
Mortgage Overpayment Simulator
Mortgage-free date — the contractual payment plus the extra, on the balance after any lump sum, solved for the month it reaches zero — with interest saved against doing nothing.
What the file tells you
Two hundred a month, a lump sum, a rate that goes up — every overpayment scenario against your balance and term, with the one number that matters: the month you are mortgage-free. And the two checks nobody does: does it fit your spare cash, and does the lump leave the emergency fund whole?
Homeowners with a bit spare each month who want to know what it actually buys.

Excel 2016+ or Microsoft 365. Or upload the .xlsx to Google Drive — it opens in Sheets with formulas and charts intact.
Yes — BLIK, Przelewy24, any card, Apple Pay, Google Pay and PayPal. Prices in PLN, EUR, USD or GBP; the currency switch is at the top.
Tick “I’m purchasing as a business” at checkout and enter your NIP / VAT ID. The invoice arrives with the download e-mail.
14-day refund, no questions. One e-mail to [email protected].