Understand the numbers. Organize the dates.

Uses the entered rate as a nominal annual interest rate divided by 12. A disclosed APR that includes charges can differ from the note rate. Assumes fully amortizing monthly payments, no rate changes, payment resets, balloon payments, or prepayments. Do not add a fee already included in principal.

Holds production constant, applies one rate increase each year after year one, and excludes utility charges, taxes, fees, and changes in production. This is a compounding illustration, not a prediction of savings. The default 2.9% over 25 years is an example, not your contract terms.

Adds the two monthly amounts and multiplies by 12 for an annual illustration. It does not include repairs, future increases, down payments, or seasonal changes. Use amounts from comparable periods.

Calculates promised minus actual and the percentage relative to promised production. A surplus is shown when actual production is higher. Verify the guarantee period, data completeness, and measured versus estimated figures. No legal conclusion or compensation is calculated.

Enter known dates only. The tool sorts events chronologically and flags unusual sequences for clarification, without changing your entries or calculating any legal deadline.