How to measure a sand or aggregate truck before it tips
A tape, a straight stick and five minutes at the tailgate: how to turn a truck body into cubic feet and brass, why damp sand looks like more than it is, and what CPWD deducts from a measured stack.
By Bulan Sarkar · Updated
Measure the inside length and width of the truck body and the depth of the load at six points, then multiply length × width × average depth. In feet that gives cft; divide by 100 for brass, or by 35.31 for m³. Do it before the truck tips, because a tipped heap can't be measured fairly. Under the CPWD 2009 specification, sand and aggregate below 40 mm are paid on the measured stack with no deduction, stone metal of 40 mm and above loses 7.5% for voids and boulders 15%.
Source: CPWD Specifications 2009, Vol. 1, Sub-head 1.0 Carriage of Materials, clause 1.27 Measurements, checked Oct 2026.
Measure the load while it's still on the truck
The truck body is a box, so the load is length × width × depth. The catch is the depth: sand and aggregate rarely sit flat. Most loads are heaped in the middle and low at the corners, and some are filled short at the tailgate. One reading in the middle overstates the load, and one at the edge understates it.
- Measure the length and width inside the body, wall to wall, with a steel tape. The outside of the body includes the steel sides.
- Lay a straight stick or a length of pipe across the top of the sides and measure down from it to the top of the load at six points: two near the front, two in the middle, two near the tailgate.
- Measure the full inside depth of the body the same way, from the stick to the floor.
- Depth of load at each point = body depth minus the gap to the stick. Add the six depths and divide by six.
- Volume = inside length × inside width × average depth. In feet, that's cft; divide by 100 for brass. In metres, it's m³; multiply by 35.31 for cft.
- Write the figure on the delivery challan before the truck tips, and get the driver to see it.
Damp sand looks bigger: the jar test from IS 2386
Sand with a little moisture in it bulks: the water films hold the grains apart, so the same sand fills more space when it's loosely tipped. IS 2386 (Part 3) gives a field method to measure how much, and admits the correction is rough, because measuring sand by loose volume is rough at best.
The quick version uses a 250 ml measuring cylinder. Pour in damp sand, shaking it down, up to the 200 ml mark. Then fill the cylinder with water and stir until the sand is fully under water. The sand settles to a lower mark, call it y. The standard takes the flooded volume as the volume the sand would have if it were dry, so:
Bulking % = (200 ÷ y − 1) × 100
The standard uses the figure for mixing: if you batch sand by the box or by the head-pan, increase the sand by the bulking percentage so the mix gets the dry quantity it was designed for. It also explains why the same truck looks fuller after rain. When you compare two quotes or two loads, compare them in the same condition.
Measuring a stack after it's tipped
If the load has already been tipped, rake it into a regular stack with flat top and straight sides, then measure length, width and height. IS 4082:1996 suggests stack sizes for fine and coarse aggregate of 2 × 2 × 0.5 m, 5 × 5 × 1 m or 5 × 1 × 0.5 m, on a hard, level patch, planks or a thin layer of lean concrete, with sand and aggregate in separate piles.
A stack has air between the stones, and the bigger the stones, the more air. CPWD's measurement clause for carriage of materials reduces the measured stack volume by a fixed percentage to reach the quantity it pays for. Sand and aggregate below 40 mm get no reduction.
Worked examples
1. A tipper of river sand billed as 2.5 brass
- Inside body: 14 ft long × 7 ft wide
- Depth of load at six points: 2.0, 2.2, 2.4, 2.1, 1.9, 2.2 ft; total 12.8 ft, average 2.13 ft
- Volume: 14 × 7 × 2.13 = 209 cft = 2.09 brass (5.92 m³)
- Billed: 250 cft; measured: 209 cft; difference 41 cft
Result: The load is about 16% short of the bill. Show the driver the six readings, note 209 cft on the challan and pay for what came.
2. Jar test on a damp load
- Damp sand shaken down to the 200 ml mark of a 250 ml cylinder
- After flooding and stirring, the sand settles at 160 ml
- Bulking = (200 ÷ 160 − 1) × 100 = 25%
- A 1 : 4 mortar batched by the box needs 4 × 1.25 = 5 boxes of this damp sand per box of cement
Result: Use 5 boxes of sand, not 4, while the sand is this damp, and repeat the test when the heap dries out.
3. Two stacks of the same size, two materials
- Stack raked to 5 m × 1 m × 0.5 m = 2.5 m³ (88.3 cft)
- 20 mm aggregate: CPWD reduction nil, so 2.5 m³ is paid
- 40 mm stone metal: 7.5% off, so 2.5 × 0.925 = 2.31 m³ (81.7 cft) is paid
Result: Same stack, 0.19 m³ (about 6.6 cft) less paid for the bigger stone. Ask which rule the supplier's quote follows before you order.
Tips and tricks
- Measure before the truck tips. Once it's dumped, the heap spreads into a shape nobody can measure fairly, and the driver has already left.
- Take the depth at six points, not one. In the first example below, the deepest reading is 2.4 ft against an average of 2.13 ft.
- Agree the unit and the basis before ordering: cft or brass, measured on the truck or in a stack, and who checks it.
- Keep sand and aggregate in separate piles on a hard patch or planks, as IS 4082 asks; sand trodden into mud is sand you paid for and can't use.
- Run the jar test whenever the sand looks wet. It takes five minutes and keeps the mix at the proportion it was designed for.
- Ask for the weighbridge slip if the supplier sells by the tonne, and keep it with the challan.
What we would do
We'd agree the price per brass and the measuring rule with the supplier first, then measure every truck inside the body at six points before it tips, and write the cft on the challan with the driver watching. On a wet day we'd run the jar test and add the bulking percentage to the sand we batch. If a load has to be tipped before we can measure it, we'd rake it into a regular stack straight away and measure that instead.
Frequently asked questions
How do I calculate sand in a truck in cft?
How many cft are in one brass of sand?
What is bulking of sand and how do I test it at site?
Is any deduction made for voids when sand is measured in a stack?
Sources and date checked
- CPWD Specifications 2009, Vol. 1, Sub-head 1.0 Carriage of Materials, clause 1.27 Measurements (stack reductions for looseness). Checked Oct 2026.
- IS 2386 (Part 3):1963, Methods of Test for Aggregates for Concrete: Specific Gravity, Density, Voids, Absorption and Bulking, clause 4 (field method for bulking). Checked Oct 2026.
- IS 4082:1996, Stacking and Storage of Construction Materials at Site, clause 4.8 (aggregates). Checked Oct 2026.
This guide covers measuring and paying for sand and aggregate. Stay clear of the tailgate while a tipper is raised. The grade and source of sand and aggregate for concrete are your engineer's call, and the CPWD rule quoted is from the 2009 edition; check the edition your contract names.