Mulch & Topsoil Calculator
Work out how much mulch or topsoil you need for garden beds. Enter area and depth to get cubic yards, bags, and totals.
This mulch calculator estimates how much mulch, topsoil, gravel, or sand you need for a landscaping project. Enter area dimensions and desired depth to get results in cubic yards (or cubic metres), bag counts, and estimated weight. It supports multiple areas with individual and combined totals, metric and imperial units, and material-specific depth recommendations. The core maths is simple: area multiplied by depth gives volume, and volume divided by 27 gives cubic yards.
Estimates only. Always verify quantities with a professional before purchasing materials. Building projects must comply with local codes and regulations.
About Mulch & Topsoil Calculator
How the Calculation Works
Volume equals length times width times depth, all in the same unit. For imperial, depth is converted from inches to feet (divide by 12), the three dimensions are multiplied together to get cubic feet, and cubic feet is divided by 27 to get cubic yards. For metric, dimensions in metres are multiplied directly to get cubic metres. Weight is the volume multiplied by the material's density per cubic yard.
Worked example: A 20 ft by 10 ft garden bed at 3 inches of mulch. Area is 20 x 10 = 200 sq ft. Depth in feet is 3 / 12 = 0.25 ft. Volume is 200 x 0.25 = 50 cu ft, which equals 50 / 27 = 1.85 cubic yards. At the typical mulch density of 600 lbs per cubic yard, that is about 1,110 lbs. In bags: 50 / 2 = 25 bags of 2 cu ft mulch.
| Step | Formula | Example (10 ft x 20 ft bed, 3 in mulch) |
|---|---|---|
| Area | Length x Width | 10 x 20 = 200 sq ft |
| Volume (cubic feet) | Area x Depth (in feet) | 200 x 0.25 = 50 cu ft |
| Volume (cubic yards) | Cu ft / 27 | 50 / 27 = 1.85 cu yd |
| Bags needed (2 cu ft bags) | Cu ft / Bag size | 50 / 2 = 25 bags |
| Weight estimate | Cu yd x Weight per yard | 1.85 x 600 = ~1,110 lbs |
Recommended Depth by Material
| Material | Recommended Depth | Purpose |
|---|---|---|
| Wood chip mulch | 2-4 inches | Weed suppression, moisture retention, aesthetics |
| Bark mulch | 2-3 inches | Decorative beds, trees, shrubs |
| Rubber mulch | 1-3 inches | Playgrounds, high-traffic areas (does not decompose) |
| Topsoil | 4-6 inches | Lawn repair, new garden beds, filling raised beds |
| Compost | 1-3 inches | Top-dressing lawns, enriching garden beds |
| Pea gravel | 2-3 inches | Pathways, drainage, decorative ground cover |
| Crushed stone | 3-4 inches | Driveways, walkways, drainage base |
| Sand | 1-2 inches | Paver base, levelling, play areas |
| River rock | 2-4 inches | Decorative landscaping, erosion control |
Material Weight and Density
| Material | Weight per Cubic Yard | Weight per Bag (2 cu ft) | Notes |
|---|---|---|---|
| Wood chip mulch | 400-800 lbs | 20-40 lbs | Lighter when dry, much heavier when wet |
| Bark mulch | 500-700 lbs | 25-35 lbs | Medium weight, decomposes over 1-2 years |
| Topsoil | 1,800-2,200 lbs | ~40 lbs | Screened topsoil is denser than unscreened |
| Compost | 1,000-1,600 lbs | ~30 lbs | Varies widely by composition and moisture |
| Pea gravel | 2,500-2,800 lbs | ~50 lbs | Heavy - consider delivery for large quantities |
| Sand | 2,400-2,700 lbs | 50 lbs | Standard play sand bags are typically 50 lbs |
Coverage Reference (One Cubic Yard Covers)
| Depth | Coverage Area | Typical Use |
|---|---|---|
| 1 inch | 324 sq ft | Light top-dressing, compost |
| 2 inches | 162 sq ft | Light mulch layer, sand levelling |
| 3 inches | 108 sq ft | Standard mulch depth, gravel pathways |
| 4 inches | 81 sq ft | Thick mulch, topsoil for new beds |
| 6 inches | 54 sq ft | Raised bed fill, deep topsoil layer |
Bags vs Bulk Delivery
| Option | Typical Cost | Best For | Considerations |
|---|---|---|---|
| Bagged (2 cu ft) | $3-8 per bag | Under 2 cubic yards | Convenient, easy to transport in a car, but more expensive per yard |
| Bagged (3 cu ft) | $4-10 per bag | Under 2 cubic yards | Fewer bags needed, still car-friendly |
| Bulk delivery | $25-60 per cubic yard + delivery | 3+ cubic yards | Much cheaper per yard, but needs driveway space for dump |
| Pickup truck load | $25-60 per cubic yard (no delivery fee) | 1-3 cubic yards | Saves delivery fee if you have a truck; one yard weighs 400-2,800 lbs |
Mulching Tips
| Tip | Why It Matters |
|---|---|
| Keep mulch 2-3 inches from tree trunks | "Volcano mulching" against the trunk causes rot and pest problems |
| Do not exceed 4 inches depth | Too-thick mulch suffocates plant roots and prevents water penetration |
| Refresh annually | Organic mulch decomposes and thins over time; top up each spring |
| Lay landscape fabric under gravel | Prevents gravel from sinking into soil and weeds from growing through |
| Order 5-10% extra | Uneven ground, settling, and spreading losses mean you always need a little more |
What Does Mulch Cost in 2026?
