Breaking your mortgage means ending your current term early to refinance at a lower rate or switch lenders. It’s a math problem: does the savings from a lower rate exceed the cost of the penalty? This guide gives you the exact framework to calculate it.
The break-even formula
Step 1: Calculate total savings from the new rate
Monthly savings = Old payment − New payment Total savings = Monthly savings × Remaining months in original term
Step 2: Calculate total cost of breaking
Total cost = Prepayment penalty + Legal fees + Appraisal fee (if needed) + Discharge fee
Step 3: Calculate net benefit
Net benefit = Total savings − Total cost
- If positive → breaking is worth it
- If negative → stay with your current mortgage
- If close to zero → stay (there’s always hidden friction and risk)
Step 4: Calculate break-even point
Break-even months = Total cost ÷ Monthly savings
If the break-even point is less than your remaining term, breaking pays off.
Detailed break-even examples
Example 1: Variable rate — easy math
| Component | Details |
|---|---|
| Current rate | 5.40% (variable, prime − 0.55%) |
| New rate available | 4.20% (5-year fixed) |
| Balance | $400,000 |
| Remaining in current term | 36 months |
| Amortization remaining | 22 years |
Penalty calculation (variable = 3 months’ interest):
| Step | Calculation | Amount |
|---|---|---|
| 3 months’ interest | $400,000 × 5.40% ÷ 4 | $5,400 |
| Legal fees (new lender) | Estimate | $1,200 |
| Discharge fee | $350 | |
| Total cost | $6,950 |
Savings calculation:
| Step | Calculation | Amount |
|---|---|---|
| Old monthly payment (5.40%, 22yr) | $2,837 | |
| New monthly payment (4.20%, 22yr) | $2,460 | |
| Monthly savings | $377 | |
| Total savings (36 months) | $377 × 36 | $13,572 |
| Net benefit | $13,572 − $6,950 | +$6,622 |
| Break-even point | $6,950 ÷ $377 | 18.4 months |
Verdict: Break it. You save $6,622, and the break-even is at 18 months — well within your remaining 36 months.
Example 2: Fixed rate — monoline lender (fair IRD)
| Component | Details |
|---|---|
| Current rate | 5.29% (5-year fixed) |
| New rate available | 4.29% (5-year fixed) |
| Balance | $450,000 |
| Remaining in current term | 30 months |
| Original amortization | 25 years (22.5 remaining) |
Penalty calculation (fair IRD):
| Step | Calculation | Amount |
|---|---|---|
| Your rate | 5.29% | |
| Current 2.5-year rate (closest to 30 months) | 4.49% | |
| IRD spread | 5.29% − 4.49% = 0.80% | |
| IRD penalty | $450,000 × 0.80% × 30/12 | $9,000 |
| 3 months’ interest | $450,000 × 5.29% ÷ 4 | $5,951 |
| Penalty (higher of the two) | $9,000 | |
| Legal fees | $1,200 | |
| Discharge fee | $350 | |
| Total cost | $10,550 |
Savings calculation:
| Step | Calculation | Amount |
|---|---|---|
| Old monthly payment (5.29%, 22.5yr) | $2,854 | |
| New monthly payment (4.29%, 22.5yr) | $2,496 | |
| Monthly savings | $358 | |
| Total savings (30 months) | $358 × 30 | $10,740 |
| Net benefit | $10,740 − $10,550 | +$190 |
| Break-even point | $10,550 ÷ $358 | 29.5 months |
Verdict: Barely worth it — only $190 net savings, and the break-even is almost at the end of your term. Not worth the hassle and risk. Wait for renewal.
Example 3: Fixed rate — big bank (posted-rate IRD)
| Component | Details |
|---|---|
| Current rate | 5.29% (5-year fixed at big bank) |
| New rate available | 4.29% (5-year fixed at monoline) |
| Balance | $450,000 |
| Remaining in current term | 30 months |
Penalty calculation (posted-rate IRD):
| Step | Calculation | Amount |
|---|---|---|
| Original posted rate | 6.79% | |
| Your discount from posted | 1.50% | |
| Current posted 2.5-year rate | 5.19% | |
| Comparison rate | 5.19% − 1.50% = 3.69% | |
| IRD spread | 5.29% − 3.69% = 1.60% | |
| IRD penalty | $450,000 × 1.60% × 30/12 | $18,000 |
| 3 months’ interest | $450,000 × 5.29% ÷ 4 | $5,951 |
| Penalty (higher of the two) | $18,000 | |
| Legal fees | $1,200 | |
| Discharge fee | $350 | |
| Total cost | $19,550 |
Savings calculation:
| Step | Calculation | Amount |
|---|---|---|
| Monthly savings | $358 | |
| Total savings (30 months) | $358 × 30 | $10,740 |
| Net benefit | $10,740 − $19,550 | −$8,810 |
Verdict: Do NOT break. You’d lose $8,810. The posted-rate IRD penalty wipes out all the rate savings and then some. Wait for renewal.
