Understand your payments. Compare your options. Read the results with confidence.
Use this calculator to estimate mortgage repayments, understand the total interest commitment and compare ways to repay earlier. In this guide, “bond” means a mortgage loan. The standard plan is the baseline with no extra repayments; the selected plan includes the extras and optimization options you choose.
Choose your currency, enter the Purchase Price and Down Payment / Deposit, then enter the Annual interest rate and Repayment period. Mortgage principal equals purchase price minus deposit, plus any fees you choose to finance. Currency selection changes display units only; it does not convert money or apply local lending rules.
For an existing mortgage, enter the outstanding balance in Purchase Price, set the deposit to zero and use the remaining term. Leave Interest-only repayments unchecked for a normal principal-and-interest mortgage. Results update as inputs change; Calculate also refreshes them.
Open Dates & convention. Enter the first scheduled payment month and any additional months beyond the whole-year term. Payment #1 is that first payment month. Choose the interest-rate convention stated in your loan agreement: nominal annual with monthly compounding, nominal annual with semiannual compounding, or effective annual.
Enter bond and transfer fees manually. If Finance fees into loan principal is checked, those fees are borrowed and attract interest. Otherwise, they are upfront costs outside the loan repayment totals. Property taxes, insurance and other monthly costs affect the initial monthly outlay only; they are not included in lifetime loan repayments.
Select EUR; purchase price €400,000; deposit €0; interest 3.2%; 30 years; no additional months; first payment October 2026; nominal annual rate with monthly compounding. Leave all fees, other costs, lump sums and optimization checkboxes at zero or off. Then enter €200 in Extra each month.
| Result | Standard plan | €200 extra / month |
|---|---|---|
| Initial monthly mortgage outlay | €1,729.87 | €1,929.87 |
| Total interest | €222,752.29 | €183,036.04 |
| Total loan repayments | €622,752.29 | €583,036.04 |
| Repayment period | 360 months | 303 months |
| Payoff month | September 2056 | December 2051 |
Result: €39,716.24 less interest and repayment 57 months earlier. The final payment is smaller than a normal monthly payment.
Start with one option, inspect the results, then combine options if needed. Extra amounts generally add together. Avoid entering the same planned payment in two places. Payments stop when the loan is cleared; oversized extras are limited to the remaining balance.
| Control | How this version applies it |
|---|---|
| Extra each month | Adds the entered amount to every scheduled monthly payment until payoff. Despite the section label “Extra repayments (Standard)”, it affects the selected plan, not the standard baseline. |
| One-off lump sum | Adds a single extra repayment in the selected calendar month. Enter a month within the loan term and before the selected plan pays off. |
| Immediate First Payment | Makes an additional principal repayment at Month 0, before any modeled monthly interest. The amount equals one initial standard monthly payment. The regular monthly schedule still starts at payment #1. |
| Single Payment | Adds the amount once, in the specified payment number. Payment #25 means the 25th scheduled monthly payment, not a calendar year. |
| Additional Payment | Adds the entered amount each month from Active Months start to end, inclusive. It adds to any amount entered in Extra each month. |
| Salary Accelerator | Raises the base regular payment annually by the entered percentage within its active window. The first increase occurs in the 13th active month. The increase compounds annually and ceases after the window ends. It does not use your actual salary. |
| Bonus | Adds the bonus amount at payments #12, #24, #36 and so on. These are loan anniversaries, not necessarily December. |
| Bonus divided by 12 | Spreads the same bonus amount equally over monthly payments from payment #1. This and Bonus are alternative choices; selecting one deselects the other. |
| Biweekly (1/12th extra/mo) | Adds one-twelfth of the initial standard monthly payment each active month. Over 12 months, this equals one extra monthly payment. It does not calculate actual fortnightly dates. |
| Double Monthly Payment | For principal-and-interest borrowing, doubles the base regular payment in the active window. If Salary Accelerator also applies, it doubles the salary-adjusted payment. Other extras remain additional. |
Start and end refer to payment numbers, and both endpoints are included. Use whole months, start no later than end, and keep the window within the term. The default end is month 360: edit it if you want an option to cover a different period. An option scheduled after early payoff has no effect.
