How We Calculate

What you enter: Gross annual income (both partners), employment type, student loan and other obligations, energy label.

How we calculate:

1. Joint test income × factor 4.7, following the 2026 lending standards (Nibud methodology).
2. Flexible or temporary contracts count for less than permanent employment.
3. Ongoing monthly obligations reduce the borrowing capacity.
4. Energy label A or better adds extra capacity, up to €40,000 for A++++.

Sources: Nibud financieringslastnormen 2026, NHG.

What you enter: Purchase price, own funds, interest rate, term, mortgage type, NHG.

How we calculate:

1. Annuity: fixed monthly payment via the annuity formula (principal × monthly rate ÷ (1 − (1 + rate)^−months)).
2. Linear: fixed repayment (principal ÷ months) plus interest over the remaining balance; interest-only: interest only.
3. Net payment: interest portion × 37.56% deduction rate (2026), offset against the eigenwoningforfait of 0.35% of the WOZ value (approximated as 90% of the purchase price).

Sources: Belastingdienst (deduction rate, eigenwoningforfait).

What you enter: Purchase price, age / first home, which cost items apply to you.

How we calculate:

1. Transfer tax: 2% of the price, or 0% with the first-time buyer exemption (18–34, price ≤ €555,000, own occupancy, once per lifetime).
2. Notary, mortgage advice, valuation and structural survey use 2026 guide prices.
3. Bank guarantee: 1% of the 10% deposit (i.e. 0.1% of the price).

Sources: Belastingdienst, market guide prices 2026.

What you enter: Current rent, purchase price, interest, municipality, household size.

How we calculate:

1. Buying costs use the same mortgage formulas as above, plus maintenance (1% of the home value per year) and municipal charges from our 105-municipality dataset.
2. The tax benefit of the interest deduction is included on the buying side.
3. The comparison shows the monthly difference and the break-even point.

Sources: Municipal tax regulations 2026 (COELO), Belastingdienst.

What you enter: City and neighbourhood, property type, floor area, construction year, energy label, condition, outdoor space.

How we calculate:

1. Base: asking price per m² for the location (July 2026), converted to expected transaction level using the local overbidding percentage.
2. Adjustments for property type (apartments have the highest €/m²), energy label (A–G spread ≈ 17%, calibrated to Brainbay/Kadaster research), condition, construction year, renovations and outdoor space — the quality factors are capped so they cannot stack unrealistically.
3. The result is a range (±8%), not a falsely precise single number. The 5-year outlook is a scenario based on bank forecasts, tiered by region.

Sources: Asking prices per m² (July 2026), Kadaster/Brainbay label research, NVM.

What you enter: Asking price, location, optional valuation, maximum mortgage, own funds.

How we calculate:

1. Bid range = asking price × (1 + ½× / 1× / 1½× the local overbidding percentage) for a cautious, average and competitive bid.
2. Financeable amount = the lowest of your bid, the valuation and your maximum mortgage (banks lend up to the valuation).
3. Own funds needed = bid − financeable amount + buyer's costs.

Sources: Local overbidding data per city/neighbourhood; national average 4.6% (Q2 2026).

What you enter: Desired monthly payment (e.g. your current rent), gross or net, interest, term, mortgage type, own funds.

How we calculate:

1. We search for the purchase price whose calculated monthly payment — using exactly the same formulas as the monthly payment calculator — matches your amount.
2. Buyer's costs and the first-time buyer exemption are included in each iteration; the search repeats until it converges, rounded to €1,000.

Sources: Same rules as the monthly payment and buyer's costs calculators.

What you enter: Home price, own funds, mortgage, years until sale, rise/fall percentages, inflation, selling costs.

How we calculate:

1. Future value = current price × (1 + growth rate)^years, for both a rising and a falling scenario.
2. Remaining debt follows the exact amortization schedule of your mortgage type.
3. Net equity = selling price − remaining debt − buyer's costs − selling costs; the real value divides this by (1 + inflation)^years.

Sources: CBS price development as context; your own scenario inputs.

What you enter: Current mortgage, interest, remaining term, extra amount (one-off or monthly).

How we calculate:

1. A month-by-month amortization schedule: each extra payment directly lowers the remaining debt.
2. Interest savings = total interest without extra payments − total interest with them; the term reduction follows from the same schedule.

Sources: Standard amortization mathematics; check your lender's penalty-free limit (often 10–20%/yr).

What you enter: Mortgage amount, term, type, and two interest rates.

How we calculate:

1. Both scenarios use the same payment formulas; we compare monthly payment and total interest over the full term.
2. Total interest: annuity = sum of all payments − principal; linear = principal × monthly rate × (months + 1) ÷ 2.

Sources: DNB interest statistics as context.

What you enter: Loan parts (amount, type, rate), start date, term.

How we calculate:

1. Remaining debt and repaid principal are computed per month per loan part, following its amortization schedule (annuity, linear or interest-only).

Sources: Standard amortization mathematics.

What you enter: Gift amount, relationship (parents or other), one-time exemption, family loan and interest.

How we calculate:

1. 2026 exemptions: parents→child €6,908/yr (one-time increased €33,129, age 18–39); other donors €2,769/yr.
2. Gift tax above the exemption: children 10% up to €158,669, 20% above; other recipients 30%/40%.
3. Family loans require an arm's-length interest rate; interest that is gifted back counts as a gift.

Sources: Belastingdienst gift tax rules 2026.

What you enter: Municipality, home value, household size.

How we calculate:

1. WOZ value is approximated as 95% of the purchase price.
2. OZB = municipal rate × WOZ value; waste charge depends on household size; sewerage is a fixed amount or a percentage of WOZ, depending on the municipality.
3. Rates for 105 municipalities come from the official 2026 tax regulations.

Sources: Municipal tax regulations 2026 / COELO.

What you enter: Home value, current energy label, selected measures, optional financing.

How we calculate:

1. Costs, savings and ISDE subsidies per measure are ranges based on Milieu Centraal/RVO figures (reference date 2026).
2. Label improvement → value uplift uses the same label factors as the house value predictor, so both tools are consistent.
3. Co-financing is capped at 106% of the home value (energy-saving budget); payback = net investment ÷ yearly savings.

Sources: RVO (ISDE), Milieu Centraal, NHG.

What you enter: Purchase/contract sum, construction schedule, current rent, extra work.

How we calculate:

1. Construction interest is charged over the drawn-down part of the loan, which increases as the build progresses.
2. Double housing costs = your current rent plus the interest during construction; the 5% retention rule is included in the checklist.
3. Monthly payment after completion uses the standard annuity formula; notary and advice use 2026 guide prices.

Sources: 2026 guide prices; standard mortgage mathematics.