Specification with Bill of Quantities 2026

Specification with bill of quantities (BoQ): detailed itemised description of all construction works as the basis for comparable tenders.

Definition: The specification with bill of quantities is the form of works description that prevails in construction procurement, in which the contracting authority breaks down all the works to be carried out into individual, fully described items, which tenderers price using unit rates and whose sum produces the tender price.

Last updated: January 2026 · Legal basis: § 7a VOB/A (Germany), § 86 BVergG 2018 (Austria)

What is the specification with bill of quantities?

The specification with bill of quantities (BoQ) is the classic, and in practice most commonly used, instrument for describing construction works in public procurement. The bill of quantities breaks down the entire construction project into individual works items, each of which contains a precise description of the nature of the work, the materials used, the qualities required and the units of measurement to be invoiced. Tenderers price each item with a unit rate; the total price is calculated by multiplying quantity by unit rate across all items.

The legal basis in Germany is § 7a VOB/A, and in Austria § 86 BVergG 2018 in conjunction with ÖNORM B 2110.

Structure of the bill of quantities

A bill of quantities is hierarchically organised and must contain all the information relevant for pricing in a complete and unambiguous manner.

Basic structure

Bill of Quantities
├── Section 1 (e.g. earthworks)
│   ├── Item 1.1 – Excavation of pit (unit: m³)
│   ├── Item 1.2 – Disposal of excavated material (unit: t)
│   └── ...
├── Section 2 (e.g. concrete works)
│   ├── Item 2.1 – Concrete C25/30, base slab (unit: m³)
│   └── ...
└── Summary (tender total)

Components of an item

Item number: Unique identifier within the BoQ
Short text: Concise descriptive heading
Long text: Full technical description including material, quality, standard
Quantity: Quantity tendered in the relevant unit
Unit: m², m³, linear m, item, hour, lump sum
Unit rate (UR): Entered by the tenderer
Total price (TP): UR × quantity (calculated automatically)

Requirements for the specification

The bill of quantities must be unambiguous, exhaustive and competitively neutral so that all tenderers can price on the same basis.

In practice this means:

No product-specific descriptions that only one manufacturer can meet (lead products are admissible only in exceptional cases)
No contradictions between the bill of quantities and other procurement documents
Complete determination of quantities by the contracting authority
Clear distinction from ancillary services (to be performed without separate remuneration)

Unit-price contract and measurement

Under the unit-price contract, which corresponds to the BoQ principle, the quantity actually delivered is measured after completion and invoiced at the agreed unit rate.

The unit-price contract offers:

Flexibility for quantity changes during construction
Clear settlement based on actual works performed
Transparency in variation management

If significant deviations from the tendered quantities occur (in Germany: more than 10 % under § 2 (3) VOB/B; in Austria: more than 20 % under § 7 ÖNORM B 2110), tenderers may request an adjustment of the unit rate.

Standard works descriptions

Standardised works manuals are available to support consistent, competitively neutral descriptions of construction works.

Key reference works:

STLB-Bau (Germany): Standard works manual for construction – maintained by DIN and GAEB
ÖNORM works descriptions (Austria): Standardised works descriptions under the ÖNORM system
GAEB format: Standardised data exchange format for BoQ data

Distinction from the performance specification

The specification with bill of quantities differs fundamentally from the specification with performance programme: under the BoQ, the contracting authority bears full responsibility for design and quantity determination; under the performance programme, design responsibility lies with the tenderer.

FAQ

What are provisional items in a bill of quantities? Provisional items are works that are described in the BoQ but tendered with a zero quantity. They are only called off if the contracting authority actually requires them. The unit rate is nevertheless binding.

What happens if the contracting authority has forgotten a work item? Missing works that are evidently necessary for completion are, in Germany, generally owed under § 1 (4) VOB/B as so-called "forgotten items" and are remunerated through variations.

Is the BoQ protected by copyright? Yes. The bill of quantities prepared by the contracting authority or its designer can enjoy copyright protection. Tenderers may not pass on BoQ data to third parties without authorisation.

Last updated: January 2026 All information without guarantee. For legally binding advice please consult a law firm specialising in procurement law.