Estimated metric calculation: what it is and how to do it


Emma Potter

In the construction sector the estimative metric computation it is a document of fundamental importance, as it is useful for estimating the quantity and costs of carrying out a construction work. An essential document for quantifying materials and workmanship and also for defining the total expenses of a project.

Below we go into detail on the topic to better understand what it is and how to draft such a document.

Estimated metric calculation: what is it

The bill of quantities is therefore the useful document for estimating the costs of carrying out a building work, a document drawn up by the designer.

In matters of public works it is a mandatory document of final projects, but also widely used in private works as a contractual means to better regulate relationships between companies and clients.

The estimated metric calculation is concretely the result of a process aimed at determination of the amounts of individual interventions to arrive at the total amount of the works to be carried out.

Drawn up on the basis of a project, the bill of quantities is used both by the companies responsible for carrying out the construction works and by the clients of the works themselves. On the basis of these documents, companies have the opportunity to formulate their offer to carry out the works envisaged by the project and thus trace the construction site needs to carry out the planned works.

For their part, the clients, thanks to the metric calculation documents, have the possibility of correct and reliable financial planning regarding the investments to be made to complete the works.

Ultimately, a document which is difficult to ignore for the purposes of creating a work. Unlike the simple metric calculation, which is useful for providing details exclusively on measurements, the estimated metric calculation also reports partial and overall expenses.

Estimated metric calculation: what it contains

The estimated metric calculation is made up of a list with the following main items:

  • Description of the interventions to be carried out
    The document describes all the processes necessary to complete the project, specifying the techniques and materials required for each phase of the work.
  • Measures
    Detail of the exact measurements and quantifications necessary for the realization of the processes, which directly influence the calculation of quantities and costs.
  • Quantity of materials
    The exact quantities of all the necessary materials are listed, such as cement, bricks, iron, wood, etc. This allows you to estimate costs and organize supply logistics.
  • Unit prices
    For each material or resource used, the bill of quantities specifies the cost per unit. This can be based on standard price lists, market quotations or agreements with suppliers.
  • Discounts
    Application of any commercial discounts or promotions on materials, labor or equipment rental, which can reduce the total cost of the project.
  • VAT
    Calculation of the Value Added Tax applicable to the various costs of the project, both on materials and labour, essential for determining the final cost to the client.

In drafting this document it becomes very important to specify the units of measurement and precisely measure the environments subject to the building interventions.

No less important is the aspect relating to the calculation of VAT because, sometimes, often out of frivolity, we tend to do the calculations without considering it. Not considering VAT when estimating the costs of carrying out a construction work is a serious shortcoming.

Estimated metric calculation: how to do it

Having reached this point, having understood the concept and content of a bill of quantities, it is time to understand how it is done. For its drafting it is necessary to act in phases, namely:

  • classifying the processes;
  • measuring the processes;
  • estimating unit prices.

The first step in drawing up the bill of quantities is the classification of the processes into homogeneous job categories, with the clear aim of uniquely associating the qualitative descriptions of the processes with precise quantifications (measurements) and unit prices. Classifying the processes into work categories is fundamental for the purposes of drafting the bill of quantities because with the classification the correspondence between the categories and the physical parts of the work is achieved.

The next phase is instead attributable to the measurement of the processes, i.e. the evaluation of the correct quantity for each process useful for carrying out the project.

The last phase takes shape with the estimate of unit prices, another crucial phase for the purposes of an effective and reliable metric calculation. This price estimate occurs with the attribution of a unit price to each process, measured and descriptive. It is possible to carry out this estimate synthetically (price lists and lists) or analytically (price analysis).

With price analysis, the individual elements of an item are analysed, considering the unit cost and quantity of each element, to arrive at a unit value of the single process.

Estimated metric calculation: benefit

To fully understand the real importance of the bill of quantities, it is sufficient to go back to its main purpose: that of estimating the total costs of the building project. This is an essential tool for the following several reasons:

  • More precise estimates, the document provides a solid basis for estimates that are as reliable as possible. Interested parties can use the bill of quantities to calculate in detail the costs for materials and labor costs to be incurred for carrying out the works;
  • Budget monitoring, with the start of the project this document becomes a constant point of reference for monitoring the estimated budget. In this case, the bill of quantities is an ally against nasty financial surprises;
  • Containment of errors, a correct metric calculation helps to prevent mistakes in planning and carrying out building interventions. All those involved in the project have this document as a point of reference, from which they can understand exactly how to move and how to respond to the precise project requests;
  • Benefits for customers, the latter benefit from the estimated calculation because the document transparently photographs the costs to be incurred. For clients, an appropriate way to effectively plan the budget to invest in construction works.

All valid reasons testifying to the fact, regardless of whether it is obligatory or not, that the bill of quantities represents a point of reference for all parties involved in the building project.