Construction Cost Plan: NRM1 Template, Worked Example, and How to Build One with AI

A construction cost plan is a structured, elemental estimate of what a building project will cost, built up from measured quantities and rates and refined at each design stage. Unlike a single lump-sum guess, a cost plan breaks the total into recognised elements (substructure, frame, external walls, services, and so on), so the client and design team can see where the money goes, test affordability against the budget, and control cost as the design develops. In UK practice cost plans follow the RICS New Rules of Measurement (NRM1), which give a common structure and set of definitions for order of cost estimates and formal cost plans.

This guide explains the NRM1 cost planning stages, what a cost plan contains, gives you a free cost plan template and a UK worked example, and shows how to build a preliminary cost plan in minutes with AI.

What a cost plan is for

A cost plan is not just a number for the client. It is the financial control document that runs alongside the design from the first sketch to the tender return. Its purposes are:

• Testing affordability. Does the emerging design sit within the client's budget? A cost plan answers this early, when changes are cheap.
• Controlling cost as the design develops. Each cost plan is compared against the last. If the frame has grown by 8 percent, the cost plan flags it before it reaches tender.
• Informing design decisions. When the team is choosing between two cladding systems or two structural options, the cost plan puts a price on each.
• Setting the pre-tender estimate. The final cost plan becomes the benchmark against which tender returns are judged. A return far above or below the cost plan is a signal to investigate.
• Supporting the business case. For public and institutional clients, the cost plan underpins funding approvals and value-for-money assessments.

The key idea is that a cost plan is a living document. It is prepared, then reconciled and reissued at each design stage, with a clear audit trail of what changed and why.

The RICS NRM1 cost planning stages

NRM1 (RICS New Rules of Measurement: Order of Cost Estimating and Cost Planning) defines how estimates and cost plans are structured and measured in the UK. It aligns with the RIBA Plan of Work stages, so the cost plan matures as the design matures.

The pattern is that early estimates rely on rates per square metre and benchmark data from similar projects, while later cost plans rely on measured quantities taken off the developing drawings. The further right you move, the more the estimate is built from real measurement and the tighter the expected accuracy.

What a cost plan contains

A formal cost plan is organised by element, following the NRM1 elemental structure. The main group elements are:

• Facilitating works. Enabling works needed before the main build: demolition, temporary works, specialist ground treatment.
• Substructure. Foundations, ground slabs, basement construction.
• Superstructure. Frame, upper floors, roof, stairs, external walls, windows and doors, internal walls and partitions.
• Internal finishes. Wall, floor, and ceiling finishes.
• Fittings, furnishings and equipment (FF&E). Fixed and loose fittings.
• Services. Sanitary, mechanical, electrical, lift and conveyor, protective and communication installations, builders work in connection.
• Prefabricated buildings and building units. Pods, modular elements.
• Work to existing buildings. Alterations, repairs, and works to retained structures.
• External works. Site works, drainage, external services, landscaping.

On top of the measured elements, a cost plan adds:

• Main contractor's preliminaries. Site management, welfare, plant, scaffolding, and running costs, usually a percentage of the works.
• Main contractor's overheads and profit (OH&P). A percentage addition.
• Project and design team fees. Consultant fees, surveys, and charges.
• Other development costs. Planning fees, Section 106 or Community Infrastructure Levy, insurances.
• Risk allowances. Design development risk, construction risk, employer change risk, and other project-specific risks (NRM1 treats these explicitly rather than hiding them in a single contingency).
• Inflation. Tender price inflation to the midpoint of construction, and construction inflation beyond that.

Setting risk and inflation out explicitly is one of the most important disciplines NRM1 introduced. A cost plan that folds everything into a vague 5 percent contingency is far weaker than one that names each risk and prices it.

A worked cost plan example

Here is a simplified order of cost estimate for a small UK project, to show how the build-up works.

Project: New 2-storey community health centre, gross internal floor area (GIFA) 1,200 m2. Location factor and specification broadly mid-range. Estimate prepared at RIBA Stage 1 using cost per m2 benchmarks.

Two things are worth noticing. First, the building works figure is only about 64 percent of the final estimate: preliminaries, fees, risk, and inflation make up a large and often underestimated share, which is exactly why an early lump-sum "it's about 2.6 million" is dangerous. Second, the risk and inflation lines are explicit, so as the design firms up you can reduce the design risk allowance with confidence rather than guessing. As the project moves into Stage 2 and 3, the single "building works" line is replaced by measured elemental targets (substructure at X per m2, frame at Y per m2, and so on), which is where the elemental structure and a good cost plan template earn their keep.

Cost plan vs estimate vs bill of quantities

These terms are often blurred, so here is how they differ.

The cost plan is the bridge between the first rough estimate and the fully measured bill. It uses more measurement and firmer rates at each stage until, by the pre-tender estimate, it is close to a priced bill in detail. If you also need to produce measured quantities, the generate a bill of quantities workflow picks up where the cost plan leaves off.

