Solar Self-Consumption Calculator
Estimate solar self-consumption, self-sufficiency, grid imports, exports, annual bill value and simple payback using editable generation, load, battery and tariff assumptions.
Default project preview
58.4 %
Direct solar use
3,500 kWh/year
Battery-shifted solar
2,340 kWh/year
Grid imports
6,160 kWh/year
Grid exports
3,900 kWh/year
Calculator
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Enter the project details and calculate a rounded material estimate.
Input and output guide
What each value means
The labels and units below are part of this calculator’s visible methodology. Replace every default with measurements or product data from the actual project.
Annual solar generation
Enter this project assumption in kWh/year. The current imperial default is 10000 kWh/year.
Annual electricity use
Enter this project assumption in kWh/year. The current imperial default is 12000 kWh/year.
Direct solar-use share
Enter this project assumption in % of generation. The current imperial default is 35 % of generation. Minimum: 0. Maximum: 100.
Battery capture of surplus
Enter this project assumption in % of surplus. The current imperial default is 40 % of surplus. Minimum: 0. Maximum: 100.
Battery round-trip efficiency
Enter this project assumption in %. The current imperial default is 90 %. Minimum: 1. Maximum: 100.
Grid import rate
Enter this project assumption in per kWh. The current imperial default is 0.18 per kWh. Minimum: 0.
Solar export rate
Enter this project assumption in per kWh. The current imperial default is 0.06 per kWh. Minimum: 0.
Installed system cost
Enter this project assumption in a unitless value. The current imperial default is 15000. Minimum: 0.
How to read the outputs
Direct solar use
used as generated. Default preview: 3,500 kWh/year.
Battery-shifted solar
after round-trip losses. Default preview: 2,340 kWh/year.
Grid imports
remaining household demand. Default preview: 6,160 kWh/year.
Grid exports
surplus after battery charging. Default preview: 3,900 kWh/year.
Annual bill value
avoided imports plus export credit. Default preview: $1,285.20.
Simple payback
installed cost ÷ annual value. Default preview: 11.67 years.
Methodology
Transparent calculation
BuildMeter converts every input to a consistent internal unit, applies the selected allowance, and rounds products up to whole purchasable units.
Direct use is the entered share of annual generation, capped by demand. Battery delivery equals captured surplus × round-trip efficiency, capped by remaining demand. Annual value combines avoided imports and export credit.
FAQ
Solar Self-Consumption Calculator questions
What is solar self-consumption?+
It is the share of generated solar energy used by the property directly or after battery storage instead of being exported.
How is self-sufficiency different?+
Self-sufficiency is the share of total electricity demand supplied by solar and battery energy.
Why is hourly modeling more accurate?+
Annual totals cannot show whether generation and demand occur at the same time or whether a battery reaches its power and energy limits.