Your cart is currently empty!
How to Calculate How Much Mulch, Soil, or Gravel You Need
Let’s be honest—one of the trickiest parts of starting a landscaping project isn’t picking the materials… it’s figuring out how much of it you actually need. Whether you’re laying down mulch in a flower bed, filling a raised garden with soil, or covering a driveway with gravel, getting the quantity right makes all the difference.
We get this question all the time at High Country Landscape Supply, and we’re here to help break it down in plain English—with simple tips, clear examples, and a handy cheat sheet to make your next project smooth from start to finish.
Step 1: Measure Your Project Area
Before we can calculate how much material you’ll need, we have to get the square footage of the area you’re working on.
✅ For square or rectangular areas:
Multiply the length x width (in feet).
Example:
If your garden bed is 12 feet long and 6 feet wide:12 ft x 6 ft = 72 square feet
✅ For circular areas:
Use the formula:
π × radius² (radius is half the width of the circle)
Example:
A round flower bed that’s 6 feet across has a 3-foot radius:3 x 3 x 3.14 = 28.26 square feet
Step 2: Decide on Your Depth
How deep should you lay your material? It depends on the type:
| Material | Recommended Depth |
|---|---|
| Mulch | 2–3 inches |
| Pine Straw | 3 inches or one bale per ~40–50 sq ft |
| Garden Soil / Topsoil | 6–12 inches depending on plant needs |
| Gravel / Stone | 2–4 inches for light use, 4–6 inches for driveways |
For most mulch or gravel projects, 2–3 inches is ideal. Raised beds or new lawn areas? You’ll want deeper coverage with soil.
Step 3: Convert Square Feet to Cubic Yards
Materials like mulch, soil, and gravel are sold by the cubic yard.
Here’s the formula to convert square feet to cubic yards:
mathematicaCopyEdit(Square Feet × Depth in Inches) ÷ 324 = Cubic Yards
Example:
You have 72 sq ft and want 3 inches of mulch:(72 × 3) ÷ 324 = 0.67 cubic yards
Round up to 1 cubic yard to be safe—you’ll always use a little more than expected!
Need a Quick Reference? Use This Table:
| Project Area (sq ft) | 2″ Depth | 3″ Depth | 4″ Depth |
|---|---|---|---|
| 100 sq ft | 0.62 yd³ | 0.93 yd³ | 1.24 yd³ |
| 200 sq ft | 1.23 yd³ | 1.85 yd³ | 2.47 yd³ |
| 500 sq ft | 3.09 yd³ | 4.63 yd³ | 6.17 yd³ |
| 1,000 sq ft | 6.17 yd³ | 9.26 yd³ | 12.35 yd³ |
Pro Tip: Always round up—it’s better to have a little extra than to come up short mid-project.
What About Pine Straw?
Pine straw is typically sold by the bale, not cubic yard. One bale of longneedle pine straw covers about 40–50 square feet at a 3-inch depth.
So if you have a 200 square foot bed:200 ÷ 45 (avg coverage) = ~4.5 bales → Round up to 5 bales.
👉 Need Pine Straw? Shop Longneedle Pine Straw
Let’s Talk Gravel, Stone & Crusher Run
If you’re working with stone like pea gravel, #57 stone, or crusher run, depth is key—especially for driveways or walkways.
| Use Case | Recommended Depth |
|---|---|
| Walkways | 2–3 inches |
| Driveways (light vehicle) | 4–6 inches |
| Driveways (heavy traffic) | 6+ inches |
For example:
A 10×20 ft driveway at 4 inches deep10 x 20 = 200 sq ft200 × 4 ÷ 324 = 2.47 cubic yards → Order 3 cubic yards
Still Not Sure? We’re Happy to Help!
We totally get it—math isn’t everyone’s thing (we prefer dirt and tractors too). If you’re not 100% sure how much to order, just give us a call or stop by and we’ll walk you through it.
We’re always happy to help you figure out the right amount based on your project, your space, and your goals.
📞 Call us at (205) 225-7155
📍 Or visit us in Alabaster, AL
Final Thoughts
Planning your next landscape project doesn’t have to be overwhelming. With just a few quick measurements and our simple formula, you’ll know exactly how much mulch, soil, or gravel to order—saving you time, money, and stress.
And remember: at High Country Landscape Supply, we’ve got all the bulk materials you need, loaded up and ready for pickup or local delivery.
