BCM LCM Tonnes Converter
A free, browser-based calculator. Runs entirely in your browser — no sign up, nothing stored.
Enter Values
How to use this calculator
- Enter any ONE of bank volume (BCM), loose volume (LCM) or mass in tonnes.
- Enter the swell (bulking) factor as a percentage and the in-situ (bank) density in tonnes per cubic metre.
- Press Calculate to see all three figures — bank volume, loose volume and mass.
How it works
Material expands when it is dug. Bank Cubic Metres (BCM) is the in-situ, undisturbed volume; Loose Cubic Metres (LCM) is the bulked-up volume after excavation. The swell (bulking) factor links them: LCM = BCM × (1 + swell% ÷ 100).
Mass is conserved — digging changes volume, not weight — so tonnes are calculated from the in-situ bank volume and the bank density: tonnes = BCM × bank density. From any one input the converter solves back to BCM first, then derives the other two.
Worked example
1,000 BCM at 25% swell and 2.4 t/m³. Loose volume = 1,000 × 1.25 = 1,250 LCM. Mass = 1,000 × 2.4 = 2,400 tonnes.
Tips
- Swell only changes loose volume — it never changes the tonnes.
- Always confirm swell and density against material testing for production and reconciliation work.
Frequently asked questions
What is a typical swell factor?
It depends on the material — sand and gravel often swell 10–15%, common soils 20–30%, and blasted hard rock 40–60%. Use site-tested figures where you have them.
Which density should I use?
Use the in-situ (bank) density of the undisturbed material, since mass is tied to the bank volume. Loose density is lower because of the added voids.
Related tools
Tip: Enter any known values to calculate the remaining results.
All calculations run in your browser. Your inputs are never saved or transmitted.