Mulch Calculator
Enter each bed's shape and size, choose a depth, and get the mulch you need in cubic yards and in bags of the sizes stores sell, with a waste allowance built in. Add several beds and the calculator adds them up.
Material and depth
About hardwood bark mulch
Extension services agree on 2-4 in: Illinois says 2-3 in for composted material and 3-4 in for coarse mulch; Clemson says fine wood and bark mulches no more than 2-3 in, coarse nuggets up to 4 in. Keep it off trunks and stems.
Derived from a bagged weight: Timberline shredded hardwood mulch is listed at 31 lb per 2 cu ft bag (15.5 lb/ft³, about 420 lb per cubic yard). Bagged mulch is dried for shipping; bulk mulch from a yard holds rain and can weigh half again as much.
Beds
Measure each area and pick its shape. Leave an area’s depth blank to use the depth above.
Prices (optional)
Enter what your supplier or store charges to see the cost both ways.
Mulch estimate
What to buy
2.15 yd³ of hardwood bark mulch
Order 2.5 cubic yards in bulk, or buy 30 bags of 2 cu ft.
Includes 10% extra. Bulk suppliers usually sell in half-yard steps, so the order is rounded up.
Hardwood bark mulch (shredded) · Depth 3 in unless set per area · 10% extra
- Area
- 211 sq ft19.63 m²
- Cubic yards
- 2.15order 2.5 yd³
- Cubic feet
- 58.1
- Cubic metres
- 1.651,645 litres
- Weight
- 0.45 tons0.41 t, 901 lb
- Edging
- 85 ftperimeter, triangles and known areas not included
| Bag size | Bags |
|---|---|
| 2 cu ft bag | 30 |
| 3 cu ft bag | 20 |
Your areas, to scale
| Area | Size | Depth | Volume |
|---|---|---|---|
| Border bed25 ft × 5 ft | 125 sq ft | 3 in | 31.3 cu ft |
| Island bed⌀ 8 ft | 50 sq ft | 3 in | 12.6 cu ft |
| Corner bedbase 12 ft × height 6 ft | 36 sq ft | 3 in | 9 cu ft |
| Total | 211 sq ft | 52.8 cu ft | |
| With 10% extra | 58.1 cu ft | ||
How to use it
- Measure each bed. Length and width for a rectangular bed; the diameter for a round one; base and height for a triangle; outer diameter and trunk diameter for a ring around a tree. Measure to the edge of the bed, not to the outermost plant, and round to the nearest half foot.
- Add a row per bed. Name it, pick the shape and type the dimensions. The diagram next to each row shows what you entered. A bed with an odd outline can be split into two rows, or entered as a plain square footage if you already know it.
- Set the depth. Use the finished depth you want on the bed. If an inch of last year's mulch is still there and you only want to top it up, enter the top-up depth, not the total. The table below gives the usual depth for each mulch type.
- Check the waste allowance. Five percent is right for flat beds you have mulched before; ten percent for rough ground, sloped beds or a lot of edging to tuck under.
- Read the result. Cubic yards for a bulk order, the bag count for each bag size, the weight when the mulch's density is known, and a per-bed breakdown. Enter a per-yard or per-bag price for a cost comparison, then print the list or copy the share link.
Depth by mulch type
The right depth is a balance. Too thin and weeds come through and the soil dries out; too thick and water and air struggle to reach the roots, and the mulch itself stays soggy and sour. Coarse mulch has bigger gaps, so it can be laid deeper than fine mulch.
| Mulch | Depth | Notes |
|---|---|---|
| Hardwood bark mulch (shredded) | 3 in | Extension services agree on 2-4 in: Illinois says 2-3 in for composted material and 3-4 in for coarse mulch; Clemson says fine wood and bark mulches no more than 2-3 in, coarse nuggets up to 4 in. Keep it off trunks and stems. |
| Pine bark mulch (nuggets) | 3 in | Clemson: a 2-3 in layer of pine bark controls weeds, and coarse pine bark nuggets let air through so they can go as deep as 4 in. Illinois: coarse mulches 3-4 in. |
| Cedar mulch (shredded) | 3 in | Extension services agree on 2-4 in: Illinois says 2-3 in for composted material and 3-4 in for coarse mulch; Clemson says fine wood and bark mulches no more than 2-3 in, coarse nuggets up to 4 in. Keep it off trunks and stems. |
| Dyed / colored wood mulch | 3 in | Extension services agree on 2-4 in: Illinois says 2-3 in for composted material and 3-4 in for coarse mulch; Clemson says fine wood and bark mulches no more than 2-3 in, coarse nuggets up to 4 in. Keep it off trunks and stems. |
| Rubber mulch | 2 in | Makers disagree slightly: GroundSmart says install and maintain 1.5-2 in in landscape beds; RubberMulch.com says 2-3 in. 2 in is stored. Playground fall surfacing is a separate, deeper spec. |
| Pine straw (bales) | 3 in | LSU AgCenter: an initial 3 in layer for shrubs and trees, about 0.5 lb per square foot; a 25 lb, 3 cu ft bale covers about 50 sq ft at 3 in. Clemson: 2-3 in of pine needles. Settles fast; top up with 1 in a year, when a bale goes about three times as far. |
- Shredded hardwood, cedar and cypress (fine, stringy): 2 to 3 in. It knits together and stays put on slopes, but it also mats, so do not go deeper.
