Pay Down Mortgage vs Maximize Super Contributions: The Australian Dilemma
G'day. Here's a question that keeps Aussie homeowners up at night: "Should I chuck extra money at my mortgage or salary sacrifice to super?" It's one of the most common financial dilemmas going around - and there's no single right answer that works for everyone.
Let's break down the trade-offs with real numbers, Aussie-specific factors (like franking credits and negative gearing), and a framework to help you work out what makes sense for your age, goals, and circumstances.
The Tax Advantage: Super's Mathematical Edge (Usually)
Right, let's start with the raw numbers, because that's where most people kick off the comparison. Spoiler alert: super wins on pure tax maths in most scenarios - but that doesn't automatically make it the right choice for you.
The Comparison: $1,000 Extra Monthly
Here's a typical scenario for an Aussie homeowner:
Sarah, 40, earning $120k in Melbourne
- Mortgage: $500,000 at 6.5% interest, 25 years to go
- Extra cash: $1,000 a month to play with
Option A: Extra Mortgage Repayments
Prepay $1,000 monthly into mortgage
Saves interest at 6.5% (effectively guaranteed return)
No tax implications (mortgage interest isn't deductible for principal place of residence)
After-tax return: 6.5%
Option B: Salary Sacrifice to Super
Contribute $1,000 pre-tax to super
Contribution tax: 15% = $150
Net invested: $850
Investment return: 7% (balanced fund average)
After-tax return: ~5.95%
Initial winner: Mortgage (6.5% vs 5.95%)
But hang on - we're missing something pretty important. If Sarah salary sacrifices $1,000 pre-tax, she reduces her taxable income by $1,000. At her marginal rate (32.5% + 2% Medicare = 34.5%), that's $345 in annual tax savings. That changes the picture a fair bit.
Tax-adjusted comparison:
Mortgage prepayment: $1,000 in after-tax dollars (costs Sarah $1,000 in take-home)
Salary sacrifice: $1,000 in pre-tax dollars (costs Sarah $655 in take-home after tax savings)
Fair comparison: Mortgage $65 annual return vs Super $384 first year (including $345 tax saved)
The super option is way ahead in year one - but the mortgage option has a permanent compounding advantage (the interest savings keep going for the life of the loan).
The Break-Even Analysis
Here's where it gets interesting: we need to work out the break-even point over time.
Mortgage strategy:
- Extra $1,000 monthly chops about 7 years off the loan
- Total interest saved: roughly $230,000 over the life of the loan
- Mortgage-free at 55 instead of 62. Not bad.
Super strategy:
- Extra $850 monthly (after 15% contributions tax)
- Compound at 7% for 20 years to age 60
- Future value at 60: around $440,000
Both options leave Sarah significantly better off - but in different ways. Good planning tools model both scenarios, showing you net worth at age 60, the cash flow impact, and what it means for the Age Pension.
The Preservation Age Factor: Liquidity Matters
Here's the catch with the "super always wins mathematically" argument: preservation age. Sarah can't touch her super until she's 60 AND meets a condition of release. But she could use mortgage prepayments to become mortgage-free earlier, which drops her required income in her 50s. That flexibility matters.
The Risk Super Can't Solve: Underemployment in Your 50s
What if Sarah loses her job at 55 and struggles to find equivalent work? It happens to a lot of Aussies.
Super Strategy Result
$600,000 in super (can't access until 60)
$300,000 remaining mortgage
$5,000 monthly living expenses + $2,500 mortgage payments
Higher wealth, less flexibility
Mortgage Strategy Result
$250,000 in super (can't access until 60)
$0 mortgage (paid off by age 55)
$5,000 monthly living expenses (no mortgage payment)
Lower fixed expenses, more resilient
Strategic insight: If you're planning to retire early (before preservation age), mortgage freedom can be more valuable than extra super. If you're planning to work to 65+, super contributions typically make more sense.
The Sequence of Returns Risk
Here's another thing to chew on: if Sarah salary sacrifices to super and the market tanks right before she turns 60, she's forced to either delay retirement and wait for recovery, or withdraw a reduced balance at the worst possible time.
Mortgage prepayments have no sequence of returns risk - every dollar extra you pay off the mortgage guarantees interest savings. Market returns? They're uncertain and lumpy. Something to think about.
Aussie-Specific Factors: Franking Credits and Negative Gearing
The Aussie tax system has some unique features that affect this comparison - specifically, dividend imputation (franking credits) and negative gearing rules.
