Open vs Closed Mortgage Calculator: BC Homeowner With $620,000 Balance Breaking a 5-Year Fixed Early — IRD Penalty, Legal Costs, and Net Savings After Refinancing

Published 2026-05-22 · 14 min read

You're 18 months into a 5-year fixed mortgage at 5.39% on a $620,000 balance in British Columbia. Current 5-year fixed rates have dropped to around 4.49%. Breaking the mortgage would save you roughly $464/month in interest — but the prepayment penalty could range from $12,800 to $32,550 depending on whether your lender is a BC credit union or a Big 6 bank. Add $1,800–$2,500 in BC legal and discharge fees, and the question becomes: do you come out ahead before the original term expires? And what if you're planning to sell within 12 months — does an open mortgage at a higher rate cost less than the penalty? This article runs every number.

Key Takeaways

  • 1.Breaking a $620K closed fixed mortgage at 5.39% to refinance at 4.49% saves approximately $464/month in interest — but the penalty varies wildly by lender type.
  • 2.BC credit union IRD penalty (Vancity, Coast Capital method): approximately $12,800. Big 6 bank IRD penalty (posted-rate method): approximately $32,550. Same balance, same rate gap — $19,750 difference.
  • 3.With BC legal and discharge fees of $1,800–$2,500, the credit-union breakeven is approximately 33 months (well within the remaining 42-month term). The Big 6 bank breakeven is approximately 74 months (not worth it).
  • 4.If you plan to sell within 12 months, an open mortgage at ~5.24% costs roughly $4,650 in extra interest vs a closed penalty of $12,800–$32,550. The open mortgage wins for short horizons.
  • 5.A blend-and-extend to ~4.76% avoids the penalty entirely but locks you into a new term with the same lender at a rate 0.27 percentage points higher than a clean refinance.

The Scenario: $620,000 Balance, 42 Months Remaining, 0.90% Rate Drop

Here are the numbers we're working with throughout this article. This reflects a typical Greater Vancouver or Fraser Valley homeowner who locked in during 2024–2025 when rates were near their peak.

Current mortgage:
Balance: $620,000
Rate: 5.39% (5-year fixed, closed)
Original term start: December 2024
Time elapsed: 18 months
Remaining term: 42 months (3.5 years)
Monthly payment (25-year amortization): ~$3,734

Refinance offer:
Rate: 4.49% (5-year fixed, closed)
Monthly payment at 4.49%: ~$3,270
Monthly savings: ~$464
Total interest saved over 42 months (if no penalty): ~$19,488

The monthly savings look compelling. But the entire decision hinges on two questions: how much is the penalty, and how much do the legal costs add? For a similar fixed-vs-variable analysis in a different province, see our 5-year fixed vs variable mortgage calculator for an Alberta buyer.

Open vs Closed Mortgages: What BC Homeowners Need to Know

Before diving into the penalty math, it's critical to understand the structural difference between open and closed mortgages — because it determines whether you face a penalty at all.

FeatureOpen MortgageClosed Mortgage
Prepayment penaltyNone3 months' interest or IRD (whichever is greater)
Typical rate premium+0.50% to +1.00% higherBase rate
Best forSelling within 6–12 months, expecting inheritance/windfallStaying for the full term
Prepayment privilegesUnlimitedTypically 10–20% of original principal per year
Available termsUsually 1 year or variable1, 2, 3, 4, 5, 7, 10 years

Rate premiums and terms vary by lender. In BC, credit unions like Vancity and Coast Capital offer both open and closed products. Open mortgages carry no prepayment penalty by definition.

The key distinction: if you hold an open mortgage, you can refinance, pay off, or switch lenders at any time with zero penalty. The trade-off is a higher rate for the duration you hold it. If you hold a closed mortgage — which is what the vast majority of BC homeowners have — breaking it early triggers a penalty that can be substantial on a $620,000 balance.

The Two Penalty Formulas: 3-Month Interest vs IRD

For a closed mortgage, the lender charges the greater of two penalties:

Penalty Option A: 3 Months' Interest

3-month interest penalty = Balance × Contract rate × (3/12)
= $620,000 × 5.39% × 0.25
= $8,355

This is the simpler calculation and is always the penalty for closed variable-rate mortgages. For closed fixed-rate mortgages, the lender compares this to the IRD and charges whichever is higher.

