Project Inputs
Formula Used
Each shape uses its standard area formula. Net depth subtracts existing mulch from target depth. Final volume includes waste and settlement allowances for purchasing.
- Rectangle: area = length × width
- Circle: area = π × radius²
- Triangle: area = base × height ÷ 2
- Trapezoid: area = (side A + side B) × height ÷ 2
- Volume: total area × net mulch depth
- Adjusted volume: volume × waste factor × settlement factor
- Bags: round adjusted volume upward to whole bags
How to Use
- Select each garden section shape and measurement unit.
- Enter dimensions, quantities, target depth, and existing depth.
- Add more sections when the landscape has separate beds.
- Choose material, allowances, bag size, and load capacity.
- Enter prices, fees, labour, and any applicable tax.
- Select Calculate Mulch to view complete purchasing estimates.
Example Data
| Area | Dimensions | Depth | Approximate volume | Two-cubic-foot bags |
|---|---|---|---|---|
| Small bed | 10 ft × 4 ft | 2 in | 6.67 ft³ | 4 |
| Medium bed | 20 ft × 6 ft | 3 in | 30.00 ft³ | 15 |
| Large bed | 30 ft × 10 ft | 4 in | 100.00 ft³ | 50 |
Frequently Asked Questions
How many bags of mulch do I need?
Enter the measured area and desired depth. Select the bag volume printed on its label. The calculator rounds purchases upward to complete bags.
How deep should mulch be?
Many beds use two to four inches. Trees often need a thinner layer near trunks. Follow plant guidance and avoid excessive mulch buildup.
How much area does one bag cover?
Coverage depends on bag volume and chosen depth. A deeper layer covers less surface area. Use exact label volume for dependable purchase planning.
How many cubic feet equal one cubic yard?
One cubic yard contains twenty-seven cubic feet. This conversion helps compare bagged and bulk prices. The calculator performs the conversion automatically for you.
Should old mulch be removed?
Removal depends on condition, depth, and contamination. Healthy mulch can often remain beneath fresh material. Enter existing depth to calculate only additional mulch.
How much extra mulch should I purchase?
Five to fifteen percent often covers waste. Complex borders may need a larger allowance. Adjust the waste setting for your project conditions.
Does mulch settle after installation?
Loose mulch normally settles after spreading and watering. Material type changes the amount of settlement. Add a settlement allowance before purchasing your mulch.
How do I measure an irregular garden?
Divide the garden into simpler measurable shapes. Calculate each section as a separate area. Add every section for one combined project total.
Is bulk mulch cheaper than bagged mulch?
Bulk pricing is often lower for large projects. Delivery fees can change the final comparison. Review all three cost estimates before ordering material.
How often should mulch be replaced?
Organic mulch breaks down at different rates. Check depth and condition before adding material. Replace only enough to restore the desired layer.
Can this calculator estimate delivery costs?
Yes, enter a delivery fee with pricing. Labour and tax can also be included. Totals remain separated for clearer purchase comparisons.