Sandbox Calculator — How Much Sand to Fill a Sandpit
Enter your sandbox dimensions and the desired sand depth, and this calculator tells you exactly how many litres of play sand you need, how much it will weigh, and how many 25 kg or 50 lb bags to buy.
Units
cm
cm
cm
Volume of play sand to fill the sandbox to the chosen depth
144 L
- 1
Volume (m³)
1.2 × 0.8 × 0.15 m = 0.144Dimensions converted from cm to metres. - 2
Volume (litres)
0.144 m³ × 1 000 = 144
How does this calculator work?
Multiply sandbox length × width × depth to get the volume, then multiply by 1.5 kg/L (packed play sand density) for the weight. A 120 × 80 cm sandbox filled 15 cm deep needs about 144 L / 216 kg of sand — roughly 9 standard 25 kg bags. Buy one bag extra as a buffer.
Formula
How this is calculated
The calculation is straightforward: multiply the three interior dimensions of the sandbox to get the cubic volume, then convert to litres (1 m³ = 1 000 L). The bag count comes from dividing the total weight by the bag size and rounding up, so you never run short.
The trickiest part is density. Dry, loose play sand has a bulk density of roughly 1 400–1 600 kg/m³; this calculator uses 1 500 kg/m³ as a practical midpoint for standard bagged play sand that has settled slightly. Very fine or wet sand can weigh more; very coarse or bone-dry sand can weigh less. The result is therefore an estimate — buying one extra bag as a buffer is always a good idea.
A fill depth of 15–30 cm (6–12 in) is the standard recommendation for children aged 2–8. Shallower than 10 cm feels thin and dries out quickly; deeper than 30 cm is unnecessary and adds significant cost. Note that play sand sold in bags has been washed and sieved specifically for children — builder's sand, beach sand, and quarry sand may contain silica dust or contaminants and should not be used in sandboxes.
Frequently asked questions
A depth of 15–30 cm (6–12 in) is the standard recommendation for children aged 2–8: deep enough to dig and build but shallow enough to be safe and easy to supervise. Shallower fills dry out quickly; going much deeper adds a lot of weight and cost without much play benefit.
The calculator divides the total weight by the bag size and rounds up to the nearest whole bag. A typical 120 × 80 cm sandbox filled to 15 cm deep needs roughly 220 kg — about 9 bags of 25 kg or 10 bags of 50 lb.
No — use only bagged play sand certified as safe for children. It is washed, sieved, and tested for hazardous minerals (such as crystalline silica) that are present in builder's sand, beach sand, and quarry sand, all of which are unsuitable for children's play areas.
Also known as
TG we-Calculate Editorial Team. (2026). Sandbox Calculator — How Much Sand to Fill a Sandpit [Online calculator]. TG we-Calculate. https://we-calculate.com/calculator/sandbox-calculator
TG we-Calculate Editorial Team. "Sandbox Calculator — How Much Sand to Fill a Sandpit." TG we-Calculate. 2026. https://we-calculate.com/calculator/sandbox-calculator.
TG we-Calculate Editorial Team, "Sandbox Calculator — How Much Sand to Fill a Sandpit," TG we-Calculate, 2026. [Online]. Available: https://we-calculate.com/calculator/sandbox-calculator
@misc{wecalculate_sandbox_calculator, title = {Sandbox Calculator — How Much Sand to Fill a Sandpit}, author = {{TG we-Calculate Editorial Team}}, howpublished = {\url{https://we-calculate.com/calculator/sandbox-calculator}}, year = {2026}, note = {TG we-Calculate} }
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