Aggregates & landscaping · free tool
Mulch Calculator
How much mulch do you need? Enter your beds and depth, pick your mulch, and get the exact cubic yards, the bags to buy, and coverage — with waste built in.
Mulch Calculator
How much mulch you need — yards, bags & cost.
1 Your beds
2 Your estimate
Order in bulk by the yard.
Or 17 × 3 cu ft bags. A cubic yard is 14 × 2-cu-ft (or 9 × 3-cu-ft) — bulk is cheaper past ~14 bags.
Estimates only — bag size and mulch settling vary; buy a little extra. See how we calculate · Updated monthly
Method · how it works
How to calculate how much mulch you need
Just volume and bag size. Here is exactly what the calculator does, so you can check it by hand.
Find the volume
Multiply bed area × depth (in feet), then divide by 27 for cubic yards.
Count bags
Divide cubic feet by the bag size. A cubic yard is 14 × 2-cu-ft bags (or 9 × 3-cu-ft).
Add a little overage
Order about 5% extra for uneven spreading and settling.
Bags or bulk
Bags suit small beds; past about 14 bags (1 yd³), bulk delivery is cheaper.
A 20 × 10 ft bed, 3 in deep
50 ÷ 27 = 1.85 yd³
50 ÷ 2 = 25 bags (2 cu ft)
2 cu ft bags, 5% overage in
Sources: Landscape Calculator · bag/coverage references · UC IPM (mulch & weeds)
Reviewed against supplier coverage tables · Updated monthly
Estimates only. Bag sizes and how much mulch settles vary — buy a little extra, and keep mulch under 4 in and off plant stems.
Mulch depth · by plant
How deep should mulch be?
Depth depends on what you are mulching. Set yours in the calculator above.
Light layer so seedlings can push through.
StrawThe everyday depth for beds and borders.
HardwoodHolds moisture; keep it off the trunk.
Bark nuggetsA fuller layer to start a fresh bed.
Any mulchCoarse mulch, up to 4 in, blocks light.
Coarse barkNever more than 4 in — and keep mulch 3–6 in off tree trunks (no volcano mulching).
The money question
How many bags of mulch in a yard?
And how far a yard (or a bag) goes at different depths.
Bags per cubic yard
| Depth | 1 yd³ covers | One 2-cu-ft bag |
|---|---|---|
| 2 in | 162 sq ft | 12 sq ft |
| 3 in | 108 sq ft | 8 sq ft |
| 4 in | 81 sq ft | 6 sq ft |
Pick your mulch
Types of mulch and when to use each
They all cover by the same volume — choose on look, longevity and where it goes.
The all-purpose choice for beds and borders; knits together well.
Large, slow to break down — great around trees; can float on slopes.
Interlocks and stays put — the pick for slopes and windy spots.
Aromatic, naturally rot- and pest-resistant; holds color a while.
Slightly acidic — good for azaleas, rhododendrons and evergreens.
Black, brown or red — keeps its color longest for a tidy look.
Playgrounds and paths — does not break down, but does not feed soil.
Light and cheap — ideal over veggie gardens and new grass seed.
Estimating other landscape materials? Try our gravel, topsoil or sand calculators.
Timing & budget
When to mulch (and what it costs)
A quick guide to timing, upkeep and rough pricing.
Mulch in mid-spring once soil warms; a fall layer protects roots for winter.
Refresh yearly to keep 2–3 in — do not just pile new on old.
Per 2-cu-ft bag; premium and dyed mulch costs more.
Cheaper per yard delivered; best past about 14 bags.
Skip landscape fabric under organic mulch — a 2–3 in layer already blocks most weeds, and fabric stops mulch from feeding the soil.
Answers
Mulch calculator FAQs
How many bags of mulch are in a yard?
A cubic yard equals 14 × 2-cu-ft bags (13.5 rounded up) or 9 × 3-cu-ft bags — since a yard is 27 cubic feet.
How much does a yard of mulch cover?
About 162 sq ft at 2 in deep, 108 sq ft at 3 in, or 81 sq ft at 4 in. Deeper mulch covers fewer square feet.
How deep should mulch be?
2–3 in for flower beds, 3–4 in for trees and shrubs, and 1–2 in for vegetable gardens. Never more than 4 in.
How much does one bag of mulch cover?
A 2-cu-ft bag covers ~12 sq ft at 2 in deep (about 8 sq ft at 3 in). A 3-cu-ft bag covers half again as much.
Should I buy bags or bulk mulch?
Bags are easiest for small beds. Once you pass about 1 cubic yard (14 bags), bulk delivery is cheaper per yard.
Does mulch stop weeds?
Yes — a 2–3 in layer blocks the light weed seeds need. For heavy weed pressure, use coarse mulch up to 4 in.
When should I mulch?
Mid-spring once the soil warms is ideal; a fall layer insulates roots. Refresh about 1 in a year to keep 2–3 in.
Can you put too much mulch?
Yes. Over 4 in can suffocate roots, and piling mulch against trunks (volcano mulching) traps moisture and causes rot — keep it 3–6 in clear of stems.