CalculationTime

Gravel Calculator

Live math canvas

Your numbers, formula and explanation together

Gravel Calculator: 70.6 cubic metres and tonnes. Gravel Calculator uses the declared inputs to produce a transparent default result. Length: 6 metres; Width: 3 metres; Depth: 50 millimetres; Allowance: 10 percent; primary comparison: 6 and 3.

Formula applied

The exact method behind this answer

CalculationTime keeps the method visible so the number can be checked instead of blindly trusted.

Base volume = length × width × (depth millimetres ÷ 1,000). Order volume = base volume × (1 + allowance percent ÷ 100). Estimated tonnes = order volume × bulk density in tonnes per cubic metre.
  1. Apply the formulaBase volume = length × width × (depth millimetres ÷ 1,000). Order volume = base volume × (1 + allowance percent ÷ 100). Estimated tonnes = order volume × bulk density in tonnes per cubic metre.70.6 cubic metres and tonnesGravel Calculator uses the declared inputs to produce a transparent default result. Length: 6 metres; Width: 3 metres; Depth: 50 millimetres; Allowance: 10 percent; primary comparison: 6 and 3.

Your live breakdown

Current inputs in the calculation

These values come from the controls above and update when the calculator changes.

Length
6 metres
Measure the finished gravel area length.
Width
3 metres
Measure the finished gravel area width.
Depth
50 millimetres
Enter the compacted target depth, not the loose pile height.
Allowance
10 percent
Use an allowance for uneven ground, edges and ordering tolerance.
Bulk density
1.6 t/m³
Supplier density varies by stone type, moisture and compaction. 1.6 t/m³ is only a planning default.

Resulting answer

70.6 cubic metres and tonnes

Gravel Calculator uses the declared inputs to produce a transparent default result. Length: 6 metres; Width: 3 metres; Depth: 50 millimetres; Allowance: 10 percent; primary comparison: 6 and 3.

Answer
70.6 cubic metres and tonnes
Live support
Gravel Calculator uses the declared inputs to produce a transparent default result. Length: 6 metres; Width: 3 metres; Depth: 50 millimetres; Allowance: 10 percent; primary comparison: 6 and 3.

Assumptions used

What this answer assumes

Use supplier density and delivery rounding for the final order.

  • The area is treated as a rectangle. Irregular areas should be split into rectangles and added together.
  • Depth is entered as the finished target depth in millimetres and converted to metres before volume is calculated.
  • Bulk density is a planning input only. Actual tonnes per cubic metre vary by aggregate type, grading, moisture, voids and compaction.
  • This calculator estimates quantity for ordering and quote notes. It does not specify drainage design, sub-base preparation or structural engineering requirements.

Master’s Tip

How to use the result well

Master’s Tip: ask the supplier what bulk density and minimum delivery increment they use before ordering. Decorative gravel, road base and drainage stone can need different depth, compaction and tonne-per-cubic-metre assumptions.

Printable record

What belongs in the saved calculation

Save the inputs, result, formula, assumptions, page URL and date together so the calculation can be reviewed later.

Length
6 metres
Measure the finished gravel area length.
Width
3 metres
Measure the finished gravel area width.
Depth
50 millimetres
Enter the compacted target depth, not the loose pile height.
Allowance
10 percent
Use an allowance for uneven ground, edges and ordering tolerance.

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Copy a clean iframe version with the required CalculationTime attribution link built in.

Formula

Base volume = length × width × (depth millimetres ÷ 1,000). Order volume = base volume × (1 + allowance percent ÷ 100). Estimated tonnes = order volume × bulk density in tonnes per cubic metre.

Worked example

For a 6 m by 3 m area at 50 mm depth: depth = 50 ÷ 1,000 = 0.05 m. Base volume = 6 × 3 × 0.05 = 0.90 m³. Add 10% allowance: 0.90 × 1.10 = 0.99 m³. At 1.60 t/m³, estimated weight = 0.99 × 1.60 = 1.58 tonnes.

Professional note

Master’s Tip: ask the supplier what bulk density and minimum delivery increment they use before ordering. Decorative gravel, road base and drainage stone can need different depth, compaction and tonne-per-cubic-metre assumptions.

Regional and unit assumptions

Defaults use metres, millimetres, cubic metres and metric tonnes. The arithmetic is general rectangular volume; supplier density, compaction, bag size and delivery rounding must be checked locally.

Assumptions and limitations

Methodology & Accuracy

How this calculator is checked

CalculationTime pages are built around visible arithmetic: the formula, assumptions, worked example and practical limitations are shown so the result can be checked rather than simply trusted.

Formula used

Base volume = length × width × (depth millimetres ÷ 1,000). Order volume = base volume × (1 + allowance percent ÷ 100). Estimated tonnes = order volume × bulk density in tonnes per cubic metre.

Standard or basis

Defaults use metres, millimetres, cubic metres and metric tonnes. The arithmetic is general rectangular volume; supplier density, compaction, bag size and delivery rounding must be checked locally.

Where a calculator follows a named legal, trade or industry standard, that standard is cited visibly. Otherwise the page uses transparent general arithmetic and states its limits.

Master's Tip

Master’s Tip: ask the supplier what bulk density and minimum delivery increment they use before ordering. Decorative gravel, road base and drainage stone can need different depth, compaction and tonne-per-cubic-metre assumptions.

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Questions

How do I calculate how much gravel I need?

Multiply length by width by depth in metres to get cubic metres, then add an allowance for uneven ground, edges and ordering tolerance.

Why does the calculator ask for bulk density?

Gravel is usually ordered by volume, weight or bag count. Bulk density converts cubic metres into an estimated tonne figure, but the supplier value can vary by material and moisture.

What depth should I use for gravel?

Use the finished target depth for your job. Decorative paths, driveways, drainage layers and sub-base materials can need different depths, so follow the project specification or supplier guidance.

Does this include compaction?

Only if you enter a depth and density that already reflect the compacted material you intend to order. Compaction changes volume and density, so record the assumption in the printable report.

Should I round up the result?

Yes for real orders. Suppliers may sell by bag, scoop, tonne or truck increment, so round after checking the supplier’s delivery and minimum-order rules.

Calculation note

Gravel estimating is simple volume arithmetic, but the practical result depends on material behaviour. The same rectangular area can produce different tonne estimates when the stone size, moisture, void spaces or compaction change.

Volume comes before weight

The core calculation is geometric: length times width times depth. Keeping cubic metres visible first makes the estimate easier to check on a drawing, quote or classroom worksheet before any supplier density is applied.

Bulk density is the uncertain part

Aggregate weight is not fixed by volume alone. Particle size, grading, stone type, moisture, air voids and compaction all affect how many tonnes fit into a cubic metre. That is why this page makes density an editable input instead of hiding one universal number.

Allowances should be recorded, not hidden

Edges, uneven subgrade, spreading loss and ordering increments often mean the bought quantity is higher than the measured geometric volume. Recording the allowance in the printable report helps a homeowner, landscaper or supplier understand why the order was rounded.

Sources and further readingCaterpillar: Earthwork volumes reference tablesNIST: SI Units — Length