en-US · guide
Mortgage calculation methodology
Short answer: MortgageBreezy calculates fixed-rate payment illustrations and shows the applicable data version, rate convention and limits.
MortgageBreezy calculates a fixed-rate payment illustration from the loan amount, nominal annual rate, term, repayment type, payment frequency and optional extra principal. A repayment loan uses a standard amortization formula; with a zero rate, principal is divided evenly across the payment periods. Canada converts quoted rates using semi-annual compounding before calculating the selected payment frequency.
Every calculation retains precision internally and rounds currency only for display. The result page states the relevant calculation-data version, effective date, review date, included costs and exclusions. Transfer-tax and registration estimates are separate from the loan payment because they are generally transaction costs rather than recurring interest.
The calculator is not a lender underwriting system. It does not model variable-rate resets, lender-specific product pricing, all insurance premiums, daily-interest conventions, early-repayment penalties or every local registration fee. Confirm the current rule with the lender and the relevant public authority.
Primary sources used for local-rule data
- HMRC SDLT residential rates — effective 2025-04-01; reviewed 2026-08-25.
- Ontario Land Transfer Tax — effective 2017-01-01; reviewed 2026-08-25.
- German Federal Ministry of Finance, tax rates by state — effective 2025-01-01; reviewed 2026-08-25.
- French tax administration, registration duties — effective 2026-06-01; reviewed 2026-08-25.
- Spanish government property purchase taxes — effective 2026-03-20; reviewed 2026-08-25.
Editorial and review policy
MortgageBreezy maintains calculation-data versions and dates in the calculator. When a stable official formula is unavailable, the tool identifies the estimate as unavailable or requires user input instead of inventing a rate.