The 20/4/10 Rule: How Much Car Can You Really Afford?
The simple framework that prevents you from being car-poor.
Why Most Canadians Overspend on Cars
The average new car price in Canada is over $66,000. Dealers will happily stretch your loan to 7 or 8 years to make the monthly payment look affordable. But a low monthly payment on a long loan is the most expensive way to own a car.
The 20/4/10 rule is a simple guardrail.
The 20/4/10 Rule
- 20% down payment - prevents being upside-down on your loan
- 4-year (48-month) loan maximum - limits total interest paid
- 10% of gross income - total transportation costs (payment + insurance + gas + maintenance)
Running the Numbers
| Gross Income | 10% Monthly Budget | After Insurance/Gas (~$300) | Max Payment | ~Max Vehicle Price |
|---|---|---|---|---|
| $50,000 | $417 | $117 | $117 | ~$6,000 |
| $75,000 | $625 | $325 | $325 | ~$18,000 |
| $100,000 | $833 | $533 | $533 | ~$30,000 |
| $150,000 | $1,250 | $950 | $950 | ~$50,000 |
Reality check: At a $75,000 salary, the 20/4/10 rule suggests a vehicle around $18,000-22,000 (with 20% down). That's a well-maintained 2-3 year old car - not a brand new SUV.
Why 4 Years Matters
Here's what happens when you stretch the same loan from 4 to 7 years:
| Loan | 4-year @ 6.5% | 7-year @ 7.5% |
|---|---|---|
| Amount financed | $28,000 | $28,000 |
| Monthly payment | $664 | $432 |
| Total interest | $3,872 | $8,288 |
| Equity at month 36 | Positive | Likely underwater |
The 7-year loan costs $4,400+ more in interest and you may owe more than the car is worth for the first 4 years.
The 20% Down Payment Rule
Cars depreciate 20-30% in the first year. If you put less than 20% down, you start the loan upside-down - meaning you owe more than the car is worth. If you need to sell or the car is totaled, you'll owe the difference.
Should You Lease Instead?
Leasing can work if you drive under 20,000 km/year and want a new car every 3-4 years. But apply the same 10% rule: your lease payment + insurance + gas should stay under 10% of gross income. Our vehicle calculator lets you compare lease vs. finance vs. buy scenarios.
Bottom Line
The 20/4/10 rule feels restrictive because most people overspend on cars. Following it means your vehicle won't eat into your ability to save for a home, invest for retirement, or handle emergencies. Run your numbers through our calculator to see exactly what fits your budget.
Use our free calculator to see exactly how this applies to your situation.
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