Quantity takeoff turns drawings into measured quantities (length, area, volume, count) for pricing and ordering.

Scope (quantity takeoff)

This page covers measuring work from drawings and specifications: lengths, areas, volumes, and counts for bills of quantities, procurement, and progress. In South Africa, contracts often reference standard methods of measurement (e.g. ARM for building, CESMM for civil works) and JBCC or bespoke preambles—always use the measurement rules and drawing list cited in your tender. The volume calculator is a geometry check for a rectangular prism; real takeoffs trace net quantities, waste, and method-specific definitions.

Volume from dimensions (concept)

  1. Confirm drawing revision and scale; measure from the correct view (plan, section, detail).
  2. Extract net internal dimensions or finished sizes per the method of measurement—do not mix gross and net without adjustment.
  3. For a prism, multiply L × W × H in consistent units (see calculator).
  4. Record the BoQ item, unit (m³, m², m, nr), and assumptions; link to takeoff software when used on the project.

Construction / Project Engineering — Quantity Takeoff (Measurements)

Turn drawings into measured quantities with clear rules, units, and audit trail.

Introduction

Quantity takeoff is the disciplined extraction of quantities for each work item: earthworks by cut/fill, concrete by element, finishes by area, and services by length or count. Accuracy depends on consistent interpretation of the specification, deductions for openings, and agreed waste and lap rules. Digital takeoff tools speed measurement and markup but still require engineering judgement on what the drawings show.

Cuboid in axonometric projection with edge lengths labelled a b c
Rectangular prism (cuboid)—volume = abc (align with L, W, H in the calculator). See licence on Wikimedia Commons
Construction drawing of a brick with dimension lines
Typical dimensioned element—takeoff reads nominal sizes from drawings/spec. See licence on Wikimedia Commons

What takeoffs feed

  • Bills of quantities — priced items for tender comparison.
  • Procurement — order quantities for materials and fabricated items.
  • Planning — productivity and duration when linked to outputs.
  • Variation assessment — baseline quantities for change evaluation.

Methods of measurement (South Africa)

Building work often uses ARM (or successor editions) with preambles; civil engineering may use CESMM-style breakdowns. Contracts specify units, what is included or excluded, and how to deal with provisional or prime cost sums. Always cross-check against the employer’s requirements and latest drawing register.

Volume of rectangular prism   V = L × W × H   (consistent units; here metres → m³).

Notation (common)

  • BoQ — bill of quantities.
  • Gross / net — before vs after deductions (openings, voids).
  • Waste — allowance for cutting and spoil per method rules.
  • nr — number (count) items.

Examples in practice

  • Structural concrete: formwork area vs concrete volume vs reinforcement mass (different items).
  • Earthworks: bulk vs compaction and cart-away vs fill from borrow.
  • Finishes: wall and floor areas with skirting and deduction rules.
  • MEP: cable and pipe runs by route length and fitting counts.

Calculator — volume (rectangular prism)

Enter L, W, and H in metres; output is V = LWH in m³.

V = L × W × H

Rectangular prism

Volume V = L × W × H for a cuboid from edge lengths in metres.

Key terms

Bill of quantities (BoQ)
Structured list of work items with quantities and units for pricing.
Takeoff sheet
Working record of measurements and calculations supporting BoQ lines.

Software and digital takeoff

2D/3D measurement, collaboration, and export to estimating packages are common on larger projects. Examples (official sites):

No product endorsement—confirm licence coverage, audit trail, and export format with your employer’s systems and procedures.

Diagram sources

Educational figures. Files in Images/quantity-takeoff-measurements/ were downloaded from Wikimedia Commons into this repo (not copied from other topic folders). Confirm licence on each Commons file page before reuse.