How to measure stockpile volume

The short answer

Measure the real surface of the pile, not an idealised shape. A tape and formula is quick but assumes the pile is a perfect cone or ridge. A drone or GPS survey measures the real surface but costs money and time. A phone scan measures the real surface in one walk round the pile.

1. Find the edge. The toe is where the pile meets the ground. Every method depends on getting it right.
2. Measure the shape. Either a few dimensions (tape) or thousands of points on the surface (drone, GPS, phone).
3. Fit the ground. The volume is the space between the pile surface and the ground under it.
4. Convert to tonnes. Multiply cubic metres by the material’s bulk density.

Method 1: tape measure and a formula

Measure the base and height, pick the closest shape and use its formula. It is free and needs no equipment, but real piles are rarely true cones, so the answer can be well out on an irregular pile.

Use the stockpile volume formulas or the free volume calculator.

Method 2: GPS survey

A surveyor walks the pile with a GPS rover, taking points on the toe, crest and faces. Accurate on simple piles, slower on large or steep ones, and you pay for the visit.

Method 3: drone survey

A drone photographs the pile from above and software builds a 3D surface. Good for big sites with many piles. A flight and processing commonly costs NZ$1,000 or more, and results take time to come back.

See drone vs phone for a side-by-side comparison.

Method 4: scan it with your phone

Stockpile is a phone app, on iPhone first with Android soon after. Walk round the pile once and it measures the real surface: volume, tonnes, contours and a 3D model, with a report you can send before you leave site.

1. Open Stockpile and choose the pile type: open pile, against a wall, in a bay, or a trench or hole.
2. Point the phone at the ground until it is found, then tap Start.
3. Walk slowly all the way round, 1.5 to 3 m from the face, until the app says Ready.
4. Tap Finish. The phone builds the pile from its photographs and gives you the volume, tonnes and a report.