How much mulch is that, really?

Mulch is sold two ways: bagged by the cubic foot (2 and 3 ft³ are the common US sizes; ~50 L in metric) and loose by the cubic yard from landscape suppliers. The conversion is simple — one yard is 27 ft³, so 13.5 of the 2 ft³ bags or 9 of the 3 ft³ bags — but the price gap is not: bagged mulch routinely runs two or three times the per-yard bulk price. The calculator shows the volume both ways and lets you price each, because “how many bags do I need” is really two questions — how much mulch, and which way to buy it.

Depth drives the answer more than area does. Every extra inch adds a third of a yard per 100 sq ft; going from 3 in to 4 in on 300 sq ft is nearly a full extra yard. If the bed already has last year’s mulch, you’re buying a top-up, not a fill — measure what’s missing, not the full target depth. The mulch depth guide goes through it use by use.

Coverage quick reference

Depth	1 yd³ covers	2 cu ft bag covers	3 cu ft bag covers
1 in	324 sq ft	24 sq ft	36 sq ft
2 in	162 sq ft	12 sq ft	18 sq ft
3 in	108 sq ft	8 sq ft	12 sq ft
4 in	81 sq ft	6 sq ft	9 sq ft
6 in	54 sq ft	4 sq ft	6 sq ft

A few honesty notes

• No waste margin on this page — mulch isn’t concrete, it doesn’t harden if you come up short. Order the geometric amount; settle-in is real (loose mulch compacts ~10–20%), so for a fresh bed bump the depth a half-inch.
• Keep it off the trunks. Mulch piled against bark — the “mulch volcano” — keeps the trunk wet and invites rot and pests. University extension guides recommend staying 3+ in back from trunks and under ~4 in total depth; both sources are cited on sources.
• Bags vs bulk isn’t just price: bulk loads dye-fade faster sitting in the driveway, and wet bagged mulch weighs more than it looks. Either way, the volume math above is the same.

Frequently asked questions

How do I calculate how much mulch I need?

Area × depth, and keep the units straight: a 20 × 4 ft bed at 3 in deep is 80 sq ft × 0.25 ft = 20 ft³ = 0.74 yd³ — ten 2 cu ft bags, or seven 3 cu ft bags. The calculator does it as you type; the depth guide covers how deep to go by use.

How many bags of mulch make a cubic yard?

A cubic yard is 27 ft³, so it's exactly 13.5 × 2 cu ft bags or 9 × 3 cu ft bags. In metric a 50 L bag is 0.05 m³, so 20 bags per m³. Since bagged mulch typically costs more per volume than bulk, the crossover is roughly when your count climbs past ~10 bags — set a per-yard bulk price above to compare.

How much area does a yard of mulch cover?

At the common 3 in depth, 1 yd³ covers 108 sq ft. At 2 in it's 162 sq ft; at 4 in, 81 sq ft. The rule: square feet covered = 324 ÷ depth in inches (or 100 ÷ depth in cm for a cubic metre). The coverage card above shows yours.

How deep should mulch be?

2–3 in for beds, ~4 in for paths, ~1 in when topping up existing mulch. University extension guidance says never exceed ~4 in total — deeper mulch suffocates roots and matted layers shed water. The full breakdown by use is in how deep should mulch be.

Does mulch settle? Should I order extra?

Yes on both counts — loose mulch compacts roughly 10–20% as it settles and decomposes, which is why beds need a thin top-up each year. This calculator gives the geometric volume without a waste margin; if you're filling a fresh bed, bumping the depth input by a half-inch is an easy way to bake in settlement.

Is it cheaper to buy mulch in bags or bulk?

Bulk wins past ~10 bags — a yard is 13.5 × 2 ft³ bags, and bulk yard prices are usually well under half the bagged equivalent. Bags earn their keep for small beds, second-floor terraces, or when you can't take a truck dump on the driveway. Type both prices above and the cost card shows the comparison.