How to build a cost plan faster with AI

Cost planning is measurement, benchmark data, and disciplined structure. AI does not replace the quantity surveyor's judgement or the firm's own rate library, but it removes a large amount of the assembly and drafting work that surrounds them.

A practical AI workflow for a preliminary cost plan looks like this:

1. Provide the project brief and parameters. GIFA, number of storeys, use class, location, specification level, and the target budget.
2. Ask AI to structure the cost plan by NRM1 elements and populate it with sensible cost-per-m2 targets for each element, clearly flagged as benchmark starting points to be replaced with your own rates.
3. Add preliminaries, OH&P, fees, risk, and inflation lines as explicit percentages so nothing is hidden.
4. Review and replace rates with your firm's data. This is the critical step: the AI gives you a complete, correctly structured skeleton, and you overwrite the numbers with your own benchmark rates and adjustments.
5. Generate the narrative. AI drafts the assumptions, exclusions, and basis-of-estimate notes that a good cost plan needs, so nothing is left implicit.

The result is that a QS spends their time on measurement, rate selection, and judgement, not on formatting spreadsheets and writing boilerplate. Our generate a preliminary cost plan workflow gives you the exact prompt, and the wider AI for cost estimation guide covers the surrounding estimating tasks. The full set of construction prompts is in the BuildCopilot Prompt Pack, and quantity surveyors will find the AI for quantity surveyors guide covers the broader role.

A word of caution: never let AI invent rates and present them as fact. Treat every AI-supplied number as a placeholder until you have replaced it with a rate you can stand behind. AI is excellent at structure, drafting, and checking for gaps; the numbers must come from real cost data.

Common cost planning mistakes

• Hiding risk in a single contingency. NRM1 asks you to name and price risks. A lump 5 percent contingency tells the client nothing and is hard to defend or reduce.
• Forgetting inflation. On a project running two or three years, inflation to the construction midpoint is a large number. Leaving it out understates the budget from day one.
• Underestimating preliminaries. Preliminaries can be 10 to 20 percent of works cost. A thin prelims allowance is a common cause of cost plans that look competitive but fail at tender.
• Comparing against the wrong benchmark. Rates from a different building type, region, or specification level will mislead. Adjust benchmark data for location, date, and specification before using it.
• Not reconciling between stages. The value of a cost plan is in the comparison. Each issue should reconcile against the last, explaining every significant movement.
• No clear basis of estimate. Assumptions, inclusions, and exclusions must be written down. A number without its basis is impossible to check or defend.

Free cost plan template

Use our free construction cost plan template to structure your estimate by NRM1 elements with the preliminaries, fees, risk, and inflation lines already in place. Pair it with the AI workflow above and your firm's rate data, and you get a complete, professionally structured cost plan in a fraction of the usual time.

Frequently asked questions

What is a construction cost plan?

A construction cost plan is a structured, elemental estimate of what a building project will cost, built up from quantities and rates and refined at each design stage. It breaks the total cost into recognised elements (substructure, frame, services, and so on) plus preliminaries, fees, risk, and inflation, so the client and design team can control cost as the design develops.

What is NRM1?

NRM1 is the RICS New Rules of Measurement: Order of Cost Estimating and Cost Planning. It is the UK standard that sets out how to structure and measure order of cost estimates and formal cost plans, aligned to the RIBA Plan of Work stages. It gives everyone a common elemental structure and consistent definitions.

What is the difference between a cost plan and a bill of quantities?

A cost plan is a design-stage cost control document that becomes more detailed as the design develops, moving from cost per square metre to measured quantities. A bill of quantities is a fully measured document issued at tender for contractors to price. The cost plan controls cost during design; the bill obtains and compares tenders.

What are the stages of a cost plan?

Under NRM1 the sequence is: an order of cost estimate at RIBA Stage 0 to 1, then formal cost plan 1 at Stage 2 (Concept Design), formal cost plan 2 at Stage 3 (Spatial Coordination), and formal cost plan 3 at Stage 4 (Technical Design), which becomes the pre-tender estimate. Each stage uses firmer measurement and rates than the last.

How accurate is a cost plan?

Accuracy improves as the design and measurement develop. An early order of cost estimate based on cost per square metre carries a wide margin, while a Stage 4 pre-tender estimate built from measured quantities should be close to the tender return. The explicit risk allowances in NRM1 are there to reflect this reducing uncertainty.

Can AI write a cost plan?

AI can structure a cost plan correctly by NRM1 elements, populate it with benchmark starting rates, add the preliminaries, fees, risk, and inflation lines, and draft the basis-of-estimate narrative. It cannot replace the quantity surveyor's measurement and rate judgement: every AI-supplied number should be treated as a placeholder until replaced with real cost data. Used this way, AI removes the assembly and drafting time while the QS keeps control of the numbers.