GuaranteeCheck
How it works
SunStrong Management Sunrun Renewbrook
Pricing FAQ Guides
Check for free
How it works
Servicers
SunStrong Management Sunrun Renewbrook Pricing FAQ Guides Check for free
Free tool

Find out if your solar lease owes you money — in under a minute.

Enter three numbers straight off your lease and your monitoring account, and this calculator estimates whether your production guarantee's true-up likely owes you a credit. No account, no data saved — just the math.

Your numbers

The annual production number your lease or PPA promises. It's usually on the first page or the production-guarantee schedule.
What your system actually produced over the same 12 months, from your monitoring account (Enphase, SolarEdge, or your utility bill's solar production line).
The dollar amount your lease pays per kWh of shortfall. Most leases fall between $0.10 and $0.50/kWh — check your lease's true-up or production-guarantee clause. If you can't find it, leave this at the placeholder and treat the result as rough.

Enter a guaranteed production number, an actual production number, and a true-up rate of 0 or more.

Estimated result

Fill in the three numbers on the left to see your estimate.

This is a rough estimate, not a real diagnostic. It assumes a simple one-year comparison with no carried-over surplus or shortfall from a prior true-up period, and no adjustment for a stated annual degradation rate -- both of which your real true-up may include. It also doesn't verify your production data against your actual meter records the way a real check does. For an accurate, servicer-specific answer -- pulling your real production data and drafting a claim letter if you're owed money -- use the free real diagnostic at GuaranteeCheck. This estimator doesn't store, send, or save anything you enter; the math runs in your browser and disappears when you leave the page.
How the math works

The same true-up logic, simplified to one year.

This mirrors the core of GuaranteeCheck's real true-up calculation: guaranteed production minus actual production, floored at zero, times your true-up rate. The real diagnostic additionally accounts for your lease's actual true-up interval (often 24 months, not 12), any surplus or shortfall carried over from a prior period, and an optional stated annual degradation rate -- see the full methodology for the complete formula.