Instant Loft Estimate
Loft Conversion Cost Calculator
Choose your loft style, add your approximate measurements and get a guide price in under a minute. Free to use, no sign up needed.
Step 01
Pick The Loft Type
Dormer, Velux, hip to gable, mansard and L shaped conversions are all priced by the same calculator.
Step 02
Enter Dimensions
Use approximate width, depth and height measurements in metres. The result is a guide price, not a quote.
Step 03
Send It Through
Email the estimate to yourself or ask for a callback. We can then arrange a survey and a fixed price written quote.
Live Pricing Tool
Loft Conversion Cost Calculator
Choose your loft style, enter your approximate measurements and get an instant guide price. Free to use, no sign up needed.
Choose Your Loft Style
Once you choose a style and run the calculator, your guide price appears here, with the option to email it to yourself or ask for a callback.
What Affects The Cost Of A Loft Conversion?
The calculator gives you a realistic starting point, but the final price of a loft conversion always comes down to a handful of practical factors. Understanding them helps you read your estimate and compare quotes properly.
Conversion Type
Velux (roof window) conversions keep the existing roof structure and sit at the lower end. Dormers add headroom and floor space for a higher spend, while hip to gable, mansard and L shaped conversions involve the most structural work.
Size & Structural Work
Floor area drives materials and labour, but so does what holds it up. Steel beams, floor strengthening and the staircase position all shape the price more than most people expect.
Bathrooms & Finish
Adding an en suite brings plumbing and drainage into the project, and the specification you choose, from flooring to fitted storage, moves the final figure in either direction.
Planning & Building Regulations
Many loft conversions fall under permitted development, but building regulations approval is always required. We confirm the planning position before work starts and manage sign off as part of the project.
Loft Conversion Types Compared
Each loft type changes the roof in a different way, which is why the calculator prices them separately. Pick the one closest to what you have in mind and run the calculator for a guide price.
Dormer Loft Conversion
A popular rear roof expansion that opens up head height and gives strong, everyday usable floor space.
Work out the Dormer guide priceL-Shape Dormer Loft Conversion
Ideal where the roof layout supports a wider new upper floor, giving a better arrangement across the loft.
Work out the L-Shape Dormer guide priceHip to Gable Loft Conversion
Often chosen for end or detached homes that need more roof width, turning sloping roof geometry into a more useful room shape.
Work out the Hip to Gable guide priceVelux Loft Conversion
A simpler route where the existing roof volume already lends itself to extra accommodation, so the roof shape stays largely unchanged.
Work out the Velux guide priceMansard Loft Conversion
A larger change to the roof, designed to create the most additional space and a fuller loft transformation.
Work out the Mansard guide priceLoft Conversions Near You
Introspec Construction is based in Preston. Read more about our loft conversions, or send us your estimate with your postcode and we will confirm whether we cover your area.
See loft conversions in Preston, Penwortham, Leyland, Chorley, Blackpool and Blackburn.
Cost Calculator FAQs
How accurate is the loft conversion cost calculator?
It gives a guide price from the loft type and the approximate measurements you enter, using the same pricing engine every time. Every loft is different, so the final figure comes from a survey followed by a fixed price written quote.
Does the calculator price include VAT?
No. The guide price the calculator shows is before VAT. Your written quote sets out the VAT position.
Is the calculator figure a quote?
No. It is a guide price to help you plan. After a survey you get a fixed price written quote, and that quote confirms the price. Timescales depend on the size and type of project and are confirmed in your written quote.
How do I measure my loft for the calculator?
Measure the width and the depth of the loft floor, and the height from the top of the ceiling joists to the underside of the ridge at the highest point. Approximate figures in metres are fine for a guide price. The survey takes exact measurements.
What is the cheapest type of loft conversion?
A Velux (roof window) conversion is usually the lowest cost, because the existing roof shape stays largely unchanged. Dormer conversions add more headroom and floor space for a higher spend, while hip to gable, mansard and L shaped conversions involve the most structural work and sit at the upper end.
What affects the cost of a loft conversion the most?
The biggest factors are the conversion type, the size of the space, the structural work involved (steels and floor strengthening), whether you add an en suite bathroom, the staircase design, and the level of finish. Building regulations approval is always required and is handled as part of our managed process.
Can I get a loft conversion price for my area?
Yes. Send the estimate to us with your postcode and we will confirm whether we cover your area and arrange a survey. We are based in Preston and cover Preston and Lancashire, the Fylde Coast, Greater Manchester, Warrington and parts of Cheshire and Merseyside.
Ready for a number you can build on? Ask for a survey and quote or call 07809 467 644 and we will turn your estimate into a fixed price written quote.