Save or pay off debt first? The maths behind the answer

Many people ask the same question: should I save what is left over, or use it to pay down debt? The feeling says that saving is safe and debt is uncomfortable.

The maths is often clearer than the feeling. If the rate on your debt is higher than the rate you earn on your savings account, you lose money by saving instead of paying down. And the gap is often large.

The main rule is to compare the rates

Savings earn you a return. Debt costs you interest. The choice is really a comparison of two numbers.

Here is what the typical rates look like in Norway in autumn 2025:

Type	Typical rate	You pay or earn
Best high-interest savings account	around 4 percent	You earn (before 22 percent tax)
Mortgage with a good margin	5 to 6 percent	You pay
Consumer loan	8 to 18 percent effective	You pay
Rolling credit card debt	22 to 28 percent effective	You pay

The "effective rate" includes fees and compounding, and is the real price tag on your loan. That is the figure to compare against.

Interest income on a savings account is taxed as capital income at 22 percent. If you earn 4 percent, you actually keep about 3.1 percent after tax.

A worked example: 50 000 kr extra

Imagine you have 50 000 kr in credit card debt at 24 percent effective interest, and that you can put aside an extra 4 000 kr each month. You face two choices.

Option A: save the money in the bank. You earn roughly 3.1 percent after tax on what you put in. At the same time, the card debt grows at 24 percent on the balance. After 12 months your savings account holds just under 49 000 kr, while the card debt has cost you around 12 000 kr in interest.

Option B: put the money on the debt. You pay 4 000 kr extra a month against the credit card. The debt is gone after about 13 months, and you have saved roughly 5 000 kr in interest you would otherwise have paid. Once the card is cleared, you can send the same 4 000 kr straight to the savings account instead.

The gap between the two options is several thousand kroner in real value over a single year. That is a good weekend, a month of fixed expenses, or half the Christmas gift budget.

But keep a small buffer first

The rule "pay down expensive debt before you save" has one important exception. If you have nothing put aside at all, an unexpected bill can force you to take on new expensive debt. Then you go in circles.

So build a starter buffer of 10 000 to 20 000 kr before you go after the debt at full speed. It should cover a broken washing machine, a dental bill, or an unexpected excess. Forbrukerrådet (the Norwegian Consumer Council) and several Norwegian banks suggest building the buffer further to one to three months of net pay over time, but that can wait until the most expensive debt is gone.

When saving and paying down can run in parallel

There are situations where it makes sense to save a little even if you have debt:

• You save in BSU (a tax-favoured savings scheme for first-time home buyers under 34) and you are still under the age limit. The tax break and the typically higher rate can make BSU worth more than extra payments on a reasonable mortgage.
• Your employer matches contributions to a share-savings plan or a pension scheme. You give up "free" money if you do not take advantage of it.
• You pay down the mortgage and save steadily in parallel. The mortgage rate is often low enough that this makes sense, as long as you do not have more expensive consumer or credit card debt sitting in the background.

Rules around BSU, tax and pensions can change. Check skatteetaten.no or talk to your bank before you reshuffle the plan.

How to make the choice in practice

1. Write down every debt you have, with the effective rate and the remaining balance.
2. Check what your savings actually return after 22 percent tax.
3. Tackle the debt with the highest rate first, but keep a small buffer in reserve.
4. Once the most expensive debt is gone, take on the next most expensive and let what you free up flow on to savings.

The important thing is not to do everything at once. It is to know which order pays off.

If you keep an eye on income, expenses and loan payments in a budgeting tool like Luma, it becomes easier to see when the extra thousand kroner should go to the card and when it can safely go to the savings account.