Mulch Calculator
Find out exactly how much mulch you need — in cubic yards and bags — plus how much you’ll need to top up next year.
Your bed or area
Good for tree rings and round beds.
Sets a typical depth of 3 in — adjust below if needed.
Covers uneven ground and spillage. 5–10% is normal.
Everything is calculated in your browser. Nothing you type is sent anywhere or stored.
Bags or bulk delivery?
Bagged is fine at this size
Next year’s refresh
0.34 yd³
Estimated top-up after 1 year
Mulch type profile
The short answer
Multiply your bed’s area by the depth in feet to get cubic feet, then divide by 27 for cubic yards. A 10 × 10 ft bed at 3 inches deep needs about 0.93 cubic yards, or roughly 13 bags of standard 2 cubic foot mulch. Add 5–10% for waste, and remember organic mulch settles and breaks down, so plan on a top-up next year.
Mulch needed for common bed sizes
Figures below use a standard 3 inch depth, before waste.
| Bed size | Area | Cubic yards | 2 cu ft bags |
|---|---|---|---|
| 5 × 10 ft | 50 sq ft | 0.46 yd³ | 7 |
| 10 × 10 ft | 100 sq ft | 0.93 yd³ | 13 |
| 10 × 20 ft | 200 sq ft | 1.85 yd³ | 25 |
| 15 × 20 ft | 300 sq ft | 2.78 yd³ | 38 |
| 20 × 30 ft | 600 sq ft | 5.56 yd³ | 75 |
Coverage per cubic yard, by depth
| Depth | Coverage | Typical use |
|---|---|---|
| 1 in | 324 sq ft | Light top-dressing, thin refresh |
| 2 in | 162 sq ft | Annual top-up on existing beds |
| 3 in | 108 sq ft | Standard mulch depth |
| 4 in | 81 sq ft | New beds, weed suppression focus |
Avoid going deeper than 4 inches — mulch piled too thick can suffocate roots and hold excess moisture against stems and trunks.
Mulch types compared
| Type | Weight per yd³ | Breaks down | Best for |
|---|---|---|---|
| Shredded hardwood | 800 lb | Fast | General beds, mats well on slopes |
| Hardwood bark chips | 750 lb | Medium | General beds, doesn’t mat as tightly |
| Cedar mulch | 700 lb | Slow | Beds near structures, natural pest resistance |
| Cypress mulch | 700 lb | Slow | Wetter areas, water-resistant |
| Pine bark nuggets | 600 lb | Slow | Large beds, doesn’t mat, can float in heavy rain |
| Pine bark mini nuggets | 650 lb | Slow | Better ground coverage than large nuggets |
| Dyed mulch | 800 lb | Medium | Consistent color, color fades before material breaks down |
| Rubber mulch | 750 lb | Does not decompose | Playgrounds, permanent decorative beds |
| Compost / soil blend | 1,000 lb | Very fast | Vegetable and flower beds needing soil enrichment |
How to calculate how much mulch you need
- Measure the bed. Length × width for a rectangle, or use the shape tools above for circles, triangles and borders.
- Decide the depth. 2–3 inches for most beds, 3–4 inches for a new bed.
- Find the volume. Area × depth (in feet) gives cubic feet; divide by 27 for cubic yards.
- Add waste. 5–10% covers uneven ground and spillage.
- Convert to bags if buying bagged. Divide cubic feet by 2 for standard 2 cubic foot bags.
Worked example
A 10 × 10 ft bed, mulched 3 inches deep, in shredded hardwood:
- Area10 × 10 = 100 sq ft
- Depth in feet3 ÷ 12 = 0.25 ft
- Cubic feet100 × 0.25 = 25 cu ft
- Cubic yards25 ÷ 27 = 0.93 yd³
- Plus 10% waste1.02 yd³
- Bags (2 cu ft)14 bags
Bagged or bulk delivery?
The crossover sits around 2 to 3 cubic yards. Below that, bagged mulch is convenient and the cost difference is small. Above it, bulk delivery is dramatically cheaper per yard, and a truckload saves carrying dozens of bags.
- Small beds — use bagsTree rings, single small beds, or topping up an existing area.
- Medium jobs — price both1 to 3 cubic yards. Ask about a delivery minimum before deciding.
- Large jobs — always bulkWhole yards and multiple beds. Bagged mulch at this scale costs several times more.
