What actually happened, and what didn't
On 10 September 2026 the European Central Bank raised its deposit rate to 2.50%. That's the second increase this year, following a similar hike in June. The cause isn't an overheating economy, but energy-driven inflation from the conflict in the Middle East, which reached 14.3% in August while core inflation fell to 2.4%.
Denmark's Nationalbank has historically followed ECB decisions within days, as it did in June. Danish mortgage lenders respond by raising rates on their variable loans (F3, F5) and by moving the price on their bond loans. In total, rates have risen around 0.50 percentage points over three months, in two steps of 0.25 each.
How much more are you actually paying
Here I'm using an ordinary annuity loan over 30 years, with 3.5% as the level before this round of hikes and 4.0% as the approximate level now. These are round, illustrative rates chosen to show the scale, not a concrete offer from a specific bank. Always confirm your own rate with your own bank or mortgage lender.
| Loan | 3.5% (before) | 4.0% (now) | Difference per month |
|---|---|---|---|
| 1,000,000 kr | 4,490 kr | 4,774 kr | +284 kr |
| 2,000,000 kr | 8,981 kr | 9,548 kr | +567 kr |
| 3,000,000 kr | 13,471 kr | 14,322 kr | +851 kr |
| 5,000,000 kr | 22,452 kr | 23,871 kr | +1,419 kr |
The point: on a 3 million kr loan, the difference between 3.5% and 4.0% is 851 kr a month. That's not a rounding error. It's a new fixed cost that wasn't in the budget six months ago.
What if it isn't over yet
According to FairRENTE, the market is pricing in a further 2-3 rate increases over the next six months. Nordea is more measured and expects fixed rates to change little through to 2028, but writes directly that "the next move in rates is more likely up than down". So it's worth running the numbers on two scenarios, not just the one that has already happened.
| Loan | +1.00 point total (rises the same again) | +2.50 points total (stress scenario) |
|---|---|---|
| 1,000,000 kr | 5,067 kr (+576 kr) | 5,996 kr (+1,505 kr) |
| 2,000,000 kr | 10,134 kr (+1,153 kr) | 11,991 kr (+3,010 kr) |
| 3,000,000 kr | 15,201 kr (+1,729 kr) | 17,987 kr (+4,515 kr) |
| 5,000,000 kr | 25,334 kr (+2,882 kr) | 29,978 kr (+7,525 kr) |
Why total interest cost isn't just rate times amount times 30 years
This is where most calculations online get it wrong. Interest is calculated on the outstanding balance, and the outstanding balance falls with every single payment. So a cost that looks like a fixed percentage of the loan is, in reality, largest at the start and nearly gone by the end.
| Loan 3,000,000 kr | Payment per month | Interest, month 1 | Interest, final month | Total interest over 30 years |
|---|---|---|---|---|
| 3.5% | 13,471 kr | 8,750 kr | 39 kr | 1,849,683 kr |
| 4.0% | 14,322 kr | 10,000 kr | 48 kr | 2,156,085 kr |
| 4.5% | 15,201 kr | 11,250 kr | 57 kr | 2,472,201 kr |
| 6.0% | 17,987 kr | 15,000 kr | 89 kr | 3,475,146 kr |
The simple formula "4.0% times 3,000,000 kr times 30 years" gives 3,600,000 kr. The real cost with amortisation is 2,156,085 kr, meaning 1,443,915 kr less. That difference isn't a rounding error, it's the fundamental point of an annuity loan: you pay the most in interest while the debt is largest, and the least at the end, when it's nearly gone.
Fixed or variable rate: what the bank doesn't say outright
Short and without dressing it up: a variable rate (F3/F5) is cheaper right now, but right now the trend isn't in your favour, so the risk of it rising is higher than usual. A fixed rate costs more today, but in return your payment stays locked in, even if rates were to hit 6%.
This isn't advice to pick a fixed rate. It's a question you should ask yourself honestly: how much would your payment rise if the stress scenario plays out instead of the optimistic one, and can your budget handle it.
Should you wait until 2027, or buy now and refinance later
According to Nordea's latest forecast, updated 12 August 2026, the only place I found a published curve running all the way to the end of 2027, rates don't fall. The fixed 30-year rate is expected to move from 4.30% at the end of 2026 to 4.36% at the end of 2027. F3 is expected to move from 2.96% to 3.00%, F5 from 3.13% to 3.22%. Nordea itself writes that homeowners hope for a rate cut soon, but that reality points the other way.
So the theory that "I'll just wait until 2027, when rates will be lower" isn't supported by any forecast I could find, if anything the opposite. But the question of buying now and refinancing later, if rates do fall after all, is still worth running the numbers on, because a forecast is a guess, not a guarantee.
