How to use this calculator
- Measure the area. Length × width of the area in feet. For irregular playground borders, break into rectangles and add results.
- Pick a depth. 6 inches for ASTM-rated playground impact attenuation; 2–3 inches for landscape use; 1–2 inches around pet kennels.
- Read your result. You get cubic yards (for bulk pricing) plus the bag count for both common bag sizes.
- Order with 10% extra. Rubber mulch settles less than wood mulch but you still want a buffer for edge work and refilling low spots.
Formula
Cubic yards = (Length × Width × Depth in feet) ÷ 27
Worked example
A 20×20 ft playground at 6 in deep needs 200 ft³ ÷ 27 = 7.4 cubic yards = ~94 bags of 2 cu ft retail rubber mulch (or 250 of the 0.8 cu ft bags). Add 10% waste → ~104 retail bags total.
Tips for accurate results
- Rubber mulch lasts 10+ years vs 1–2 for wood mulch — higher upfront cost, lower lifetime cost.
- For ASTM F1292 fall-rating compliance, install 6 inches over a geo-textile fabric base.
- Use a metal or hard plastic edging — rubber mulch migrates over time on smooth borders.
- Hose-rinse occasionally to remove dust and pollen; rubber mulch does not break down or absorb moisture.