Kill the Expensive Debt First — a Ranked Order for Every Spare Pound

Every spare pound you find — a pay rise, a bonus, the gym membership you finally cancelled — faces the same question: where should it go? The internet will give you a hundred answers. In truth there's a simple ranking, and it turns on a single idea: a pound that clears expensive debt earns you a guaranteed, tax-free return equal to that debt's interest rate — and almost nothing else in finance is guaranteed.

The priority ladder

1. A small starter buffer

Before anything, hold a little cash — say £1,000, or a month's essentials — so a surprise bill doesn't send you straight back to the credit card. This isn't your full emergency fund yet; it's a firebreak.

2. Expensive debt (roughly 8%+ interest)

Credit cards, overdrafts, payday loans, most car finance. Clearing a card charging 24% is a guaranteed 24% return. No investment reliably matches that. This is the highest-value use of a spare pound, full stop — attack it before you invest a penny beyond the next step.

3. Free money: the employer pension match

If your workplace matches pension contributions, grabbing the full match is an instant, guaranteed uplift on your own money — often 50% or 100%. Even while clearing debt, contribute enough to capture every penny of the match. Turning it down is leaving salary on the table.

"Clearing a 24% credit card is a guaranteed 24% return. Your investments would kill for that — and they can't promise it."

4. Your full emergency fund

Now build cash to three to six months of essential spending, in an easy-access account. This is what lets you stay invested and employed-on-your-own-terms when life lurches.

5. Tax-advantaged investing

With expensive debt gone and a buffer in place, fill your ISA and pension and feed a low-cost global index fund. This is where long-term wealth is actually built.

6. Overpay cheap debt (the mortgage)

A mortgage at a low fixed rate is the last priority, not the first. If your mortgage costs less than you might reasonably expect investments to earn over the long run, investing usually wins — though overpaying offers a certain, emotionally satisfying return. It's the one rung where the "right" answer is partly about how you sleep at night.

Follow the ladder in order and you never have to agonise again. Expensive debt, free money, safety, then wealth — cheap debt last. Boring, ruthless, and right far more often than the clever alternatives.

Compound provides general information, not financial advice.