When to use this calculator
A site can have high self-consumption but low self-sufficiency if its solar system is small relative to demand.
Explore the solar generation & value calculators for other questions in this topic. For a related calculation, use the Solar String Open Circuit Voltage Calculator: Add chosen design open-circuit voltages for a series solar string.
PUTTING IT INTO PRACTICE
Solar Self Sufficiency: a worked example
The values below are an illustrative example, not a recommendation. Replace them with measurements or assumptions that match your question.
| Input | Example value |
|---|---|
| Solar energy supplying site demand (kWh) | 1,800 |
| Total site demand (kWh) | 4,000 |
| Result | 45 % |
- Check the input labels and enter the example values above.
- Apply the relationship: Self-sufficiency (%) = solar supplied demand/total demand × 100.
- The result is 45 %, rounded for display.
How to interpret your result
Use matched demand and supply periods; clarify how stored solar and conversion losses are counted.
Peak sun hours describe equivalent full-power sunlight, not total daylight. Self-consumption and self-sufficiency have different denominators. On-site use and exports may have different monetary values.
Frequently asked questions
Are self-consumption and self-sufficiency the same percentage?
No. Self-consumption divides solar used on site by solar generated; self-sufficiency divides solar supplying demand by total site demand.
When is the solar self sufficiency calculator useful?
A site can have high self-consumption but low self-sufficiency if its solar system is small relative to demand.
How do I use the solar self sufficiency calculator?
Enter solar energy supplying site demand (kwh), total site demand (kwh). The result updates automatically. Use the units shown beside each input; the example values illustrate the method.
Which formula does this calculator use?
Self-sufficiency (%) = solar supplied demand/total demand × 100.
What should I check before using the result?
Use matched demand and supply periods; clarify how stored solar and conversion losses are counted.
How are results rounded?
Scalar numbers display up to six decimal places, with scientific notation for very large or small values. Text, fraction, date and schedule outputs use the format described on the tool. Intermediate calculations use JavaScript floating-point arithmetic. Keep sensible precision for your measurements.
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