How much does a bag of sand weigh?

Standard builder's-yard bags of sand are typically sold in 25 kg units in most of Europe, while US/Canadian bagged sand commonly comes in 50 lb (≈22.7 kg) bags. Larger bulk/tonne bags (also called builder's bags or FIBC bags) typically hold around 800 kg to 1 tonne. Always check the bag's printed weight, since it varies by supplier and region.

How do I calculate cubic meters of sand?

Multiply length × width × depth, all measured in metres, to get volume in cubic metres (m³). For example, a 4 m × 3 m area filled to 0.05 m (5 cm) deep needs 4 × 3 × 0.05 = 0.6 m³ of sand before adding any waste allowance.

What is the volume of 1 tonne of sand?

One tonne of dry sand occupies roughly 0.62 m³, based on a typical dry bulk density of about 1,600 kg/m³ (1,000 kg ÷ 1,600 kg/m³ ≈ 0.625 m³). Wet or compacted sand is denser, so the same tonne takes up slightly less volume — around 0.52–0.55 m³ for wet sand at roughly 1,900 kg/m³.

Is wet sand heavier than dry sand?

Yes — wet sand typically weighs about 15–20% more than dry sand for the same volume, because the water fills the gaps between grains and adds its own weight. A cubic metre of dry sand is roughly 1,600 kg, while the same volume of wet sand is closer to 1,900–1,950 kg.

How much sand do I need for a paver base?

For a typical paver bedding layer, plan on a 2.5–5 cm (1-2 in) sand depth over a compacted gravel sub-base. Multiply your patio's length × width by that depth (in metres) to get the raw volume, then add a 10% waste allowance for compaction and spillage — this calculator does that math for you once you enter the area and pick a depth.

What is the difference between sharp sand and building sand?

Sharp sand (also called concreting sand) is coarser and used for concrete and paving bedding, where its larger particles help with strength and drainage. Building sand (or soft sand) is finer and more workable, used for mortar and plastering mixes, but it is not suitable for structural concrete because it lacks the coarse aggregate needed for strength.

Do I need MOT Type 1 as well as sand for a patio base?

Usually yes for anything load-bearing. MOT Type 1 crushed stone forms the compacted structural sub-base, and a thin sharp sand layer (2.5-5 cm) on top of that provides the bedding/levelling course for the paving slabs. Sand alone, without a compacted sub-base beneath it, is prone to uneven settlement under foot traffic or vehicle loads.

Sand Calculator | Sharp Sand & Building Sand Volume, Weight & Cost

How Much Sand Do You Need?

Figuring out how much sand to order comes down to one simple relationship: the volume of the space you're filling, multiplied by the density of the sand you're using. Get the area and depth right, pick a realistic density for the type of sand you're actually buying, and you'll land on a volume and weight that matches what the yard delivers — instead of guessing and either running short mid-job or paying to have half a tonne of leftover sand sitting in your driveway.

This calculator is built for the jobs people actually search for: a paver base or bedding layer under a patio or walkway, a sandbox or playground fill, a bedding layer for a shed or pool, or the sand component of a concrete or mortar mix. Enter the length, width and depth of the area, pick the sand type (dry, wet, packed, sharp/builder's, or manufactured M-sand — each with a different bulk density), and add a waste allowance for compaction and spillage. The calculator returns the volume needed, the total weight in tonnes, and — because sand is very commonly sold in fixed-size bags rather than loose by weight — how many bags that works out to.

Sand density is the part most calculators skip or oversimplify, and it's also the single biggest source of error in a manual estimate. Dry, loose sand is noticeably lighter per cubic metre than the same sand once it's wet or compacted, and mixing that up can throw your weight estimate off by 15–20%. This tool ships with sourced density presets for the sand types people actually buy, rather than a single generic figure, so the weight and cost numbers reflect what you're really ordering.

Whether you're pricing out a paver base for a patio, filling a sandbox, or working out the sand quantity for a mortar mix, the steps below walk through exactly how to use the inputs, the math behind the result, and the mistakes — mostly around moisture and compaction — that most commonly throw a sand order off.

How to Use the Sand Calculator

Enter the length and width of the area you're filling — a patio base, sandbox, trench, or bedding layer — choosing whichever unit (metres, feet, etc.) matches your measurement. The calculator multiplies these to get the area automatically.
Enter the depth of the sand layer. Typical depths run from about 5 cm (2 in) for a bedding/leveling layer under pavers to 15–30 cm (6–12 in) for a structural sub-base or a deep sandbox fill — check your project spec if one exists, since depth has a direct 1:1 effect on volume.
Pick a sand type from the preset list — dry sand, wet sand, packed/compacted sand, sharp/builder's sand, or M-sand (manufactured) — or enter a custom density in kg/m³ if you have a supplier spec sheet with an exact figure. Each preset uses a different bulk density, which changes the weight (and therefore cost) for the same volume.
Set a waste/compaction allowance. Sand settles and compacts once it's placed and walked on or rained on, and some spillage is unavoidable during delivery and spreading — a 10% allowance is a sensible starting default, and the calculator lets you adjust it between 0% and 25%.
Read off the volume needed, total weight in tonnes, the number of standard bags that works out to, and an estimated cost based on a per-tonne price you can edit to match your local supplier's quote.

