How this mulch calculator works
Mulch is the friendliest volume math on the site — by the yard in bulk, by the 2 ft³ bag at the store, and the only question is depth:
bags = ft³ ÷ 2, rounded up · 13.5 bags per yard
The calculator adds a small 5% allowance for settling and spillage, rounds the bulk order to the quarter yard a landscape yard will actually scoop, and prices the same load both ways. At the defaults — a 20 × 10 ft bed, 3 in deep — that’s 2 yd³ or 27 bags; the line-by-line math is in the worked example below.
What type of mulch should I buy?
Shredded hardwood for staying power on slopes, bark nuggets for looks on flat beds, dyed mulch for color that lasts a season longer, and stone when you never want to do this again — every option covers the same square feet, so pick by behavior, then price:
Shredded hardwood
The default double- or triple-shred: it knits together, stays put on grades, and breaks down into the soil over a couple of seasons. Cheapest per yard in most markets and the safe answer for foundation beds.
Bark nuggets
Chunky pine or fir bark that lasts longer than shred but floats — literally. Keep nuggets off slopes and out of drainage paths, where one storm relocates the whole bed.
Dyed black, brown and red
Ground wood colored with iron-oxide or carbon pigments; the color outlives the wood. Quality varies with the feedstock — ask whether it’s ground pallet or forest wood — and let a fresh load dry a day before spreading against siding.
Cedar and cypress
Aromatic, slow to rot, naturally insect-shy, and the priciest wood on the list. Cedar’s the premium look; cypress harvesting raises sourcing questions worth asking your supplier.
Compost as mulch
A 1–2 in topdress of compost mulches and feeds at the same time — the horticulture-first answer for vegetable and perennial beds. The compost calculator runs those numbers at compost depths.
Stone instead of wood
River rock never rots, never blows away, and never feeds the soil — right for xeriscapes and drip lines, wrong for beds you replant. The river rock calculator sizes it by the ton with depth matched to the stone.
| Type | Typical range |
|---|---|
| Shredded hardwood | $30–45 |
| Dyed (black / brown / red) | $35–55 |
| Bark nuggets | $40–60 |
| Cedar / cypress | $45–70 |
| Bagged, any (2 ft³) | $3–6 / bag |
How deep should mulch be?
Two to three inches, and the discipline is keeping it there — mulch fails more often from too much than too little:
- Planted beds: 2–3 in — holds moisture and shades weed seed without smothering roots.
- Open ground and between shrubs: 3–4 in where nothing is growing through it.
- Around trees: a wide, flat 2–3 in ring out to the drip line, tapered to bare soil at the flare. Never the volcano — piled bark holds moisture against the trunk, rots it, and invites borers.
- Annual top-ups: 1 in over last year’s bed usually restores the look — rake first, and skip a year if the old layer is still 2 in deep.
- Weed suppression on paths: 3–4 in over cardboard or fabric.
How much does a yard of mulch cover?
One cubic yard is 27 ft³, so coverage is 27 divided by the depth in feet — 108 ft² at the standard 3 in. Table 2 gives the engine’s coverage line, Table 3 the store math, and Table 4 whole beds turned straight into orders.
| Depth | 1 yd³ covers |
|---|---|
| 1″ | 324 ft² |
| 2″ | 162 ft² |
| 3″ | 108 ft² |
| 4″ | 81 ft² |
| Unit | Covers |
|---|---|
| 2 ft³ bag | 8 ft² |
| 3 ft³ bag | 12 ft² |
| 1 yd³ bulk (13.5 bags) | 108 ft² |
| Bed | Order | 2 ft³ bags |
|---|---|---|
| 10 × 10 ft | 1 yd³ | 14 |
| 20 × 10 ft | 2 yd³ | 27 |
| 30 × 15 ft | 4.5 yd³ | 60 |
| 50 × 20 ft | 9.75 yd³ | 132 |
How to measure a bed for mulch
Beds curve, but mulch forgives — measure honestly, average generously, and the 5% allowance covers the wobble. Dimension fields take feet-inches (20, 12 ft 6 in) or metric (6 m).
- Measure the length of each bed along its longest line — pace the curve for island beds, following the shape rather than cutting the chord.
- Measure an average width: take the widest and narrowest points and split the difference. Precision buys nothing here; depth is where the volume lives.
- Several beds? Run each one and add the orders — or tally every bed, border and ring in one pass with the landscape calculator.
- Pick the depth from the guide above — 3 in for a new bed, 1–2 in for an annual refresh over old mulch.
- Leave the allowance at 5%. Mulch settles a little and spills a little; it doesn’t compact like stone, so it needs no more than that.
