Three things to know
- Multiply length, width and depth in metres.
- Do not count overlapping excavation twice.
- Do not automatically convert m³ into tonnes or truckloads.
Regular excavation volume
Enter the dimensions of a regular pit or one trench section in metres.
This calculation does not specify suitable excavation dimensions. Divide irregular shapes into sections and do not count overlaps twice. The result is not a loose stockpile volume, weight or number of trips.
Contents of this guide
- The calculation: length × width × depth
- Calculate trenches and separate sections individually
- Why volume does not directly give you tonnes
- Separate the excavated quantity from the quantity to be removed
- Confirm truck requirements against the actual load
- Worked example: two intersecting trenches without double counting
- What to send if the soil is already stockpiled
The calculation: length × width × depth
First convert every dimension to metres. An example pit measuring 8 × 3 × 1.5 m has an in-situ geometric volume of 36 m³. These figures explain the calculation; they do not specify the dimensions of your excavation. To plan removal, you also need to identify the material, its condition after excavation and the portion staying on site.
Calculate trenches and separate sections individually
An example trench measuring 18 × 0.4 × 0.7 m gives 5.04 m³. Again, these are not prescribed dimensions for a utility connection. If dimensions vary along the route, divide it into sections and add their volumes. Do not count any overlapping excavation twice.
For an irregular excavation, agree how the volume will be estimated from drawings or a survey. If depth varies across the area, one measurement in a corner is not enough. It is better to send the documents and identify unknown values than to produce an apparently precise figure from an uncertain estimate.
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| Example shape | Calculation in metres | Volume before excavation |
|---|---|---|
| Regular pit | 8 × 3 × 1.5 | 36 m³ |
| Regular trench | 18 × 0.4 × 0.7 | 5.04 m³ |
Why volume does not directly give you tonnes
Cubic metres describe volume; kilograms and tonnes describe mass. A conversion requires the appropriate bulk density of the actual material. One universal conversion for topsoil, wet soil, stony fill and material mixed with concrete would be misleading.
For transport, material in its original position and material after excavation are not interchangeable either. Loosening and actual composition affect how the load space is used, while weight also limits the load. State whether your quantity is a design excavation volume, an estimated stockpile or an already documented weight.
BIPM — the International System of Units (volume and mass) ↗
Separate the excavated quantity from the quantity to be removed
Not everything the excavator digs up has to leave the site. Identify material to be retained for an agreed use and where it should be stored. Keep topsoil and other layers separate as specified. For future backfill or a particular structure, confirm suitability with the responsible contractor.
Make a simple three-part list: estimated quantity excavated, quantity retained and quantity for removal. Use a consistent estimation basis. Subtracting a casually measured loose stockpile volume from an in-situ excavation volume does not produce an accurate removal figure.
Confirm truck requirements against the actual load
Transport planning requires the material type, access, loading arrangements and the particular vehicle. The references on our website to vehicles up to 3.5 t and an Iveco Eurocargo 15 t describe vehicle weight categories. They do not mean those weights of soil can be loaded.
Do not confirm the number of trips from body size alone. Explain where the truck can stand and whether another machine must move soil to the loading point. Conditions for accepting the material at its destination are agreed separately. Calculating volume does not replace these parts of the job.
Worked example: two intersecting trenches without double counting
Consider only regular example trenches with level bottoms and equal depths. One measures 12 × 0.4 × 0.7 m and the other 8 × 0.4 × 0.7 m. They cross at right angles across their full widths and at the same level, so their shared space is counted just once. These dimensions are purely for calculation, not a utility connection design.
If depths, widths, wall shapes or junction arrangements differ, this particular deduction cannot simply be reused. The drawing must reflect the actual geometry. At intersections in particular, a drawing is more useful than two lengths with no explanation of how the excavations meet.
Swipe sideways to see all columns.
| Example item | Calculation | In-situ volume |
|---|---|---|
| First trench | 12 × 0.4 × 0.7 | 3.36 m³ |
| Second trench | 8 × 0.4 × 0.7 | 2.24 m³ |
| Shared space — deduct once | 0.4 × 0.4 × 0.7 | 0.112 m³ |
| Total without double counting | 3.36 + 2.24 − 0.112 | 5.488 m³, approximately 5.49 m³ |
What to send if the soil is already stockpiled
Send photographs from several sides, approximate stockpile length, width and height, and a description of any mixed-in materials. Dimensions help with an initial estimate, but an irregular pile is not a solid rectangular block. Have the quantity estimate confirmed together with loading and transport arrangements.
For work in Prague, Prague-West, Kladno or Beroun, add the municipality, access photographs and details of what should remain on site. With SORTI, you can enquire about excavation, handling and removal together. The quote can then address the whole project rather than a single figure in m³.
Frequently asked questions
How many tonnes are in one cubic metre of soil?
You cannot reliably determine that without information about the actual material. Include volume and composition in your enquiry; an accurate conversion requires the appropriate bulk density.
Can I divide excavation volume by the truck body size?
That is not enough. The number of trips also depends on load weight, soil condition and the particular vehicle's capabilities.
Should I add a contingency to the calculation?
Start by describing the actual excavation shape and uncertainties. An arbitrary percentage does not replace missing dimensions or a transport estimate.
How do I add two trenches that intersect?
Calculate the individual sections and count their shared space only once. The deduction must match the actual shape and depths; this guide gives just one regular example.
Have excavation dimensions and need soil removed?
Attach the calculation or drawing and explain what the m³ figure represents. Add the material type, the portion staying on site and loading-area photographs.