Gravel Calculator

Estimate a uniform gravel layer

1. Choose Metric or Customary, then Rectangle or Known area. Enter metres and centimetres in Metric, or feet and inches in Customary. Changing profiles restores separate drafts; it does not convert the measurements you entered.
2. Enter the layer depth and an extra allowance from 0 to 50 percent. Leave bulk density blank for a volume-only estimate. For mass, supply density in kg/m³ or lb/ft³ that matches the material, moisture and packing state of the volume you are estimating.
3. Select Calculate. Read the adjusted volume and, if density was supplied, the conditional mass estimate. Copy includes the inputs and qualifications. Editing any input removes the old result; Clear resets both profiles. Use example fills a metric case, ready for you to calculate.

Volume, bulk density and material state

Base volume is area multiplied by depth in compatible units. The adjusted volume multiplies that base by one plus your extra percentage divided by 100. An allowance of zero leaves the base volume unchanged. No hidden waste or compaction percentage is added.

Bulk density means mass per bulk volume, including spaces between the particles. It is not the density of the stone particles themselves. Even a material property named bulk specific gravity is not automatically the heap density this field needs; do not fill it by multiplying specific gravity by water density.

Density changes with packing and moisture. A value for loose dry gravel is not automatically suitable for a wet or compacted layer. This calculator does not establish a loose-delivery-to-installed-volume conversion. Ask the supplier or project method which material state its quantity and density describe.

Every calculated quantity is approximate and shown to at most four significant digits. Very small or large values use scientific notation so a positive quantity is not displayed as zero. A metric tonne is 1000 kg; a US short ton is 2000 lb. The tool does not silently use a 2240-lb long ton.

Two unit-explicit examples

A 5 m by 3 m rectangle at 5 cm depth has a base volume of 0.75 m³. With a chosen 10 percent allowance, adjusted volume is approximately 0.825 m³. If a compatible bulk density is 1600 kg/m³, estimated mass is approximately 1320 kg, or 1.32 metric tonnes. The density and allowance are illustrative, not recommendations.

A 12 ft by 9 ft rectangle at 3 in depth and zero extra has a volume of 27 ft³, which is 1 yd³. With an illustrative compatible density of 100 lb/ft³, estimated mass is approximately 2700 lb, or 1.35 US short tons. Entering a known area of 108 ft² gives the same geometry.

If you know a 15 m² area and want a 5 cm layer, select Known area. With a 10 percent allowance the adjusted volume is approximately 0.825 m³. Leave density blank when it is unknown: you still get volume, but no invented weight or zero-mass result.

A quantity estimate, not a delivery or design guarantee

The model covers one area with a uniform depth. It does not choose a suitable construction depth, model slopes or changing thickness, or assess drainage, loads and structural suitability. Known area can come from another measurement method; this page does not design the shape.

There are no universal density presets, automatic compaction factors, bag counts, prices or multiple-layer totals. An extra allowance is your explicit choice, not a certified conversion between loose and compacted material. Check the compatible state, ordering unit and delivery terms with the supplier.

Measurements accept up to three fractional digits and extra up to two, using a dot or comma as the decimal mark, without thousands separators. Each raw field is limited to 32 UTF-16 units. The displayed input bounds are application limits, not proof of physical suitability; malformed supplied density blocks calculation rather than being ignored.

Keep project measurements in this tool

The tool does not upload measurements, put them in a shareable URL or save them in browser storage. Drafts last only while the tool remains open. Copy shares the current qualified estimate only when you choose it; this tool-specific behavior is not a claim that the whole site has no analytics.