Quick reference: break-even tables
Rate savings needed to break even (monoline lender, fair IRD)
Assumes $400,000 balance, 25-year amortization. Includes $1,550 in legal/discharge fees.
| Remaining Term | Penalty (est.) | Monthly Savings Needed | Rate Drop Needed |
|---|---|---|---|
| 48 months | $6,000 + $1,550 | $157/month | ~0.40% |
| 36 months | $5,500 + $1,550 | $196/month | ~0.55% |
| 24 months | $4,500 + $1,550 | $252/month | ~0.70% |
| 18 months | $3,500 + $1,550 | $281/month | ~0.80% |
| 12 months | $2,500 + $1,550 | $338/month | ~0.95% |
Rate savings needed to break even (big bank, posted-rate IRD)
Same assumptions. Big bank penalties are typically 1.5–2.5× higher than monoline.
| Remaining Term | Penalty (est.) | Monthly Savings Needed | Rate Drop Needed |
|---|---|---|---|
| 48 months | $14,000 + $1,550 | $324/month | ~0.90% |
| 36 months | $12,000 + $1,550 | $376/month | ~1.05% |
| 24 months | $10,000 + $1,550 | $481/month | ~1.35% |
| 18 months | $8,000 + $1,550 | $531/month | ~1.50% |
| 12 months | $6,000 + $1,550 | $629/month | ~1.75% |
Key insight: With a big bank, you typically need rates to drop 1.0–1.5%+ with 2+ years remaining for breaking to make sense. With a monoline, a 0.5–0.7% drop is often enough.
The blend-and-extend alternative
Instead of breaking and paying a penalty, many lenders offer a blend-and-extend:
| Feature | Break and Refinance | Blend and Extend |
|---|---|---|
| How it works | Pay penalty, get new mortgage at new rate | Lender blends your current rate with their current rate for a new (extended) term |
| Penalty | Full penalty applies | No explicit penalty (embedded in the blended rate) |
| Cash out of pocket | Penalty + legal fees ($5,000–$25,000) | $0–$500 (minimal fees) |
| New rate | Best available market rate | Blended rate (higher than market) |
| New term | Fresh 5-year term | Fresh 5-year term |
| Best when | Large rate drop, long time remaining, low penalty | Moderate rate drop, want to avoid cash outlay |
Blend-and-extend calculation
| Component | Details |
|---|---|
| Current rate | 5.29% |
| Remaining term | 30 months |
| Current market rate (5-year fixed) | 4.29% |
| New blended term | 60 months |
| Blended rate | (5.29% × 30 + 4.29% × 30) ÷ 60 = 4.79% |
The blended rate (4.79%) is lower than your current rate (5.29%) but higher than the market rate (4.29%). You save money compared to doing nothing, but less than you’d save by breaking and getting the full market rate.
| Scenario | Rate | Monthly Payment ($450K, 22.5yr) | 5-Year Interest Cost |
|---|---|---|---|
| Do nothing (current rate) | 5.29% | $2,854 | ~$107,000 |
| Blend and extend | 4.79% | $2,684 | ~$98,000 |
| Break and refinance (monoline) | 4.29% | $2,496 | ~$89,000 + $10,550 penalty = ~$99,550 |
| Break and refinance (big bank) | 4.29% | $2,496 | ~$89,000 + $19,550 penalty = ~$108,550 |
In this scenario:
- Blend and extend saves ~$9,000 vs doing nothing — and costs nothing upfront
- Breaking at monoline saves ~$7,450 vs doing nothing — but costs $10,550 upfront
- Breaking at big bank costs ~$1,550 more vs doing nothing — terrible deal
Decision tree
Should you break your mortgage?
| Question | If Yes | If No |
|---|---|---|
| Is your mortgage variable rate? | Penalty is just 3 months’ interest → easier to justify breaking | Go to next question |
| Do you have 24+ months remaining? | More time to recoup → go to next question | Probably wait for renewal |
| Is the rate drop 0.75%+ (monoline) or 1.25%+ (bank)? | Likely worth investigating → get a penalty quote | Probably not worth it |
| Have you gotten an actual penalty quote? | Use the formula above to calculate net benefit | Call your lender and get one |
| Is the net benefit more than $2,000? | Break it — the savings are real and meaningful | Consider blend-and-extend or wait |
Costs you might forget
| Cost | Typical Amount | Notes |
|---|---|---|
| Prepayment penalty | $3,000–$25,000 | The main cost — get the exact number |
| Legal fees (new mortgage) | $800–$1,500 | For the new lender’s registration |
| Discharge fee | $250–$400 | Current lender charges to remove their mortgage |
| Appraisal fee | $300–$500 | If the new lender requires one |
| Title insurance | $200–$400 | For the new lender’s title search |
| Bridge financing | $500–$2,000 | If closing dates don’t align (rare for refinance) |
| Lost rate lock | Variable | If you break to refinance and rates rise before you close |
| Typical total (beyond penalty) | $1,550–$2,800 |
When breaking almost never makes sense
| Situation | Why Not |
|---|---|
| Less than 12 months remaining | Not enough time to recoup — wait for renewal |
| Big bank with IRD penalty and small rate drop | Posted-rate penalty will wipe out savings |
| Rate drop is less than 0.50% | Savings too small to justify cost and hassle |
| You’re planning to move soon anyway | Port the mortgage instead |
| You have a collateral charge and want to switch lenders | Discharge costs add to the penalty |
When breaking almost always makes sense
| Situation | Why |
|---|---|
| Variable rate with 2+ years left, rates dropped 1%+ | 3-month penalty is small; savings are large |
| Monoline lender, 3+ years remaining, 1%+ rate drop | Fair IRD keeps penalty reasonable |
| Refinancing to access equity for high-interest debt consolidation | Savings on consolidated debt often exceed penalty |
| Fixed-rate mortgage converting to variable in a falling-rate environment | If BoC is cutting aggressively, converting early captures savings |
The bottom line
- Always get the actual penalty number — call your lender; don’t estimate
- Variable-rate mortgages are cheap to break — penalty is just 3 months’ interest
- Big bank fixed-rate penalties make breaking very expensive — you typically need a 1.25%+ rate drop
- Monoline fixed-rate penalties are more reasonable — breaking can pay off with a 0.5–0.75% rate drop
- Blend-and-extend is a good compromise — lower rate with no upfront cost
- If the break-even is within 60% of your remaining term, it’s worth it — if it’s at 90%+, skip it