Aggregate and Gravel Calculator
1 m³ of nominal M20 concrete (1:1.5:3) needs 0.84 m³ of coarse aggregate (1.54 × 3 ÷ 5.5): about 29.7 cft, or 1.26 tonnes at 1,500 kg/m³.
For gravel or soling, volume = area × thickness: 20 m² at 100 mm is 2 m³. Tonnes = m³ × loose density ÷ 1,000.
Calculate aggregate or gravel quantity
1,500 kg/m³ is an editable example within the cited 20 mm sample range, not an IS 383 limit. Use a measured value for gravel, soling or another stone size.
The shared mix engine uses dry volume = wet volume × 1.54. M25 and higher need an approved design mix; use its aggregate mass directly.
- Loose aggregate volume
- 0.84 m³
- Cubic feet
- 29.664 cft
- Brass (100 cft)
- 0.2966
- Weight at entered density
- 1.26 tonnes
- Weight at cited sample densities
- 1.1819–1.2886 tonnes
Tonnes are approximate until the supplier confirms loose bulk density. Weighbridge mass is the delivery check.
Apply your quantity to the dated aggregate prices, with source dates, units and delivery terms.
Coarse aggregate per m³ of nominal concrete
Each m³ of nominal concrete needs 0.84 m³ (M20) to about 0.95 m³ (M7.5) of coarse aggregate. The table uses the same mix ratios as the concrete calculator.
| Mix, by volume | Aggregate m³ | cft | Brass |
|---|---|---|---|
| M7.5 (1:4:8) | 0.94769 | 33.467 | 0.3347 |
| M10 (1:3:6) | 0.924 | 32.631 | 0.3263 |
| M15 (1:2:4) | 0.88 | 31.077 | 0.3108 |
| M20 (1:1.5:3) | 0.84 | 29.664 | 0.2966 |
The ratios and 1.54 factor are estimating assumptions, not a batching schedule. IS 456:2000, clause 9.3 allows nominal mixes only up to M20, so M25 and above need a design mix and are left out. The figure is total coarse aggregate; split it into 10 mm and 20 mm only as the mix design says.
20 mm aggregate density: tonnes per m³
Two Indian lab studies report 1,407 and 1,534 kg/m³ for loose 20 mm aggregate, so 1 m³ weighs about 1.4–1.5 tonnes. These are test samples, not a range every quarry will meet.
- Malla Reddy Engineering College hosted study, Table 2.3 (2020) reports 1,407 kg/m³ loose and 1,566 kg/m³ dry-rodded for 20 mm angular aggregate.
- Goa University thesis, Table 3.7 (2024) reports 1,534 kg/m³ loose and 1,745 kg/m³ dry-rodded for 20 mm coarse aggregate.
The 1,500 kg/m³ default sits between them; change it to your supplier’s figure. For comparison, IS 875 (Part 1):1987, Table 1, lists dry, well-shaken broken stone ballast at 1,600–1,870 kg/m³. Loose density includes the voids between stones, so compacted stone weighs more.
Bulk density is tested to IS 2386 (Part 3), which separates loose and compacted values. None of these figures is a limit in IS 383:2016, the aggregate specification (BIS product manual). Sources checked 21 October 2026.
Worked example: M20 aggregate in m³, cft, brass and tonnes
1 m³ of M20 needs 0.84 m³ of coarse aggregate: about 29.66 cft, 0.297 brass or 1.26 tonnes.
- Dry ingredients = 1 × 1.54 = 1.54 m³. Total mix parts = 1 + 1.5 + 3 = 5.5.
- Coarse aggregate = 1.54 × 3 ÷ 5.5 = 0.84 m³.
- Using the shared conversion 35.3147 cft/m³: 0.84 × 35.3147 = 29.664348 cft; ÷ 100 = 0.29664348 brass.
- At 1,500 kg/m³: 0.84 × 1,500 ÷ 1,000 = 1.26 tonnes. At the two study densities: 1.18188–1.28856 tonnes.
One brass is taken as 100 cft; check the supplier’s unit on the quote. For the sand in the same mix, use the sand calculator; for other cubic-foot conversions, the cft calculator.
Gravel and soling fill: area × thickness
Gravel volume = area × thickness: 20 m² filled 100 mm deep is 20 × 0.1 = 2 m³.
Laid loose, that weighs 3 tonnes at the 1,500 kg/m³ default, or 3.2 tonnes at the 1,600 kg/m³ that IS 875 (Part 1) lists for loose gravel. If 100 mm is the compacted thickness, enter a loose-volume factor from the supplier or the specification before converting to delivery tonnes; there is no universal factor.
Hand-packed soling stone needs its own density; the 20 mm figures do not apply. Bedding, blinding and void filling are separate layers, so keep them out of the stone depth.
Frequently asked questions
How much aggregate is required for 1 m³ of M20 concrete?
0.84 m³ of loose coarse aggregate, using the nominal 1:1.5:3 mix and a 1.54 dry-volume factor. That is the total for all stone sizes, not 0.84 m³ of each.
How many tonnes are in a cubic metre of 20 mm aggregate?
About 1.4–1.5 tonnes loose: two Indian lab studies report 1,407 and 1,534 kg/m³, and the calculator defaults to 1,500. Get the figure for your quarry, grading and moisture.
How much aggregate is in one brass?
One brass is 100 cft, about 2.83 m³ (100 ÷ 35.3147). At 1,500 kg/m³ that is about 4.25 tonnes; use your supplier’s loose density for a firm figure.
Can I use this for M25 or M30 concrete?
Multiply the concrete volume by the coarse aggregate kg per m³ in the approved design mix. Nominal volume ratios cannot stand in for a design mix, so this tool stops at M20.
Does gravel fill use the 1.54 concrete factor?
No. Gravel fill is area × thickness. Only a loose-volume factor you enter changes that volume for delivery. The 1.54 factor applies to nominal concrete only.
For quantities across a whole building, get a BOQ from your drawings.