Knowing how much gravel/stone you need to be able to carry out your garden project is key before you begin. If you haven’t worked this out, it makes purchasing all your materials difficult and can leave you short or with too much product at the end. 

Not knowing how much material you need and how far the product will spread could cause delays for you if you end up requiring more. As much as we strive to deliver as quickly as possible, no one likes starting a job and having to pause to wait for another delivery. So to help you avoid this, we have put together a little guide with some handy tips to give you a good estimate.  

We sell our aggregates in two forms: 20KG Pre-Packed Bags or our Bulk Bags (Builders Bags). The Bulk Bags vary in weight depending on the type of aggregate as some are heavier than others, they range from 750-850KG. 

How do I work it out? 

To work out how much aggregate you’ll need, you will need to know the size of the area first and foremost. Measuring the length and the width will give you your dimensions. To work out the square footage of the area, multiply the length by the width. This will give you a general idea of the area needing to be covered. 

As we all know, not every garden is perfectly square. A handy tip to make calculations easier for yourself is to split your garden down into square or rectangular sections where possible, you can then add the square footage figures together to get a complete total. 

As a general rule of thumb a 20KG bag would cover an area 0.3m in length by 0.3m in width to a depth of 40mm. So for an area 1m by 1m at a depth of 40mm you would require 3 bags. 

On average a 750KG Bulk Bag contains approximately 37 bags worth of aggregates. 

The perk of the Bulk Bags is the money saving aspect. For example 1 20KG bag of Cotswold Chippings is £4. A Bulk Bag of Cotswold Chippings weighs approximately 850KG. This means there is an estimate of 42 bags in 1 Bulk Bag. 

42 x 20KG bags at £4 per bag = £168

1 850KG Bulk Bag = £89 

Depth of 40mm 1m (3.3 Foot**) 2m (6.6 Foot**) 3m (9.9 Foot**) 
1m3 bags 6 bags 9 bags
2m6 bags12 bags 18 bags 
3m9 bags18 bags 27 bags 

*This is an approximate guide, this may vary depending on the size of the stone and the base you are laying on. 

** Figures have been rounded to the nearest decimal point. 

If you are using the gravel/stone for a driveway that will be driven on regularly, you want to lay your aggregates at a thicker depth than if they are being used for decorative purposes. 

How do I know how deep my aggregate needs to be?  

As stated above, the size of the aggregate you are using can have an effect upon how much you need. Different sized aggregates need to be laid at different depths to ensure a good coverage and level of stability. Our guide below will give you an idea of how deep our aggregates need to be laid. 

Aggregate Type inc. Approximate Size GradingDepth for Decorative Purposes(Recommended) Depth for use on Driveways (Recommended)
Pea Gravel 10mm30-45mm 50-60mm 
White Spar 10mm 30-45mm 50-60mm 
Cornish Cream 14mm30-45mm 50-60mm 
Champagne Gold 14mm 30-45mm 50-60mm 
Cheshire Pink 14mm 30-45mm 50-60mm 
Blue Slate 20mm30-45mm 50-60mm 
Plum Slate 20mm 30-45mm 50-60mm 
Cotswold 20mm 30-45mm 50-60mm 
Golden Flint 20mm 30-45mm 50-60mm 
Moonstone 20mm 30-45mm 50-60mm 
Dorset Pebbles 20-40mm 30-45mm 50-60mm 
Blue Slate 40mm 40-50mm  50-60mm 
Plum Slate 40mm 40-50mm  50-60mm 
Scottish Pebbles 50-75mm 40-50mm  50-60mm