Example: a 10% Salary Accelerator starting at month 1 uses the base regular payment for months 1-12, 110% for months 13-24 and 121% for months 25-36, if the active window continues.
| On-screen result | Meaning |
|---|---|
| Monthly mortgage payment | The standard plan’s regular payment. It does not include selected extras or other housing costs. |
| Initial monthly outlay · selected plan | The first scheduled monthly payment, its extra repayment and entered monthly housing costs. It excludes the deposit, upfront fees and Month 0 payment. Later payments can differ. |
| Total Cost / Optimized Cost | Total principal and interest repaid under the standard and selected plans. Includes financed fees within principal and any maturity balloon. Excludes the deposit, fees paid upfront and monthly housing costs. |
| You Save / Interest saved | Reduction in modeled lifetime interest from the selected payments. It excludes prepayment penalties and tax effects. |
| Months / Repayment period reduced by | How many scheduled monthly periods earlier the selected plan ends. Both interest-only plans may end at maturity even when one has a much smaller balloon. |
| Repayment multiple / per-unit callout | Total repayments divided by loan principal. A multiple of 1.56 means €1.56 repaid per €1.00 borrowed, including approximately €0.56 interest. This is a nominal lifetime ratio, not an annual return or net lender profit. |
The two bars compare total repayments on the same scale. Each separates repayment of principal from interest. With positive interest, effective extras usually shorten the selected bar by reducing interest. The underlying principal is repaid in both plans.
Select Remaining Balance to follow outstanding debt, or Cumulative Interest Paid to see interest paid to date. Blue represents the standard plan; green represents the selected plan. Move the pointer over the chart to see values for a month. On a touch screen, slide a finger across the chart to inspect values. Horizontal positions show elapsed years; tooltip dates identify payment months.
After early payoff, the selected balance stays at zero and cumulative interest stays at its final total. With interest-only borrowing, a final drop to zero includes the assumed balloon payment: it does not mean the principal disappeared.
Expand Repayment schedule (amortization) and choose standard or selected repayments. Principal* includes any extra principal repayment. Do not add Extra paid to that principal column again. Total cash paid for a row is Regular payment plus Extra paid. Month 0 identifies an immediate payment; a maturity payment may include a balloon.
Download CSV exports the selected schedule for a spreadsheet. Print / save as PDF opens the browser’s print dialog. Expand the schedule or educational sections you want to include before printing, and check the preview. Reset restores the input defaults and clears optimization selections; the chart view may remain on its current tab.
When selected, ordinary payments cover interest on the remaining debt. Extras reduce principal and can lower later interest charges. Any principal still unpaid at the end of the term is included in the final payment. Inspect the last schedule row: the payoff date assumes this final amount is paid.
Example: €400,000 at 3.2% nominal interest, monthly compounding, over 30 years gives an initial interest-only payment of €1,066.67. With no extras, the last payment is €401,066.67: €400,000 principal plus that month’s interest. At 0% interest, regular interest-only payments are zero and the principal remains due at maturity.
For interest-only loans, Salary Accelerator uses the original interest-only payment as its base. Double Monthly Payment adds that original payment to current monthly interest; if Salary Accelerator also applies, its multiplier is applied to that combined amount. These rules differ from simply doubling current interest. Review the schedule when combining them.
Choose an adjustment or enter a custom one. A +1.00% adjustment means one percentage point: 3.2% becomes 4.2%. The panel recalculates a separate scenario using the adjusted rate from the beginning for the entire term. It does not model a later reset date, introductory period or lender rate caps. The main graphs remain based on the main interest-rate input.
Optimization Interest Cushion is the interest saved by the selected payments compared with standard repayments at the simulated rate. It is not a reduction of the quoted monthly rate-rise impact. Rates below zero are floored at zero.
Inflation and alternative investment yield are optional assumptions, not live data. Their messages compare entered rates; they do not calculate an investment portfolio, future property value or guaranteed investment outcome. They do not change the repayment schedule.
In this version, the inflation-adjusted calculation assumes nominal annual interest compounded monthly, even if another convention is selected. Use that panel only with the monthly convention. The investment comparison uses the entered annual mortgage rate directly, so it is not always a like-for-like effective annual comparison.
Enter valid, nonnegative figures and complete dates. When an error appears, correct it and press Calculate before reading results or exporting: some panels can retain an earlier scenario. Keep lump sums and option windows within the term. A zero-loan scenario is not a reliable results view in this version. Check that the final balance is zero; extreme rate/term combinations can leave a residual. Small per-unit savings are rounded: use the total interest-saving amount for precision.
Calculations use a constant rate per scenario, monthly interest before extras and unrounded internal amounts. Actual lender schedules can differ through daily interest, rounding and contractual rules. Totals are nominal, not inflation-adjusted present values. Early-repayment charges, tax relief and future rate changes are not modeled.
The credit-creation and risk panels provide separate educational commentary. Their cash ratios describe repayments relative to principal; they do not calculate probabilities of loss or jurisdiction-specific legal rights.
This calculator provides educational estimates based on your inputs and the stated assumptions. Actual repayments and costs may differ according to your loan agreement, fees and interest calculation method. Results are not a lender quotation or personalized financial advice.