Mulch Calculator
Bags, cubic feet and cubic yards of mulch for garden beds.
Quick answer
- Formula: Volume (cu ft) = Length × Width × (Depth ÷ 12); Bags = ceil(Cu ft ÷ bag size); Cu yd = Cu ft ÷ 27
- Worked example — Bed area: 100.0 sq ft (full example below).
Mulch Calculator
| Bed area | 100.0 sq ft |
| Volume | 25.0 cu ft |
| Volume (bulk) | 0.926 cu yd |
| Bags needed | 13 |
A 10 × 10 ft bed at 3 inches deep needs 25 cu ft of mulch — 13 bags of 2 cu ft, or 0.93 cu yd if you buy in bulk.
Enter the bed length and width and how deep you want the mulch, and get the volume in cubic feet and cubic yards plus the number of standard bags. Bagged mulch is most commonly sold in 2 cu ft bags, which is the default here — change the bag size input if yours differ (3 cu ft bags are also common).
As a guide, 2 inches of mulch is enough for an annual top-up over existing mulch, while 3 inches is the standard depth for suppressing weeds in a new bed. Bag counts are rounded UP to whole bags.
The formula
Worked example
A 10 × 10 ft bed at 3 inches deep needs 25 cu ft of mulch — 13 bags of 2 cu ft, or 0.93 cu yd if you buy in bulk.
The example is pre-loaded in the result panel — press Calculate with your own numbers to replace it.
Frequently asked questions
How many bags of mulch are in a cubic yard?
13.5 bags of 2 cu ft make a cubic yard (27 ÷ 2). Beyond about one cubic yard, bulk delivery is usually much cheaper than bags.
How deep should mulch be?
3 inches for new beds and weed suppression, 2 inches for a seasonal refresh. Keep mulch a few inches away from tree trunks and house siding to avoid moisture and pest problems.
How do I estimate an irregular bed?
Measure its rough rectangle and use about 80% of that area, or split the bed into rectangles and circles and add the results together.
Category: Construction & Home calculators
Sources & methodology
This calculator applies the formula shown on this page exactly as written, using the standard definitions for its inputs. Results are computed from the values you enter — no data is stored — and are rounded only for display.
Content last reviewed by CalcHub Editorial.
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