How to justify a construction quote increase to a hesitant client
The live-data scripts and worked examples to have an evidence-based conversation about why 2026 numbers are higher than 2022 numbers.
Source: ONS Construction Output Price Indices, via the Trails Cost Tracker. Values auto-refresh each quarter.
Every QS and principal has had the conversation. The client remembers a number from a friend's build or a project they half-priced three years ago, and the current quote looks offensive by comparison. The instinct is to defend the number with detail, overhead, spec. That often doesn't land. What does land is showing the client, with specific ONS figures, that their anchor isn't wrong for the time it comes from; the time has just moved on.
This guide gives you the live figures to use, a worked anchor converter to run their specific reference number through, and three response scripts keyed to how the conversation usually goes.
The Anchor Converter
Type in the client's reference number, the quarter it comes from, and the region. You get today's equivalent, pulled live from the ONS construction output price index, with the labour and materials contribution estimated.
Three scripts, keyed to your client's anchor
The conversation tends to follow one of three shapes. The key is not to argue the current quote upward. It's to move the client's anchor forward in time so the current quote stops looking like a surprise.
"Here's the same number, today"
"That's a reasonable reference. Let me show you what it would be if that project were priced today. Between then and now, the ONS construction output price index has risen by N/A, which means the same build today is around N/A rather than £100,000. That's not a Trails figure, that's ONS. Our quote sits inside that adjusted range."
When to use: the client's anchor is genuinely close in spec and scope to what you're quoting; the issue is just time.
"Here's what's changed"
"The rise isn't uniform. Materials rose hard in 2022, then stabilised; they're up N/A over the last year. Labour has been the bigger driver since then, up N/A year-on-year and still climbing. Your project is roughly 50% labour by value; that's where most of the increase sits. It's not contractors widening their margins, it's the underlying trade cost."
When to use: the client suspects the contractor is padding. Showing them the split separates the two questions.
"Here's what you can do"
"Three options if the number is outside budget. One, phase the work: do the structural elements now and fit-out in 2027. Inflation risk transfers to you, but so does the scheduling flexibility. Two, reduce spec: standard kitchen instead of bespoke, standard glazing rather than structural. That's a 10 to 15% saving on the finishing trades. Three, adjust scope: drop the most labour-intensive elements (bespoke joinery, complex roof, re-wiring beyond what's needed). Happy to price any of these if useful."
When to use: the anchor is real, the data is fair, the budget just doesn't stretch. Turning the conversation to scope keeps it constructive.
When the client's anchor is a friend's completed job
The tricky version: the reference isn't a quote, it's "my neighbour did theirs for X." That number is often remembered at below what it actually cost. A few reasons to be alert to:
- Optimistic recall. People remember the headline number from the contract, not the end cost. Variations, overruns, extras, VAT treatment, and client-supplied items get edited out.
- Different spec than is visible. The neighbour's extension might look similar but have simpler foundations, fewer service runs, standard glazing instead of structural, and builder's kitchen instead of bespoke. Cost differences of 20 to 30% hide behind similar-looking finished work.
- Older projects priced in different regimes. A project finished in 2020 was priced in 2019. Today's equivalent is materially higher, and the client is comparing a seven-year-old number to a current quote.
The script here is softer: "those numbers are often remembered from contract stage, and the finished cost can be 10 to 20% higher after variations. If we take even the headline figure and bring it forward, today's equivalent is in the range we're quoting." You're not calling the neighbour a liar; you're inviting the client to compare like with like.
When to walk away
A client who cannot or will not engage with the converted figure is telling you something. If after walking through the ONS adjustment and showing the labour/materials split they still describe your quote as "ridiculous" or "greedy" without engaging with the data, they're likely to be the same client during variations. The work is not worth the stress. A polite walk-away early costs less than a contested valuation late.
To run the underlying adjustment on any amount, period, or region, the live tool is the Cost Tracker.