Building a new driveway or perhaps just sprucing up an existing one? Ordering the correct amount of gravel the first time can save you money, time and the worry of a follow-up delivery. Order the correct amount and you don't have to worry about storing the excess material or having it taken away.
Order too little and you will have to wait for a top-up, usually at a much higher cost for a small load.
Whether your new driveway is 3 meters long and 3 meters wide or 100 meters long by 6 meters wide, the principles still remain the same, you need precise measurements, the right depth for the traffic load and to understand how the gravel is going to bed down when laid. In this guide we'll show you exactly how to work out what quantity you need, what things influence the total, some figures to keep in mind and why choosing a reputable supplier such as Formula Transport makes the process from quote to delivery that much easier.
Why Getting the Right Gravel Quantity Matters?
Ordering too little gravel: If you don't order enough, you have an annoying wait for your delivery of gravel to refill the truck, typically at a higher cost per tonne on the small load. Ordering too much: Ordering excess gravel wastes money, costs you storage space, and creates disposal issues. A good order quantity will maintain uniform depth and compaction throughout the length of your driveway, a critical factor for longevity, drainage and performance, in the variable Australian climate.
The Basic Gravel Calculation Formula
Calculating gravel volume comes down to a simple formula:
Length (m) Width (m) Depth (m) = Volume (m)
From this you can then convert to tonnes using the density of the particular gravel type, as most companies will sell and deliver by weight rather than volume, once you know the volume in cubic metres. There is a rough conversion which can be used which is approximately 1.5 to 1.7 tonnes in a cubic metre of compacted gravel, but this will depend on the stone type and density.
Step-by-Step: Measuring Your Driveway
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Measure the Length and Width
Use a tape measure or wheel to walk the entire length of the driveway and note its width at several points if it varies. If the driveway has irregular shape, subdivide it into smaller rectangular or triangular sections, measure each segment and sum up the results.
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Decide on Your Depth
The depth is determined by the intended usage of the driveway and the subsoil:
- Light foot or occasional car traffic: 50-75mm of gravel may be enough
- Residential driveways: 75-100mm is typical standard recommendation
- Heavy vehicles, trucks, or normal use: 100-150mm that is often used in a compacted base layer and sometimes in a top layer
- New driveways where there isn't an existing base: add an additional 50-100mm of road base below the gravel to provide some stability
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Convert to Tonnes
To work out the total weight of your gravel required, multiply the volume in cubic meters by the density of your selected gravel (confirm with your supplier, but 1.5-1.7 tonnes per m is a reasonable average for most crushed rock or road base products) and order accordingly.
Worked Example
Let's say your driveway is 15 meters long, 3 meters wide and you want a compacted depth of 100mm(0.1m):
V= 15x3x0.1=4.5m
Tonnage = 4.5 1.6 (average density) 7.2 tonnes
Almost all suppliers will advise you to round up to the nearest half or full tonne, due to compaction of the feed in the bag and small amount of spillage. In this case, you would probably be buying about 7.5 tonnes.
Gravel Supply and Pricing: Key Stats to Know
Here are some key figures you might want to keep in mind when doing your budget for your driveway project. Sand and gravel quarrying is also still an important part of the construction supply chain in Australia, with IBISWorld industry revenues in 2025 at US$886.3 million.
Cost will vary by material and council area (for example, a good indicator of prices in the real world are published prices of products supplied by Fairfield City Council, Sustainable Resource Centre (NSW): natural aggregate and roadbase products are most often priced in the $78-$97 per tonne range, bulk fill and sands tend to be priced lower).
Another consideration is settlement: in the case of un-compacted, fresh gravel, it will settle about 15-20% of its depth under traffic and this is one reason why a small margin is added to your volume as you compute and not a wasteful, additional expense.
Factors That Can Change Your Total
Type of Gravel
The various materials used like crushed rock, road base, decorative pebbles or blue metal will have different densities and may need to be compacted to different levels. The course materials will not compact as much as fine gravel resulting in the need for more material for the same finished depth.
Existing Ground Conditions
Loose, uneven or clay-heavy soil may require extra base material to form a level foundation for your upper layer of gravel to be laid upon, thereby increasing your volume requirements.
Slope and Drainage
Because of rain runoff, gravel will be moved on a slope driveway. It's better to reserve some room (5-10% more of the initial volume) to fill in the future.
Compaction Method
Properly compacted gravel with a plate compactor produces a more stable, denser layer of gravel than gravel raked off and left without compaction. Under-compacted gravel will appear to be providing a solid surface but will thin out and move when driven on.
Common Mistakes to Avoid
- Neglecting to consider the effects of compaction, which could bring your loose gravel depth down 20-30% once packed
- The other flaw was not measuring the width of the driveway of each rod and only measuring the length.
- Failure to set a correct base course, causing potholes and gravel to sink into soft ground
- Under estimating tonnage on sloped or curved driveways where drainage removes material over time
Recommended Gravel Depth by Driveway Use
|
Driveway Use |
Recommendation on Depth |
Comments |
|
Light foot traffic or light usage by cars |
50-75mm |
For garden pathways or side access that sees little use |
|
Residential driveway (standard type) |
75-100mm |
Commonly used for regular use of family cars |
|
Trucks and heavy vehicles |
100-150mm |
Used as a road base plus top gravel layer |
|
Brand new driveway without any base at all |
50-100mm extra |
An extra road base is required below the gravel |
Why Choose Formula Transport for Your Gravel Delivery?
After you've worked out the required volume of gravel for your driveway, the next step is to find a supplier of quality product and a reliable delivery service. Formula Transport stocks a variety of road base, gravel and aggregate products to suit residential and commercial driveways throughout the local region. Easy access to reliable delivery by experienced local drivers and a fleet of well maintained tipper trucks makes it easy for you to receive the right tonnage delivered to the right place at a time that suits, whether you're topping up an existing driveway or building from the ground up.
Unsure how much you need? Let Formula Transport's staff assist you by verifying the calculations, considering your driveway dimensions and planned usage, ensuring you receive an accurate quote and the correct volume of material in one delivery.
FAQs
How much gravel do I need for a driveway?
Estimate the volume by multiplying the length by width by depth in meters and convert to tonnes using an average density of 1.5-1.7 tonnes per cubic meter depending on what type of gravel you decide upon.
What depth of gravel is best for a driveway?
Most residential driveways will require between 75-100mm of compacted gravel. For heavier vehicles, such as buses or long vehicles, they would require closer to 100-150mm of gravel, often used as a compacted base and a finer top coat.
How many tonnes of gravel do I need per square metre?
For a 100mm depth it works out to approximately 0.16 tonnes per m2 of gravel-based on an average density of 1.6 T/m3 after compaction.
Does gravel settle after it's laid?
Yes, un-compacted gravel usually sinks about 15-20 percent of its depth when compacted or driven on it so it would be a good idea to order a little more than you need to keep your depth.
What's the difference between road base and decorative gravel?
Road base is compacted crushed rock used as a supporting layer, whereas gravel is finer and generally a coloured top layer.
Should I add extra gravel for a sloped driveway?
Yes, it does wash away some gravel from rain water run-off. Allow another 5-10 percent of gravel cost for future top ups.
