Source: https://www.quantsurv.com/resources/glossary/rom Content format: Markdown version of the public page. Content reviewed: 2026-09-30 # ROM (rough order of magnitude): definition and example An early, rough estimate of cost, given before the design is developed enough to price properly. By [Jack Butler-Kettle]() · Updated 30 September 2026 Guidance for England and Wales. Check the contract, amendments and facts that apply to your job. ## What it means in practice Read this alongside [NRM 2: Detailed measurement for building works](). A rough order of magnitude is an early estimate based on limited information. It should state assumptions, exclusions, uncertainty and the purpose for which it can be used. It is different from an agreed quotation or a supported claim calculation, even when all three are expressed in pounds. Keep estimates clearly labelled as information develops. [Unpaid variation prevention]() helps distinguish early indications from instructed and agreed changes. ## Worked example ### The facts A specialist gives an initial £8,000 to £12,000 estimate before the revised design is issued. ### What happens 1. It records the assumed scope and explains why the figure is a range. 2. After receiving the design, it prepares a separate detailed quotation. ### What this shows The earlier estimate provides planning context without being represented as the final agreed price. ## Sources 1. [NRM 2: Detailed measurement for building works, UK 2nd edition, October 2021 (reissued October 2022 as RICS practice information)](). RICS.