Mortgage prices could soar by hundreds of pounds a year if the Bank of England decides to hike interest rates tomorrow.
Experts think the Bank of England will put it up its base rate from 1.25% to 1.75%.
That 0.5 percentage point rise would be the highest in 27 years if it happens.
Any increase in the base rate, also known as interest rate or Bank rate, means the price of some mortgages will go up.
Moneyfacts data shows the cheapest rate for someone looking for a two-year £200,000 mortgage now is 2.89%.
This is currently being offered by Monmouthshire Building Society.
Over 25 years that works out at £937 a month.
If a 0.5% base rate rise is passed on, these monthly repayments would go up by £52 to £989 - that's an extra £624 a year.
And that is just for the cheapest deal out there.
The average two-year fixed mortgage was 3.46% last month, according to broker L&C Mortgages.
Someone borrowing the same amount as above would be paying £997 a month with this rate.
That would go up to £1,051 a month if base rate rises by 0.5% - or an extra £648 a year.
One common type is a tracker mortgage, which as the name suggests "tracks" base rate.
Base rate changes are almost always passed on by banks very quickly to tracker mortgages.
Quick mortgage hikes are also likely come for people on standard variable rates (SVRs).
SVRs are the rates paid when your normal mortgage term runs out, and are normally 3-6% higher than standard home loan rates.
Currently most SVRs are around 4.5% to 5%.
Using the £200,000 mortgage example above, someone with a 5% home loan rate would be paying £1,169 a month.
That will go up to £1,228 if base rate goes up 0.5% - that's another £59 a month, or £708 more a year.
Capital Economics said further base rate rises are likely.
It said: “[The Bank of England] may be willing to raise rates by 0.5 percentage points at future meetings if there are no signs that domestic price pressures are easing.
“That would support our view that interest rates will peak at 3% by May next year, if not before.”
Of course, how much your mortgage could rise by depends on several factors - including how much you're currently paying and the type of deal you're on.
People with fixed-rate mortgages are protected against any increases to the Bank of England base rate until their mortgage term ends.
Why do interest rates change?
The Bank of England sets the base rate in the United Kingdom every month.
Base rate is basically a financial 'lever' that the Bank can pull to help control the economy.
Rising base rate means it's more expensive to borrow, so consumers and businesses save instead - meaning spending drops and inflation does too.
Lowering base rate does the opposite, encouraging everyone to spend and not save, which means higher inflation.
