Excavation Calculator
Estimate excavation volume, bulked soil volume and truck loads for any general dig, from a small trench to a full site excavation.
Excavation Calculator
Estimate excavation volume, bulked soil volume and truck loads for any dig.
Estimating Excavation Volume And Bulking
Excavation volume starts as a simple calculation: length (m) × width (m) × depth (m). The more important figure for planning truck movements is the bulked volume — once soil is dug up, it no longer compacts back to its original density, and typically expands by around 25 per cent depending on soil type. This calculator applies a standard 25 per cent bulking allowance to give you a realistic figure for how much material will actually need to be carted away.
The bulked volume is then converted into 10 m³ truck loads — a standard tandem tipper size — so you have a practical number for scheduling trucks or comparing quotes from earthmoving contractors.
What Information You Need To Enter
Enter the length, width and depth of your excavation in metres. If your excavation is an irregular shape, break it into rectangular sections, run the calculator for each, and add the results together.
Understanding Your Results
You will see the raw excavation volume, the bulked volume after the 25 per cent allowance, and the number of 10 m³ truck loads required. Rock or heavy clay can bulk at a different rate than general soil, so treat this as a solid planning estimate rather than an exact figure for unusual ground conditions.
Why Accurate Estimating Matters
Underestimating bulked volume is one of the most common causes of budget blowouts on excavation work, since disposal costs are usually charged per truck load. Getting a realistic figure upfront helps you budget correctly and schedule the right number of trucks for the job.
Frequently Asked Questions
What does "bulking" mean in excavation?
Bulking refers to the increase in volume that occurs when compacted, in-ground soil is dug up and loosened. Soil that measured 1 cubic metre in the ground can occupy around 1.25 cubic metres once excavated, which is why truck and disposal quantities are based on bulked volume, not the raw dig volume.
Does the bulking factor change for rock or clay?
Yes. Different soil types bulk at different rates -- clay and rock can bulk more than general soil. This calculator uses a standard 25 per cent allowance suited to typical Melbourne residential sites; unusual ground conditions should be confirmed on site.
How big is a standard excavation truck load?
Most tandem tipper trucks used for residential excavation carry around 10 cubic metres per load. Larger triaxle trucks can carry more, which your excavation contractor can advise on for bigger projects.
Do I need a permit for excavation in Melbourne?
This depends on the depth of the excavation, its proximity to boundaries, and council requirements in your municipality. Your builder or excavation contractor can advise what applies to your project.
What is the difference between this and the Site Cut Calculator?
This calculator estimates volume for a general excavation using length, width and depth. The Site Cut Calculator is specifically designed to compare your existing ground level against your finished floor level to determine whether you need to cut or import fill.
Related Calculators & Services
Need An Exact Price, Not Just An Estimate?
The Excavation Calculator gives you a fast, useful planning figure. For a fixed, accurate price backed by a site assessment, request a free professional quotation from HPL Construction.
