Converting a loft into two rooms costs £34,500 to £40,500 as a Velux conversion and £48,500 to £56,500 as a rear dormer with an en-suite at West Midlands rates, including VAT and professional fees. That sounds like a lot until you price a move: on a £375,000 purchase in England, stamp duty alone is £8,750, and none of the moving costs come back to you. Here is the side-by-side, with every loft figure taken from Quoteio’s calculator.
- Velux, West Midlands: £34,500 to £40,500
- Dormer with en-suite, West Midlands: £48,500 to £56,500
- Dormer with en-suite, inner London: £63,500 to £81,000
- Hip to gable with en-suite, West Midlands: £53,000 to £62,500
Price your own loft with the free calculator, or see prices by region.
How much does it cost to convert a loft?
The type of conversion decides most of the price. A Velux conversion works inside the existing roof and adds rooflights. A dormer builds a box out from the rear slope to gain headroom and floor space, which is why it costs more but gives a far more usable room. A hip to gable rebuilds a sloping end of the roof as a vertical wall, which is common on semis and detached houses with hipped roofs.
Prices also move with region. Here are both typical conversions in every part of the UK:
| Region | Velux, 2 rooms | Dormer, 2 rooms + en-suite |
|---|---|---|
| Inner London | £45,500 to £58,000 | £63,500 to £81,000 |
| Outer London | £41,000 to £52,000 | £57,500 to £72,500 |
| South East | £38,500 to £46,500 | £53,500 to £65,000 |
| East of England | £36,500 to £44,500 | £51,000 to £62,500 |
| South West | £35,500 to £43,500 | £49,500 to £60,500 |
| East Midlands | £33,500 to £41,000 | £47,000 to £57,000 |
| West Midlands | £34,500 to £40,500 | £48,500 to £56,500 |
| North West | £33,500 to £41,000 | £47,000 to £57,000 |
| Yorkshire and the Humber | £32,500 to £40,000 | £45,500 to £55,500 |
| North East | £32,000 to £39,000 | £44,500 to £54,500 |
| Wales | £32,500 to £40,000 | £45,500 to £55,500 |
| Scotland | £34,000 to £41,500 | £47,500 to £57,500 |
| Northern Ireland | £30,500 to £37,000 | £42,500 to £52,000 |
For a closer look at your area, open the London, South East or North East pages, and see our full loft conversion cost guide for mansards, one room lofts and spec levels.
What does moving house actually cost?
Moving costs fall into two groups. The first is money that is simply gone: stamp duty, agent and legal fees, surveys and removals. The second is the price gap between the house you sell and the bigger one you buy, which you finance but keep as equity.
Stamp duty is the one fixed by law. Here is what a home mover in England pays at a few prices (first-time buyers and second homes are taxed differently):
| Purchase price | Stamp Duty Land Tax |
|---|---|
| £250,000 | £2,500 |
| £375,000 | £8,750 |
| £550,000 | £17,500 |
| £800,000 | £30,000 |
England home mover rates from 1 April 2025. Scotland uses Land and Buildings Transaction Tax and Wales uses Land Transaction Tax, both with different bands. Northern Ireland uses SDLT.
The other fees vary by firm, so treat the next section as a worked example and swap in your own quotes. We have assumed a selling agent charging 1.2% plus VAT, £2,500 for conveyancing on both the sale and purchase, £600 for a survey and £1,200 for removals. These are assumptions, not averages.
Loft conversion vs moving: which costs more?
Two families each want a fourth bedroom. One owns a £300,000 house and would buy at £375,000; the other owns a £450,000 house and would buy at £550,000. Here is moving set against a dormer loft with an en-suite at West Midlands rates:
| Cost | £300,000 to £375,000 | £450,000 to £550,000 |
|---|---|---|
| Stamp duty (England) | £8,750 | £17,500 |
| Selling agent (assumed) | £4,320 | £6,480 |
| Conveyancing, survey, removals (assumed) | £4,300 | £4,300 |
| Moving costs you don’t get back | £17,370 | £28,280 |
| Price gap to finance | £75,000 | £100,000 |
| Dormer loft with en-suite instead | £48,500 to £56,500 | £48,500 to £56,500 |
Loft figure from the Quoteio engine, West Midlands rates, VAT and fees included. Moving costs other than stamp duty are assumptions for the example.
The comparison isn’t simply one number against another. Moving costs are spent and gone, while the price gap buys a bigger house that you own. A loft conversion is spent too, but you keep the room, and some of the cost may come back in value when you eventually sell. How much depends on what buyers in your street pay for an extra bedroom, so ask a local estate agent rather than trusting a national rule of thumb.
When does moving make more sense?
- The loft can’t take it. Low head height, a shallow roof pitch or a trussed roof can make a conversion impractical or much more expensive.
- You need more than bedrooms. A loft won’t give you a bigger kitchen, a garden or a better school catchment.
- Planning is unlikely. If your house is in a conservation area or needs a mansard or front dormer, full planning is usually required and isn’t guaranteed.
- You would overdevelop the street. If yours would become the most expensive house on the road, you may not recover the spend.
When does converting the loft win?
- You like where you live. Schools, commute and neighbours stay the same.
- Your roof suits it. Many rear dormer and Velux conversions are permitted development in England, which usually means no full planning application. Check with your council and get a lawful development certificate for certainty.
- You want to stay put during the work. Most loft work happens from scaffold outside, so families usually live at home throughout.
- Moving costs are high. The higher your next purchase price, the more stamp duty takes, as the table above shows.
What about time and disruption?
Neither option is quick. A move depends on a chain: finding a buyer, finding the right house, surveys, mortgage offers and solicitors on both sides, and any link in the chain can slow the whole thing down. A loft conversion has its own lead time for drawings, the structural engineer, Building Regulations and party wall notices before work starts, then the build itself. The difference is control. With a loft you set the timetable with one builder; with a move, other people’s sales and purchases set it for you. Factor in time off work for viewings and moving day, and the cost of living with builders, when you compare the two.
How do I decide?
Price both properly. Get a free estimate for your loft from the Quoteio calculator using your postcode, then ask a local agent for a valuation and a realistic asking price for the next house up. Add up the moving costs from real quotes, not assumptions. If the loft still looks good, get three written quotes from loft builders and check each one includes Building Regulations and party wall costs. Our methodology page explains exactly what the estimate includes, and the loft room guide covers single room conversions.
Common questions
How much does it cost to convert a loft in the UK?
On Quoteio a two room Velux loft conversion costs £34,500 to £40,500 and a two room dormer with an en-suite costs £48,500 to £56,500 at West Midlands rates, including VAT and professional fees. The same dormer runs £63,500 to £81,000 in inner London and £44,500 to £54,500 in the North East.
Does a loft conversion add value to my house?
Often, but how much depends on your local market, the number of bedrooms buyers expect in your area, and whether the conversion has Building Regulations sign-off. A local estate agent can tell you what an extra bedroom is worth on your street, which is a better guide than any national average.
How much stamp duty would I pay if I moved instead?
In England a home mover pays nothing on the first £125,000, 2% up to £250,000, 5% up to £925,000, 10% up to £1.5 million and 12% above that. On a £375,000 purchase that comes to £8,750. Scotland (LBTT) and Wales (LTT) use their own rates; Northern Ireland uses SDLT.
Can I live in the house during a loft conversion?
Usually, yes. Most of the work happens in the roof space with access from scaffold outside, and the house is only badly disrupted when the new staircase is opened up into the floor below. That is one of the main practical advantages over an extension.