Penalty Option B: Interest Rate Differential (IRD)

The IRD attempts to compensate the lender for the interest income they lose when you break the contract. This is where BC homeowners face the biggest variance — because every lender calculates the “comparison rate” differently.

How BC Credit Unions vs Big 6 Banks Calculate IRD — The $19,750 Gap

This is the single most important section in this article. The same $620,000 balance and the same rate environment produce vastly different penalties depending on the lender's IRD methodology.

Credit Union Method (Vancity, Coast Capital, First West)

BC credit unions generally use their actual current rate for the closest matching term as the comparison rate. No posted-rate games, no discount clawback.

Credit union IRD calculation:

Contract rate: 5.39%
Current 3-year fixed rate (closest to 42 months remaining): 4.80%
Rate differential: 5.39% − 4.80% = 0.59%

IRD = $620,000 × 0.59% × (42/12)
IRD = ~$12,803

3-month interest = $8,355
Penalty charged: $12,803 (IRD is greater)

Big 6 Bank Method (RBC, TD, BMO, Scotiabank, CIBC, National Bank)

Big 6 banks typically use their posted rate for the remaining term, minus whatever discount you received off the posted rate when you originally signed. Since posted rates are inflated well above what anyone actually pays, this method widens the differential.

Big 6 bank IRD calculation:

Contract rate: 5.39%
Original posted rate at signing: 7.04%
Original discount: 7.04% − 5.39% = 1.65%

Current posted 3-year rate: 5.54%
Comparison rate: 5.54% − 1.65% = 3.89%
Rate differential: 5.39% − 3.89% = 1.50%

IRD = $620,000 × 1.50% × (42/12)
IRD = ~$32,550

3-month interest = $8,355
Penalty charged: $32,550 (IRD is greater)

The gap: $32,550 − $12,803 = $19,747. Same balance, same contract rate, same rate environment — but the Big 6 bank method produces a penalty that is 2.5× larger than the credit union method. This difference alone can determine whether breaking the mortgage is financially viable. If you are choosing a lender for a new fixed-rate mortgage in BC, the IRD methodology should be a factor alongside the rate.

BC Legal and Discharge Costs: $1,800–$2,500

Breaking a mortgage in BC involves several hard costs beyond the penalty. Here's what to budget.

CostTypical RangeNotes
Mortgage discharge fee$200–$350Charged by current lender to release the charge on title
Legal/notary fees (new mortgage)$800–$1,500BC notaries and lawyers both handle mortgage registrations
BC Land Title Office registration$75–$670$75.26 for first $25K + $1 per additional $1,000 of mortgage
Title search fee$15–$25Standard BC Land Title search
Appraisal (if required)$300–$500Often waived by lender; more common for credit unions
Total (excluding penalty)$1,800–$2,500Some lenders cover legal fees as a refinance incentive

Costs are typical for BC in 2025–2026. BC Land Title fees are set by statute. Legal/notary fees vary by firm and complexity. Some lenders offer cash-back or legal fee coverage on refinance transactions, which can reduce out-of-pocket costs by $800–$1,200.

For this analysis, we'll use $2,500 as the total legal/discharge cost (mid-to-high estimate, no lender rebate). For a broader look at BC property costs, see our BC property transfer tax calculator.

Breakeven Analysis: When Does Refinancing Pay for Itself?

The breakeven point is the number of months it takes for the monthly savings to recover the total break cost (penalty + legal fees). If breakeven occurs before the original term expires (42 months remaining), the refinance is profitable.

ScenarioPenaltyLegal CostsTotal Break CostMonthly SavingsBreakevenNet Savings at 42 Mo
Credit union IRD$12,803$2,500$15,303$464~33 months+$4,185
Big 6 bank IRD$32,550$2,500$35,050$464~76 months−$15,562
3-month interest only$8,355$2,500$10,855$464~23 months+$8,633

Monthly savings of $464 is the approximate difference in interest between 5.39% and 4.49% on a $620,000 balance. Actual savings decrease slightly each month as the balance amortizes. Breakeven = Total break cost ÷ monthly savings. Net savings = (monthly savings × 42) − total break cost. The 3-month interest scenario applies to closed variable-rate mortgages.

