Use our comprehensive Loft Conversion Cost Calculator to get a quick and reliable estimate for your home renovation project. Input your desired area, conversion type, and finish quality to determine the estimated total investment.
Loft Conversion Cost Calculator
Estimated Total Cost
Loft Conversion Cost Calculator Formula
Variables
- Floor Area to be Converted (sqm): The total floor space you plan to create. This is the primary driver of material and labor costs.
- Type of Loft Conversion: This factor dictates structural complexity. Velux is cheapest, Dormer is mid-range, and Mansard is the most complex and expensive.
- Quality of Finish: Determines the cost of internal materials (insulation, flooring, fixtures, bespoke joinery). Standard, Mid-Range, or High-End finishes apply a corresponding cost multiplier.
- Include an Ensuite Bathroom: Adds a fixed, estimated cost to cover plumbing, tiling, and sanitary ware installation.
What is a Loft Conversion Cost Calculator?
A Loft Conversion Cost Calculator is an essential tool for homeowners planning to expand their living space into the unused attic area. It provides a data-driven estimate based on key variables like the size of the conversion and the specific type of construction required (e.g., Dormer or Mansard). The goal is to budget accurately and understand the potential financial investment needed before consulting architects and builders.
Costs for a loft conversion can vary dramatically depending on location, existing roof structure, and the level of luxury desired. This calculator helps to standardize the initial budgeting process by applying common industry cost per square meter figures and adjusting them using multipliers for complexity and finish quality.
How to Calculate Loft Conversion Cost (Example)
- Determine Area: Assume a conversion area of 30 sqm.
- Select Type & Quality: Choose a Dormer Conversion (Multiplier: 1.3) and a Mid-Range Finish (Base Cost: £1,500/sqm).
- Calculate Base Cost: \( 30 \text{ sqm} \times £1,500/\text{sqm} \times 1.3 = £58,500 \).
- Add Features: Decide to include an Ensuite Bathroom (Fixed Cost: £8,000).
- Total Estimated Cost: \( £58,500 + £8,000 = £66,500 \).
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Frequently Asked Questions (FAQ)
What is the difference between a Velux and a Dormer conversion cost?
Velux (or rooflight) conversions are the cheapest because they require minimal structural change—they simply use the existing roof line and add windows. Dormer conversions are more expensive as they involve building a vertical wall and flat roof section, which significantly increases head height and usable space.
Does location affect loft conversion costs?
Absolutely. Labor costs are significantly higher in London and the South East of England compared to other regions, which can increase the total cost by 15% to 25% or more.
What is usually included in the “Standard Finish” cost?
A standard finish typically covers basic flooring, simple plastering and painting, standard insulation, and basic electrical fittings (e.g., spotlights). It does not usually cover bespoke wardrobes or high-end fixtures.
Should I factor in contingency?
Yes. A loft conversion is a major construction project. It is highly recommended to add a 10% to 15% contingency fund to the estimated cost to cover unforeseen structural issues or unexpected changes during the build.