Enter the size of the bed or play area and the depth you need. The calculator gives the bags of rubber mulch to buy, the cubic yards and the approximate weight in tons for bulk orders.
How to use the rubber mulch calculator
- Choose a rectangle or a circle and enter the size of the area. For a playground, measure the whole use zone around the equipment, not just the footprint of the set.
- Enter the depth: about 1.5 in for a landscape bed and 6 in under play equipment.
- Enter the bag size printed on the bag. Retail bags are often 0.8 ft³.
- Leave the weight at 26 lb per cubic foot unless your supplier gives another figure, and enter a price per bag for a cost.
Rubber mulch formulas
Volume (ft³) = area (ft²) × depth (ft) Bags = volume ÷ bag size (ft³), rounded up Cubic yards = volume ÷ 27 Weight (lb) = volume × weight per ft³; tons = lb ÷ 2,000
Rubber mulch does not break down or settle the way wood mulch does, so the calculator adds no extra by default. The GroundSmart 0.8 ft³ bag sold at Lowe’s is rated to cover 6.4 ft² at 1.5 in, which is exactly 0.8 ÷ (1.5 ÷ 12).
Worked example: a 20 × 20 ft playground, 6 in deep
- Area: 20 × 20 = 400 ft².
- Volume: 400 × (6 ÷ 12) = 200 ft³, or 7.41 yd³.
- Bags of 0.8 ft³: 200 ÷ 0.8 = 250 bags.
- Weight at 26 lb/ft³: 200 × 26 = 5,200 lb, or 2.6 tons.
The same 400 ft² as a landscape bed at 1.5 in needs only 50 ft³, or 63 bags.
How deep should rubber mulch be?
For landscape beds, GroundSmart rates its bags at a depth of 1.5 inches, half the usual depth for wood mulch, because rubber nuggets do not decompose or blow away as easily. Under playground equipment, the U.S. Consumer Product Safety Commission’s Public Playground Safety Handbook recommends 6 inches of shredded or recycled rubber, which it rates for fall heights up to 10 feet. The handbook asks for at least 9 inches of other loose-fill materials such as wood chips; rubber is the exception. Check the depth regularly, because loose fill gets kicked out of high-traffic spots under swings and slide exits.
Rubber mulch per bag at different depths
| Depth | One 0.8 ft³ bag covers | Bags per 100 ft² | Cubic yards per 100 ft² |
|---|---|---|---|
| 1 in | 9.6 ft² | 11 | 0.31 |
| 1.5 in | 6.4 ft² | 16 | 0.46 |
| 2 in | 4.8 ft² | 21 | 0.62 |
| 3 in | 3.2 ft² | 32 | 0.93 |
| 6 in | 1.6 ft² | 63 | 1.85 |
How much does rubber mulch weigh?
Bulk rubber mulch is sold by weight, often in 2,000 lb sacks. AAA State of Play says 13 pounds covers one square foot at 6 inches before compaction, which works out to about 26 lb per cubic foot, the default here. Shred size and the source of the rubber change the weight, so ask your supplier and enter their figure when you buy by the ton.
Tips for buying rubber mulch
- Lay landscape fabric first. It keeps weeds down and stops the nuggets from working into the soil.
- Edge the area. A border holds rubber mulch in place, especially on a playground where it gets kicked around.
- Compare bags and bulk. For a playground at 6 in, bulk sacks are usually far cheaper than hundreds of retail bags.
- Check for certification under play sets. For a playground, choose a product the seller states has been tested for impact attenuation.
Questions
How much rubber mulch do I need for a playground?
Multiply the area in square feet by 0.5 (6 inches) to get cubic feet. A 20 × 20 ft area takes 200 ft³: 250 bags of 0.8 ft³, about 7.4 cubic yards or 2.6 tons.
How many square feet does a bag of rubber mulch cover?
A 0.8 ft³ bag covers 6.4 ft² at 1.5 in, 3.2 ft² at 3 in and 1.6 ft² at 6 in.
Is rubber mulch sold by the ton or the yard?
Both. Retail bags are sold by volume, while bulk rubber mulch is usually sold by weight. At about 26 lb per cubic foot, a cubic yard weighs around 700 lb, so a ton covers roughly 2.9 cubic yards.
Do I need more rubber mulch than wood mulch?
No. In a landscape bed, rubber mulch is usually laid about half as deep as wood mulch. On a playground it is the other way round per square foot of safety: 6 in of rubber against at least 9 in of wood chips.
Sources
- Public Playground Safety Handbook, U.S. Consumer Product Safety Commission.
Used for: 6 in of shredded or recycled rubber recommended, rated to a 10 ft fall height; 9 in minimum for other loose fill. - GroundSmart 0.8 cu ft Black Rubber Mulch, Lowe’s.
Used for: 0.8 ft³ bag size; coverage of 6.4 ft² at 1.5 in depth. - Rubber Mulch, 2,000 lb, AAA State of Play.
Used for: 13 lb covers 1 ft² at 6 in before compaction (about 26 lb per ft³). - NIST Guide to the SI, Appendix B.8: Factors for units listed alphabetically, National Institute of Standards and Technology.
Used for: Exact inch and foot definitions; cubic foot and cubic yard conversions.