The verdict on refinancing: If your mortgage is with a BC credit union using actual-rate IRD, breaking makes financial sense — you recoup costs by month 33 and net approximately $4,185 in savings by the end of the original term. If your mortgage is with a Big 6 bank using the posted-rate IRD method, breaking is a losing proposition — you'd need 76 months to break even, but only have 42 months left. Consider a blend-and-extend instead.

The Blended Rate Alternative: Avoid the Penalty Entirely

Most lenders offer a “blend-and-extend” option where you combine your existing rate with the current rate for a new term, avoiding the penalty. Here's how that math works on our $620,000 scenario.

Blend-and-extend calculation:

Existing rate: 5.39% with 42 months remaining
New rate: 4.49% for a 5-year (60-month) term

Blended rate = (5.39% × 42 + 4.49% × 18) / 60
Blended rate = (226.38 + 80.82) / 60
Blended rate = ~5.12%

Monthly payment at 5.12%: ~$3,635
Monthly savings vs current 5.39%: ~$99/month
No penalty. No legal fees.

Total savings over 42 months: ~$4,158

The blend-and-extend saves roughly $4,158 over 42 months with zero break cost. Compare that to the credit union refinance net savings of $4,185 — the two are nearly identical in total savings, but the blend-and-extend carries no upfront cash outlay. The trade-off: you're locked into a new 5-year term with the same lender, and your rate (5.12%) is still 0.63 percentage points higher than the clean refinance rate of 4.49%. If rates continue to drop over the next five years, you may wish you had taken the penalty and started fresh at 4.49%.

The Open Mortgage Option: Best for Selling Within 12 Months

If you're planning to sell your BC property within 6–12 months — relocating, upsizing, downsizing, or separating — paying the closed penalty to refinance into another closed mortgage makes no sense. Instead, compare the penalty against the cost of an open mortgage for the short holding period. For related property cost considerations, see our HELOC vs refinance vs second mortgage comparison.

StrategyRatePenalty at SaleLegal CostsExtra Interest (12 Mo)Total Cost
Keep current closed (pay penalty at sale)5.39%$12,803–$32,550$0$0$12,803–$32,550
Break → open mortgage5.24%$0$2,500$0$12,803–$32,550 + $2,500
Wait — port mortgage to new property5.39%$0$800–$1,500$0$800–$1,500

Open mortgage rate of 5.24% is illustrative (typically 0.50–1.00% above the comparable closed rate of 4.49%). “Port” means transferring the existing mortgage to a new property, which most lenders allow with minimal fees — but requires purchasing within a lender-specified window (usually 30–120 days). Not all lenders permit porting.

The table above reveals an important third option: porting the mortgage. If you're selling to buy another property in BC, most lenders allow you to transfer your existing mortgage to the new home with minimal fees and no penalty. Porting preserves your existing rate — which is currently above market — but eliminates the penalty entirely. It's the cheapest option if you're buying and selling simultaneously.

If you are truly selling and not buying (downsizing to rent, leaving BC), then the penalty is unavoidable on a closed mortgage. In that case, you simply pay it at discharge. An open mortgage would have avoided this cost, but the rate premium over the prior 18 months would have cost approximately $6,975 (0.75% × $620,000 × 18/12) — which is less than the credit union IRD of $12,803 but may not be less than the 3-month interest penalty of $8,355. For homeowners who know they will sell within a year, choosing an open mortgage at origination is often the right call.

Side-by-Side: Total Cost of Each Strategy Over 42 Months

Here's the full comparison assuming you stay for the remaining 42 months of the original term.

StrategyTotal Interest (42 Mo)PenaltyLegal CostsTotal Cost
Do nothing (stay at 5.39%)~$110,400$0$0~$110,400
Break + refinance (credit union)~$90,912$12,803$2,500~$106,215
Break + refinance (Big 6 bank)~$90,912$32,550$2,500~$125,962
Blend-and-extend to ~5.12%~$106,242$0$0~$106,242

Interest amounts are approximate based on a 25-year amortization with the stated rates applied to the outstanding balance. Actual interest depends on payment frequency and balance reduction. All figures assume the homeowner stays for the full 42-month remaining term.

Credit union refinance and blend-and-extend produce nearly identical total costs (~$106,200). The Big 6 bank refinance is the worst option — you pay$15,562 more than simply staying at the existing rate. The “do nothing” option costs approximately $4,200 more than breaking with a credit union penalty or blending.

