RRSP vs TFSA when your income bounces around

The standard advice assumes your income stays roughly the same: RRSP above $60k, TFSA below. But what if you earned $45k last year, $85k this year, and you're not sure about next year?

Irregular income breaks the which-account-first math because RRSPs lock you into claiming the deduction based on this year's tax rate - but you might want to save that deduction for a higher-income year.

Here's the catch most people miss: you don't have to claim your RRSP deduction the year you contribute. You can contribute now and carry the deduction forward to use when your income is higher. The CRA tracks your unused deduction room on your Notice of Assessment.

Say you're a contractor who made $50k last year but expects $90k this year. If you contribute $9k to an RRSP in January (based on 18% of last year's $50k), you could skip claiming that deduction on this year's return. Wait until next year when you're earning more, then claim it against the higher tax rate.

At $50k in Ontario, your marginal rate is roughly 20.1%. At $90k, it jumps to 31.5%. That $9k deduction is worth $1,809 at the lower rate versus $2,835 at the higher rate - a difference of over $1,000.

The TFSA doesn't have this timing complexity. Money goes in after-tax, grows tax-free, comes out tax-free. Your income next year doesn't change the value of putting money in this year.

But here's where it gets tricky for irregular earners: TFSA room accumulates whether you use it or not. RRSP room expires if you don't contribute within the year after you earn it. Miss your RRSP contribution window and that room is gone forever.

If your income swings between $40k and $100k, consider this approach: prioritize TFSA in low-income years, but max out RRSP contributions in high-income years - even if you don't claim the deduction immediately.

TaxSplit.ca will show you exactly what each deduction is worth at your current marginal rate versus what it might be worth if you carry it forward.

The real decision point isn't just this year's income - it's whether you expect your average income over the next few years to be higher or lower than it is right now. If higher, lean RRSP but time the deduction claim carefully. If lower or uncertain, the TFSA's flexibility usually wins.

One more consideration: if you're self-employed with irregular income, you might not know your exact earnings until tax time. RRSP contributions can be made up to 60 days after year-end, giving you time to see the final numbers before deciding how much to contribute.