Sand Calculator
Estimate cubic metres, tonnes, bulk bags and small bags of sand from the area, depth and chosen sand type.
How much sand do I need?
Enter the length and width of the area, the required depth and the closest sand type. BuildCalcs calculates the volume, applies your allowance and then converts the result to an approximate weight, bulk bags and smaller bags.
Sand volume formula
Volume (m³) = length (m) × width (m) × depth (m)
The weight estimate then uses the selected planning density. Sand density varies with grading, moisture and compaction, so the supplier's figure should take priority when you are ready to order.
Worked example: 5 m × 3 m at 50 mm
A 5 m by 3 m area at 50 mm deep has a base volume of 0.75 m³. Using the default sharp-sand density of 1.60 t/m³ gives approximately 1.20 tonnes before the allowance is added. With a 5% allowance the estimate becomes about 1.26 tonnes.
Sharp sand, building sand, play sand and kiln-dried sand
Sharp sand is a coarser material often used in paving and concrete-related applications. Building sand is finer and is commonly associated with bricklaying mortar. Play sand is sold for play applications, while kiln-dried sand is typically used dry for narrow paving joints. Choose the product required by the job rather than relying solely on density.
Bulk bags and small bags
Merchant bulk bags do not all contain the same weight. The calculator therefore lets you enter the advertised bulk-bag weight and small-bag weight. This makes the bag count more useful when comparing suppliers.
Using the calculator for paving
For a sand laying bed, enter the paved area and the intended compacted bed depth. If you are also calculating the sub-base and slabs, use the linked MOT Type 1 and Paving Slab calculators so each layer is estimated separately.
Frequently asked questions
How many 25kg bags are in one tonne?
By weight, one tonne equals 40 × 25 kg bags. Your project quantity may not be an exact tonne, so BuildCalcs rounds the required number of whole bags upward.
How many bulk bags do I need?
The calculator divides the estimated project weight by the bulk-bag weight you enter and rounds up to a whole bag.
Can I use this as a sharp sand calculator?
Yes. Sharp sand is the default selection, with an approximate planning density that you can compare with your supplier's product data.
Can I use this for building sand?
Yes. Select Building sand from the dropdown. The quantity calculation remains the same, but the estimated weight uses the selected density.