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myLoft Conversion Cost Calculator
Loft conversions can be a great way of adding extra living space to your property without the stress (and cost) of moving house.
What's the typical cost of a loft conversion in the UK?
Depending on the type you choose, conversion costs vary:
- The cheapest loft conversion is typically a Velux at £20,000.
- The most expensive is a mansard conversion at £55,000.
Looking for a personalised loft conversion quote?
To help you estimate the total cost of your attic conversion, our loft conversion cost calculator can give you a quick estimate to move you closer to the loft conversion you're dreaming of.
And it couldn't be easier to get started.
How to Use This Loft Conversion Cost Calculator
It's incredibly simple to get started on your project:
- Choose the type of conversion you want (e.g., dormer, mansard, Velux).
- Estimate the size required (e.g., single, double, or multiple bedroom-sized).
- Select whether you want to add a bathroom or not.
- Indicate your finish level (basic, average, premium).
- Identify if the conversion will share a wall with a neighbour.
- Pick your location from the options.
- Click calculate to get your loft conversion cost estimate!
Loft Conversion Cost Calculator
Table of Contents
Average Loft Conversion Costs
The average cost to install a loft conversion is around £40,000.
The exact cost will depend on how you approach the following choices:
- Type and size of loft conversion.
- Complexity of build and amount of structural work required (e.g., adding in a staircase).
- Additional plumbing, electrics, insulation, and new window installations.
- Level of finish.
- Site access and scaffolding costs.
- Planning permission and building regulation requirements.
Loft Conversion Cost Calculator Breakdown
Let's break those total project costs down and look at the individual labour costs for different types of loft conversion:
- Velux Loft Conversion — £9,000 to £14,000.
- Dormer Loft Conversion — £20,000 to £40,000.
- Hip-to-Gable Loft Conversion — £20,000 to £35,000.
- Mansard Loft Conversion — £25,000 to £45,000.
The bottom line: You can expect loft conversion labour costs to make up around 50% to 60% of your total project fee.
If you're looking for the best budget option...
A Velux conversion will be your best bet, as they make the most of your existing roof shape and require far less structural work than other loft conversions, helping to keep costs down.
If you're looking for the best space option...
A mansard conversion will give you the most headroom and floor area, without compromising on sloping ceilings like you would with a Velux conversion.
Ready to Get a Quote?
Once you've used the loft conversion cost calculator, the next step is to get quotes.
At MyJobQuote, you can get up to three free, no-obligation quotes from loft conversion builders near you. It's a quick and simple way to compare local tradespeople and find the right trader for you.
Factors That Impact Loft Conversion Costs
Here's a closer look at the cost factors that impact UK loft conversions to help you build a budget for your project:
Property Size
The size of your property, and how much loft space you already have, will have a big impact on your loft renovation costs.
Bigger lofts usually require more building materials, labour, and time, which can increase the cost. You'll also probably find that bigger spaces need additional structural work, which also increases attic conversion costs in the UK.
The shape and height of your loft can also make a difference to the overall cost.
Lofts with good head height tend to be easier and quicker to convert, whereas low-roof structures are usually more complex, meaning they're more time-consuming to work on.
Type of Loft Conversion
There are a number of loft conversion types in the UK, all with different benefits and drawbacks, which means their prices can vary.
When you're planning a loft conversion, you'll need to choose between:
- Roof Light Loft Conversion/Velux Loft Conversion — Often the most affordable option, working within your existing roof structure. These loft conversions tend to involve adding windows, insulation, flooring, and stairs.
- Dormer Loft Conversion — Hugely popular in the UK, created by extending part of the roof outwards to create additional headroom and floor space.
- Hip-to-Gable Loft Conversion — These involve altering the sloping side of the roof to create a vertical wall, increasing the amount of usable space inside.
- Mansard Loft Conversion — Typically the most expensive loft conversion option, requiring alterations to the roof structure, including raising party walls and creating a rear slope.
Simple loft conversions tend to be cheaper, whereas larger projects (meaning those involving major roof alterations, steel supports, and additional construction work) increase loft conversion costs.
Intended Use of the Space
The vision you have for your renovated space can also affect the overall cost of the loft conversion.
Layouts with minimal fixtures and fittings are usually cheaper, but rooms that require plumbing, electrical work, or bespoke features will usually cost more. The more features added to the loft, the higher the overall price is likely to be.
Lots of homeowners in the UK convert their loft into an en-suite bedroom, whereas others use the space as a home office, playroom, or extra living area. The cost of each differs. Creating an en-suite bedroom can have additional costs because of the extra plumbing, drainage, and bathroom installation work required.
For example:
- Adding an en-suite to your loft conversion can add £5,000 to £12,000 to your overall cost.
- A specialist space for an at-home gym can add between £1,500 and £3,000 for the structure alone.
- If you want to add a self-contained flat with plumbing and electrics, add £15,000 to £25,000 to your costs.
Additional Features
Many homeowners choose to add special features during a loft conversion, and these can have an impact on the final cost.
Though some additional features are straightforward, others involve extra labour, bespoke work, or more complex installation.
Popular features include en-suite bathrooms, built-in storage, roof windows/skylights, bespoke staircases, and underfloor heating.
Bespoke designs and complex specifications cost more. A standard staircase can cost between £1,500 and £2,500, while a bespoke staircase can be closer to £5,000+.
Regional Price Differences
Loft conversion costs vary depending on where you live in the UK.
Labour rates and construction costs tend to be higher in London and the South East, which makes loft renovation projects more expensive in these areas. You'll likely find the cost of a loft conversion is slightly lower elsewhere.
Here's how loft conversion costs per m² look in practice:
- London/Surrounding Areas — £1,800 to £2,700 per m².
- Midlands — £1,450 to £2,100 per m².
- South West — £1,550 to £2,200 per m².
- North — £1,250 to £1,900 per m².
- Wales — £1,400 to £1,900 per m².
- Scotland — £1,300 to £1,900 per m².
Ready for a personalised quote?
Using your exact location helps our loft conversion cost calculator to provide a more realistic estimate, with costs based on average prices in your area.
Why Use MyJobQuote?
Whether you're looking for dormer loft conversion costs or you're planning another type of loft renovation, using our cost calculator is one of the quickest ways to get quotes.
Instead of switching between different websites, MyJobQuote keeps all your results on one page, allowing for easy comparison between traders.
Why hire a professional builder for your loft conversion project?
Professional loft conversion specialists help to ensure the work is carried out safely and in line with UK building regulations, including:
- Ensuring the work is structurally safe.
- Complying with building regulations.
- Installing insulation, electrics, and plumbing correctly.
- Completing the project efficiently and safely.
Loft conversions often require builders, electricians, plumbers, roofers, and plasterers to work together, and hiring experienced tradespeople helps to ensure the conversion is completed to a high standard.
Last updated by MyJobQuote on 17th August 2026.
