Aggregate calculator: tonnes and bulk bags
Enter the area and depth and pick the material. You'll see the tonnes to order, with a little extra for compaction and spillage, and how many bulk bags or grab loads that is.
Estimate only. Not a quote.
Order about
5.7 tonnes
Type 1 for 25.0 m² at 100 mm: 2.5 m³ compacted, with 10% extra.
- Bulk bags
- 7 bagsAbout 850 kg each.
- Grab lorry
- A half loadAbout 16 tonnes a full load.
- Loose on the lorry
- 3.6 m³What arrives, before it's spread and rolled.
- Per square metre
- 0.23 tonnes at 100 mm
- Area
- 25.0 m²
The price is confirmed when you book or when we quote, under our terms.
Densities and bulking vary with material, moisture and compaction. Order a little extra and check with your builder or supplier. This is not engineering or structural advice.
This calculator works on your device. Nothing you type is stored or sent to us unless you choose to book or ask for a quote.
How it works
Area times depth gives the volume. Sub-base that's rolled needs more stone than its finished depth, so compaction is added, then a little extra for spillage and settling. Times the weight of the material gives the tonnes to order.
Measure the area
Measure the length and width of each bed, path or base. For a round one, measure across it.
Work out the volume
Multiply the area by the depth in metres (100 mm is 0.1 m). For a circle the area is 3.14 x radius x radius.
Allow for compaction
Sub-base is rolled down, so it needs more loose stone than the finished depth: about 30% more for Type 1.
Work out the tonnes
Multiply by the weight of the material as delivered, about 1.6 tonnes per m³ for Type 1, and add 10% for spillage and settling.
Count the bags or loads
Divide by about 0.85 tonnes for a bulk bag, or 16 tonnes for a full grab load.
Tonnes per square metre, extra included
| Material | Tonnes per m³ loose | Compaction | Extra | 50 mm | 100 mm | 150 mm |
|---|---|---|---|---|---|---|
| Type 1 (MOT) sub-base | 1.6 | +30% | 10% | 0.11 t | 0.23 t | 0.34 t |
| Scalpings | 1.6 | +25% | 10% | 0.11 t | 0.22 t | 0.33 t |
| Crushed concrete (recycled sub-base) | 1.5 | +30% | 10% | 0.11 t | 0.22 t | 0.32 t |
| Ballast (all-in, 20 mm) | 1.7 | None | 10% | 0.09 t | 0.19 t | 0.28 t |
| Sharp sand | 1.6 | None | 10% | 0.09 t | 0.18 t | 0.26 t |
| Building (soft) sand | 1.5 | None | 10% | 0.08 t | 0.17 t | 0.25 t |
| 10 mm gravel or pea shingle | 1.6 | None | 10% | 0.09 t | 0.18 t | 0.26 t |
| 20 mm gravel or shingle | 1.5 | None | 10% | 0.08 t | 0.17 t | 0.25 t |
| Topsoil (screened) | 1.4 | None | 15% | 0.08 t | 0.16 t | 0.24 t |
Bulk bags are worked out at about 850 kg each (they're sold at 800 kg to 1 tonne). A grab load is shown from 4 tonnes: about 16 tonnes or 14 cubic yards a full load.
Worked example
A patio base 5 m by 5 m, with 100 mm of Type 1 under it.
- About 5.7 tonnes of Type 1 (2.5 m³ compacted, with 10% extra). That's about 7 bulk bags, or a half grab load.
- That's about 0.23 tonnes per square metre at 100 mm.
Estimate only. Not a quote. The price is confirmed when you book or when we quote, under our terms.
Aggregate questions
How much Type 1 do I need for a driveway?
At 150 mm compacted, about 0.34 tonnes per square metre including 10% extra. A 40 m² drive needs about 13.7 tonnes.
How much does a bulk bag cover?
Bags are typically 800 kg to 1 tonne. At 50 mm deep, a bag of 10 mm gravel covers about 10 m².
Why add extra?
Sub-base like Type 1 is rolled down, so it needs about 30% more loose stone than its finished depth, and some is lost on uneven ground. We add compaction for sub-base and 10% on top (15% for topsoil, which settles).
Can you deliver it?
Ask us for a delivery price. Send the figures with the form on this page, or on WhatsApp, and we'll come back to you.
Ask us for a delivery price
Press Ask us for a delivery price on the estimate and your figures go into this form. Add the address, and a photo if you can, then press Send for an estimate. Nothing is sent until you do.
- Tell us the material, roughly how much, and where it's going.
- A photo of where it's to be tipped helps us work out the delivery.
- The calculator's figures are a guide, and so is any price until we confirm it.
Digging out first?
The muck-away calculator works out the tonnes and grab loads for the spoil, with guide prices.