Paying down your mortgage gives you a guaranteed, risk-free return equal to your mortgage rate. Investing in your TFSA gives you tax-free growth — but with market risk. This guide runs the numbers across different rates, returns, and timelines to help you decide.
The core comparison
Since mortgage interest on your principal residence is not tax-deductible in Canada, and TFSA investment returns are completely tax-free, the comparison is clean — no tax adjustments needed:
| Option | Return | Guaranteed? | Tax on Return |
|---|---|---|---|
| Extra mortgage payment | Equal to your mortgage rate | ✅ Yes — guaranteed | Tax-free (savings, not income) |
| TFSA investment | Depends on investments | ❌ No — market risk | Tax-free |
The math is simple: if your TFSA investments earn more than your mortgage rate, investing wins. If they earn less, the mortgage paydown wins.
Break-even analysis by mortgage rate
| Your Mortgage Rate | TFSA Return Needed to Break Even | Likely Winner (long-term equity investor) |
|---|---|---|
| 3.00% | > 3.00% | TFSA (easily) |
| 4.00% | > 4.00% | TFSA (likely) |
| 5.00% | > 5.00% | TFSA (probable, with patience) |
| 6.00% | > 6.00% | Closer call — mortgage paydown is competitive |
| 7.00%+ | > 7.00% | Mortgage paydown is very attractive |
Historical context: The S&P/TSX Composite has returned approximately 9–10% annually over long periods. Global equity portfolios (XEQT, VEQT) have returned 7–9% historically. GICs currently return 3.5–4.5%. A HISA returns 3–4%.
20-year projection: $500/month extra — TFSA vs mortgage
Scenario: $400,000 mortgage at 5.00%, 25-year amortization
Option A: $500/month extra mortgage payment
| Year | Mortgage Balance | Interest Saved (Cumulative) |
|---|---|---|
| 0 | $400,000 | $0 |
| 5 | $298,200 | $18,900 |
| 10 | $172,100 | $54,600 |
| 15 | $11,800 | $95,200 |
| ~15.5 years | $0 (paid off) | $98,500 |
Mortgage paid off approximately 9.5 years early. Total interest saved: ~$98,500.
Option B: $500/month into TFSA (invested at 7% average return)
| Year | TFSA Value | Mortgage Balance (normal payments) |
|---|---|---|
| 0 | $0 | $400,000 |
| 5 | $35,800 | $339,500 |
| 10 | $86,200 | $262,700 |
| 15 | $158,400 | $164,200 |
| 20 | $260,500 | $32,500 |
| 25 | $405,200 | $0 |
At the end of 25 years: mortgage paid off on schedule, plus a $405,200 tax-free TFSA portfolio.
Head-to-head comparison
| Metric | Mortgage Paydown | TFSA Investment (7%) |
|---|---|---|
| Mortgage-free date | Year ~15.5 | Year 25 (on schedule) |
| Interest saved | $98,500 | $0 |
| Portfolio value at year 25 | $0 | $405,200 |
| Net wealth gain at year 25 | $98,500 | $405,200 |
At 7% returns, the TFSA investor is $306,700 wealthier at the 25-year mark. But they carry the mortgage for 9.5 years longer.
Sensitivity analysis: What if returns are lower?
| TFSA Return | TFSA Value at Year 25 | Net Wealth vs Mortgage Paydown | Winner |
|---|---|---|---|
| 4.00% | $257,400 | +$158,900 | TFSA |
| 5.00% | $298,600 | +$200,100 | TFSA |
| 6.00% | $346,500 | +$248,000 | TFSA |
| 7.00% | $405,200 | +$306,700 | TFSA |
| 8.00% | $475,100 | +$376,600 | TFSA |
Even at 4% returns (barely below the mortgage rate), the TFSA still wins because of 25 years of tax-free compounding. The mortgage paydown saves $98,500 in interest, but the TFSA investor accumulates $257,400 — a net gain even at below-mortgage returns, because the compounding timeline is longer.
The TFSA only loses if: returns are negative or near-zero for extended periods, OR you would have invested in a savings account/GIC earning less than the mortgage rate with no growth.
