Enter the size of your sandbox and how deep you want the sand. The calculator gives the number of 50 lb bags of play sand to buy, the cubic feet and the total weight to carry home.
How to use the sandbox sand calculator
- Choose a square or rectangle, or a circle for a round sandbox or a tractor tire, and enter the inside size.
- Enter the depth of sand. Leaving the sand a few inches below the rim keeps more of it in the box.
- Keep 0.5 ft³ and 50 lb for standard bags, or enter the size printed on the bag you buy.
- Enter a price per bag to compare with a bulk delivery.
Sandbox sand formula
Volume (ft³) = length × width × depth (or π × (diameter ÷ 2)² × depth) Bags = volume ÷ bag size (ft³), rounded up Weight = bags × bag weight
Lowe’s lists Quikrete play sand as a 50 lb bag holding 0.5 ft³, which is the default here: two bags fill one cubic foot.
Worked example: a 6 × 6 ft sandbox, 8 in deep
- Area: 6 × 6 = 36 ft².
- Volume: 36 × (8 ÷ 12) = 24 ft³, or 0.89 yd³.
- Bags: 24 ÷ 0.5 = 48 bags of 50 lb play sand.
- Weight: 48 × 50 = 2,400 lb, about 1.2 tons, which is several trips in a car.
Bags of play sand by sandbox size
Using 0.5 ft³ per 50 lb bag:
| Sandbox | 6 in deep | 8 in deep | 12 in deep |
|---|---|---|---|
| 4 × 4 ft | 16 | 22 | 32 |
| 5 × 5 ft | 25 | 34 | 50 |
| 6 × 6 ft | 36 | 48 | 72 |
| 8 × 8 ft | 64 | 86 | 128 |
| 4 ft round | 13 | 17 | 26 |
| 6 ft round | 29 | 38 | 57 |
Bags or bulk sand?
Bagged play sand is washed and screened for sandboxes, and is easy to carry in small amounts. For a big sandbox, a landscape supplier can deliver sand by the cubic yard or ton, which costs much less per cubic foot; one cubic yard is 27 ft³, the same as 54 bags. Ask for a clean, washed play sand, and see the sand calculator for tons.
Tips for filling a sandbox
- Lay fabric first. Landscape fabric under the sand keeps weeds out and lets water drain.
- Add a cover. A lid keeps out leaves, rain and animals.
- Plan for top-ups. Sand leaves the box on shoes and clothes; a few spare bags a year keep the level up.
- Fill tires and odd shapes with the circle option, using the inside diameter.
Questions
How many bags of sand do I need for a 4 × 4 sandbox?
About 22 bags of 50 lb play sand at 8 in deep, or 16 bags at 6 in.
How much sand for a 6 × 6 sandbox?
About 48 bags (24 ft³) at 8 in deep, or 36 bags at 6 in.
How many cubic feet is a 50 lb bag of play sand?
About 0.5 ft³, so two bags fill one cubic foot.
How deep should sand be in a sandbox?
Deep enough to dig in, with room left below the rim. Six to eight inches is a practical range for most small sandboxes.
Sources
- QUIKRETE 0.5 cu ft 50 lb Play Sand, Lowe’s.
Used for: 50 lb bag of play sand holds 0.5 ft³. - NIST Guide to the SI, Appendix B.8: Factors for units listed alphabetically, National Institute of Standards and Technology.
Used for: Inch and foot definitions; cubic foot to cubic yard and cubic metre.