Aggregate Calculator
Pick your aggregate, then type the area and depth. This free calculator shows the tonnes, m³ and bulk bags you need.
Measure your project
Your answer
That is 2.00 m³ before packing.
If you buy bulk bags
Each aggregate has its own weight per m³, so pick the right one. For a drive or a base that holds weight, check your local building rules or ask a builder or engineer.
What it costs
£75 a bulk bag, with VAT, is the middle price of only 3 UK sellers (Oct 2026). Treat it as a rough guide.
Quick answers
- A 6 × 2.5 m path of Type 1, 100 mm deep
- About 3.12 tonnes once packed. That is 4 bulk bags of 800 kg.
- Aggregate per m², 50 mm deep
- About 104 kg of Type 1, 83 kg of ballast or 76 kg of sand.
- What one 800 kg bulk bag covers
- At 50 mm deep, about 10 m² of gravel, 10.6 m² of sand or 7.7 m² of packed Type 1.
- Price per tonne
- About £94 a tonne for an 800 kg bulk bag, with VAT. A full lorry load can be under £24 a tonne if you take 16 tonnes or more.
How to work it out
- Pick the aggregate. Each one has its own weight per m³.
- Measure the length and width in metres. Multiply them to get the area in m².
- Change the depth to metres: mm ÷ 1,000. Then area × depth gives the volume in m³.
- Multiply the m³ by the weight of 1 m³ to get tonnes. For Type 1, that is 2.08.
- Divide the tonnes by 0.8 to get 800 kg bulk bags. Round up to a whole bag.
Type 1 path: 6 × 2.5 × 0.1 = 1.5 m³
1.5 × 2.08 = 3.12 tonnes
3.12 ÷ 0.8 = 3.9 → 4 bulk bags
Aggregate weights: convert m³ to tonnes
Each weight comes from a seller's own figure for what one bag or tonne covers. For Type 1, it is the weight once packed down. We treat crusher run the same way.
| Aggregate | Tonnes in 1 m³ | kg per m², 50 mm | 800 kg bag covers, 50 mm |
|---|---|---|---|
| MOT Type 1 | 2.08 | 104 | 7.7 m² |
| Ballast | 1.65 | 83 | 9.7 m² |
| Sharp sand | 1.51 | 76 | 10.6 m² |
| Building sand | 1.51 | 76 | 10.6 m² |
| Gravel (20 mm) | 1.6 | 80 | 10 m² |
| Crusher run | 1.82 | 91 | 8.8 m² |
Wickes figures, except crusher run (Greenvale). Weights can change by about 5% with how wet the stone is.
Just need the volume? Our cubic metre calculator works out m³ from any shape.
Which aggregate for which job?
- MOT Type 1: the sub-base under drives, paths and patios. It packs down hard. Our Type 1 calculator has depths by job.
- Crusher run: also a sub-base. It has no set standard and more fine dust, says Lightwater Quarries. The Type 1 calculator compares the two.
- Ballast: sand and gravel mixed. You add cement to make concrete. See our ballast calculator.
- Sharp sand: for paving beds, screed and concrete. Building sand is softer and goes in mortar. See the sand calculator.
- Gravel: for paths, borders and the top of a drive. See the gravel calculator.
- Decorative stone, such as Cotswold chippings, slate or gabion stone, has its own stone calculator.
Tonnes of aggregate for 10 m²
Here is 10 m² at three depths, in tonnes. For 20 m², double it. The Type 1 and crusher run depths are after packing.
| Aggregate | 50 mm | 100 mm | 150 mm |
|---|---|---|---|
| MOT Type 1 | 1.04 | 2.08 | 3.12 |
| Ballast | 0.83 | 1.65 | 2.47 |
| Sharp sand | 0.76 | 1.51 | 2.27 |
| Building sand | 0.76 | 1.51 | 2.27 |
| Gravel (20 mm) | 0.80 | 1.60 | 2.40 |
| Crusher run | 0.91 | 1.82 | 2.73 |
Nothing extra added. Divide by 0.8 for 800 kg bulk bags.
