Mulch Coverage and Cost Calculator
Estimate mulch volume, bag quantities and the cost difference between bagged and bulk supply.
What this tool calculates
Area multiplied by depth gives cubic metres. The calculator adds your allowance, converts the result to litres, rounds bag quantities up and compares estimated bagged and bulk material costs.
How to use it
Measure each garden section separately and add the areas. Exclude paths, buildings and large rocks. Choose a depth appropriate to the mulch and plants, then enter local bag sizes and delivered bulk pricing.
Useful examples
- Ordering mulch for a revegetation or community planting day.
- Comparing trailer-load delivery with garden-centre bags.
- Budgeting weed suppression around trees and garden beds.
Important limits
Bulk sellers may round to half or whole cubic metres and charge delivery. Slopes, coarse pieces, settling and irregular bed edges change coverage. Keep mulch away from trunks and stems where required.
Measuring irregular beds
Break curved or irregular beds into smaller rectangles and triangles, calculate each area and add them. It is usually safer to order a little extra than to leave thin patches, but an excessive layer can hold too much moisture or interfere with airflow around some plants.
Worked example
Covering 50 square metres to 7.5 cm requires 3.75 cubic metres before allowance. Adding 10% gives 4.13 cubic metres or 4,125 litres. That equals 83 fifty-litre bags after rounding, allowing a direct price comparison with local bulk supply.