Comparing contractor quotes: why they are never comparable, and how to analyse the bids

Why are three quotes for the same trade package never comparable?

Because in the absence of an imposed template, every tradesperson drafts their quote in their own format: their units, their quantities measured their own way, their scope of services, their ranges of materials and their options. Three quotes for the same trade package therefore describe three different projects, and lining up their totals amounts to comparing documents that are not talking about the same thing. Before any reading of prices, the bids have to be brought back to a common scope.

The divergences always hide in the same places:

• Units. A line item priced per square metre by one company, per linear metre by another, as a lump sum or an "ensemble" by the third. A lump sum is neither cheaper nor dearer than a unit price: it is unreadable until you know what it covers.
• Quantities. Each company measures or estimates on its own: 42 m² of painting for one, 55 m² for the other on the same walls, depending on whether ceilings and reveals are counted.
• Omitted or added services. Stripping out the existing, removing rubble, site protection, final cleaning: present here, absent there, rarely in the same place in the document.
• Material variants. "Acrylic paint, two coats" says nothing about the brand, the range or the preparation of the substrate. Two lines with the same wording can cover a two-to-one difference in quality.
• Unpriced options. "Subject to substrate condition", "excluding compliance upgrade", "to be defined": so many doors left open to extras that the displayed total does not show.

A lived example in electrical works: ask three electricians for a "compliance upgrade". The first prices a consumer unit and twenty-four outlets as one global lump sum. The second details every circuit, every socket, every light point. The third announces a "complete electrical renovation" as a single line item that includes, without saying so, the chasing and making-good that the other two leave to the drywaller. Three totals, three scopes, no comparison possible as they stand.

What is the difference between a DPGF and a quote?

A DPGF (décomposition du prix global et forfaitaire, the bill of quantities used on French private renovation projects) is a pricing template drawn up by the architect, which breaks the project down into trade packages and line items (each with its description, its unit and its quantity), and whose prices, left blank, are filled in by every company tendered. A quote, on the other hand, is the commercial document issued by the tradesperson, in their own format, with their own wording and quantities. The DPGF imposes the scope; the quote chooses it.

That is the whole difference. When you wait for free-form quotes, each company decides what it prices and how it presents it: you inherit the comparability problem described above. When you send an identical DPGF to every company, the scope is fixed once and for all: same line items, same quantities, same descriptions of the work. The bids that come back can then be read line by line, item against item, and the gaps become information instead of noise.

This is the heart of the tender process as we detailed it in our guide from the DPGF to the client's approval: the template is built from your estimate, the one produced at the works estimating stage, then goes out, prices blank, to at least two companies. The quotes remain the companies' contractual documents; the DPGF remains your analysis tool. The two coexist, they do not replace each other.

The bid analysis method, trade package by trade package

Bid analysis is a procedure, not a reading of totals. Here it is, in order:

1. Draw up the common template. One DPGF per trade package, line items described, quantities set, prices blank. This is what makes everything else possible.
2. Log the bids as they arrive. For each one: date of receipt, period of validity, conditions (deposit, lead times, reservations). A bid that has expired by decision time is worth nothing.
3. Level the bids. Spot the unpriced items, the quantities altered by the company, the added services. Price every gap (at the rate of the most detailed bid or of your own estimate) to bring all the bids back to the same scope. Without this step, the comparison is rigged from the start.
4. Compare line by line. Item by item: who is lowest, what is the gap against your estimate, who did not respond. An attractive total can hide a forgotten item; a high total can be explained by a more complete service on the package that matters.
5. Read for best value, not just for lowest price. The lowest bidder (moins-disant) is the bid with the lowest price, nothing more. The best-value bid (mieux-disant) is the bid with the best value for money, once completeness, the quality of the proposed services, lead times and the company's references are taken into account. The best-value bid is the one you recommend; the lowest bid, you explain.
6. Hand over the analysis report, and let the client approve. A written document: comparison per trade package, points of attention, reasoned recommendation. The choice belongs to the client: they approve the award: a dated agreement in principle, not the signing of an estimate. The contractual documents remain the companies' quotes.

Example: three bids on the same plumbing package, before levelling

A complete shower room, sanitaryware supplied by the client. Here are the three bids as they arrive, before any levelling:

On the totals alone, A looks like the lowest bidder. After levelling, the strip-out missing from its bid, priced at €480 elsewhere, takes its real total to €4,230: B is actually the cheapest, and the only complete bid. As for C, its "package" lump sum is neither expensive nor cheap: it is incomparable until it is broken down, and it is up to the company to detail it. If you had awarded to A on its displayed total, the missing €480 would have resurfaced mid-project as additional works — at full price, and without competition this time.

What should you do with price gaps between bids?

Gaps are the raw material of the analysis, provided you know how to read them. Context first: according to an OpinionWay study for the French renovation network illiCO travaux, reported by Journal de l'Agence (May 2026), one renovation project in three exceeds its initial budget. And according to the French consumer association UFC-Que Choisir, cited in the same coverage, those overruns average 20 to 30 % of the initial quote. The illiCO travaux network itself recommends keeping a contingency of 10 to 15 % of the total works budget (MySweetImmo, 31 May 2026). In other words: budget drift is very often born at the moment the bid is chosen, not halfway through the works.

On a given line item, a gap of more than 20 to 30 % between two levelled bids is not a bargain: it is a signal. Three explanations come up almost every time:

• A misread quantity. The company priced 20 m² where the template says 35, or the reverse. The error is fixed with one email, before the award, not after.
• A service not included, or not understood. "Substrate repair" can mean a localised filler or a full skim coat. The same words, two very different scopes.
• A loss-leader bid. A deliberately low price to win the project, to be clawed back along the way through additional works. This is the most expensive scenario, because it only reveals itself once the company is on site.

In all three cases the answer is the same: a gap gets questioned, not taken. Putting the question to the company in writing ("your item X is 40 % below the two other bids, can you confirm the scope?") costs five minutes and avoids the regularisations. While you are at it, check that the bids are stated at the same VAT rate, a trap we covered in our guide to French VAT at 10 or 20 %. And an abnormally low price should also trigger a check of the company's paperwork, ten-year liability insurance first: see our checklist for vetting a contractor before hiring. Picking a bid on the sticker price alone is, in fact, one of the 7 mistakes that blow up a renovation budget, and it is rarely the cheapest option in the end.

So, what about Nodal?

Nodal equips this method end to end: the template (DPGF) goes out identical to every company tendered, the returns are entered or imported without retyping, and the comparison happens line by line, online, with gaps and unpriced items flagged. The award is made per trade package, the bid analysis report is generated with your comments and your reasoned recommendation, and the client approves the selected bid from their own portal. A time-stamped approval, never the signing of an estimate.

Tenders run in Nodal are also building, project after project, a base of real price gaps between bids, per trade package. We will publish a barometer of price gaps between contractor quotes as soon as the sample is statistically significant. No French data of this kind exists today.

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