Conversion Build Budget Estimator

Each system (insulation, electrical, water, heating, furniture) carries its own low/high range for the level chosen, scaled by van size — then furniture is scaled again if the build is commissioned rather than DIY, and a flat homologation/certification allowance is added if selected.

• Each category range is a rule-of-thumb aggregated from published 2026 van-conversion cost guides, expressed here at a 'medium van' baseline — not a quote from any workshop or supplier.
• Van size applies a multiplier to every category: a longer/taller van needs more insulation area, more cabinetry material and longer wiring runs at the same specification level.
• Commissioning furniture to a professional shop (instead of building it yourself) applies a labour multiplier, consistent with the 40-60%+ professional-build premium widely cited across conversion cost guides — carpentry sits at the higher end of that premium because it is especially labour-intensive.
• Homologation/certification is a flat allowance for inspection and paperwork, not scaled by van size — no single homologation regime is global (UK IVA, EU individual approval and national equivalents all differ), so treat this figure as illustrative only and confirm the real fee with your own country's registration authority.
• Build costs vary enormously by country, year and local labour market. This estimator gives an order of magnitude for planning a budget envelope, not a market tariff.