MORTGAGE CALCULATOR
Your mortgage.
A clearer way forward.
Explore the numbers. Then review your next step with Marcin.
Your numbers stay in this tab. Clear your inputs when using a shared device.
Already found a property? Enter its price and your deposit to explore the monthly mortgage payment.
A KNOWN PROPERTY
Calculate the repayment.
Use your property price and deposit. This mode calculates repayment mathematics, not borrowing capacity.
Enter a property price, an explicit deposit (0 if none), and 60–420 whole months. The deposit must be less than the price.
Additional assumptions
RATE & PRODUCT
Make the assumptions visible.
The starting rate is an illustrative 6% nominal annual rate, fixed for five years. It is not a current bank quote. Configuration reviewed 2026-10-05.
The rate is not guaranteed beyond this period.
Optional. If blank, the projection holds the initial nominal rate unchanged. This is an assumption, not a guarantee.
Optional, percentage points above the KNF minimum. Banks can use a higher buffer.
A home of your own.
A plan that feels clear.
Start with your details. Your payment, projected interest and repayment timeline will come together here.
YOUR INPUTS → YOUR PERSONAL PROJECTIONSee the whole journey.
Your balances, cash flow and the details behind your result.
Assumptions, sources & review.
Sources reviewed: . Review again before relying on a product offer; lender rules and programme conditions can change.
- KNF — Recommendation S (2023)
Recommendations 7, 9 and 15: recommended term up to 25 years, maximum 35; assessment limited to 25 years for longer requests. 80% LTV standard and 90% conditional protection. Income sustainability, expenses and retirement need individual review. DStI 40%/50% are risk indicators, not universal approval limits.
- KNF — interest-rate buffer amendment
Periodically fixed: minimum buffer = 2.5 × (T − x) / (T − 60) percentage points, where T and x are months and x ≥ 60; 5-year fixed in a longer loan gives 2.5 points. Full-term fixed: no interest-rate-change buffer. Variable: max(5 − NBP reference rate, 2.5) + σ; σ = 1.5 when the last 100-business-day standard deviation is ≥ 0.5 points and the current NBP rate exceeds that period’s mean, otherwise 0. Banks may use higher buffers.
- BGK — Rodzinny kredyt mieszkaniowy
Separate guarantee, household, property, price and lender conditions apply. Low or no deposit is a review path, not an automatic rejection or confirmed qualification. This calculator does not calculate a BGK entitlement, guarantee amount or subsidy.
- GPW Benchmark
Use the actual contractual benchmark, tenor, observation date and margin. No live benchmark values are supplied by this tool.
- Site planning assumptions — require Marcin’s validation
The 6% starting nominal rate is illustrative. The preliminary cash-flow ceiling uses entered expenses, not verified bank living-cost minima; it applies no generic DStI approval cap. Unknown reserves, unused credit limits and income sustainability remain unconfirmed. Price equals property valuation in the LTV scenario. None of these choices constitutes lender policy.
YOUR NEXT STEP
Your home plans deserve a closer look.
A calculator cannot capture your whole situation. Speak with Marcin about your income, deposit and possible next steps towards buying a home.
- Free consultation
- No obligation
- Your questions, answered personally
