When you’re ordering mulch, screened topsoil, compost, or gravel/stone, the most common question is:
“How many yards do I need?” Here’s a clear, copy‑and‑paste guide (with a quick calculator) that works for
flower beds, lawns, and hardscape areas.

First Things First: What’s a Cubic Yard?

A cubic yard measures volume (not weight). Picture a box that’s 3 ft × 3 ft × 3 ft.
Fill that box to the top—that’s 1 cubic yard (27 cu ft).

• 1 cubic yard = 27 cubic feet
• Volume ≠ Weight (weight varies by material and moisture)

The Quick Formula

Use this every time:

Cubic Yards Needed = (Area in sq ft × Depth in inches) ÷ 324

Why 324? Because 1 yard = 27 cu ft and 1 inch = 1/12 ft, so 27 ÷ (1/12) = 324.

Coverage Per Yard (At Common Depths)

Many suppliers use a rule of thumb that 1 yard covers ~100 sq ft at 3″ to build in a small buffer for
settling and irregular edges. The exact math is shown below.

Tip: For neat beds, use the exact numbers. For natural edges or older beds that will settle, plan 5–15% extra.

Recommended Depths by Material

• Mulch (refresh): 2–3″
• Mulch (new beds or weed suppression): 3–4″
• Topsoil (lawn prep before seed/sod): 2–3″ over large areas (more for low spots)
• Compost (topdress or amend): 0.5–1″ topdress, or mix 1–3″ into soil
• Stone/Gravel cover: 2″ for most decorative layers; 3–4″ for drive areas (base design may vary)

How to Measure Your Area (Fast)

Measure in feet, then use the formula above. For curved beds, approximate—this is common and totally fine.

• Rectangle / Square: Length × Width
• Circle: 3.14 × (radius)²  (radius = half the diameter)
• Triangle: 0.5 × Base × Height
• Oval / Curvy Beds: Length × Average Width × 0.8 (good landscape approximation)
• Multiple Beds: Add all square footages before you calculate yards

Worked Example (Real‑World)

Scenario: Three planting beds at ~3″ of mulch.

1. Front left bed: 4 ft × 20 ft = 80 sq ft
2. Front right bed: 4 ft × 10 ft = 40 sq ft
3. Back curved bed (oval): length 15 ft, width varies 2–8 ft → avg width ~5 ft
   Area ≈ 15 × 5 × 0.8 = 60 sq ft

Total area = 80 + 40 + 60 = 180 sq ft

Yards needed = (180 × 3) ÷ 324 = 1.67 yards

Order: Round up to 2 yards to account for edges and settling. If your beds are deeper or wider, scale the math—same formula.

Instant Yardage Calculator

Enter your dimensions and target depth. Uses the exact formula.

Typical Weights per Cubic Yard (Approx.)

Moisture matters. Freshly rained‑on material can weigh significantly more.

Bulk vs. Bags (Quick Equivalents)

• 1 cubic yard ≈ 27 bags at 1 cu ft each
• 1 cubic yard ≈ 18 bags at 1.5 cu ft each
• 1 cubic yard ≈ 13–14 bags at 2 cu ft each

Bulk is usually more economical and faster to install for anything over ~½ yard.

Pro Tips for Ordering & Spreading

• Account for settling: Organic materials (mulch/compost) can settle 10–30%.
• Edge first, then fill: Keep a clean edge and backfill to depth for a crisp finish.
• Depth gauges help: A simple ruler or marked garden trowel keeps you consistent.
• Plan the dump spot: Choose a level, accessible area and protect the driveway with a tarp if desired.
• Multiple areas? Do one bed at a time so you don’t under‑ or over‑use material.