£21,500 Just to Move. That's Before You've Bought a Bigger House

 Here's a number that stops most Croydon homeowners in their tracks. Trading up from an average Croydon home to something 60 percent larger triggers around £21,500 in stamp duty alone, and that's before the estate agent, the solicitor, the surveyor and the removal van have taken their cut. Put that figure next to the cost of extending the house you already own, and the maths starts to look very different. The Architects in Croydon video is worth a watch, but the numbers below are the real story.

What moving actually costs in Croydon

The average house in Croydon sold for around £395,000 in mid 2026. A typical family wanting more space might trade up to something near £630,000, and that's where the bill lands hard.

On that £630,000 purchase, HMRC stamp duty comes to roughly £21,500. Add agent fees to sell your current home, two sets of conveyancing, a survey, removals and the inevitable chain contingency, and the all-in cost of that move sits somewhere around £42,000. None of that money goes into bricks and mortar you get to keep. It's the price of the transaction itself, paid and gone.

That's the figure people underestimate, because moving costs are split across two deals, selling one home and buying another, so they never see the full total in one place until they add it up.

What extending the same home costs instead

Now the alternative. Rather than spending £42,000 to move, you spend on making your current house bigger, and the money stays in the property as space and value.

At Croydon's outer London build rates of around £3,300 per square metre, a high-specification 22 square metre single-storey rear extension comes to roughly £109,000 all-in. That figure already includes professional fees, VAT and a contingency. It's more than the cost of moving in absolute terms, yes, but here's the difference: almost all of it becomes permanent space and value in your home, rather than tax and fees that vanish.

For a bigger jump, a 45 square metre double-storey extension runs closer to £209,000 and turns a three-bed semi into a genuine five-bed family home, the kind of transformation that would cost far more to buy in the open market.

The value it puts back

This is the part that tips the balance. Extending doesn't just cost less in wasted fees, it actively adds to what your home is worth.

Nationwide's research found that adding a double bedroom lifts a home's value by around 13 percent, and a full loft conversion plus extension can add as much as 24 percent to a three-bedroom, one-bathroom house. So the money you put into an extension works twice, once as the space your family actually needs, and again as equity when you eventually sell.

Contrast that with the £21,500 of stamp duty on a move, which returns nothing. One spend grows, the other simply disappears.

Where moving still makes more sense

To be fair, extending isn't always the winner, and it's worth being honest about that. There's a crossover point.

On a like-for-like Croydon trade-up, moving can actually be the cheaper route right up until the target price gets quite high, because at lower price points the stamp duty is modest. The real argument for extending gets stronger the more expensive the home you'd be moving to, since stamp duty scales steeply on higher purchases. So a family looking to jump substantially in size and value is exactly who benefits most from staying put and building.

The other honest limit is your street's ceiling price. Every road has a level buyers won't pay above, however lovely your extension. If your improved home would push past what the street commands, some of that spend won't come back. Establishing that ceiling before you commission a single drawing is the smart first move.

The practical suits Croydon's housing perfectly

Croydon happens to be well suited to extending rather than moving, which strengthens the case further. The borough is full of 1930s semi-detached homes with wide plots and deep gardens.

That housing lends itself naturally to exactly the projects that add the most value: single and double-storey rear extensions, two-storey side extensions, garage conversions, over-garage extensions and hip-to-gable loft conversions. These aren't awkward additions squeezed onto tight plots, they're the natural next step for the kind of house most of Croydon lives in. The space to build is already there, waiting.

Run your own numbers before deciding

So before you start browsing property listings for something bigger, do one calculation. Take what your current home is worth, work out the stamp duty and fees on the move you're contemplating, and set that total against the cost of extending to get the same space where you already live.

For a lot of Croydon families, that side-by-side comparison settles the question on the spot. The £21,500 tax bill that buys you nothing tends to look very different once you realise the same money, spent on your own four walls, could add a bedroom, a bigger kitchen and a chunk of lasting value. If the sums point toward building, a practice offering architects in Croydon services can tell you quickly what your specific house will take and what it's likely to add, which is the number that really matters.