Bulk mulch typically runs $30-$55 per cubic yard for standard wood chip, and $60-$110 per cubic yard for dyed or premium bark, per Angi's 2026 cost data. Delivery adds $50-$150 depending on distance and load size, so most homeowners end up paying around $100-$175 per cubic yard delivered. Bagged mulch at big-box stores sits around $3-$8 for a 2 cu ft bag, which works out to roughly $40-$110 per cubic yard - comparable to bulk for small jobs but far more expensive once you need 3+ yards.
| Project Size | Cheapest Route | Typical Total (2026) |
|---|---|---|
| Under 1 cu yd (a few beds) | Bagged from big-box store | $30-$80 |
| 1-2 cu yd (full front yard) | Bagged or pickup truck load | $60-$200 |
| 3-5 cu yd (whole garden) | Bulk delivery | $200-$800 |
| 6+ cu yd (large property) | Bulk delivery with bulk discount | $500-$1,500+ |
Regional pricing varies. HomeGuide's 2026 data shows urban yards at $45-$65, suburban at $30-$50, and rural at $20-$40 per cubic yard for the material alone. Installation (spreading) adds another $20-$45 per yard if you hire it out.
How Deep Should You Actually Go?
The US Forest Service and most university extension services recommend 2-4 inches for wood mulch around trees and in garden beds. Less than 2 inches is too thin to block weeds or hold moisture, and more than 4 inches starts to suffocate roots and create the classic "mulch volcano" around trees that causes trunk rot. For playground surfaces, the Consumer Product Safety Commission's public playground handbook recommends 9 inches of engineered wood fibre or 6 inches of shredded rubber for a 5-foot fall height, with 12 inches for a 10-foot fall height.
Topsoil for a new garden bed wants 6-8 inches if you're building on poor subsoil, or 2-4 inches for overseeding a lawn. Gravel for a walkway works at 2-4 inches with a compacted base below, while driveway gravel needs 4-6 inches with a crushed-stone sub-base beneath that.
Common Mulch and Topsoil Mistakes
| Mistake | Why It Matters | Fix |
|---|---|---|
| Volcano mulching against tree trunks | Traps moisture, invites pests and fungus, causes root girdling | Keep a 2-3 inch gap between mulch and trunk; taper like a doughnut, not a cone |
| Piling mulch over 4 inches deep | Starves roots of oxygen; water runs off instead of soaking in | Maintain 2-4 inches; refresh only to restore depth, don't add on top |
| Buying "topsoil" without asking what's in it | Cheap fill-grade topsoil is often subsoil or construction spoil with low organic content | Ask for screened topsoil with stated organic matter (5% minimum for planting) |
| Skipping landscape fabric under gravel | Gravel sinks into soil within 1-2 years and weeds push through | Use woven geotextile under decorative gravel; avoid under play sand |
| Measuring a curved bed as a rectangle | Overestimates volume by 20-40% for kidney or crescent beds | Split into trapezoids, or use a string to trace the perimeter and work out the true area |
| Forgetting to order 5-10% extra | Uneven ground, settling, and spill during spreading always eat more than expected | Round up after adding 5-10%; bulk suppliers usually sell half-yard increments |
Metric or Imperial? Units Around the World
The cubic yard is mainly used in the US and parts of Canada. The UK, Europe, Australia, and New Zealand sell landscape material by the cubic metre, the tonne, or the litre for bagged products. One cubic yard equals 0.7646 cubic metres, and one cubic metre equals 1.308 cubic yards. For bagged mulch, UK and EU garden centres typically sell 50 L, 75 L, or 100 L bags - a 75 L bag is roughly 2.65 cubic feet, comparable to a US "2 cu ft" bag. Use the unit toggle at the top of this tool to switch systems at any time; existing dimensions are converted rather than cleared so nothing is lost.
How This Compares to Other Volume Tools
This mulch calculator is tuned for landscape materials with built-in density figures, depth recommendations, and bag conversions. For a more general volume calculation without material presets, the cubic yards calculator handles any shape and returns volume only. If you only need to measure the area of a bed before choosing a depth, the square footage calculator converts dimensions to square feet or square metres. For hardscaping jobs that need concrete instead of loose fill, the concrete calculator uses similar volume maths but with the density and bag coverage of ready-mix concrete.
All calculations run in your browser. Nothing is stored or sent anywhere.
Sources
Frequently Asked Questions
How much mulch do I need for a 10x10 area?
For a 10x10 foot area at 3 inches deep, you need about 0.93 cubic yards, which is roughly 13 bags of 2-cubic-foot mulch. At 4 inches deep, you need 1.23 cubic yards or about 17 bags.
How many bags of mulch are in a cubic yard?
There are about 13.5 bags of 2-cubic-foot mulch in one cubic yard (27 cubic feet per yard divided by 2 cubic feet per bag). If you are using 3-cubic-foot bags, you need 9 bags per cubic yard.
How deep should mulch be applied?
Apply mulch 2-4 inches deep for garden beds and around trees. Keep mulch a few inches away from plant stems and tree trunks to prevent rot. For playgrounds, 6-12 inches is recommended for safety.
What is the difference between mulch and topsoil?
Mulch sits on top of soil to retain moisture, suppress weeds, and regulate temperature. Topsoil is nutrient-rich soil used to fill, level, or improve existing soil for planting. They serve different purposes and have different weights per cubic yard.
How much does a cubic yard of gravel weigh?
A cubic yard of gravel weighs approximately 2,800 pounds (about 1.4 tons). This varies by gravel type - pea gravel is lighter around 2,500 lbs, while crushed stone can be heavier at 3,000+ lbs per cubic yard.
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