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Every building cost calculator, priced for Northern Ireland
13 free calculators covering extensions, conversions, insulation, materials and outdoor works. All of them apply a regional multiplier from your postcode, and all of them show you the assumptions behind the number.
Extensions
Work out what an extension should cost in Belfast and across Northern Ireland, including professional fees and contingency.
Loft & Conversions
Convert space you already own. These calculators cover loft conversions, garage conversions and garden rooms.
Loft Conversion Cost Calculator
Free loft conversion cost calculator for Belfast and Northern Ireland. Rooflight, dormer, hip-to-gable and mansard prices with fees and contingency.
Garage Conversion Cost Calculator
Free garage conversion cost calculator for Belfast and Northern Ireland. Price a single or double garage with floor, insulation and door options.
Garden Room Cost Calculator
Free garden room and garden office cost calculator for Belfast and Northern Ireland. Price insulation, electrics, cladding, plumbing and the base.
Insulation & Energy
Estimate insulation quantities, installed cost, U-value improvement and indicative heating savings, using the same building physics as SAP and RdSAP assessments.
Loft Insulation Calculator
Free loft insulation calculator for Belfast and Northern Ireland. Rolls to order, installed cost, U-value before and after, and a realistic annual saving.
Wall Insulation Calculator
Free wall insulation calculator for Belfast and Northern Ireland. Compare cavity, external and internal insulation costs, U-values and realistic savings.
Materials
Quantity calculators for trades and self-builders. Tell us the dimensions and we will tell you what to order, how much of it, and roughly what it costs.
Brick Calculator
Work out how many bricks you need for any wall, plus packs, sand and cement, with 2026 Northern Ireland brick and bricklaying prices and full workings.
Concrete Calculator
Work out how much concrete you need for a slab, footing or post holes, with cement, sand and aggregate quantities and 2026 Northern Ireland prices.
Fencing Calculator
Work out how many fence panels, posts, gravel boards and postmix bags you need, plus installed cost at 2026 Northern Ireland rates. Free calculator.
Driveways & Outside
Northern Ireland outdoor works pricing, including Tobermore and locally supplied paving rates.
Driveway Cost Calculator
Free driveway cost calculator for Belfast and Northern Ireland. Block paving, tarmac, resin, gravel and concrete prices per square metre for 2026.
Patio Cost Calculator
Free patio cost calculator for Belfast and Northern Ireland. Indian sandstone, porcelain, concrete and natural stone prices per square metre, 2026.
Kitchen Renovation Cost Calculator
Free kitchen renovation cost calculator for Belfast and Northern Ireland. Price units, worktops, appliances, fitting, flooring and the rip-out.
Roof Replacement Cost Calculator
What a new roof costs in Belfast and Northern Ireland in 2026: concrete tile, clay, fibre-cement and natural slate, with scaffolding and stripping included.