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Mortgage Penalty Estimator

Estimate early-payout penalties using 3-month interest and a simple IRD model. Apply a one-time prepayment, or auto-calc months from a maturity date. Export (CSV) or a branded printout.

Private in your browserEducational estimatePrint/export ready

Mortgage Basics

For fixed-rate mortgages, lenders typically charge the greater of IRD or 3 months’ interest.

If your product allows a prepayment (e.g., 10–20%), entering it here reduces the balance used in the penalty.

Remaining Term

IRD (Simple) Inputs

IRD estimates can vary by lender. We use: Effective Balance × (Contract − Comparison) × (Remaining Months ÷ 12). For a closer estimate, enter your lender’s current comparable rate for the remaining term.

Often the lender’s posted/discounted rate for a term matching your remaining months.

Some lenders add a fixed processing or discharge fee.

Quick Results

Effective Balance (after prepayment)$520,000
Remaining Term Used24 months
3-Month Interest$6,357
IRD (Simple)$15,600
Base Penalty (per rule above)$15,600
Admin / Discharge Fee$300
Estimated Total$15,900
Assumptions & Notes
  • 3-Month Interest = Effective Balance × Contract Rate × (3/12).
  • IRD (simple) = Effective Balance × (Contract − Comparison) × (Remaining Months ÷ 12).
  • Lenders may use posted vs. discounted rate methods, exact day-counts, amortization left, or other rules. Your agreement governs.
  • Prepayment privileges vary (and may reset annually). Some products (open, blend-and-extend, portability) can change or reduce penalties.
  • This tool is an estimate and not financial advice.
Mortgage Penalty — Estimate
Prepared February 13, 2026

3-Month Interest Detail

Typically used for variable-rate mortgages or when it’s greater for fixed-rate penalties.

Effective Balance$520,000
Contract Rate4.89%
Penalty (3 months)$6,357

IRD (Simple) Detail

This estimate compares your contract rate to a current comparable term rate.

Effective Balance$520,000
Contract Rate4.89%
Comparison Rate3.39%
Remaining Term24 months
Penalty (IRD)$15,600