- Enter local prices — the yard’s bulk rate and the store’s bag price — and read which way wins. Under half a yard, just buy bags.
Worked example: mulch for a 20 × 10 ft bed
The defaults, worked line by line — 200 ft² of bed, 3 in deep, 5% allowance, $40 bulk against $4 bags:
volume = 200 × (3 ÷ 12) = 50 ft³ = 50 ÷ 27 = 1.85 yd³
allowance = 1.85 × 1.05 = 1.94 → order 2 yd³ (¼-yd rounding)
bulk cost = 2 × $40 = $80
bags = (50 × 1.05) ÷ 2 = 26.25 → 27 bags ≈ $108
weight = 2 × 800 ÷ 2,000 = 0.8 tons
Sanity-check it against the coverage line: one yard covers 108 ft² at 3 in, so 200 ft² wants a hair under two yards — same answer from the other direction. The $28 gap between bulk and bagged is small at this size; it triples by the time the bed does.
What this mulch estimate doesn’t include
The calculator prices the mulch pile. The rest of a bed refresh is prep — cheap lines individually, worth listing so the Saturday doesn’t run long:
- Delivery. Commonly $20–50 locally, often free past a minimum load — and worth it the first time you smell two yards in a sedan.
- Edging. Steel, aluminum or a fresh spade-cut edge to keep the bed line crisp and the mulch out of the lawn.
- Bed prep. Weeding, pre-emergent if you use it, and cardboard or fabric under paths (skip fabric in planted beds — it defeats the soil-feeding point of wood mulch).
- Soil work first. If the bed needs building up, that’s a soil order before the mulch goes down — the topsoil calculator handles it.
- Spreading labor. Hired crews commonly charge $40–80 per yard spread; a wheelbarrow and a rake charge nothing.
- Haul-off. Removing old rock, fabric or diseased mulch before the new layer.
Mulch FAQ
How much mulch do I need?
Bed area × depth in feet ÷ 27: the default 20 × 10 ft bed at 3 in deep is 1.85 yd³ — order 2 cubic yards with the 5% allowance, or 27 two-cubic-foot bags. Bulk runs about $80 against $108 in bags at the default prices.
How much mulch do I need for 1,000 square feet?
At the standard 3 in depth, 1,000 ft² takes 9.75 yd³ with the 5% allowance — call the yard for ten — or 132 two-cubic-foot bags. Bulk at $40 a yard runs about $390 versus $528 bagged, and a load that size is two to three heaped pickup trips.
How many bags of mulch are in a yard?
13.5 of the standard 2 ft³ bags equal one cubic yard (27 ÷ 2). Quick store math: divide the yards the calculator gives you by two and buy that many bags per half-yard — or just read the bag line, which rounds up for you.
How deep should mulch be?
2–3 inches on beds — enough to hold moisture and shade out weeds, not enough to suffocate roots. Go 3–4 inches only on open ground between plants, and pull it back to bare soil at trunks and stems.
How much does a yard of mulch cover?
108 ft² at 3 in deep — 162 ft² at 2 in, 81 ft² at 4 in. A single yard handles most foundation beds; the live coverage line recomputes for your depth.
Is bulk mulch cheaper than bagged?
Almost always past one yard: the default bed is $80 bulk versus $108 bagged, and the gap widens with volume. Bags win only when you need less than half a yard, want a specific dyed product, or can’t take a delivery pile.
How many yards of mulch fit in a pickup truck?
About 2 cubic yards heaped in a full-size 8 ft bed — and at 800 lb per dry yard that is roughly 1,600 lb, right at a half-ton truck’s payload. Volume runs out before weight does with mulch; wet loads flip that, so tarp it and split soaked loads.
How much does a yard of mulch weigh?
Around 400–800 lb dry depending on the wood and grind — the calculator uses 800 lb as a conservative hauling figure — and soaked mulch can double that. Two yards ride fine in a pickup by weight; volume runs out first.
Sources and standards
The depth and placement guidance on this page follows the published horticultural consensus, not landscaping folklore:
- University extension horticulture guidance: the 2–3 in bed depth and 3–4 in open-ground ceiling repeated across land-grant extension publications.
- Arboricultural best practice (ISA guidance): wide flat rings, exposed root flares, and the case against mulch volcanoes.
- Manufacturer bag volumes: bag coverage uses the printed 2 ft³ and 3 ft³ fills — the number on the bag governs.
- Supplier yard measure: bulk mulch is sold by the loader bucket calibrated to the cubic yard; the ¼-yd rounding here matches how yards actually scoop.
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