The US national debt just passed $40 trillion. If that number feels abstract, consider this: it's climbing by roughly $90,000 every second. That's not a prediction or a worst-case scenario. That's happening right now.
For most UK homeowners, American fiscal policy feels about as relevant as a hurricane in Kansas. But here's the uncomfortable reality: what happens in Washington shapes what you'll pay when you remortgage.
How we got here
The story of American debt is one of relentless acceleration. It took nearly two centuries for the US to accumulate its first trillion pounds of debt. That happened in 1981, and President Ronald Reagan treated it like a national emergency. He addressed the nation on television to warn Americans that the moment demanded serious attention.
Fast forward to 2024. The US is now spending more on interest payments alone each year than it spent on the entire national debt in 1981.
The doubling happened quickly. When Donald Trump took office in 2016, US debt stood at just under $20 trillion. A decade later, it's doubled. Both the Trump and Biden administrations ramped up spending significantly, driven by responses to crisis situations including the 2008 financial collapse and the Covid pandemic. Meanwhile, tax revenues stalled and borrowing accelerated.
The real problem isn't the debt itself. Wealthy nations can carry heavy debt loads. The problem is the cost of servicing it. When governments borrow enormous sums, they have to offer better returns to attract investors. That drives interest rates higher across the board.
Why UK borrowers should pay attention
Long-term US interest rates have hit their highest levels in decades. Part of that reflects concerns about inflation. Part of it reflects serious worries about the scale of American government borrowing. When the world's largest economy struggles to fund its debt affordably, global capital markets respond. Bond investors demand higher returns everywhere.
That directly affects your mortgage rate. The UK base rate sits at 3.75%, and the average five-year fixed mortgage rate is currently 4.79%. Those numbers don't exist in isolation. They're influenced by what's happening in global debt markets, particularly in the US.
There's another factor at play too. American technology companies are borrowing eye-watering sums to invest in artificial intelligence. Those companies are competing with governments for investor cash, which pushes rates even higher. It's a perfect storm for borrowing costs.
What this means for your property plans
If you're considering remortgaging, timing matters more than ever. Current fixed-rate deals offer some stability, but refinancing costs remain elevated compared to the ultra-low rates of 2020 and 2021. The average two-year fixed rate stands at 6.6%, which is still uncomfortable for many households.
For first-time buyers, the picture is mixed. UK house prices have grown by 2% over the past year, with the average property now valued at £272,188. That's barely keeping pace with inflation at 2.9%. Properties aren't becoming dramatically more expensive in real terms, but affordability remains stretched because mortgage rates stay stubbornly high. You're paying more to borrow less.
Property sellers face a subtly different challenge. In a world where borrowing costs remain elevated, buyer demand tends to soften. Fewer people can afford the monthly payments on a mortgage, even if the asking price stays reasonable. This is already visible in regional markets, where transaction volumes have slowed compared to a year ago.
Should you be worried?
Economists aren't predicting collapse. The US remains the world's largest economy, and the dollar is still the global reserve currency. That status provides some buffer. But the trajectory is concerning. Congressional forecasters estimate US debt could climb to around $64 trillion by 2036.
The more immediate concern is this: if American interest rates stay elevated for years, UK mortgage rates will likely stay elevated too. That's not a temporary pinch. It's a structural shift in the cost of borrowing.
The practical takeaway? If you're planning to buy or sell a home in the coming year, don't assume rates will fall dramatically. Plan your finances around current pricing, not hopes of better conditions. If you're currently on a tracker or standard variable rate, locking into a fixed deal might protect you from further rises, even if rates don't fall as quickly as hoped.
The American debt milestone matters, not because it signals an immediate crisis, but because it signals that the era of cheap money is genuinely over. For UK property buyers and owners, that's the new reality you're working with.