Extra on the Mortgage, or Invest It?
You've got some spare cash. Throwing it at the mortgage kills interest and gets you mortgage-free sooner — a guaranteed, tax-free win. Investing it could grow faster, but the return isn't certain and gets taxed. This weighs both over the years ahead so you can see which leaves you wealthier. Everything stays in your browser.
Your mortgage
What you owe today
Sets your normal repayment
The guaranteed, tax-free saving
Spare cash to put to work
Extra repayment, or invested
One-off amount, if any
How long you're weighing this
If you invested instead
Average annual, before tax & fees
PIE fund tax rate — often 28%
Annual management fee drag
The mortgage's return is guaranteed and tax-free — the rate you avoid. The investment's return is uncertain, and is taxed and charged fees, so we net those off.
Results update live as you edit these figures — everything stays in your browser.
Saved comparisons
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The Two Paths
Wealth added over your horizon
- Extra equity built
- $151,772
- Reinvested after payoff
- $0
- Mortgage cleared
- Not within horizon
Wealth added over your horizon
- Investment balance
- $129,085
- Net return used
- 4.7% p.a.
Wealth Built Over Time
Each line is the wealth a path adds versus doing nothing extra — for the mortgage, the extra equity built (plus anything reinvested once it's paid off); for investing, your fund balance. Where the dashed line climbs above the solid one, investing has pulled ahead.
Key Findings
Better choice
Pay down mortgage
Based on the wealth each path adds over your horizon
Gap between the two
$22,687
How far ahead the winning path finishes
Mortgage interest saved
$61,772
Interest avoided by making the extra repayments
Investing pulls ahead
Not within horizon
From when the invested path stays ahead of paying down debt
Our Recommendation
Paying down the mortgage looks better — a guaranteed 6.50% tax-free saving beats the 4.7% the investment is projected to net after tax and fees, leaving you about $22,687 ahead over 15 years. You'd save roughly $61,772 in mortgage interest. It's also the certain option — no market risk.
Informational only, not financial advice. The investment return is an assumption, not a guarantee — real markets rise and fall, and a bad run early on can change the outcome. Paying down the mortgage is the certain, risk-free option; money in a fund also stays accessible in a way home equity doesn't. Tax is a simplified PIE-fund estimate at your PIR; your own situation may differ.