I get a version of this question every few weeks. Someone owns a townhouse in Ashburn or Brambleton, they have outgrown it, and they want to know what it actually takes to get into a detached house with a yard.
The first number is easy to find. In Loudoun County right now, the median townhouse sells for about $703,000 and the median detached house sells for about $983,600. Call it a $280,000 gap. (Source: Bright MLS, June 2026.)
Most people stop there. They look at the gap, decide whether they can stomach it, and start scrolling listings. But that gap is only half the story, and the other half is the part that actually decides whether the move works.
Here is what gets missed. If you bought or refinanced between 2020 and 2022, you are probably carrying a mortgage somewhere around 3 percent. When you sell and buy again, you do not just borrow the extra $280,000 at today's rate of roughly 6.5 percent. You re-borrow everything, including the balance you already had, at today's rate.
Run it on a $300,000 balance. At 3 percent, principal and interest costs about $1,265 a month. That same $300,000, borrowed today at 6.49 percent, costs about $1,894. You have not bought a single additional square foot and the payment is already up more than $600.
Now add the move itself. Say the townhouse sells at the county median, you pay off the $300,000, cover your closing costs, and walk away with roughly $360,000. Put every dollar of it down on a $983,600 detached house and you are financing about $625,000. At today's rate that runs roughly $3,950 a month in principal and interest, before taxes and insurance.
So the honest comparison is not a $280,000 gap. It is a payment going from about $1,265 to about $3,950. Those are round numbers on a median-to-median move, not a quote on your house, but the shape of it holds.
I am not laying this out to talk anyone out of moving. I am laying it out because I would rather you see the real number sitting across from me than find it three weeks into a search, after you have already walked through the house you want.
There is a genuinely good side to this, too. The same math that makes the move expensive is what makes your townhouse so easy to sell. Everyone holding a 3 percent loan is running this arithmetic, and a lot of them are deciding to stay put, which is why active listings in the Ashburn zip codes are down between 27 and 47 percent from a year ago. Loudoun homes are going under contract in about 13 days and closing right around 101 percent of asking. You would be selling into the strong side of this market. (Source: Bright MLS, April through June 2026.)
And for plenty of people the math still works. If you need the space now, if a job moved, if you are sitting on a large amount of equity and a small remaining balance, the payment jump can be far smaller than my example. I have had sellers run these numbers expecting bad news and find out they were closer than they thought. The answer depends on your loan balance and your equity, not on the price gap everybody quotes at each other.
The gap is the number people talk about. Your balance is the number that decides it.
That is a twenty minute conversation with real figures on your actual house, and I am glad to have it whether you move this year or in five. 571-496-9009.