Estimate playground surfacing quantity from length, width, desired depth and coverage rated at 3 inches. The reference depth is a conversion basis, not a recommended protective depth.

Quantity estimate only. It does not select a safe surfacing material or certify fall protection. Use tested playground surfacing and the required maintained depth for the equipment, fall height and local rules.

Use a supplier rating at exactly this reference depth. Pure geometry gives 108 ft²/yd³ or 13.12336 m²/m³; settling is not included.

Related Calculators

Playground Mulch Formula

The calculator uses the coverage rating at a 3-inch depth as the reference point. Pure geometry gives 108 square feet per cubic yard at 3 inches deep (27 cubic feet divided by 0.25 feet). This excludes settling, compaction and displacement.

M = (L × W × (D / 3)) / C
  • M = amount of mulch needed, in cubic yards
  • L = playground length, in feet
  • W = playground width, in feet
  • D = mulch depth, in inches
  • C = coverage per mulch unit at 3 inches deep, in square feet per cubic yard

When solving for a missing value, the same formula is rearranged:

L = (M × C × 3) / (W × D)
W = (M × C × 3) / (L × D)
D = (M × C × 3) / (L × W)
C = (L × W × (D / 3)) / M

Choose the value to solve for, enter the four known values and select the result unit. The calculation uses consistent SI conversions with the same fixed 3-inch (7.62 cm) coverage reference. Coverage is area per volume; supplier ratings should use that exact reference depth.

Common Playground Mulch Coverage at Different Depths

These values assume 1 cubic yard of mulch covers 108 square feet at 3 inches deep.

Mulch Depth Coverage per Cubic Yard Calculation
3 inches 108 sq ft 108 × 3 / 3
6 inches 54 sq ft 108 × 3 / 6
9 inches 36 sq ft 108 × 3 / 9
12 inches 27 sq ft 108 × 3 / 12

Estimated Mulch Needed for Common Playground Sizes

The estimates below use 108 square feet per cubic yard at 3 inches deep.

Playground Size Area 6 in Depth 9 in Depth 12 in Depth
10 ft × 10 ft 100 sq ft 1.85 cu yd 2.78 cu yd 3.70 cu yd
12 ft × 16 ft 192 sq ft 3.56 cu yd 5.33 cu yd 7.11 cu yd
20 ft × 20 ft 400 sq ft 7.41 cu yd 11.11 cu yd 14.81 cu yd
30 ft × 40 ft 1,200 sq ft 22.22 cu yd 33.33 cu yd 44.44 cu yd

Example Calculations

Example 1: Calculate cubic yards of mulch

You have a playground that is 20 feet long and 15 feet wide. You want 9 inches of mulch. The coverage is 108 square feet per cubic yard at 3 inches.

M = (20 × 15 × (9 / 3)) / 108
M = 900 / 108 = 8.3333

You need about 8.33 cubic yards of mulch.

Example 2: Calculate depth from mulch amount

You have a 12-foot-by-16-foot playground and 6 cubic yards of mulch. The coverage is 108 square feet per cubic yard at 3 inches.

D = (6 × 108 × 3) / (12 × 16)
D = 1944 / 192 = 10.125

The mulch depth is about 10.13 inches.

FAQs

How deep should playground mulch be?

Required depth depends on the surfacing product and equipment fall height. Use playground surfacing with appropriate impact-test data and follow its installation, maintained-depth and local requirements. Ordinary landscape mulch is not automatically suitable. See the CPSC Public Playground Safety Handbook, July 2025, sections 2.4.2–2.4.2.2. The 3-inch reference and example depths here are calculation examples, not safety recommendations.

Why is coverage based on 3 inches?

Mulch suppliers often list coverage at a standard 3-inch depth. The calculator adjusts that coverage for your desired depth. If you double the depth from 3 inches to 6 inches, the same amount of mulch covers half as much area.

Should you order extra mulch?

It is usually practical to allow extra for settling, uneven ground, edging gaps, and future top-ups. Playground mulch can compact over time, so the installed depth may drop after use and weather exposure.