The Sand Volume and Weight Formula

The underlying formula has three steps. First, volume: Volume = Length × Width × Depth, with all three dimensions converted to the same unit (typically metres) before multiplying, giving a result in cubic metres (m³). Second, a waste allowance is added on top of that raw volume to cover compaction and spillage. Third, weight: Weight = Volume × Density, where density is the bulk density of the specific sand type you selected, in kilograms per cubic metre (kg/m³).

Worked example: say you're laying a paver base 4 m long, 3 m wide, and 5 cm (0.05 m) deep, using dry sand at a bulk density of roughly 1,602 kg/m³. Raw volume = 4 m × 3 m × 0.05 m = 0.6 m³. Adding a 10% waste allowance brings that to 0.6 × 1.10 = 0.66 m³. Weight = 0.66 m³ × 1,602 kg/m³ ≈ 1,057 kg, or just over 1.05 tonnes.

If you're buying in bags rather than in bulk, divide that weight by the bag size — a common builder's-yard bag is around 25 kg, so 1,057 kg ÷ 25 kg ≈ 43 bags. The calculator does this division for you and rounds up, since a partial bag still means buying a whole one.

One conversion worth keeping in mind: roughly 1 tonne of dry sand occupies about 0.62 m³ (or, in imperial terms, a cubic yard of dry sand weighs somewhere around 2,600–2,700 lb depending on moisture and compaction) — useful for a quick sanity check against a supplier quote given in tonnes rather than volume.

Sand Density Reference (Bulk Density, kg/m³)

Sand density varies significantly with moisture content and compaction — the same sand can weigh noticeably more once it's wet or has been compacted underfoot than it did loose and dry off the truck. These are standard reference bulk densities (sources: Engineering ToolBox bulk material density tables; typical manufactured-sand supplier spec sheets for M-sand):

Dry sand (loose): ≈ 1,602 kg/m³ (≈ 100 lb/ft³) — the standard reference figure for uncompacted dry sand
Wet sand: ≈ 1,922 kg/m³ (≈ 120 lb/ft³) — moisture bulking adds roughly 20% over dry weight
Packed/compacted sand: ≈ 1,682 kg/m³ (≈ 105 lb/ft³) — sits between loose dry and wet once tamped or walked on
Sharp/builder's sand: ≈ 1,600 kg/m³ — the standard concreting/mortar-mix sand grade used in the UK and much of Europe
M-sand (manufactured sand): ≈ 1,750 kg/m³ — crushed-rock manufactured sand runs denser than natural river sand due to its angular particle packing

UK Sand and Aggregate Terminology

UK builders' merchants distinguish between several named sand and aggregate products rather than a generic "sand": "sharp sand" (coarse, washed sand for concrete and bedding), "soft/building sand" (finer sand for mortar and plaster mixes, unsuitable for structural concrete), "ballast" (a pre-mixed sand-and-gravel aggregate for on-site concrete, typically a roughly 4:1 sharp-sand-to-gravel blend), and "MOT Type 1" (a graded crushed-stone sub-base material, distinct from sand, used under driveways and patios). Aggregate is generally sold and priced by the tonne — in bulk bags or loose-tipped loads — rather than by cubic yard (source: general UK builders'-merchant terminology, consistent across major suppliers such as Travis Perkins and Jewson).

Pro Tips and Common Mistakes

Sand behaves differently depending on how it's handled between the yard and your project, and most estimating errors come down to one of two things: measuring the wrong depth, or using the wrong density for the moisture/compaction state the sand will actually be in once placed.

Worked cost example: for the 0.66 m³ (roughly 1.06 tonnes with a 10% waste allowance) paver-base example above, at a typical UK sharp sand price of around £35 per tonne, that's approximately 1.06 × £35 ≈ £37 in material cost — before any delivery surcharge, which many merchants add for loose-tipped loads under a minimum tonnage.

Compaction changes volume, not just density — a layer of loose sand can compact down by 10–15% of its depth once tamped or plate-compacted, so if your project spec calls for a compacted final depth, order slightly more loose volume than that final figure to allow for settlement.
Moisture content swings weight more than most people expect — sand straight from a supplier is rarely bone dry, and wet sand can weigh 15–20% more per cubic metre than dry sand for the exact same volume. If you're being charged by weight (per tonne) rather than by volume, ask your supplier which moisture state their quoted density assumes.
Don't skip the waste allowance — spillage during barrow trips, over-excavation, and uneven sub-grade all eat into your order in ways a clean length × width × depth calculation doesn't capture. 10% is a reasonable default for a straightforward job; go higher (15–20%) for an uneven site or a first-time DIY job.
Common mistake: forgetting to convert depth to the same unit as length and width before multiplying. Depth is very often measured in centimetres or inches while length and width are in metres or feet — mixing units without converting is the single most common source of a wildly wrong sand-volume estimate.
For paver bases specifically, the sand layer is a bedding/leveling course, not the structural sub-base itself — check whether your project also needs a compacted gravel or crushed-stone base beneath the sand, since sand alone over soft or unprepared soil will settle unevenly.