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Gravel Calculator
Computes the volume of loose aggregate needed to cover an area to a given depth and converts it to weight with a typical bulk density for gravel, crushed stone, sand, topsoil or mulch (or a custom density).
When to use
You need to order gravel, crushed stone, sand, topsoil or bark mulch by volume (m³, yd³) or by weight (tonnes, US tons) for a driveway, path, bed or sub-base.
Do not use when: The material is concrete (use concrete-slab) or you need the density of a specific product: use the supplier's figure via material = custom and density_t_per_m3.
Formula
area = length × width (or area); volume_m³ = area_m² × depth_m; yd³ = m³ / 0.764555; tonnes = m³ × density_t_per_m³; short tons = tonnes × 1.10231. Densities: gravel 1.6, crushed stone 1.6, sand 1.5, topsoil 1.2, mulch 0.4 t/m³.
Loose bulk densities vary with moisture and grading (dry gravel ≈ 1.68 t/m³, dry sand ≈ 1.56 t/m³, loose earth ≈ 1.22 t/m³ per Engineering ToolBox); compacted sub-base settles by 10–20 %, so order extra for compacted layers.
Inputs
| Parameter | Type | Unit | Required | Description |
|---|---|---|---|---|
unit_system | enum: metric | imperial | default metric | Unit system of the length inputs (metric: m / cm / mm; imperial: ft / in). Outputs are reported in both systems. | |
length | number | m or ft | no | Length of the area (m or ft). Give length and width, or area. Range: > 0, ≤ 10000 |
width | number | m or ft | no | Width of the area (m or ft). Range: > 0, ≤ 10000 |
area | number | m² or ft² | no | Area to cover (m² or ft²); used instead of length × width when given. Range: > 0 |
depth | number | cm or in | yes | Depth of the layer in centimetres (metric) or inches (imperial). Typical: 5 cm / 2 in decorative gravel, 10–15 cm / 4–6 in driveway base, 7.5 cm / 3 in mulch. Range: > 0, ≤ 500 |
material | enum: gravel | crushed_stone | sand | topsoil | mulch | custom | default gravel | Selects a typical loose bulk density in tonnes per cubic metre. | |
density_t_per_m3 | number | t/m³ | no | Bulk density in tonnes per m³ (= kg/L); required for material = custom and overrides the preset otherwise. Range: > 0, ≤ 10 |
Outputs
| Output | Type | Unit | Description |
|---|---|---|---|
area_m2 | number | m² | Area covered. |
volume_m3 | number | m³ | area × depth. |
volume_cubic_yards | number | yd³ | Same volume in cubic yards. |
volume_cubic_feet | number | ft³ | Same volume in cubic feet. |
density_used_t_per_m3 | number | t/m³ | Bulk density applied. |
weight_tonnes | number | t | volume_m3 × density (metric tonnes). |
weight_kg | number | kg | Weight in kilograms. |
weight_us_tons | number | US short tons | Weight in US short tons (1 t = 1.10231 short tons). |
Example
10 m × 5 m of gravel, 5 cm deep: {"unit_system":"metric","length":10,"width":5,"depth":5,"material":"gravel"} → {"area_m2":50,"volume_m3":2.5,"volume_cubic_yards":3.27,"volume_cubic_feet":88.29,"density_used_t_per_m3":1.6,"weight_tonnes":4,"weight_kg":4000,"weight_us_tons":4.409}
20 ft × 10 ft of mulch, 3 in deep: {"unit_system":"imperial","length":20,"width":10,"depth":3,"material":"mulch"} → {"area_m2":18.58,"volume_cubic_feet":50,"volume_cubic_yards":1.852,"volume_m3":1.416,"weight_tonnes":0.566,"weight_us_tons":0.624}
GET https://tttkmbb.com/api/v1/calculate/gravel?unit_system=metric&length=10&width=5&depth=5&material=gravel
Machine access
- API:
GET https://tttkmbb.com/api/v1/calculate/gravel(query parameters) orPOSTwith a JSON body{"inputs": {...}} - Schema: https://tttkmbb.com/api/v1/calculators/gravel · Markdown: https://tttkmbb.com/construction/gravel.md · JSON definition: https://tttkmbb.com/construction/gravel.json
- MCP: server
https://tttkmbb.com/mcp, toolrun_calculator with calculator_id="gravel" - OpenAPI operationId:
estimate_gravel_volume - Freshness:
static. Authentication: none. Rate limit: fair use (see rate limits).
Sources
- Engineering ToolBox – Densities of dirt, mud, gravel and sand (reference)
- Wikipedia – Bulk density (reference)
FAQ
Do suppliers sell by weight or volume?
Bulk aggregates are usually sold by the tonne or by the cubic yard/metre; a bulk bag holds about 0.5 m³ (≈ 0.8 t of gravel). Use whichever figure matches the supplier's price list.
How much extra should I order?
Add 5–10 % for uneven ground and spillage, and 10–20 % more for layers that will be compacted (road base, sub-base under paving).
Related calculators
- Concrete Slab Calculator — Concrete poured on the sub-base.
- Volume Converter — Convert between m³, yd³ and litres.
- Density Calculator — Mass from volume and density for other materials.