Aggregate by the tonne: bulk bags or loose loads
Bulk bags are easy for a small job. A tipper lorry can drop loose stone, which costs less per tonne for a big job.
| How you buy it | Type 1 or sub-base | Ballast | Who |
|---|---|---|---|
| Bulk bag (800 kg) | £94 | £94 | Middle of 3 sellers |
| Small tipper load | £70 | £69 | Tiny Tipper (Sussex and Kent) |
| Lorry, 16 tonnes or more | £23 | £24 | TARS (Essex and Suffolk) |
| Lorry, 20 tonnes | £26 | £35 | Fulney Sand & Gravel (Lincolnshire) |
Ballast is 10 mm in the small load and 20 mm in the lorry loads. The 16 tonne Type 1 is recycled concrete. The 20 tonne sub-base is 40 mm limestone.
- Each loose price is from one firm in one area, so get local quotes.
- TARS (Essex and Suffolk) sets a 16 tonne minimum to avoid a part-load charge.
- Fulney charges delivery per mile. It needs room for an 8-wheel tipper.
- Tiny Tipper adds delivery at checkout.
- The firms that charge without VAT had 20% added here.
Why aggregate calculators give different answers
- Weight per m³. Other UK Type 1 tools use 2.0 or 2.4 tonnes per m³. We use 2.08. For our 6 × 2.5 m path, that is 3.0, 3.1 or 3.6 tonnes.
- Wet or dry. Wickes says its bag weight can change by about 5% with moisture.
- Bag size. A bulk bag is 800 kg at Wickes, but 850 kg at Mainland Aggregates.
- Packing down. Type 1 and crusher run shrink as you pack them. Loose, they take about 1.33 times the room, but the tonnes stay the same. Sand, ballast and gravel are not packed in our sums.
Before you compare answers, ask which weight per m³ the tool or supplier uses.
Questions people ask
How do I calculate how much aggregate I need?
Area in m² × depth in metres × the weight of 1 m³ gives tonnes. A 6 × 2.5 m path of Type 1, 100 mm deep, takes about 3.1 tonnes.
How do I convert m³ to tonnes of aggregate?
Multiply the volume by the weight of 1 m³. That is 2.08 for Type 1, 1.65 for ballast, 1.6 for 20 mm gravel and 1.51 for sand. To go back, divide tonnes by the same number.
How much aggregate do I need per m²?
It depends on the depth. At 100 mm, 1 m² takes about 208 kg of packed Type 1, or 160 kg of gravel.
How many bulk bags make a tonne?
A tonne is 1,000 kg, so it fills 1.25 bags of 800 kg. Some sellers fill bags with 850 kg or more, so check the weight on the bag.
What is MOT Type 1 aggregate?
Type 1 (people also say "type one") is crushed stone from 40 mm down to dust. It is made to Clause 803 of the Specification for Highway Works, a road standard.
How much does aggregate cost per tonne?
In 800 kg bulk bags, about £94 a tonne with VAT. One small tipper firm charges about £70. Full lorry loads cost far less per tonne, but you need room for the lorry.
What aggregate do I need for a driveway?
A gravel drive needs two aggregates: MOT Type 1 for the sub-base, and 20 mm gravel on top. Our gravel driveway calculator works out both layers.
Where our numbers come from
- Type 1 weight and price: Wickes 800 kg bag (checked Oct 2026)
- Crusher run weight: Greenvale Products (1 tonne covers about 11 m² at 50 mm)
- Ballast weight: Wickes ballast bulk bag (800 kg covers 9.7 m² at 50 mm)
- Gravel weight: Wickes UK 20 mm gravel bulk bag (800 kg covers 20 m² at 25 mm)
- Sand weight: Wickes sharp sand bulk bag (800 kg covers 10.6 m² at 50 mm)
- Building sand weight: Wickes building sand bulk bag
- Small bags: Wickes Major Bags (22.5 kg sand, 22.5 kg gravel)
- Ballast small bag: Wickes 22.5 kg Major Bag £4.10
- Mainland Aggregates: 850 kg bulk bags
- Bulk bag prices: the middle price from 3 UK sellers each (Wickes, Tippers, Lawsons; Oct 2026)
- Packing down: Penn State road-stone guide (8 in loose packs to 6 in)
- Type 1 vs crusher run: Lightwater Quarries
- UK government guide to paving front gardens
- Mainland Aggregates: gravel driveway guide
- Other UK Type 1 calculators: our look at 3 tools (2 state 2.0 or 2.4 t per m³)
- Small-access loose loads per tonne: Tiny Tipper (inc VAT)
- Full-load prices per tonne: TARS Essex & Suffolk (+ VAT)
- 20-tonne loose loads: Fulney Sand & Gravel (+ VAT)
Made by BuildersCount. Last checked 4 Oct 2026.
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