How to use this calculator
- Enter or choose yearly solar generation.
- Enter or choose self-consumption.
- Enter or choose export tariff per kWh.
- Enter or choose import price per kWh.
- Enter or choose yearly export fees.
- The export income per year updates as you type. Use Copy result or Share to keep it.
Method
Exported = Generation × (1 − Self-use%); Export income = Exported × Export tariff; Saving = Generation × Self-use% × Import price; Total = Income + Saving − Fees
- Self-use%
- share of generation consumed on site
- Export tariff
- payment per kWh exported
- Import price
- what you would otherwise pay per kWh
Worked example
- Exported: 5,000 × 65% = 3,250 kWh × 0.15 = 487.50.
- Used on site: 1,750 kWh × 0.28 = 490.00 saved.
- Total benefit: 487.50 + 490.00 = 977.50 a year.
With these example tariffs, exporting 3,250 kWh earns 487.50 and the 1,750 kWh used at home saves 490, a total of 977.50 a year.
What the result means
When the export tariff is well below the import price, each kWh you shift into your own use is worth more than one you export. That gap is what makes batteries, timers and EV charging during the day pay.
Assumptions and limits
- Flat export and import rates; time-of-use rates are averaged.
- Self-consumption is an annual average.
- Export income may be taxable or capped in some schemes; check your contract.
Questions
How do I find my self-consumption?
Subtract the exported kWh on your export meter from total generation on the inverter, then divide by total generation.
Is this the same as net metering?
No. Under net metering exports offset imports at a set credit rate over the billing period; use the Net Metering Estimate Calculator for that.