Mulch Calculator
Enter your garden bed area or dimensions and get real cubic yards, bag counts, coverage per bag, and cost, based on your coverage depth.
Bed area & depth
You'll need
1.85 cubic yards
(50.0 cubic feet over 200 sq ft)
With 10% waste, order
2.04 cu yd
2 cu ft bags needed
28
Coverage per bag
8.0 sq ft
Cost
Bulk, by the cubic yard
Estimated cost: $71.30
Bagged, 28 bags
Estimated cost: $112.00
Bulk (by the cubic yard) is almost always cheaper than bags once a bed needs more than a few -- bags are for small touch-ups or beds you can't easily wheelbarrow into.
Keep going
- Garden beds usually get a layer of topsoil first and mulch on top; the topsoil calculator sizes that fill layer underneath. Topsoil Calculator
- Using gravel instead of mulch for a low-maintenance bed or border? The gravel calculator prices that out by weight and bag instead. Gravel Calculator
How it's calculated
Volume is area (sq ft) × (depth (in) ÷ 12), whether you enter a total area directly or a length × width the calculator multiplies first. Dividing cubic feet by 27 gives cubic yards, since mulch delivered in bulk is sold by the yard. Waste is applied as a straight percentage before bags are counted: ordered cubic feet = raw cubic feet × (1 + waste% ÷ 100).
Bag count is ceil(ordered cubic feet ÷ bag size), using whichever bag size (2 or 3 cubic feet) is selected -- both standard retail sizes. Coverage per bag is bag size (cu ft) ÷ depth (ft): the same bag volume spread thinner covers more area, spread thicker covers less.
Worked example
Using the calculator's own defaults -- a 20×10 ft bed, 3 inches deep, 2 cu ft bags, 10% waste, $35/cu yd and $4/bag pricing:
- Area: 20 × 10 = 200 sq ft. Raw volume: 200 × (3 ÷ 12) = 50 cubic feet = 1.85 cubic yards.
- With 10% waste, order 2.04 cubic yards (55 cubic feet) -- about $71.30 at $35/cu yd.
- 55 ÷ 2 cu ft bags = 27.5 → 28 bags, about $112 at $4/bag.
- Coverage per bag at 3" deep: 2 ÷ 0.25 = 8 sq ft per bag.
Standard trade advice is to order 5-10% extra to cover settling and uneven spreading -- running short mid-bed is a bigger problem than a little leftover mulch.
Frequently Asked Questions
How deep should mulch be?
2-3 inches is the standard trade recommendation for most garden beds. Less than 2" doesn't suppress weeds well; more than 4" can actually suffocate plant roots and hold too much moisture against stems.
How many bags of mulch is a cubic yard?
A standard 2 cubic foot retail bag: about 13.5 bags to a cubic yard (27 cu ft ÷ 2). At the larger 3 cubic foot bag size, it's 9 bags to a yard. Buying in bulk (by the cubic yard) is almost always cheaper than bags once you need more than a handful.
How often should I re-mulch?
Organic mulch (bark, wood chips) breaks down over time and is typically refreshed once a year, though a thinner top-up rather than a full fresh layer is often enough if the existing mulch hasn't fully decomposed.
Should I buy 2 cu ft or 3 cu ft bags?
Either covers the same area for the same total cubic feet -- 3 cu ft bags just mean fewer, heavier bags to carry. Compare the price per cubic foot between the two sizes at your retailer; the larger bag is sometimes, but not always, the better per-unit price.
How much area does one bag of mulch cover?
It depends on your depth: coverage (sq ft) = bag size (cu ft) ÷ depth (ft). A 2 cu ft bag at the standard 3" depth covers 8 sq ft; the same bag spread thinner at 2" covers 12 sq ft. The calculator above shows this for whatever depth and bag size you pick.