How much sand do I need for a sandpit?
Published · Updated · By Sai Nath
Multiply the inside length, width and sand depth in metres. A 1.8 × 1.8 m sandpit filled 300 mm deep holds 1.8 × 1.8 × 0.3 = 0.972 m³, or 972 litres. For 20 kg bags, multiply the cubic metres by the sand’s density in kg/m³ and divide by 20: at 1,500 kg/m³ that is 73 bags.
In the app: Gravel in MeisterCalc, with a worked example and real screens.
Checked on 5 November 2026. A sandpit is a box of sand, so the volume is length × width × depth. The part that takes care is the weight: play sand is sold in 20 kg bags or by the tonne or cubic metre, and sand does not have one density. The depths here come from two linked building guides; the density is the supplier’s.
How do I work out the sand for a sandpit?
- Measure the inside of the frame, not the outside: the timber takes up room.
- Decide the depth of sand, not the height of the sides. Leave the top of the frame clear so the sand stays in.
- Multiply length × width × depth, all in metres, for cubic metres. × 1,000 gives litres.
- For bags or tonnes, multiply the cubic metres by the sand’s density in kg/m³ for kilograms; ÷ 20 for 20 kg bags, ÷ 1,000 for tonnes. Round bags up.
Worked example: a 1.8 m square sandpit, 300 mm of sand
A frame 1.8 m × 1.8 m inside, filled 300 mm deep.
- Volume: 1.8 × 1.8 × 0.3 = 0.972 m³, or 972 litres.
- Weight at an example density of 1,500 kg/m³: 0.972 × 1,500 = 1,458 kg, or 1.458 t.
- 20 kg bags: 1,458 ÷ 20 = 72.9, so 73 bags.
The 1,500 kg/m³ is an example to show the sum, not a figure for your sand: use the supplier’s.
How deep should the sand in a sandpit be?
The guides differ, so pick a depth that suits the frame:
- Australian Native Landscapes’ sandpit guide says to dig out “to about 200mm below the grass or finished sand level” before setting the frame (ANL, how to build a sandpit).
- A New Zealand build guide says “A good depth is 300mm deep” (L&L, how to build a sandpit, 2017).
Depth drives the order. The same 1.8 m square pit at 200 mm is 1.8 × 1.8 × 0.2 = 0.648 m³; at 300 mm it is 0.972 m³, half as much again.
How many 20 kg bags of sand do I need?
Bags are sold by weight, so the bag count needs a density. Sand has no single one: it changes with the product, how damp it is and how loose it lies, which is also why how much sand for paving gives no table. Ask the supplier for the kg per m³, or use the coverage printed on the bag.
For the 0.972 m³ pit, three example densities show how much it moves the count:
| If the sand is | Weight | 20 kg bags |
|---|---|---|
| 1,300 kg/m³ | 0.972 × 1,300 = 1,263.6 kg | 63.2, so 64 |
| 1,500 kg/m³ | 0.972 × 1,500 = 1,458 kg | 72.9, so 73 |
| 1,600 kg/m³ | 0.972 × 1,600 = 1,555.2 kg | 77.8, so 78 |
That spread, 64 to 78 bags, is why the supplier’s figure matters more than any rule of thumb. A bought sandpit kit usually states how many bags it takes; use that.
How much sand for a round sandpit?
A round pit is π × radius² × depth. One 1.5 m across, with 200 mm of sand, has a 0.75 m radius: 3.1416 × 0.75 × 0.75 × 0.2 = 0.3534 m³, about 353 litres. At an example 1,500 kg/m³ that is 0.3534 × 1,500 = 530 kg, or 530 ÷ 20 = 26.5, so 27 bags.
In MeisterCalc, Home ▸ Concrete ▸ Holes is a cylinder: enter Diameter 1500 mm, Depth 200 mm and Number of Holes 1 and it shows Per Hole 0.3534 m³, Total 0.3534 m³ and Order (+10%) 0.3888 m³. It is free.
Bags or a bulk load?
Bags are easy to carry into a back yard and suit a small pit. Past a cubic metre or so, the number of bags gets long, and a landscape yard’s bulk load, sold by the tonne or cubic metre, is worth pricing. Ask whether the sand is washed and sold for play, and what the yard’s smallest load is. If you are collecting it, check what your trailer can carry: how many cubic metres fit in a trailer.
What MeisterCalc does and doesn’t do
- Gravel gives volume, tonnes and a +10% order in tonnes for the density you enter, between 100 and 5,000 kg/m³.
- Concrete ▸ Slab (rectangles, with litres) and Concrete ▸ Holes (circles) give the volume and are free.
- There is no sand preset, no bag counter and no sand densities. Divide by the bag weight yourself.
- It doesn’t pick the sand. Ask the supplier for sand sold for play.
Try it
Concrete, Stairs and Check Square are free to use, with no trial and no card needed. The other 13, Soil and Gravel included, unlock with a one-time purchase, no subscription required, or with a weekly subscription that starts with a 3-day free trial; Google Play shows the prices in your currency. Calculations work offline on Android 7.0 or later.
Sources
- Australian Native Landscapes, how to build a sandpit: excavate about 200 mm below the grass or finished sand level; sand in 20 kg bags. Checked on 5 November 2026.
- L&L (Lucinda Diack), how to build a sandpit, 4 August 2017: a good depth is 300 mm. Checked on 5 November 2026.