# Gravel calculator for gravel, sand, soil and mulch

> Gravel calculator: cubic metres, cubic yards, tonnes, bags and truck loads of gravel, sand, topsoil or mulch for an area and depth.

Interactive version: https://www.calcopenly.com/construction/gravel-calculator
Subject: Construction and home calculators

Volume is length × width × depth, plus an allowance for settling and compaction. Weight is that volume times the material's loose bulk density; the material list uses 1,680 kg/m³ for dry gravel, 1,555 for dry sand, 1,280 for loam and 400 for wood chips. Bags and truck loads are the volume divided by the bag or truck size, rounded up.

The default 10 × 3 m path, 10 cm deep, holds 3 m³. With 10% extra that is 3.3 m³ (4.32 yd³), about 5.5 tonnes of gravel, or 234 bags of 0.5 ft³.

Suppliers sell by the cubic metre, cubic yard or tonne. Density changes with stone size and moisture, so when you pay by weight, enter the supplier's figure under Other (enter density).

## Inputs

- **Length**
- **Width**
- **Depth**: Mulch 5–8 cm (2–3 in); driveway gravel 10–15 cm (4–6 in).
- **Material** (options: Gravel (dry, 1680 kg/m³), Sand (dry, 1555 kg/m³), Topsoil / loam (1280 kg/m³), Wood-chip mulch (400 kg/m³), Other (enter density))
- **Bulk density**
- **Extra for settling and compaction**: Gravel compacts and mulch settles; 5–15% is typical.
- **Bag size**: Printed on the bag: gravel is often 0.5 ft³, mulch 2 ft³ or 50 L.
- **Truck capacity**

## Results

- Volume to order (m³) — main result
- Volume to order (yd³)
- Volume to order (ft³)
- Volume before extra (m³)
- Weight (t)
- Weight (US tons)
- Bags (bags)
- Truck loads (loads)

## Formula

$$
V = \ell \times w \times d \times (1 + \text{extra}),\qquad m = V \rho
$$

## Worked examples

### 10 × 3 m gravel path, 10 cm deep, 10% extra

- Length: 10 m
- Width: 3 m
- Depth: 10 cm
- Material: Gravel (dry, 1680 kg/m³)
- Extra for settling and compaction: 10%
- Bag size: 0.5 ft³
- **Volume before extra: 3 m³**
- **Volume to order: 3.3 m³**
- **Volume to order: 4.32 yd³**
- **Weight: 5.54 t**
- **Weight: 6.11 US tons**
- **Bags: 234 bags**
- **Truck loads: 1 load**
- Checked against: Python decimal: 3 m³ × 1.1 = 3.3 m³ ÷ 0.764554857984 = 4.3162 yd³; × 1680 kg/m³ = 5.544 t; ÷ 0.5 ft³ bags = 233.08 → 234

### Mulch bed 20 × 5 ft, 3 in deep, 2 ft³ bags

- Length: 20 ft
- Width: 5 ft
- Depth: 3 in
- Material: Wood-chip mulch (400 kg/m³)
- Extra for settling and compaction: 0%
- Bag size: 2 ft³
- **Volume to order: 25 ft³**
- **Volume to order: 0.93 yd³**
- **Bags: 13 bags**
- **Weight: 0.28 t**
- Checked against: Hand calculation: 20 × 5 × 0.25 = 25 ft³ = 0.926 yd³; 25 ÷ 2 = 12.5 → 13 bags; 0.7079 m³ × 400 kg/m³

### Edge: exactly one cubic yard of topsoil

- Length: 9 ft
- Width: 3 ft
- Depth: 1 ft
- Material: Topsoil / loam (1280 kg/m³)
- Extra for settling and compaction: 0%
- Bag size: 0.75 ft³
- **Volume to order: 1 yd³**
- **Bags: 36 bags**
- **Truck loads: 1 load**
- **Weight: 0.98 t**
- Checked against: Hand calculation: 27 ft³ = 1 yd³; 27 ÷ 0.75 = 36 bags exactly; 0.764555 m³ × 1280 kg/m³ = 0.9786 t

### Custom density 100 lb/ft³, 40 L bags

- Length: 4 m
- Width: 2 m
- Depth: 5 cm
- Material: Other (enter density)
- Bulk density: 100 lb/ft³
- Extra for settling and compaction: 0%
- Bag size: 40 L
- **Volume to order: 0.4 m³**
- **Weight: 0.64 t**
- **Bags: 10 bags**
- Checked against: Python decimal: 4 × 2 × 0.05 = 0.4 m³; 100 lb/ft³ = 1601.85 kg/m³ → 0.6407 t; 400 L ÷ 40 L = 10 bags

## Questions

### How do I calculate how much gravel I need?

Multiply length × width × depth to get volume, then add an allowance for compaction; this calculator adds 10% by default. A 10 × 3 m area 10 cm deep is 3 m³, or 3.3 m³ with the extra. In feet, divide cubic feet by 27 to get cubic yards: 20 × 5 ft at 3 in deep is 25 ft³, or 0.93 yd³.

### How much does a cubic yard of gravel weigh?

About 1.28 tonnes (1.42 US tons) at the 1,680 kg/m³ this calculator uses for dry gravel, because a cubic yard is exactly 0.764554857984 m³. At the same density a cubic metre weighs 1.68 t. Dry sand at 1,555 kg/m³ comes to 1.19 t per cubic yard and loam at 1,280 kg/m³ to 0.98 t; wet material weighs more.

### How many bags of gravel make a cubic yard?

54 bags of 0.5 ft³, because a cubic yard is 27 ft³. Bags of 2 ft³ take 13.5 per cubic yard, and 50 L bags take 15.3, since a cubic yard is 764.6 L. For a whole job, divide the volume to order by the bag size and round up, as the Bags result does.

### How much area does a cubic yard of mulch cover?

108 ft² at 3 in deep, 162 ft² at 2 in and 324 ft² at 1 in, because a cubic yard is 27 ft³ and coverage is volume divided by depth. In metric, 1 m³ covers 20 m² at 5 cm and 10 m² at 10 cm. Add the settling allowance on top when ordering.

### How accurate is the gravel calculator?

Accuracy depends on your inputs and the method's assumptions. Decimal arithmetic uses 50 significant digits, but estimates, numerical methods and source data can be less precise; the displayed rounding does not remove those limits. It is checked against 4 worked examples whose answers come from independent sources; for example, “10 × 3 m gravel path, 10 cm deep, 10% extra” is checked against Python decimal: 3 m³ × 1.1 = 3.3 m³ ÷ 0.764554857984 = 4.3162 yd³; × 1680 kg/m³ = 5.544 t; ÷ 0.5 ft³ bags = 233.08 → 234.

### Where does the method come from?

Engineering ToolBox — Dirt and mud densities (gravel, sand, loam); Engineering ToolBox — Densities of common products (wood chips, bark).

## Sources

- [Engineering ToolBox — Dirt and mud densities (gravel, sand, loam)](https://www.engineeringtoolbox.com/dirt-mud-densities-d_1727.html)
- [Engineering ToolBox — Densities of common products (wood chips, bark)](https://www.engineeringtoolbox.com/density-materials-d_1652.html)