Quick answer: Monthly solar saving = (imported kWh × import tariff) − (exported kWh × export tariff). Under net metering, surplus daytime units offset night-time imports, so right-sizing the system matters more than maximising panels. Enter your monthly import, export and both tariffs below to compare bills with and without solar.
Last reviewed: September 2026
Estimate only — tariffs, net-metering rules and fixed charges vary by utility and country.
Key facts
- Saving = import kWh × import tariff − export kWh × export tariff.
- Export tariffs are usually lower than import tariffs — self-consumed solar saves the most. The saving figure is the export credit only — solar you consume directly already cut your import, which is extra benefit on top.
- Net-metering / net-billing rules and tariffs vary by utility and country.
- Fixed monthly charges and taxes are not included — this is an energy-charge estimate.
This free solar savings calculator estimates your monthly electricity bill and savings under net metering, imported energy billed at your import tariff minus exported solar credited at your export tariff. Enter your own tariffs for an instant personalized estimate, wherever you live. Fixed charges are excluded from the estimate.
Enter your monthly import/export and both tariffs for an instant estimate. No sign-up, works on mobile and desktop.
How to use
- Enter your monthly import in kWh (from your bill).
- Enter your import tariff per kWh.
- Enter your expected monthly export in kWh (your installer's estimate).
- Enter the export tariff your utility pays per kWh.
- Read your estimated bill and monthly saving.
How solar savings are calculated
| Term | Meaning |
|---|---|
| Import | kWh you draw from the grid, billed at the import tariff. |
| Export | Surplus solar kWh you send back, credited at the export tariff. |
| Self-consumption | Solar kWh you use directly — worth the full import tariff. |
Because export tariffs are usually lower than import tariffs, every kWh you consume yourself saves more than one you export.
Worked examples
400 kWh import, 300 kWh export
Import tariff 0.15, export tariff 0.08. Bill without solar = 400 × 0.15 = 60.00. Export credit = 300 × 0.08 = 24.00.
Net bill = 36.00; export-credit saving = 24.00 (40.0% of the bill). Self-consumed solar already reduced the 400 kWh import, which is additional benefit beyond this figure.
High self-consumption case
Import 250 kWh at 0.20 = 50.00. Export 100 kWh at 0.06 = 6.00.
Net bill = 44.00; saving = 6.00 — smaller, because most solar is consumed directly (which already avoided import charges).
What affects your real saving
| Factor | Effect |
|---|---|
| Export tariff level | Higher export tariff = bigger credit |
| Self-consumption share | Using solar directly avoids the full import tariff |
| Fixed charges & taxes | Stay on the bill even with solar |
| Seasonal generation | Export peaks in sunny months |
Frequently asked questions
How do I estimate my solar savings?
Multiply your monthly grid import (kWh) by your import tariff, then subtract exported kWh times the export tariff. The calculator above does it instantly.
Why is the export tariff lower than the import tariff?
Most utilities credit exported solar at a wholesale or avoided-cost rate, which is below the retail import tariff. Some regions use 1:1 net metering — check your utility's current policy.
Does this include fixed charges and taxes?
No. This estimates the energy portion of the bill. Fixed charges, meter rent and taxes usually remain payable.
Is it better to consume solar or export it?
Consume it: self-consumed solar offsets the full import tariff, while exported solar only earns the (usually lower) export tariff.
How accurate is this estimate?
It is a planning estimate. Real bills depend on your utility's exact net-metering rules, tariff slabs and seasonal generation — confirm with your installer and utility.
Will I still have an electric bill with solar?
Almost always, yes. Net metering only offsets the energy portion of your bill — fixed monthly charges, meter rent and taxes usually stay payable even if your panels cover all your energy use.
How long does it take solar panels to pay for themselves?
Typically 4 to 12 years, depending on system cost, your tariffs and available sunshine. Divide the net installation cost by your estimated annual saving for a rough payback figure. Panels usually last about 25 years, so most of their life is pure saving after payback.
What is the difference between net metering and net billing?
Under net metering, exported solar kWh usually offset imported kWh one-for-one (a 1:1 credit). Under net billing, exports are credited at a lower export tariff than the import tariff, so each exported kWh is worth less than each imported one. This calculator follows the net-billing style with separate import and export tariffs; if your utility uses 1:1 net metering, just set both tariffs equal.
Sources
Key takeaways
- Net bill = import × import tariff − export × export tariff.
- Self-consumed solar is worth more than exported solar.
- Fixed charges and taxes stay on the bill.
- Confirm your utility's current net-metering rules before deciding.
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