Mulch Calculator

Use Mulch Calculator

Figures update as you type. Nothing you enter leaves this tab, and no values are stored.

Bed length (ft)Bed width (ft)Depth (in)

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About Mulch Calculator

A mulch calculator works out how much mulch a garden bed needs from its length, width and the depth you want to lay, in both cubic yards - how bulk mulch is sold - and 2-cubic-foot bags. Buy too little and the bed shows through; buy too much and you have a mound of mulch to shift. The right depth matters too: too thin and weeds push through, too thick and you suffocate the roots. The tool multiplies the bed area by the depth to get the volume, then converts to cubic yards (27 cubic feet each) and to standard 2-cubic-foot bags. A depth of 2 to 3 inches suits most beds; go lighter around shallow-rooted plants. For several beds, total their areas or run each and add the results. Bulk mulch by the yard is far cheaper than bags once you pass a few cubic yards, which is why the tool shows both.

Using Mulch Calculator

Measure the bed in feet and enter the intended layer depth in inches. For an irregular bed, divide the outline into manageable rectangles and sum their volumes.
Read cubic feet for the physical volume and cubic yards for a bulk supplier. The bag count assumes 2 cubic feet per bag and rounds up; check the actual bag volume before buying.
Compare delivered bulk volume with bagged volume on the same basis. Include delivery access and where material can be placed when choosing between them.

Where mulch calculator helps

Mulching a bed

A 20×10 ft bed at 3 inches deep needs about 1.85 yd³, or roughly 25 two-cubic-foot bags.

Before you use the result

For a 20 by 10 ft bed at 3 inches deep, the calculation is 200 x 3/12 = 50 cubic feet. That is about 1.85 cubic yards, or 25 bags of 2 cubic feet. A different bag size changes the count even though the required volume stays 50 cubic feet.
The entered depth represents the layer you intend to add. If useful mulch is already present, assess the additional depth needed rather than calculating a completely new layer over the whole bed.
Settling, uneven ground and excluded areas can change the delivered quantity. Choose an appropriate depth for the planting and material from horticultural guidance; this volume calculation does not assess plant health, drainage or an appropriate clearance around stems.

Questions about Mulch Calculator

How deep should mulch be?

2–3 inches for most beds - enough to suppress weeds and hold moisture without smothering roots. The tool takes your depth and gives the volume.

Is my data saved or uploaded?

No. Mulch Calculator calculates the result entirely in this browser; the values you enter are not stored or sent to a server.