The fundamental distinction: lump sum against unit rates
The difference lies not in the form, both are tables structured by item, but in the nature of the commitment created between client and contractor.
Under a global fixed-price contract, priced through a lump-sum pricing schedule, the contractor undertakes to carry out everything described in the specification for the amount it has entered. If the real quantities turn out to exceed what it allowed, that is its risk: differences between the quantities carried out and those in the breakdown do not alter the lump-sum price (CCAG-Travaux 2021, art. 10.3.1, for a public contract that refers to it). An additional payment requires a change ordered in due form. On a public contract, this is a written site instruction, approved beforehand by the client where it comes from the design team and modifies the amount (art. 3.8.1), which opens a right to fair remuneration at new prices set under article 13 (art. 3.8.6; public procurement code, L2194-3). On a private lump-sum contract, within the meaning of article 1793 of the Civil Code (construction of a building to a plan settled and agreed with the landowner), there must be a change authorised in writing and a price agreed with the client, two cumulative conditions.
Under a remeasurable contract, priced through a bill of estimated quantities, the contractor enters a rate for each unit of work, the cubic metre of concrete, the linear metre of excavation, the square metre of render. Final payment is calculated by multiplying those rates by the quantities actually carried out, measured after the works. If the real quantities exceed the estimates, it is the client who pays the difference.
Comparison
| Criterion | Lump-sum pricing schedule | Priced bill of quantities |
|---|---|---|
| Type of contract | Global fixed price | Remeasurable, unit rates |
| What the contractor enters | A lump sum per item | A unit rate per item of work |
| Final payment | The fixed sum, subject to variations | Actual quantities × unit rates |
| Quantity risk | Carried by the contractor | Carried by the client |
| Comparison between offers | Item by item on the lump sums | On unit rates and the anticipated total |
| Recommended use | Well-defined work, known quantities | Uncertain or evolving quantities |
| Example packages | New-build structure, mechanical services, finishes, joinery | Earthworks, demolition, heavy refurbishment |
| Handling variations | Additional work sits outside the lump sum | Quantities can change without a variation if the contract so provides |
ℹ The golden rule The lump-sum schedule transfers the quantity risk to the contractor. The priced bill keeps it with the client. Choose the schedule when quantities are well known and the project well defined. Choose the bill when quantities are uncertain or depend on ground conditions unknown at tender.
Example of a lump-sum schedule: structural package, extract
Here the contractor enters a lump sum for each item. If it has misjudged the quantities for item 01.04 it cannot claim more, that is its entrepreneurial risk.
| No. | Item | Lump sum excl. VAT (€) | Notes |
|---|---|---|---|
| 01.01 | Earthworks and general excavation | To be completed | Includes disposal of spoil |
| 01.02 | Foundations, strip and pad footings | To be completed | To the engineer's drawings |
| 01.03 | Masonry to elevations, all levels | To be completed | 200 mm blockwork or equivalent |
| 01.04 | Floors, beam-and-block or solid slab | To be completed | All levels including the fifth |
| 01.05 | Reinforced concrete stairs, 4 flights | To be completed | Balustrades excluded, package 08 |
| 01.06 | Slabs and levelling screeds | To be completed | Ground floor and parking |
| 01.07 | Site set-up and cleaning | To be completed | Lump sum, structural package |
| TOTAL PACKAGE 01: STRUCTURE, EXCL. VAT | To be completed |
Example of a priced bill: earthworks package, extract
Here the contractor enters only its unit rates. The anticipated amount is calculated by the economist as quantity × rate, but is not a firm commitment: if the excavation reveals a greater volume than foreseen, the package will be paid on the real quantities.
| No. | Item | Unit | Estimated quantity | Unit rate excl. VAT (€) | Amount excl. VAT (€) |
|---|---|---|---|---|---|
| 01.01 | Bulk excavation, ordinary ground | m³ | 480 | To be entered | n/a |
| 01.02 | Fine excavation to trenches | m³ | 120 | To be entered | n/a |
| 01.03 | Loading and removal of spoil to a licensed tip | m³ | 580 | To be entered | n/a |
| 01.04 | Trench excavation for strip footings | m³ | 95 | To be entered | n/a |
| 01.05 | 50 mm blinding concrete under foundations | m² | 210 | To be entered | n/a |
| 01.06 | Reinforced concrete strip footings 300 × 600 | linear m | 85 | To be entered | n/a |
| ANTICIPATED TOTAL, PACKAGE 01 | n/a |
Note: the estimated quantities in a priced bill are established by the economist from the project and serve only to calculate an indicative amount for comparing offers. They are not a contractual commitment on the real quantities.