Franking Credits: The Super Edge
Aussie shares pay fully franked dividends, meaning the company has already paid 30% tax on the profits. Your super fund receives these dividends with franking credits attached - which can be used to offset tax or refunded.
In Accumulation Phase (15% tax)
- You receive $700 dividend + $300 franking credit = $1,000 total income
- Tax payable: $1,000 x 15% = $150
- Franking credit offset: $300
- Net refund: $150
This means the effective tax rate on franked dividends in super can be zero or negative (you actually get money back). Franking credits are more valuable inside super because the contribution tax (15%) is lower than most people's marginal tax rate. Pretty handy.
Negative Gearing: When Mortgage Wins
Here's where the comparison flips: if you've got an investment property (not your principal place of residence), mortgage interest is tax-deductible.
Strategic insight: Paying down your home mortgage is usually inferior to salary sacrificing (mathematically speaking). But paying down an investment property loan is more competitive because you're giving up valuable tax deductions. Different situation entirely.
Age-Based Strategies: What to Do When
The best split between mortgage and super changes a fair bit through life. Here's a framework based on age and where you're at.
Ages 25-35: Building the Foundation
Priority: Mortgage + Emergency Fund
At this stage, super contributions should generally stick to the employer SG (11.5%). Why?
- Liquidity matters: You might need money for a car, career break, starting a family - life happens
- Preservation age is ages away: 25-35 years until you can touch super
- Compound growth has time: Even starting extra super contributions at 40 instead of 30 leaves plenty of runway for compounding
- Mortgage freedom early: Smashing your mortgage in your 30s sets you up for flexibility in your 40s and 50s
Strategy: 90% of extra cash to mortgage prepayments, 10% to emergency fund and short-term goals.
Ages 35-50: Time to Accelerate
Priority: Balance Mortgage Reduction with Super Building
| Your Situation | Recommended Split |
|---|---|
| High income ($150k+), low mortgage rate (<5%) | 70% super / 30% mortgage |
| Moderate income ($80-150k), moderate mortgage rate (5-6.5%) | 50% super / 50% mortgage |
| Planning early retirement (age 55-60) | 30% super / 70% mortgage |
| Planning traditional retirement (age 65+) | 70% super / 30% mortgage |
Ages 50-60: The Home Stretch
Priority: Optimise for When You Want to Retire
At this stage, your strategy depends entirely on when you want to pull the pin:
Retiring at 55 (before preservation age):
- 80-100% to mortgage prepayment
- Goal: Mortgage-free by retirement so your fixed expenses are low
- Use super for catch-up contributions from 55-60 (if still working a bit) via carry-forward provisions
Retiring at 60+ (at or after preservation age):
- 60-80% to super contributions
- 20-40% to mortgage (knock it down, but not at the expense of super)
- Goal: Max out super balance while keeping mortgage manageable
Making the Decision: A Simple Framework
Step 1: Check Your Mortgage Rate
- If your mortgage rate is under 5%: Super contributions are probably better for most people
- If your mortgage rate is over 7%: Mortgage prepayments become very attractive
- If your mortgage rate is 5-7%: It depends on your age, goals, and how much risk you're comfortable with
Step 2: Compare Your Marginal Tax Rate to Super Tax Rate
| Your Marginal Rate | Income Range | Tax Saving from Salary Sacrifice |
|---|---|---|
| 45% | Over $180,000 | 30% (45% - 15%) |
| 32.5% | $45,000 - $120,000 | 17.5% |
| 19% | Under $45,000 | 4% |
The higher your income, the more valuable salary sacrificing becomes.
Step 3: Think About Your Timeline
| Years Until Preservation Age | General Strategy |
|---|---|
| 20+ years | Lean towards super (compounding has time, mortgage can wait) |
| 10-20 years | Balance both (50/50 or 60/40 split) |
| 5-10 years | Lean towards mortgage (guaranteed returns, flexibility for early retirement) |
| 0-5 years | Go hard on mortgage (freedom before retirement) |
How Talk Through Wealth Helps
Have a play with both strategies side-by-side using Aussie-specific considerations:
- Compare extra mortgage repayments vs salary sacrifice scenarios
- Factor in franking credits and their impact on super returns
- Model different retirement ages (55, 60, 65, 67)
- See what it means for Age Pension eligibility
- Account for sequence of returns risk using Monte Carlo simulations
- Run the numbers for your specific mortgage rate, income, and timeline
Model Your Mortgage vs Super Strategy
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