Long-term math · Buyer calculator

Blended mortgage rate calculator

Weighted blended rate when you increase a mortgage mid-term — your old rate blended with today's rate on new money.

Calculator · Refi / port

Blend-and-extend rate

When you port a low-rate mortgage to a new property and need additional financing at today's higher rate, your lender blends the two. This is what your new effective rate looks like.

Blended rate
3.32%
On a $550,000 mortgage
Old chunk
$400,000
at 2.50%
New chunk
$150,000
at 5.50%

What a blended rate is

A blended rate combines your existing mortgage rate with the lender's current rate on new money, producing a weighted average. Lenders offer it as an alternative to breaking your existing mortgage when you want to increase the loan balance (renovation, debt consolidation) or extend the term. The big benefit: no break penalty.

Two flavours: blend-to-term and blend-and-extend

Blend-to-term keeps your current term length. Your remaining time on the existing rate gets weighted with the new money's time at today's rate. Useful when you want to increase the loan without disturbing the term.

Blend-and-extend resets your term (usually to a fresh 5 years) at the blended rate. Useful when you want rate certainty further out. The lender benefits because they keep your business for a longer commitment.

How the math works

Example. You have $400K remaining at 3.5% with 2 years left on a 5-year fixed. You want to add $100K for a renovation. Current rate on a 5-year fixed is 5.0%. The lender blends: $400K of old money at 3.5% for the remaining 2 years, plus $100K of new money at 5.0% for the same 2 years, plus the full $500K at the new 5-year rate after that. The first 2 years' blended rate is roughly (400×3.5 + 100×5.0) / 500 = 3.8%. The blend math saves you the break penalty that would otherwise apply on the old $400K.

When to blend vs break

Blend if the penalty would be substantial and the new total loan is meaningfully more than your current balance. Break if you're significantly under-leveraged for the new total (e.g., refinancing to a completely new structure) and the penalty is manageable. Our refinance break-even calculator compares both paths.

How to use this calculator

Plug in your current balance, current rate, remaining term, new money amount, and today's rate. The output is the blended rate plus the new monthly payment. Book a 20-minute chat with the FRIVE team if you're weighing a blend-and-extend offer from your lender.

Frequently asked questions

Does every lender offer blended rates?

Most A-lenders do. Monoline lenders sometimes don't offer blend-and-extend, only blend-to-term. Smaller credit unions vary. Ask your broker before assuming.

Is there a fee for blending?

Usually not. Blending is a retention tool; the lender wants to keep your business. The new rate is the cost.

Is the blended rate always lower than today's rate?

Only if your existing rate is lower than today's. In a falling-rate environment, blending actually produces a higher rate than today's market. In a rising-rate environment, blending protects you from the full force of today's higher rate.

Can I blend a variable-rate mortgage?

Less common. Variable rates already adjust with prime, so there's less benefit to blending. Some lenders allow variable-to-fixed conversion mid-term at the current fixed rate, which is conceptually similar.

Does blending affect my amortization?

Yes if you increase the loan. The new money is amortized over a fresh schedule. The combined loan has a recalculated monthly payment.

Should I blend for a small renovation?

Usually no. For small amounts ($20K or less), a HELOC or unsecured line of credit is usually cheaper and faster. Blends make sense for larger increases ($50K+) where the rate spread matters.

What if I blend and rates drop further?

You're locked into the new blended term. Breaking again triggers a penalty. Blending is a commitment.

Is a blended rate the same as the actual rate I pay?

The blended rate is what your lender quotes. The actual rate on each portion of money is its underlying rate. From your perspective, the blended rate is what matters for the monthly payment.

Can I qualify for a blend without re-qualifying for the mortgage?

Most lenders require new qualification if the loan amount increases. If you're just blending without adding money (rare), re-qualification may not be required.

Does the federal stress test apply to blends?

Yes if the loan amount increases. The new total loan must pass OSFI's B-20 stress test at the qualifying rate.

Sources

  1. Financial Consumer Agency of Canada — Refinancing your mortgage. canada.ca/fcac
  2. OSFI Guideline B-20 — Stress test on refinances. osfi-bsif.gc.ca

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