The TFSA’s unique advantage: Contribution room is scarce
| TFSA Fact | Implication |
|---|---|
| Annual contribution limit is $7,000 (2025+) | Room is limited — once filled, you can’t add more until next year |
| Cumulative room grows slowly | Total room for someone eligible since 2009: $102,000 in 2026 |
| Room lost to mortgage payments doesn’t come back | Every dollar sent to the mortgage instead of the TFSA is room you can’t use later |
| TFSA withdrawals restore room the following year | But only if you had invested in the first place |
This is the strongest argument for TFSA first: mortgage prepayment capacity is unlimited (up to your annual prepayment privilege), but TFSA room is finite and precious. Prioritize the scarce resource.
The mortgage paydown’s unique advantage: Guaranteed return, zero risk
| Mortgage Paydown Advantage | Details |
|---|---|
| Guaranteed return | Equal to your mortgage rate — no market risk |
| Psychological benefit | Becoming mortgage-free is a powerful feeling of security |
| Reduced mandatory expenses | Once paid off, your monthly housing cost drops dramatically |
| Protection against rate increases | Paying down faster reduces exposure at renewal |
| No sequence-of-returns risk | You won’t lose value in a market crash |
For risk-averse Canadians, the certainty of mortgage paydown has real value beyond the raw math.
Decision framework
| Your Situation | Recommendation |
|---|---|
| Mortgage rate < 4%, unused TFSA room | TFSA first — easy decision |
| Mortgage rate 4–5%, long time horizon (15+ years) | TFSA first — returns likely exceed mortgage rate |
| Mortgage rate 5–6%, 10+ year horizon | Hybrid — maximize TFSA room, then extra mortgage payments |
| Mortgage rate > 6% | Mortgage first — guaranteed high return is compelling |
| Significant unused TFSA room ($20K+) | TFSA first — capture the room before it’s wasted |
| TFSA already maxed | Mortgage paydown — or consider RRSP/FHSA |
| Approaching renewal at higher rate | Mortgage paydown — reduce the balance before the rate increases |
| Risk-averse / values being debt-free | Mortgage paydown — the guaranteed return matches your temperament |
| Comfortable with market volatility, long horizon | TFSA first — maximize tax-free compounding |
The hybrid strategy (often the best answer)
| Step | Action | Why |
|---|---|---|
| 1 | Maximize TFSA annual contribution ($7,000) | Capture scarce tax-free room |
| 2 | If employer RRSP match exists, contribute enough to get the full match | Free money — guaranteed 50–100% return |
| 3 | If FHSA-eligible, contribute $8,000/year | Tax deduction + tax-free growth + tax-free withdrawal |
| 4 | Direct remaining surplus to mortgage prepayment | Guaranteed return, reduces debt |
Hybrid example: $1,500/month surplus
| Allocation | Monthly | Annual | Purpose |
|---|---|---|---|
| TFSA | $583 | $7,000 | Tax-free compounding |
| Mortgage prepayment | $917 | $11,000 | Guaranteed return; early payoff |
Result after 25 years (assuming 7% TFSA return, 5% mortgage):
- TFSA portfolio: ~$405,000 (tax-free)
- Mortgage paid off approximately 8 years early
- Total interest saved: ~$72,000
- Combined net wealth gain: ~$477,000
This beats both the pure TFSA approach and the pure mortgage paydown approach by capturing the best of both.
TFSA vs mortgage vs RRSP: Priority order
| Priority | Account | Why |
|---|---|---|
| 1 | FHSA (if eligible) | Tax deduction + tax-free growth + tax-free withdrawal — best account in Canada |
| 2 | TFSA (if unused room) | Tax-free compounding; limited room |
| 3 | RRSP (if employer match) | Guaranteed return from match |
| 4 | Mortgage prepayment | Guaranteed return equal to mortgage rate |
| 5 | RRSP (no match) | Tax-deferred growth |
| 6 | Non-registered investing | Growth is taxable |
This priority order assumes a mortgage rate of 4–6% and a long investment horizon. Adjust if your mortgage rate is exceptionally high or you are close to retirement.