Personal finance guru Martin Lewis has issued a stark and "important warning" to credit card users across Britain, cautioning that a seemingly trivial oversight could prove devastatingly expensive. The founder of Money Saving Expert (MSE) highlighted a critical rule that could see a mere one-penny shortfall on a payment result in interest being charged on the card's entire balance, potentially amplifying costs to as much as £1,000.
The Peril of the Partial Payment
In a detailed video published on the MSE platform, Lewis meticulously explained the mechanics behind this costly pitfall. He illustrated the scenario with a clear example: imagine you have spent £1,000 on your credit card. If you repay the full £1,000 by the due date, you incur no interest for that billing cycle. However, if you pay £999.99—leaving just a single penny unpaid—the consequence is not interest on that solitary penny.
"You don't pay interest on a penny for the month, you still pay interest on the entire £1,000," Lewis emphasised. This mechanism means the effective cost of that one penny becomes the interest applied to the whole original sum, which, depending on the card's annual percentage rate (APR) and the time the debt persists, can escalate dramatically.
Why 'In Full' is Non-Negotiable
This revelation underpins Lewis's long-standing financial mantra. "This is why for years, my catchphrase has been pay off your credit card in full—the 'in full' is important," he stated. He noted that this advice is crucial even when using cards for benefits like cashback or favourable foreign exchange rates, as settling the complete balance "neuters the credit card's ability to charge you interest."
Lewis starkly summarised the risk: "If you miss even a penny, it can still charge you a whack." The potential for a small oversight to snowball into a significant financial burden is a key message for the millions of Britons who regularly use credit cards for purchases or cash advances.
Beyond the Penny: The Minimum Payment Trap
The MSE guidance extends beyond this specific warning. The website also cautions users about the dangers associated with only making the minimum monthly repayment. While missing the minimum payment entirely incurs a late fee and a negative mark on your credit file for up to six years, consistently paying only the minimum can be equally perilous.
"Only making the minimum repayment can keep you in debt for years and even decades," MSE advises. This practice means the principal debt reduces very slowly while interest continues to accumulate, creating a prolonged and expensive cycle of debt. The firm strongly recommends paying as much off as possible each month to clear balances swiftly and avoid excessive interest charges.
For consumers navigating credit, this warning from Martin Lewis serves as a critical reminder of the fine print in lending agreements. Vigilance in managing repayments, ensuring the full statement balance is cleared, and understanding the true cost of borrowed money are essential steps to avoid unexpected and substantial financial penalties.