What it costs to change your mind, if rates do fall
If the new mortgage deed is registered before the old one is cancelled, and the amount doesn't increase, you only pay the variable registration duty on the difference between the new and old loan amount, not on the whole new loan again. The exemption has to be used within one year of registering the new document. The flat duty of 1,825 kr, the same one from our review of registration duty on the deed and the mortgage, has to be paid in full again. On top comes the bank's own fee for the refinancing, which in practice typically runs somewhere between 8,000 and 15,000 kr. That isn't an official rate, banks don't publish a fixed table, so treat the figure as a practice-based range, not a price you can bank on to the krone.
| Example | Loan 3,000,000 kr, falls from 4.0% to 3.5% after 15 months |
|---|---|
| Savings per month after refinancing (same remaining term) | 824 kr |
| Cost of refinancing (1,825 kr duty + 8,000-15,000 kr bank fee) | 9,825-16,825 kr |
| Payback period | 12-20 months |
On a 2,000,000 kr loan, the same rate move gives only 549 kr in monthly savings, and the payback period stretches to 18-31 months. The rule of thumb from the industry: refinancing clearly pays off once rates fall around 1-1.5 percentage points, not at 0.5.
There's a crucial difference between loan types here. With a fixed-rate loan, you have to actively refinance and pay for it if you want to benefit from a rate cut. With a variable loan (F3/F5), the rate adjusts automatically on the scheduled reset date, with no new registration duty and nothing for you to do.
The point: waiting for a rate cut that no forecast currently predicts costs you rent and zero equity built in your own home while you wait. Buying now and refinancing, if rates do fall enough, costs a one-off 10,000-17,000 kr and is typically paid back within one to two years. That's not an argument for buying tomorrow at any price. It's an honest comparison between two real scenarios, not between reality and a hope.
How to use this before you sign
- Work out your own payment at both the current rate and a stress scenario, not just the rate the bank shows you today.
- Ask the bank directly what happens at the next rate reset, if you're considering an F3 or F5 loan.
- Don't mix up the registration duty with rate movements. One is fixed, the other moves, and the two figures shouldn't be added together in your head as "everything's getting equally more expensive".
- If you're considering waiting, put a number on what waiting costs you in rent and in the equity you're not building in your own home, and weigh that against the uncertain gain from a rate cut that hasn't been predicted yet.
- Add the interest cost on top of the other transaction costs before you decide your offer, see the full list in the review of every fee in buying a home.
In short
Don't just ask "what's the rate right now". Ask "what does it cost me a month if rates rise the same amount again, and have I worked out what waiting costs compared to buying now and refinancing later if I'm wrong".
Frequently asked questions
How much will my monthly payment go up if rates rise?
It depends on the size of the loan. On a 3,000,000 kr loan, a move from 3.5% to 4.0% costs around 851 kr more a month. On 1,000,000 kr it's around 284 kr, on 5,000,000 kr around 1,419 kr.
Should I wait to buy until rates fall?
There's no published forecast pointing to a rate cut before the end of 2027. Nordea's latest forecast actually points to a slight further rise. Waiting for a cut that no bank is predicting has its own cost, in rent paid and equity not built.
What does it cost to refinance my loan if rates fall later?
The flat registration duty of 1,825 kr has to be paid again. The variable duty is charged only on the difference, if the new mortgage deed is registered before the old one is cancelled, within one year. On top of that comes the bank's own fee, which in practice typically runs around 8,000-15,000 kr, though that isn't an official rate.
How much do rates need to fall before refinancing is worth it?
As a rule of thumb, rates need to drop around 1-1.5 percentage points before refinancing clearly pays off. A drop of just 0.5 points can still be worth it, but the payback period stretches out, typically somewhere between one and two and a half years depending on loan size and the bank's fee.
Do I automatically get the lower rate on an F3 or F5 loan if rates fall?
Yes. At the scheduled rate reset, the rate adjusts automatically, with nothing for you to do and no new registration duty. That doesn't apply to a fixed-rate loan, where you have to actively refinance to benefit from a rate cut.
Has the registration duty gone up along with rates?
No. The registration duty is a fixed statutory rate that doesn't depend on the interest rate level. It doesn't change whether rates rise or fall.
Why isn't the total interest cost over 30 years just rate times loan amount times 30?
Because interest is calculated on the outstanding balance, which falls every month as you pay it down. At the start of a 3,000,000 kr loan at 4.0%, interest makes up around 10,000 kr of the monthly payment; in the final month, only around 48 kr. The simple formula of rate times amount times 30 years significantly overstates the real cost.
This is general information about a calculation, not financial advice for your specific situation. Interest rates, forecasts and fees change over time, and your own circumstances may differ from the illustrative examples here. Talk to your bank or an independent adviser before making a decision about loan type or refinancing.
