https://calculating.ca/calculators/real-estate/mortgage-prepayment-savings-calculator/
Real Estate / THE MITEY TOOLKIT
Mortgage Prepayment Planner
Compare your scheduled mortgage with an initial lump sum and an extra monthly payment.
Modeled interest saved
$57,304.07
From your inputs. Explore the breakdown below.
- Time saved
- 4 yr 4 mo
- Regular payment
- $2,213.89
- New payoff time
- 20 yr 8 mo
- Interest with prepayments
- $206,863.48
- The lump sum is applied immediately; the regular payment is kept unchanged.
- Prepayment privileges and penalties vary by contract. Check them before acting.
FOLLOW THE CASH FLOW
Annual cash-flow totals
Balance is the period-end value; growth and payments are totals for that year or final partial year. Download the ledger for every modeled period. Figures in CAD.
| Year | Closing balance | Interest / growth | Payment / withdrawal |
|---|---|---|---|
| Now | $390,000.00 | $0.00 | $10,000.00 |
| 1 | $378,181.43 | $17,148.13 | $28,966.70 |
| 2 | $365,825.04 | $16,610.31 | $28,966.70 |
| 3 | $352,906.36 | $16,048.02 | $28,966.70 |
| 4 | $339,399.80 | $15,460.14 | $28,966.70 |
| 5 | $325,278.60 | $14,845.51 | $28,966.70 |
| 6 | $310,514.81 | $14,202.90 | $28,966.70 |
| 7 | $295,079.16 | $13,531.06 | $28,966.70 |
| 8 | $278,941.10 | $12,828.64 | $28,966.70 |
| 9 | $262,068.66 | $12,094.26 | $28,966.70 |
| 10 | $244,428.42 | $11,326.46 | $28,966.70 |
| 11 | $225,985.43 | $10,523.72 | $28,966.70 |
CHANGE ONE VARIABLEWhat moves your answer?
Compare five values while keeping every other input the same. These are scenarios, not likelihoods or forecasts.
| Input value | Primary result | Use scenario |
|---|
BEHIND THE ANSWER
Formula and method
Balance next month = balance × (1 + monthly rate) − scheduled payment − extra payment.
The baseline and prepayment schedules use the same original balance, rate and scheduled payment. The initial lump sum reduces the balance before interest accrues. Extra monthly money goes toward the remaining principal; the last payment is clipped to the amount owed.
Context sources checked October 24, 2026
These sources explain the subject. The model follows the formula and assumptions shown here; a source link does not imply endorsement.
Worked examples
Lump sum plus monthly extra
- Mortgage balance:
- 400000
- Annual fixed rate:
- 4.5
- Remaining amortization:
- 25
- Lump sum paid now:
- 10000
- Extra paid each month:
- 200
Modeled interest saved: $57,304.07
Interest-free arithmetic check
- Mortgage balance:
- 100000
- Annual fixed rate:
- 0
- Remaining amortization:
- 10
- Lump sum paid now:
- 0
- Extra paid each month:
- 500
Modeled interest saved: $0.00
Assumptions and limits
- Canadian fixed-rate semi-annual compounding, paid monthly.
- The entered rate is held for the full model; future renewals can change the saving.
- No penalty or fee is included and no contractual prepayment entitlement is determined.
This tool provides an educational estimate. Rules, rates and personal circumstances can change the answer. Review the assumptions before relying on a result. Report a correction.
Common mistakes to avoid
- Treating an illustrative rate as a lender quote or a return forecast.
- Comparing scenarios with different time periods or leaving out relevant fees.
Frequently asked questions
Will my lender allow this prepayment?
The calculator does not decide that. Check the amount, timing and restrictions in your mortgage contract, and ask for any applicable penalty before paying.
Does a lump sum lower the regular payment here?
No. This model holds the original scheduled payment and shortens repayment. A lender-approved recast or changed contract would need a different payment schedule.
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