- Bark nuggets and wood chips (coarse): 3 to 4 in. The pieces leave air gaps and do not mat, and they last longer before they need topping up. They float, so avoid them where water sheets across a bed.
- Compost or leaf mould used as mulch: 1 to 2 in. It is fine-textured and breaks down fast; its job is feeding the soil as much as suppressing weeds.
- Around annuals, vegetables and shallow-rooted perennials: 1 to 2 in of whatever you use, so the crowns are not buried.
- At trunks and stems: none. Pull the mulch back a few inches so the bark can dry. A cone of mulch piled against a trunk keeps it wet, invites rot and rodents, and is the single most common mulching mistake.
Depth and density figures for the mulches in the calculator come from:
- University of Illinois Extension, Proper Mulching Techniques (2-4 in; composted 2-3 in, coarse 3-4 in) (read 2026-10-05)
- Clemson HGIC 1604, Mulch (read 2026-10-05)
- Elitsac (True Value) listing: Timberline 2 cu. ft. Hardwood Mulch, model 52055476, 31 lb (read 2026-10-05)
- Home Depot listing: Vigoro 2 cu. ft. Premium Brown Wood Shredded Bagged Mulch 52050196 (bag size only) (read 2026-10-05)
- Lowe's listing: Royal Gardens 3-cu ft Natural Dark Brown Hardwood Mulch HARG30P (read 2026-10-05)
- Home Depot listing: Vigoro 2 cu. ft. Pine Bark Bagged Mulch Nuggets 52055472 (bag size only) (read 2026-10-05)
- Home Depot listing: Timberline 2 cu. ft. Cedar Blend Shredded Bagged Mulch 52058060 (bag size only) (read 2026-10-05)
- Elitsac (True Value) listing: Landscape Select 2 cu. ft. Dyed Black Shredded Hardwood Mulch, model LS2DBLK, 44.3 lb (read 2026-10-05)
- GroundSmart Rubber Mulch FAQ (landscape depth 1.5-2 in) (read 2026-10-05)
- Lowe's listing: GroundSmart 12+ Year Nugget 0.8-cu ft Black Rubber Mulch (covers 4.8 sq ft at 2 in; no weight listed) (read 2026-10-05)
- Elitsac (True Value) listing: GroundSmart 0.8 cu. ft. Brown Recycled Nugget Rubber Mulch, model GSNG08BN72, 20.465 lb (read 2026-10-05)
- RubberMulch.com, Brown landscape rubber mulch: 1.55 cu ft / 40 lb bags, 77 cu ft / 2,000 lb pallet, 2-3 in deep (read 2026-10-05)
- LSU AgCenter, Pine straw makes excellent mulch (Owings, 2009) (read 2026-10-05)
How far a cubic yard goes
A cubic yard is 27 cubic feet. Spread 1 in deep it covers 324 sq ft; every extra inch of depth divides that figure. The table is computed by the same engine as the calculator, for a 500 sq ft bed:
| Depth | Sq ft per cu yd | Sq ft per 2 cu ft bag | Sq ft per 3 cu ft bag | Cu yd for 500 sq ft |
|---|---|---|---|---|
| 1 in | 324 | 24.0 | 36.0 | 1.54 |
| 2 in | 162 | 12.0 | 18.0 | 3.09 |
| 3 in | 108 | 8.0 | 12.0 | 4.63 |
| 4 in | 81 | 6.0 | 9.0 | 6.17 |
Bulk suppliers sell in half-yard or whole-yard steps, so round the last column up before you order.
