I’ve reviewed plenty of cost plans over the years and there can be a huge difference in quality. Some are little more than a spreadsheet populated with £/m² rates. Others provide clients with a robust commercial strategy that supports investment decisions throughout the project lifecycle.
The challenge for many clients is knowing the difference.
Most people only procure a major fit-out or refurbishment every five to ten years. They shouldn’t be expected to understand what sits behind the numbers. However, asking a handful of straightforward questions will quickly tell you whether your Cost Consultant has produced a robust piece of work or simply generated an estimate (or worse, use AI to do it for them).
A Budget Is Not a Cost Plan
One of the first conversations I have with clients is about the difference between a budget and a cost plan.
A budget simply defines how much money is available. A cost plan explains how that money is expected to be spent.
I often use the analogy of a cake.
The budget determines how big the cake is.
The cost plan determines exactly how it will be sliced.
It allocates funding across each building element, identifies where the major cost drivers sit, allows for inflation and risk, and develops alongside the design. As more information becomes available, confidence in the forecast should increase.
A cost plan is therefore much more than an estimate. It becomes the commercial framework against which every subsequent decision is tested.
First, understand what a cost plan is trying to achieve
The purpose of a cost plan is not to predict the final number to the nearest pound.
Its purpose is to give the client sufficient confidence to make informed decisions.
A good cost plan should answer some fundamental questions.
- Can we afford the current design?
- Where is the budget being spent?
- Which parts of the project present the greatest commercial risk?
- What happens if inflation changes?
- How much contingency is genuinely required?
If these questions cannot be answered clearly, the project is being managed with unnecessary uncertainty.
A cost report then performs a different role. It measures performance against the agreed cost plan and forecasts the likely outturn cost as the project progresses.
One establishes the commercial strategy.
The other monitors whether that strategy remains on track.
What does good cost planning look like?
Good cost planning is rarely about producing more information.
It’s about producing better information.
The strongest cost plans generally share several characteristics.
They are built from evidence rather than assumptions. Benchmarking should be supported by priced abnormals, recent tender returns, current market intelligence, measured quantities and supply chain feedback rather than relying solely on historical £/m² rates.
They become progressively more detailed as the design develops. Early cost plans inevitably contain assumptions, but these assumptions should reduce at every design stage as more information becomes available. Confidence in the estimate should therefore increase throughout the project.
They recognise that risk and inflation are dynamic rather than static. Construction inflation does not affect every trade package equally, and contingency should reflect identified project risks rather than being expressed as an arbitrary percentage.
Finally, they help clients make decisions before money is committed. This is where the advice provided by a Cost Consultant is fundamentally different to that provided by an agent or a contractor. A good Cost Consultant doesn’t simply report the cost of the chosen solution; they test alternative options, explain the commercial implications of each, and help the team maximise value from the available budget.
Ten questions every client should ask their Cost Consultant
1. How was this cost plan prepared?
A professional cost plan should explain the methodology used, the source of the data and the level of design information available when the estimate was produced. If this cannot be explained, confidence in the numbers should be reduced accordingly.
2. What assumptions have you made?
Every estimate contains assumptions. Good practice is to record them within a formal assumptions register so there is complete transparency about what has, and has not, been allowed for.
3. What has been excluded?
Understanding exclusions is just as important as understanding inclusions. Items such as IT infrastructure, statutory fees, loose furniture or landlord works are commonly omitted and can significantly affect the overall project budget if not identified early.
4. How have you allowed for inflation?
Inflation should not simply be applied as a single percentage across the entire project. Different trade packages experience different market conditions. Your Cost Consultant should be able to explain how those allowances have been derived.
5. How has contingency been calculated?
Contingency should reflect identified project risks rather than an arbitrary percentage. Ask which risks have been included, how they have been quantified and how contingency will be managed as the project develops.
6. Which elements of the estimate carry the greatest uncertainty?
No estimate is equally certain across every element. Mechanical services, specialist installations and provisional design packages often carry greater uncertainty than finishes or general building work. Understanding where those uncertainties exist allows better-informed decisions to be made.
7. Which trade packages have been tested with the market?
Market engagement is one of the best ways of validating an estimate. If key packages have been discussed with specialist subcontractors or compared against recent tender returns, confidence in the estimate increases significantly.
8. How will this cost plan evolve?
A cost plan should never become static. Ask how often it will be updated, how changes will be reconciled and whether each revision will clearly explain movements in cost, risk and inflation.
9. What would you change if the budget reduced by 10%?
This is often the question that separates experienced advisers from estimators. A good Cost Consultant should already understand the principal value drivers within the project and be able to recommend where savings can be achieved while protecting operational performance and long-term value.
10. How confident are you in these figures?
Perhaps the simplest question is also the most revealing.
An experienced Cost Consultant should be comfortable explaining where confidence is high, where uncertainty remains and what information is required to improve the estimate.
Final thoughts
Good cost planning is not about producing the lowest estimate or creating false certainty. It is about giving clients the information they need to make sound investment decisions with confidence.
The most successful projects I’ve worked on haven’t necessarily had the biggest budgets. They’ve had the strongest commercial foundations. Clear assumptions, realistic allowances, transparent reporting and informed decision-making create certainty long before work starts on site.
In my experience, that’s where a good Cost Consultant delivers the greatest value – not by counting costs, but by helping clients invest with confidence.
How EthosEQ Can Help
A robust cost plan is one of the most valuable tools a client has during the design process. It provides the commercial framework for investment decisions and helps prevent costly surprises later in the project.
We typically support clients by:
- Developing evidence-based cost plans using industry benchmarking and current market intelligence.
- Testing design options and providing cost advice as the design develops.
- Advising on appropriate contingency, inflation and project risk allowances.
- Preparing Pre-Tender Estimates to validate the design before it goes to the market.
- Reviewing tender returns, identifying pricing gaps and recommending the most commercially advantageous tender rather than simply the lowest price.
- Providing ongoing cost reporting and commercial advice throughout project delivery.
Our role is to provide independent advice that enables clients to make informed decisions with confidence, while protecting their commercial position from project inception through to final account.
Links
Using Cost Planning to Shape Design Decisions
RICS NRM: New Rules of Measurement
Copyright
© 2026 EthosEQ Limited. All rights reserved.
This publication is the intellectual property of EthosEQ Limited. No part of this document may be reproduced, stored in a retrieval system or transmitted in any form or by any means without prior written permission, except for brief quotations used for review, commentary or non-commercial educational purposes, provided EthosEQ is acknowledged as the source.
Disclaimer
This article has been prepared by EthosEQ Limited for general information purposes only. It reflects the author’s professional opinion and experience at the time of publication and is intended to promote good practice in cost management and project delivery.
The content does not constitute legal, contractual, financial or professional advice and should not be relied upon as the sole basis for making project or investment decisions. Every project is unique and should be assessed on its own commercial, technical and legal merits.