The 2025–2026 Rate Environment: Why This Decision Matters Now

The Bank of Canada's rate-cutting cycle through 2025 has brought 5-year fixed rates down significantly from the 5.5–6.5% range seen in late 2023 and 2024. For BC homeowners who locked in at or near peak rates, the current environment creates a window where refinancing can save meaningful money — but only if the penalty math works.

Importantly, IRD penalties increase as rates fall. The wider the gap between your contract rate and the current comparison rate, the larger the IRD. This creates a paradox: the more rates drop (making refinancing attractive), the higher the penalty becomes (making refinancing expensive). This paradox is most acute at Big 6 banks where the posted-rate methodology amplifies the differential. For related rate analysis, see our fixed vs variable mortgage rate comparison for an Ontario couple.

Decision Framework: Should You Break Your BC Mortgage?

Break and refinance if:
• Your lender uses actual-rate IRD (most BC credit unions)
• You have 3+ years remaining on your term
• The rate drop is 0.75%+ (enough to produce meaningful monthly savings)
• You plan to stay in the home for the full remaining term

Blend-and-extend if:
• Your lender uses posted-rate IRD (Big 6 banks) making the penalty prohibitive
• You want to avoid upfront cash outlay
• You don't mind staying with the same lender for a new term

Switch to an open mortgage if:
• You plan to sell within 6–12 months
• The open rate premium × holding period is less than the closed penalty
• You cannot or do not want to port your mortgage

Do nothing if:
• You have less than 18 months remaining on your term
• The rate drop is less than 0.50%
• You expect to port the mortgage to a new property

What to Do Before You Call Your Lender

Before requesting a penalty quote, gather these details from your mortgage documents:

  1. Your contract rate and original posted rate (both appear on your commitment letter)
  2. Your current balance (monthly statement or online banking)
  3. Your maturity date (the date your current term ends)
  4. Your prepayment privileges (typically 10–20% annual lump sum — use these first to reduce the balance before triggering a penalty)
  5. Whether your mortgage is portable (if you're buying another property)

Request the penalty quote in writing. Lenders in BC are required to provide the exact penalty amount upon request. Compare this number against the breakeven analysis above. For mortgage stress test considerations on the new mortgage, see our BC mortgage stress test calculator.

Important Disclaimer

This article provides general information about mortgage prepayment penalties and refinancing strategies for BC homeowners. It is not financial, legal, or mortgage advice. The IRD calculations shown are illustrative — every lender uses a different methodology, and the only way to know your exact penalty is to request a quote from your lender. Posted rates, comparison rates, and current fixed rates cited are representative of the 2025–2026 rate environment and change frequently. BC Land Title Office fees are set by the Land Title Act and may be updated. Legal and notary fees vary by firm. The blend-and-extend calculation is simplified — actual blended rates depend on the lender's formula, which may weight differently. The Bank of Canada rate outlook is not a forecast or recommendation. Credit union IRD methodologies (Vancity, Coast Capital, First West) are described based on general industry practice and may vary by product or change over time. Consult a licensed mortgage broker or your lender directly before making any mortgage break or refinance decision.

Frequently Asked Questions

What is the difference between an open and closed mortgage in BC?

An open mortgage allows you to pay off, refinance, or renegotiate the balance at any time without a prepayment penalty. A closed mortgage locks you into a fixed term (commonly 1–5 years) and charges a penalty — either 3 months' interest or the Interest Rate Differential (IRD), whichever is greater — if you break the contract early. Open mortgages typically carry rates 0.50–1.00 percentage points higher than comparable closed mortgages to compensate the lender for the prepayment flexibility. In BC, both types are available from major banks, credit unions like Vancity and Coast Capital, and monoline lenders.

How is the IRD penalty calculated on a closed fixed-rate mortgage in BC?

The IRD (Interest Rate Differential) penalty is calculated as the difference between your current contract rate and the lender's current posted rate for the remaining term, multiplied by your outstanding balance and the remaining months, divided by 12. For example, on a $620,000 balance with a 5.39% contract rate and a 3.89% comparison rate with 42 months remaining, the IRD would be approximately (5.39% − 3.89%) × $620,000 × (42/12) = $32,550. However, every lender in BC calculates the comparison rate differently — Big 6 banks typically use their posted rate minus your original discount, while credit unions like Vancity and Coast Capital often use their actual current rate, which usually produces a lower IRD. Always request the exact penalty quote from your lender.