Particular cases and combinations
The mixed contract: a schedule for some packages, a bill for others
It is entirely common, and often advisable, for a single tender to use a lump-sum schedule for the packages whose quantities are well defined and a priced bill for those carrying risk. On a heavy refurbishment, for instance: a schedule for the external joinery and the services packages, whose scope is defined, and a bill for the demolition and earthworks, whose quantities depend on the state of the existing fabric.
The detailed schedule as an analysis tool
A pricing schedule can be more or less detailed. One with a single item per package ("structural package, lump sum: … €") permits no comparative analysis. One broken into six to ten items per package lets the economist spot under- or over-priced items during the tender analysis and steer the negotiation towards where savings are available.
The schedule used for interim payment
On some contracts the administrative conditions provide that the schedule submitted by the contractor also serves to calculate the monthly valuations, each item being valued at its percentage of completion. The structure must then be fine enough to allow a realistic assessment of progress item by item.
ℹ The trap of a priced bill on a public contract On public projects a poorly established bill can generate serious dispute if the real quantities significantly exceed the estimates. It is not the public procurement code that governs variations in quantities but the CCAG-Travaux 2021, for contracts that refer to it, and it opens a right to compensation, not a renegotiation of the unit rate. Under a remeasurable contract, if the value of the works exceeds the contract amount by more than 25 %, or falls below it by more than 20 %, the contractor is entitled to be compensated in the final account for any loss it may have suffered beyond those limits, which are 5 % under a lump-sum contract (art. 14.3 and 15.1). If the quantities of a type of work increase by more than a third or decrease by more than a quarter against the bill of estimated quantities, as a result of site instructions or of circumstances that are neither its fault nor its doing, it is entitled to the same compensation (art. 16.2). Modifications to the contract are, for their part, governed by the code (L2194-1 and R2194-1 to R2194-9). The economist must establish the estimated quantities with all possible rigour, and set out in the administrative conditions the rules applicable if they are exceeded.
The effect on tender analysis
The choice between the two has a direct effect on how the economist analyses the offers.
On a lump-sum package, the analysis focuses on the coherence of the breakdown: are the items properly valued? Are there abnormally low items suggesting deliberate under-pricing? A competitive overall offer can hide a front-loaded price structure that will be recovered through variation claims.
On a remeasurable package, the analysis bears on the unit rates: are they consistent with the market? Some contractors practise a strategy of unbalanced pricing, very low rates on the items whose quantities are likely to fall, very high rates on those that could rise. That strategy is hard to detect without close analysis and can prove very costly to the client if the movements go the contractor's way.
In summary
The lump-sum pricing schedule and the priced bill are instruments of different natures, whose contractual value depends on the list of contract documents: the schedule breaks down a lump-sum price, which differences in quantities do not alter; the bill applies unit rates to estimated quantities, and it is the quantities carried out that are paid. The schedule fixes a lump sum whose quantity risk belongs to the contractor, the bill fixes unit rates whose quantity risk returns to the client. The choice depends on how well defined the work is and how uncertain the quantities are. A single tender can and should use both, package by package, to allocate risk optimally. In either case, the quality of the structuring, number of items, consistency with the specification, level of detail, directly governs the quality of the tender analysis.
The nature of the figures quoted
Amounts and rates set by a text are quoted with their article and their date. The other percentages and amounts on this page, dated benchmarks or a fictitious example, are orders of magnitude for framing, not measurements: they substitute neither for a tender exercise nor for an estimate prepared on drawings.
Sources: the BT construction cost indices published monthly by INSEE on its 2010 base, used to update the figures · construction cost statistics from SDES, the statistical service of the ministry responsible for construction · regulatory texts published in the Journal officiel and consolidated on Légifrance for the requirements cited.