FreeTools Labs Glossary
Concrete volume and materials
Learn how dimensions become a geometric volume and then a practical concrete quantity. Allowance and bag demand help put an order quantity into context.
Relevant tool
Concrete quantity starts with the geometry of the element, then separates base volume from an entered reserve and, where relevant, from whole-bag purchasing quantities.
Functions and inputs
Nine geometric forms are available: slab, block, wall, strip footing, round and rectangular columns, hollow cylinder/pipe, post hole and solid stairs. Lengths normalize to metres; results can be shown as m³, litres, ft³ and yd³.
Calculation model
The selected shape supplies the volume relationship before a reserve is applied to that geometric result: V = l × w × d; Vcyl = π × (d ÷ 2)² × h; Vtotal = Vbase × (1 + reserve ÷ 100).
How the calculator model works
A positive integer quantity multiplies the volume of one element. Reserve is an entered percentage applied after the base geometry; ready-mix keeps a volume result, while bagged concrete uses the entered product yield and rounds only the number of whole bags upward.
Checked examples
This checked slab calculation shows the distinction between base volume, reserve and rounded bag count: 5 m × 4 m × 0.1 m; r=10 % → 2.2 m³ = 2,200 L. ceil(301 kg ÷ 25 kg) = 13.
Units, display and interpretation
Volume can be read in metric or imperial display units, whereas bag output is deliberately rounded upward to complete bags: m³ · L · ft³ · yd³; whole bags use ceil, displayed quantities are formatted afterwards.
Scope and limits
The model does not supply a mix design, density substitute, price, reinforcement, strength class, footing design, frost depth, structural analysis or building-law assessment. Units and geometry must be entered consistently.