How much does it cost to discharge and register a new mortgage in BC?

In BC, the typical costs to break and refinance a mortgage include: mortgage discharge fee from your current lender ($200–$350), legal fees for the new mortgage registration ($800–$1,500 depending on the lawyer or notary), BC Land Title Office registration fee ($75.26 for the first $25,000 of mortgage principal plus $1 per additional $1,000), title search fee (~$15–$25), and potentially an appraisal fee ($300–$500 if required). Total out-of-pocket costs excluding the penalty itself typically range from $1,800 to $2,500 in BC. Some lenders offer to cover legal fees as part of a refinance promotion, which can reduce costs by $800–$1,200.

Do BC credit unions calculate IRD differently than the Big 6 banks?

Yes. The Big 6 banks (RBC, TD, BMO, Scotiabank, CIBC, National Bank) typically calculate IRD using their posted rate for the remaining term, minus whatever discount you originally received. Since posted rates are artificially high, this method often produces a larger IRD. BC-dominant credit unions such as Vancity, Coast Capital Savings, and First West Credit Union generally use their actual current rate for the remaining term as the comparison rate, without re-adding a historical discount. This means credit union IRD penalties are often significantly lower — sometimes 30–50% less — than Big 6 bank penalties on the same balance and rate gap. If you are choosing a new fixed-rate mortgage in BC and think you might break early, the lender's IRD methodology should be a factor in your decision.

Is it worth breaking a 5-year fixed mortgage 18 months in to refinance at a lower rate?

Whether breaking makes financial sense depends on the penalty amount, legal costs, the rate drop, and the remaining term. For a $620,000 balance at 5.39% with 42 months remaining, refinancing to 4.49% saves approximately $464/month in interest. If the total break cost (penalty + legal fees) is $15,300, the breakeven point is approximately 33 months — meaning you recoup the cost before the original term expires (42 months left), netting roughly $4,200 in savings. If the IRD penalty is calculated using the Big 6 bank method and comes to $32,550, breakeven extends to about 74 months — well past the original term — making the break unprofitable. The lender's penalty calculation method is the single biggest variable.

When does an open mortgage make more sense than paying a closed mortgage penalty in BC?

An open mortgage typically makes sense when you plan to sell or pay off the mortgage within 6–12 months. The rate premium on an open mortgage (usually 0.50–1.00% higher than a comparable closed rate) costs less over a short horizon than the penalty for breaking a closed mortgage. For a $620,000 balance, a 0.75% open premium costs approximately $4,650 over 12 months vs a potential closed penalty of $12,800–$32,550. If your holding period is under 12 months, the open mortgage almost always wins. Beyond 18–24 months, the ongoing rate premium accumulates and a closed mortgage with its lower rate becomes cheaper — even accounting for the penalty risk.

How does the 2025–2026 Bank of Canada rate-cutting cycle affect the decision to break a mortgage in BC?

The Bank of Canada cut the overnight rate multiple times through 2025, bringing variable rates and new fixed rates down significantly from 2023–2024 peaks. This creates two effects for BC homeowners considering a break: (1) lower current fixed rates widen the gap between your contract rate and available refinance rates, increasing the potential monthly savings; and (2) the IRD penalty formula uses current rates as the comparison, so a larger rate gap also increases the IRD penalty on closed fixed mortgages at Big 6 banks. The net effect depends on your lender's IRD methodology and the remaining term. For variable-rate closed mortgages, the penalty is always 3 months' interest regardless of rate movements, making the break decision simpler.

What is a blended rate mortgage and is it available in BC?

A blended rate (or "blend-and-extend") is an alternative to breaking your mortgage outright. Your lender combines your existing contract rate with the current rate for a new term, weighted by the remaining balance and time. For example, blending a 5.39% rate with 42 months remaining into a new 5-year term at 4.49% might produce a blended rate of approximately 4.76%. The advantage is that most lenders waive the prepayment penalty for a blend-and-extend. The disadvantage is that the blended rate is higher than the straight refinance rate, and you are typically locked into a new full term with the same lender. In BC, most major banks and credit unions offer blend-and-extend, but monoline lenders generally do not.