What are my credit cards really costing me?

A credit card balance tells you how much you owe today. It does not tell you how much the card is costing you, how quickly the debt is changing, or what effect it is having on everything else you are trying to do with your money.

Take someone with £3,000 on a credit card who pays £150 towards it every month. Over six months, £900 has left their bank account. It would be reasonable to expect the balance to have fallen quite a lot.

Now imagine the card charges an illustrative 24% APR and, during those same six months, around £70 a month of groceries, fuel and other everyday spending goes back onto it. Using a deliberately simplified calculation of roughly 2% interest a month, the balance after six months would still be around £2,874.

They have paid £900, but the debt has fallen by only about £126.

Around £420 of new spending has gone onto the card and roughly £350 has been added in interest. The exact numbers on a real card will differ because interest calculations, transaction dates, fees and rates vary, but the example exposes something that looking at the £150 payment alone does not.

This person is not only repaying a credit card. They are still relying on it.

A repayment can hide what is happening underneath

Imagine the person in that example is Sarah. She earns enough to cover her normal bills and has also been putting £200 a month towards a house deposit. She knows she has credit-card debt, so she pays £150 towards that as well.

On paper, her finances can look quite organised. £200 is going into savings and £150 is going towards the card every month.

But by the final week before payday, there is often not enough money left in her current account for groceries and fuel. Around £70 ends up back on the card.

Seen as separate transactions, nothing looks especially dramatic. The savings transfer happens. The credit-card payment happens. The supermarket shop happens.

Put them together and Sarah’s income is being asked to fund her current lifestyle, save £200 towards a future goal and reduce an existing debt at the same time. At the moment, there is not quite enough room to do all three without borrowing again.

That does not automatically tell Sarah which part to change. There may be very good reasons for keeping cash available or continuing to build savings. Her spending may contain things she would happily change, or very little that she can. Her income may be about to increase. The card may be on a temporary promotional rate. Her house deposit may have a particular deadline.

What the complete picture does is reveal the trade-off.

MoneyAngel was built around exactly this problem. Its starting principle is that looking at income, spending, assets, debts or goals independently can leave someone with an incomplete financial picture. Bringing them together gives the person more context for the decisions they make.

With credit cards specifically, MoneyAngel records not only the balance but how the card is normally repaid, because paying it in full, paying a fixed amount and making minimum repayments create very different paths for the debt. Card transactions also form part of the spending picture because everyday expenditure may be happening on the credit card rather than through the current account.

Sarah’s £3,000 balance is therefore only one number in the story.

The interest is a cost, but so is the commitment

Interest is the most obvious cost of carrying a credit-card balance. We cover the calculation in more detail in How much interest will I pay on my credit card?

For this question, it helps to look beyond the rate.

If £150 is leaving your income every month to service a card, that £150 is already committed before it can do anything else. Some of it may reduce the balance. Some may cover interest or fees. Either way, the full payment has an effect on the money available for the rest of the month.

Suppose two people both have £3,000 of card debt at the same interest rate.

One has £900 left each month after normal living costs and is steadily reducing the balance without adding new spending. The other has £200 left and regularly needs the card again before payday.

Their statements might show the same debt today, but they are not in the same financial position. For one, the balance may simply be a debt being worked down over time. For the other, the card may have become part of how the monthly budget works.

There is also the effect on other plans. £150 committed to a card may be £150 that is not currently available for a savings goal, an emergency fund, a future move or more room in the monthly budget. That does not make any of those alternatives automatically more important. It means the debt has a place in the same financial system as everything else.

This is why MoneyAngel’s original positioning identifies “What are my credit cards really costing me?” as one of its core questions. The intended approach is to surface what is happening, connect it to the person’s goals and leave the decision with them rather than telling them to switch, move or buy something.

The current debt modelling also looks across debts and planned repayments and can compare what different repayment periods mean for the cost of a debt. For credit cards, that includes the relationship between the repayment pace and the interest that continues to be paid while the balance remains.

Look at movement, not just the balance

One of the simplest ways to understand a credit card is to stop looking at one statement in isolation.

Go back several months and compare three things: what you owed, how much you paid and how much new spending went onto the card.

A balance that has fallen from £4,000 to £3,200 tells one story. A balance that has stayed around £4,000 despite regular repayments tells another. A balance that falls after payday and grows again before the next one may tell you something about the monthly cashflow as much as it tells you about the debt itself.

Minimum repayments can make that movement particularly slow. MoneyHelper gives the example of a £2,000 balance at 22% APR with a 2.5% minimum repayment taking around 14 years to clear. FCA rules also define persistent debt around whether, over an 18-month period, more has been paid in interest, fees and charges than has been repaid from the amount borrowed.

That is a very different way of looking at a payment. Instead of asking only whether the minimum was paid, it asks what the payments are achieving.

MoneyAngel’s Spending DNA can add another layer by showing borrowing costs alongside the rest of someone’s expenditure, with the ability to look more deeply at areas such as mortgage and credit-card costs. The purpose of that spending view is to understand what is happening now before deciding what the next budget looks like.

For Sarah, that might reveal that her £3,000 card is steadily shrinking and comfortably fits alongside everything else she wants to do. It might show that most of her repayments are being undone by new spending each month. Or it might show that the balance is falling, but the repayment is leaving so little room elsewhere that another part of her finances is under pressure.

Those are three different positions, even though the card could show the same £3,000 balance on the day she first looks at it.

The real cost of a credit card therefore is not contained in one number. It sits in the interest and charges, the income committed to repayments, the time the balance remains, any spending still being added and the effect all of that has on the rest of your financial life.

Once those pieces are visible together, you can understand what the card is actually doing rather than simply knowing what you owe.

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