Articles
The complete guide
Automated Bill of Quantities: How Drawings Become Quantities
An automated bill of quantities is produced by software that reads construction drawings (DWG, PDF or IFC) and measures elements directly into billing units: structural steel and rebar in tonnes, concrete in cubic metres. Its value depends less on speed than on transparency. Every line should trace back to the drawing, and every unclear dimension should be asked about rather than assumed.
10 min read
Rebar
Rebar Quantity Calculation: From Bar Diameter to Tonnes
To calculate rebar quantity, measure the total length of bars for each diameter, including laps, hooks and bends, then multiply by the mass per metre of that diameter (about d²/162 kg/m with d in millimetres). Add up all diameters and report the result in tonnes. Rebar is billed by weight because its cost and handling follow mass, not length.
7 min read
Concrete
Concrete Quantity Calculation: Formulas for Every Element
To calculate concrete quantity, measure each element as a volume in cubic metres: length × width × depth for slabs, rafts, beams, columns, pedestals and footings, and π × r² × length for circular piles. Measure every element net, so that zones where elements meet are counted only once. The most common error is a slab thickness taken from the wrong place or not found at all.
7 min read
Workflow
Bill of Quantities Errors: 3 Silent Mistakes That Cost Money
The most expensive bill of quantities errors are the silent ones: dimensions that were assumed rather than read, elements counted twice across sheets, and elements that fall out of the takeoff entirely, such as piles or cages. None of them looks wrong on the page. Each can be caught before submission by tracing quantities to their source and treating every unresolved value as a question, not a default.
7 min read
Tools
Bill of Quantities Software: A Fair Comparison and What to Test
Bill of quantities software comes in two main forms: generic measuring tools, where an estimator still traces every element on screen, and AI that reads the drawings and extracts quantities itself. Both are measured against manual takeoff. Judge any tool on four things: output in your trade's units, traceability back to the drawing, how unclear items are handled, and how it performs on your own complex drawings.
7 min read
Steel
Structural Steel Quantities: How to Calculate Weight from Profiles
Structural steel quantities are calculated by weight: the length of each member multiplied by the mass per metre of its profile, taken from a standard section table, plus plates calculated from area and thickness. The result is summed and billed in tonnes. The main risks are a wrong profile, missing plates and connections, and conflicts between the plan and the section.
6 min read
Workflow
Bill of Quantities Checklist: 10 Checks Before You Submit
A bill of quantities checklist is a fixed routine run before every submission. The ten checks cover units against the contract, the latest revision of every sheet, drawing scale, duplicates across sheets, missing elements, typical details, contradictions, element groups, traceability and a final sanity review. Running the same list every time catches the errors that totals alone never reveal.
7 min read
Tools
DWG vs PDF vs IFC: Which Format Works Best for Quantities?
DWG files carry precise vector geometry, layers and blocks; PDF files are universal but range from clean vector sheets to flat scans; IFC models describe elements as objects with properties. Each can support a quantity takeoff, but none is complete on its own. The completeness of the drawing set, with plans, sections, elevations and typical details, matters more than the file format.
7 min read
Articles on bills of quantities
Practical guides for contractors, estimators and structural engineers: how to calculate rebar, concrete and steel quantities from drawings, how to catch errors before you submit, and what to test in a takeoff tool.
The complete guide
Automated Bill of Quantities: How Drawings Become Quantities
An automated bill of quantities is produced by software that reads construction drawings (DWG, PDF or IFC) and measures elements directly into billing units: structural steel and rebar in tonnes, concrete in cubic metres. Its value depends less on speed than on transparency. Every line should trace back to the drawing, and every unclear dimension should be asked about rather than assumed.
10 min read
Rebar
Rebar Quantity Calculation: From Bar Diameter to Tonnes
To calculate rebar quantity, measure the total length of bars for each diameter, including laps, hooks and bends, then multiply by the mass per metre of that diameter (about d²/162 kg/m with d in millimetres). Add up all diameters and report the result in tonnes. Rebar is billed by weight because its cost and handling follow mass, not length.
7 min read
Concrete
Concrete Quantity Calculation: Formulas for Every Element
To calculate concrete quantity, measure each element as a volume in cubic metres: length × width × depth for slabs, rafts, beams, columns, pedestals and footings, and π × r² × length for circular piles. Measure every element net, so that zones where elements meet are counted only once. The most common error is a slab thickness taken from the wrong place or not found at all.
7 min read
Workflow
Bill of Quantities Errors: 3 Silent Mistakes That Cost Money
The most expensive bill of quantities errors are the silent ones: dimensions that were assumed rather than read, elements counted twice across sheets, and elements that fall out of the takeoff entirely, such as piles or cages. None of them looks wrong on the page. Each can be caught before submission by tracing quantities to their source and treating every unresolved value as a question, not a default.
7 min read
Tools
Bill of Quantities Software: A Fair Comparison and What to Test
Bill of quantities software comes in two main forms: generic measuring tools, where an estimator still traces every element on screen, and AI that reads the drawings and extracts quantities itself. Both are measured against manual takeoff. Judge any tool on four things: output in your trade's units, traceability back to the drawing, how unclear items are handled, and how it performs on your own complex drawings.
7 min read
Steel
Structural Steel Quantities: How to Calculate Weight from Profiles
Structural steel quantities are calculated by weight: the length of each member multiplied by the mass per metre of its profile, taken from a standard section table, plus plates calculated from area and thickness. The result is summed and billed in tonnes. The main risks are a wrong profile, missing plates and connections, and conflicts between the plan and the section.
6 min read
Workflow
Bill of Quantities Checklist: 10 Checks Before You Submit
A bill of quantities checklist is a fixed routine run before every submission. The ten checks cover units against the contract, the latest revision of every sheet, drawing scale, duplicates across sheets, missing elements, typical details, contradictions, element groups, traceability and a final sanity review. Running the same list every time catches the errors that totals alone never reveal.
7 min read
Tools
DWG vs PDF vs IFC: Which Format Works Best for Quantities?
DWG files carry precise vector geometry, layers and blocks; PDF files are universal but range from clean vector sheets to flat scans; IFC models describe elements as objects with properties. Each can support a quantity takeoff, but none is complete on its own. The completeness of the drawing set, with plans, sections, elevations and typical details, matters more than the file format.
7 min read