Worked example: three beds
A border bed 25 ft by 5 ft, a round island bed 8 ft across and a triangular corner bed with a 12 ft base and 6 ft height, all mulched 3 in deep with 5 percent extra:
Result
| Bed | Area (sq ft) | Cubic feet |
|---|---|---|
| Border bed | 125.0 | 31.3 |
| Round island bed | 50.3 | 12.6 |
| Corner bed | 36.0 | 9.0 |
- Total area211.3 sq ft
- Volume with 5% extra55.5 cu ft
- Bulk order2.05 cu yd
- 2 cu ft bags28
- 3 cu ft bags19
- Approximate weight860 lb
The three beds come to 211.3 sq ft. At 3 in that is 52.8 cubic feet, 55.5 with the allowance, or 2.05 cubic yards. A supplier would deliver 2.5 yards; buying bags means 28 of the 2 cu ft bags or 19 of the 3 cu ft bags.
Bags or bulk?
Divide 27 by the bag size to see how many bags make a yard: 13.5 of the 2 cu ft bags, 9 of the 3 cu ft bags. Bags cost more per cubic foot but need no delivery fee, no tarp on the driveway and no wheelbarrow route through the gate. Bulk is cheaper once the job passes about a yard, is usually fresher material from the same pile landscapers buy, and can be dumped where you want it. For a single yard the two often cost about the same; for three yards bulk is clearly cheaper. The calculator shows both totals when you enter prices.
When to refresh mulch
Organic mulch breaks down from the bottom, which is the point: it turns into soil. A bed mulched 3 in deep typically loses an inch a year, more in a hot, wet climate and faster for fine mulch than for nuggets. Each spring, rake the old mulch to break up any crust, check the depth with a ruler in a few places and top it up to the finished depth you want. That top-up is usually 1 to 2 in, not a full new layer, so enter the top-up depth here rather than the total. Every few years, when the old layer has become a thick band of black compost, pull some of it into the soil before adding new mulch rather than letting the bed rise year after year.
Mistakes people make
- Measuring to the plants. Mulch goes to the edge of the bed. Measure the bed, not the planting.
- Forgetting what is already there. If an inch remains, you need a 2 in top-up, not 3 in. Depth is the biggest number in the formula, so this error costs a third of the order.
- Using one depth for every mulch. Three inches of fine shredded mulch is a lot; three inches of nuggets is about right.
- Piling it against trunks. Keep a mulch-free ring around trees and shrubs.
- Buying bags for a big job. A three-yard job is 41 of the 2 cu ft bags. Price it both ways.
- Rounding yards down. Suppliers sell in half-yard steps; round up, and let the waste allowance cover the rest.
Frequently asked questions
How many bags of mulch are in a cubic yard?
A cubic yard is 27 cubic feet, so divide 27 by the bag size: 13.5 of the 2 cu ft bags, 9 of the 3 cu ft bags. Bags are rounded up, so a job that needs 1 cubic yard of bulk mulch needs 14 of the 2 cu ft bags or 9 of the 3 cu ft bags.
How much does a cubic yard of mulch cover?
324 sq ft at 1 in, 162 sq ft at 2 in, 108 sq ft at 3 in, 81 sq ft at 4 in. The rule is 324 divided by the depth in inches. Those are the figures before any waste allowance; the calculator adds the percentage you set on top.
How deep should mulch be?
Two to four inches, finished. Fine, shredded mulch packs tightly and should stay nearer 2 to 3 in so water and air still reach the soil; coarse bark nuggets and wood chips leave more gaps and can go 3 to 4 in. Around annuals and shallow-rooted perennials, 1 to 2 in is plenty. Keep every kind of mulch a few inches away from trunks and stems.
How much does a yard of mulch weigh?
It depends on the mulch and how wet it is. For hardwood bark mulch the calculator uses 15.5 lb per cubic foot, which is about 419 lb (0.21 tons) per cubic yard. A load that has been rained on can weigh considerably more. Mulch is sold by volume, not weight, so the number mostly matters for what your truck can carry.
Should I put landscape fabric under mulch?
Under organic mulch, usually not. Shredded bark and wood chips break down into a layer of compost on top of the fabric, weeds root into that layer anyway, and the fabric stops the finished compost from improving the soil beneath. Fabric makes more sense under stone, where there is nothing to decompose. If you use it, the calculator's depth is still measured from the fabric up.
Is it cheaper to buy mulch in bulk?
Per cubic foot, bulk is nearly always cheaper, but delivery is a flat fee. For a bed or two, bags cost less in total and can be carried through the house. Once you need more than a yard or so, bulk wins; above two or three yards the saving is large. Enter the per-yard and per-bag prices you were quoted and the calculator shows the two totals.
Can I use this for compost, wood chips or pine straw?
Compost and wood chips, yes: they are bought and spread by volume exactly like mulch, and the topsoil calculator has compost among its materials. Pine straw is sold by the bale and spread to a loose depth that settles, so volume math is only a rough guide; a bale's coverage at the depth you want is printed on most bale labels, and that is the better figure.