use patterns.

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