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Concentrate Moisture & Dry Tonnage Calculator

Convert between wet metric tonnes (WMT), dry metric tonnes (DMT) and wet- or dry-basis moisture, then work out dry-basis grade, contained product and the water to remove to hit a target moisture.

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How to use this calculator

Enter values

Calculated results

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More needed
  • Enter wet mass + moisture (or two of WMT / DMT / moisture).

Before you rely on this: First-pass guide only. Verify safety-critical or regulated work against the relevant standards, your project requirements and a qualified professional.

How to use this calculator

  1. Enter the wet mass and the wet-basis moisture (or any two of WMT, DMT and moisture).
  2. Optionally add an assay grade and choose whether it is on a dry or wet basis.
  3. Read DMT, water tonnes, both moisture bases, the dry-basis grade and the contained product.

How it works

Wet-basis moisture is water ÷ wet mass, so DMT = WMT × (1 − M_wb) and the water is WMT × M_wb. The dry basis expresses water against dry solids: M_db = M_wb/(1 − M_wb). Grades convert the same way — a wet-basis assay is diluted by the moisture, so dry-basis grade = wet-basis grade/(1 − M_wb), and contained product = DMT × dry-basis grade.

For a target moisture, the dry solids are held constant: final wet mass = DMT/(1 − M_target), and the water to remove is the current water minus the target water. Shipments and payabilities always work in dry tonnes and dry-basis grade, so getting the basis right matters commercially.

Worked example

1,000 WMT at 8% moisture, 6% Li₂O. DMT = 1,000 × (1 − 0.08) = 920 t, carrying 80 t of water. The dry basis is 0.08/(1 − 0.08) = 8.69565%. At 6.0% Li₂O (dry basis) the shipment contains 920 × 6.0% = 55.2 t of Li₂O.

Common mistakes

  • Mixing moisture bases — wet-basis and dry-basis moisture are different numbers (8% wb = 8.696% db).
  • Applying a wet-basis assay to dry tonnes (or vice versa) without converting.
  • Quoting contained metal on wet tonnes; always use DMT and dry-basis grade.

Frequently asked questions

What is the difference between WMT and DMT?

Wet metric tonnes include the moisture; dry metric tonnes are the solids only. Concentrates are shipped and assayed as WMT but paid on DMT and dry-basis grade.

Can dry-basis moisture exceed 100%?

Yes — dry-basis moisture is water relative to dry solids, so very wet material can exceed 100% db. Wet-basis moisture, water relative to wet mass, is always below 100%.

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Cite this tool

Zerdly. (2026). Concentrate Moisture & Dry Tonnage Calculator. Retrieved from https://www.zerdly.com/tools/concentrate-moisture-dry-tonnage-calculator/

Tip: Enter any known values to calculate the remaining results.

All calculations run in your browser. Your inputs are never saved or transmitted.