Planning the annual refresh
Unlike stone or gravel, organic mulch breaks down. Most types lose 15–30% of their depth to decomposition and settling each year, which is why beds need topping up annually and a fuller refresh every 2–3 years. Slower-decomposing types like cedar, cypress and pine bark nuggets stretch that timeline out further, while compost blends and dyed mulch need refreshing sooner.
Common mistakes
- Piling mulch too deepMore than 4 inches can suffocate roots and trap excess moisture against stems, encouraging rot.
- Building a “mulch volcano” around treesPiling mulch directly against the trunk traps moisture and invites pests and rot. Keep a 3–6 inch gap.
- Forgetting mulch settles and decomposesA bed mulched once will thin out significantly within a year. Budget for an annual top-up, not just the initial fill.
- Mixing types on refreshAdding a different color or type on top of old mulch each year can create an uneven, patchy look. Stick with one type for a bed.
- Confusing mulch with compostCompost enriches soil and breaks down fast; bark and wood mulch is mainly for moisture retention and weed suppression and lasts longer.
- Not accounting for bag size differencesMost bags are 2 cubic feet, but some brands sell 1 or 3 cubic foot bags — always check before ordering.
What this calculator assumes
Adjust your result if your project differs from these.
- Uniform depth across the whole area
- Standard dry-ish densities per type, as listed in the comparison table above
- A mulch bag size of 2 cubic feet, the most common size sold
- Annual decomposition rates of roughly 15–30% of depth depending on mulch type
- Bulk orders rounded up to the nearest quarter yard
- Prices are whatever you enter; they are not live market rates
Common questions
How much mulch do I need for a garden bed?
A 10 × 10 ft bed at 3 inches deep needs about 0.93 cubic yards, or roughly 13 bags of standard 2 cubic foot mulch.
How deep should mulch be?
2 to 3 inches is standard for most garden beds. Go no deeper than 4 inches, since mulch piled too thick can suffocate roots and hold excess moisture against the trunk or stems.
How many bags of mulch are in a cubic yard?
About 13.5 bags of standard 2 cubic foot mulch make one cubic yard, since a cubic yard is 27 cubic feet.
How much area does a cubic yard of mulch cover?
About 162 sq ft at 2 inches deep, 108 sq ft at 3 inches, or 81 sq ft at 4 inches.
How often should I replace mulch?
Most organic mulches need a top-up every year and a full refresh every 2 to 3 years as they decompose and settle. Cedar, cypress and pine bark nuggets break down slower and can go longer between refreshes.
Should I remove old mulch before adding new mulch?
Not usually. A thin layer of decomposing mulch enriches the soil. Rake the old layer to break up any matting, then add fresh mulch on top, keeping the total depth around 2–3 inches.
Is bagged or bulk mulch cheaper?
Bulk mulch is significantly cheaper per cubic yard once you need more than about 2–3 cubic yards. Below that, bagged mulch is more convenient and the price difference is small.
How far should mulch be kept from a tree trunk?
Leave a gap of 3 to 6 inches around the trunk. Piling mulch against the bark — a “mulch volcano” — traps moisture and encourages rot and pests.
Do I need landscape fabric under mulch?
It’s optional for weed suppression, but many gardeners skip it in planted beds since it can restrict water and nutrients to plant roots over time. It’s more common under decorative, non-planted mulch areas.
What is the difference between mulch and compost?
Mulch is a surface layer mainly for retaining moisture and suppressing weeds. Compost is decomposed organic matter mixed into or applied on soil to add nutrients. Compost blends do both, but break down faster than bark or wood mulch.
How many cubic feet are in a bag of mulch?
Most bagged mulch comes in 2 cubic foot bags, though some brands sell 1 or 3 cubic foot bags. Always check the bag before calculating, since this changes the bag count significantly.
Embed this calculator
Related calculators
Mulch Estimate
—
materialcalculate.com/mulch-calculator/
Project
| Shape | — |
| Dimensions | — |
| Depth | — |
| Area | — |
| Mulch type | — |
| Waste allowance | — |
Volume & weight (incl. waste)
| Cubic yards | — |
| Cubic feet | — |
| Weight | — |
Shopping list
| Bulk order | — |
| Bagged alternative (2 cu ft) | — |
| Next year’s refresh (est.) | — |
| Estimated cost | — |
Notes
Estimate generated by materialcalculate.com. Assumes uniform depth and standard mulch densities. Confirm quantities with your supplier before ordering.