Construction Area and Depth Quantity Reference
SiteCalculators · sitecalculators.net
Use this sheet for a quick independent quantity check. The tables deliberately separate measured geometry from material behaviour. Area and depth determine net volume. Waste, compaction, bulking, moisture and purchasing increments are separate decisions and are not hidden inside the tabulated values.
Metric area × depth reference
For square metres and millimetres, divide the depth by 1,000 before multiplying. Every volume in this table is a net geometric volume with no allowance.
| Finished depth | Depth in metres | Volume per 10 m² | Volume per 100 m² | Area covered by 1 m³ |
|---|---|---|---|---|
| 25 mm | 0.025 m | 0.25 m³ | 2.5 m³ | 40 m² |
| 40 mm | 0.040 m | 0.40 m³ | 4 m³ | 25 m² |
| 50 mm | 0.050 m | 0.50 m³ | 5 m³ | 20 m² |
| 75 mm | 0.075 m | 0.75 m³ | 7.5 m³ | 40/3 m² (13⅓) |
| 100 mm | 0.100 m | 1 m³ | 10 m³ | 10 m² |
| 125 mm | 0.125 m | 1.25 m³ | 12.5 m³ | 8 m² |
| 150 mm | 0.150 m | 1.5 m³ | 15 m³ | 20/3 m² (6⅔) |
| 200 mm | 0.200 m | 2 m³ | 20 m³ | 5 m² |
| 250 mm | 0.250 m | 2.5 m³ | 25 m³ | 4 m² |
| 300 mm | 0.300 m | 3 m³ | 30 m³ | 10/3 m² (3⅓) |
The fractions shown for repeating coverage values are exact. The quick rule is that every 10 mm of depth over 100 m² equals exactly 1 m³.
US customary area × depth reference
For square feet and inches, divide by 324 to obtain cubic yards. The 324 ft² column is especially useful because a 1-inch layer over 324 ft² is exactly 1 yd³.
| Finished depth | Depth in feet | Volume per 324 ft² | Volume per 1,000 ft² | Area covered by 1 yd³ |
|---|---|---|---|---|
| 1 in | 1/12 ft | 1 yd³ | 250/81 yd³ (3.086) | 324 ft² |
| 1½ in | 1/8 ft | 1.5 yd³ | 125/27 yd³ (4.630) | 216 ft² |
| 2 in | 1/6 ft | 2 yd³ | 500/81 yd³ (6.173) | 162 ft² |
| 3 in | 1/4 ft | 3 yd³ | 250/27 yd³ (9.259) | 108 ft² |
| 4 in | 1/3 ft | 4 yd³ | 1,000/81 yd³ (12.346) | 81 ft² |
| 6 in | 1/2 ft | 6 yd³ | 500/27 yd³ (18.519) | 54 ft² |
| 8 in | 2/3 ft | 8 yd³ | 2,000/81 yd³ (24.691) | 40.5 ft² |
| 12 in | 1 ft | 12 yd³ | 1,000/27 yd³ (37.037) | 27 ft² |
Fractions are the exact values; parenthesised decimals are rounded to three decimal places for field use. One cubic yard contains exactly 27 cubic feet.
Keep net volume and order volume separate
The reference tables report only the shape that is measured: a horizontal plan area multiplied by a uniform finished depth. If an allowance is justified, show it explicitly so another person can reproduce the check.
An allowance might cover trimming loss, local level variation, contamination, delivery increments or a stated construction tolerance. It does not automatically convert a loose delivered volume to a compacted placed volume. Use a project-approved conversion, supplier declaration or trial data when the material condition changes.
From volume to indicative weight
Density is not part of the area-by-depth geometry. Apply it only after volume has been calculated, and make sure the density describes the same material condition as the volume: loose, placed, compacted, laid or hardened. The values below are estimating starting points used by the SiteCalculators material tool; they are not product certificates.
US mass (short tons) = volume (yd³) × 27 × density (lb/ft³) ÷ 2,000
| Material | Density basis | kg/m³ | lb/ft³ | t per m³ | short tons per yd³ |
|---|---|---|---|---|---|
| Type 1 granular sub-base | Indicative compacted | 2,200 | 137.34 | 2.20 | 1.854 |
| 6F2 recycled aggregate | Indicative compacted | 2,000 | 124.86 | 2.00 | 1.686 |
| Asphalt / tarmac | Indicative laid | 2,350 | 146.71 | 2.35 | 1.981 |
| Normal-weight concrete | Indicative hardened | 2,400 | 149.83 | 2.40 | 2.023 |
| Gravel / shingle | Indicative loose | 1,650 | 103.01 | 1.65 | 1.391 |
| Dry construction sand | Indicative loose | 1,600 | 99.88 | 1.60 | 1.348 |
| Screened topsoil | Indicative loose | 1,300 | 81.16 | 1.30 | 1.096 |
| Crushed concrete | Indicative compacted | 2,100 | 131.10 | 2.10 | 1.770 |
Worked checks
Metric: Type 1 sub-base
A measured area of 600 m² at a uniform finished depth of 150 mm has a net geometric volume of 600 × 150 ÷ 1,000 = 90 m³. A separately stated 10% ordering allowance gives 99 m³. Using the indicative compacted density of 2,200 kg/m³ gives 217.8 t. Round an order only after checking supplier density, delivery capacity, layer specification, compaction evidence and commercial increments.
US customary: loose gravel
An area of 3,240 ft² at a uniform 4-inch depth has a net geometric volume of 3,240 × 4 ÷ 324 = 40 yd³. At the indicative loose density of 103.01 lb/ft³, that is about 55.6 US short tons before any allowance. This weight is approximate because moisture, grading and void ratio change actual loose density.
Geometry and use assumptions
- Plan area: area is measured horizontally. Surface area on a slope is not substituted unless that is genuinely the specified basis.
- Uniform depth: each table assumes a constant finished depth. Divide variable work into zones or use a measured strip or surface-volume method.
- Net shape: openings, ducts, pipes, kerbs and other exclusions are not deducted unless you deduct them from the plan area.
- No hidden factors: waste, bulking, settlement, shrinkage, compaction and purchasing allowance are all zero in the reference tables.
- Matching density basis: a loose density must not be applied to a compacted volume, or the reverse, without a verified relationship.
- Mass definitions: one metric tonne is 1,000 kg; one US short ton is 2,000 lb. This page does not use the 2,240 lb imperial long ton.
- Rounding: retain unrounded values through the calculation, then round to a precision justified by the measurement and ordering method.
Engineering-adjacent estimate: This reference supports quantity checking; it does not certify material compliance, finished levels, compaction, vehicle loading, structural capacity or a supplier order. Reconcile the result with current drawings, specifications, survey information, supplier data and competent project review.