FixMargin is commercial control software for UK drylining, ceilings and interiors subcontractors. The margin priced at tender rarely survives to the final account. Supplier prices move, call-offs drift from the BoQ, invoices don't match the order, and variations get done on site but never signed. By month-end nobody can say exactly where the money went. FixMargin keeps it in one place: • A costed BoQ generated from the manufacturer system — 3,054 British Gypsum, Knauf, Siniat and Fermacell systems broken down into components and quantities. • Supplier quotes compared on the same BoQ, normalised per sheet, per metre and per box. • Call-offs raised against the BoQ; supplier invoices checked against the order and the delivery. • A Gantt planner per job with material readiness. • Variations and daily site reports on the phone — photo, signature and PDF. • Priced vs committed vs claimed, per project, live. Public pricing, no "price on request". Built in the UK by someone who has delivered drylining and interiors packages. Send us one real BoQ and two supplier quotes — we'll show you the comparison on your own job in 30 minutes.