# How much mulch do I need?

Computes the mulch for an area at a chosen depth, with a waste allowance, in cubic yards, cubic feet, cubic metres and bags, and its weight and cost.

- Page: https://www.acalculator.org/construction/mulch-calculator
- JSON spec: https://www.acalculator.org/construction/mulch-calculator.json
- Version: 005b3847653d

## Default answer

Example with the default inputs (Area Total area, Total area 100 ft², Depth 3 in, Mulch type Wood chips, Waste and settling 10%, Price is Per cubic yard): 100 ft² at 3 in deep needs 1.02 yd³ of mulch, waste included.

## Inputs

| Key | Label | Description |
| --- | --- | --- |
| areaType | Area | Whether you know the total area or the length and width. |
| area | Total area | The area to cover with mulch. |
| len | Length | The length of the bed. |
| wid | Width | The width of the bed. |
| dep | Depth | How thick the layer of mulch is. 2 to 4 inches is usual. |
| mulchType | Mulch type | The kind of mulch, which sets its typical weight per cubic foot. |
| wasteFactor | Waste and settling | Extra mulch for waste and settling, as a percent of the volume. |
| density | Mulch density | The weight of one cubic foot of the mulch. Leave empty to use the typical density of the chosen type. |
| price | Price | The price of the mulch per volume unit or per bag. Leave empty to skip the cost. |
| priceUnit | Price is | What the price is for: a volume unit or one bag. |

## Outputs

| Key | Label | Description |
| --- | --- | --- |
| cubicYards | Mulch to order | The volume to order, waste included: area × depth × (1 + waste ÷ 100). |
| cubicFeet | Cubic feet | The volume to order in cubic feet. |
| cubicMeters | Cubic metres | The volume to order in cubic metres. |
| bags2 | 2 cu ft bags | Whole 2 cubic foot bags that hold the volume to order. |
| bags3 | 3 cu ft bags | Whole 3 cubic foot bags that hold the volume to order. |
| bags60 | 60 L bags | Whole 60 litre bags that hold the volume to order. |
| coverage | Area covered | The area the mulch covers, before the waste allowance. |
| weight | Weight | The volume to order × the mulch density, in US short tons of 2,000 lb. |
| tonnes | Weight (metric) | The same weight in metric tonnes (1,000 kg). |
| cost | Estimated cost | The volume to order in the price unit × the price; bags are counted whole. |

## Method

volume = area × depth × (1 + waste ÷ 100); weight = volume × density; bags = volume ÷ bag size, rounded up

## Assumptions

- The waste allowance is added to the volume before the bags, weight and cost are worked out.
- Bags are counted whole: 2 cu ft and 3 cu ft bags, and 60 L bags when the price is per 60 L bag.
- The typical densities are loose, dry bulk densities: wood chips 25 lb/ft³, bark 15, ground rubber 37.5 and gravel 105. Wet mulch weighs more. Pine straw and compost have no published value, so type one to see a weight.
- Weight is in US short tons of 2,000 lb.

## Worked examples

1. areaType = total-area, area = 9.290304, dep = 0.0762, mulchType = wood-chips, wasteFactor = 10%, priceUnit = per-cubic-yard gives cubicFeet = 0.778713, bags2 = 14, bags3 = 10, weight = 311.844754. Source: Engineering ToolBox, Densities of common Products (woodchips 20 to 30 lb/ft³, bark 10 to 20 lb/ft³, ground rubber 25 to 50 lb/ft³). https://www.engineeringtoolbox.com/density-materials-d_1652.html.
2. areaType = dimensions, len = 6.096, wid = 1.524, dep = 0.0762, mulchType = wood-chips, wasteFactor = 10%, price = $4.00, priceUnit = per-2-cubic-foot-bag gives cubicFeet = 0.778713, cost = $56.00. Source: Engineering ToolBox, Densities of common Products (woodchips 20 to 30 lb/ft³, bark 10 to 20 lb/ft³, ground rubber 25 to 50 lb/ft³). https://www.engineeringtoolbox.com/density-materials-d_1652.html.
3. areaType = total-area, area = 46.45152, dep = 0.0508, mulchType = bark-mulch, wasteFactor = 0%, price = $35.00, priceUnit = per-cubic-yard gives cubicYards = 2.359737, cost = $108.02, weight = 566.990463. Source: Engineering ToolBox, Densities of common Products (woodchips 20 to 30 lb/ft³, bark 10 to 20 lb/ft³, ground rubber 25 to 50 lb/ft³). https://www.engineeringtoolbox.com/density-materials-d_1652.html.
4. areaType = total-area, area = 10, dep = 0.05, mulchType = pine-straw, wasteFactor = 0%, priceUnit = per-60-liter-bag, price = $6.00 gives cubicMeters = 0.5, bags60 = 9, cost = $54.00. Source: Engineering ToolBox, Densities of common Products (woodchips 20 to 30 lb/ft³, bark 10 to 20 lb/ft³, ground rubber 25 to 50 lb/ft³). https://www.engineeringtoolbox.com/density-materials-d_1652.html.

## FAQ

### How much mulch do I need?

The amount of mulch needed depends on the area to be covered and the desired depth. Generally, a 2-4 inch layer provides good coverage. Multiply the area by the depth, add an allowance for waste and settling, and divide by 27 to get cubic yards. For example, 100 sq ft at 3 inches with 10% extra is 100 × 0.25 × 1.1 = 27.5 cubic feet, or 1.02 cubic yards.

### What are the benefits of mulch?

Mulch helps regulate soil temperature, retain moisture, prevent weed growth, reduce soil erosion, and improve soil health. It also enhances the visual appeal of your landscape.

### What types of mulch are available?

Common mulch types include wood chips, bark mulch, pine straw, rubber mulch, stone mulch, and compost. Each type has different properties, costs, and maintenance requirements.

### How deep should I apply mulch?

For most applications, apply mulch 2-4 inches deep. Too little mulch won't provide adequate benefits, while too much can prevent water from reaching plant roots.

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

A cubic yard is 27 cubic feet, so it takes 13.5 bags of 2 cubic feet (buy 14) or 9 bags of 3 cubic feet.

### How often should I replace mulch?

Organic mulches typically need replacement every 1-3 years as they decompose. Synthetic mulches like rubber can last 10+ years. Monitor your mulch and replace when it becomes thin or decomposed.

### Can I use mulch around trees and shrubs?

Yes, but keep mulch 2-3 inches away from tree trunks and shrub stems to prevent rot and pest issues. Apply mulch in a donut shape around the base of plants.

## Sources

- Engineering ToolBox, Densities of common Products (woodchips 20 to 30 lb/ft³; bark 10 to 20 lb/ft³; ground rubber 25 to 50 lb/ft³). https://www.engineeringtoolbox.com/density-materials-d_1652.html
- NIST Handbook 44 (2026), Appendix C, General Tables of Units of Measurement: 1 cubic yard = 27 cubic feet; 1 short ton = 2,000 pounds. https://www.nist.gov/document/2026-nist-handbook-44-appendix-c