What a dmtu measures
A metric tonne unit (mtu) is one percent of a metric tonne, which is 10 kilograms. Applied to an ore, it counts the metal inside: a tonne of ore that assays 44% manganese holds 44 units, or 440 kg of contained manganese. The d in dmtu says the tonne is counted dry, with the moisture taken out.
Pricing by the unit means the price follows the metal, not the rock. Two parcels at different grades are compared fairly by the dollars paid per unit of contained metal.
From dmtu to a price per tonne
Multiply the price per dmtu by the grade in percent. At $4.50 per dmtu, 44% ore is 4.50 × 44 = $198 per dry tonne, and 40% ore is $180 per dry tonne. USGS reported that high-grade manganese ore delivered to China averaged about $4.50 per mtu in 2025, which is about $198 per tonne of 44% ore.
To price a shipment, convert the wet weight to dry weight first. Five thousand wet tonnes with 3% moisture is 4,850 dry tonnes, and 4,850 tonnes at $198 is $960,300, before any deductions. The ore price calculator on this site does these steps for you.
Why the tonne is dry
Ore arrives carrying water, and the amount varies with weather, storage and handling. Paying on the dry weight stops the buyer paying for water. It also makes moisture a quality parameter in its own right: index specifications set a base and a maximum for it, and the assay certificate has to report it.
Other units you may meet
Older contracts and some markets use a long ton unit (ltu), which is 1% of a long ton, 22.4 lb or 10.16 kg, and a short ton unit (stu), 1% of a short ton, 20 lb or 9.07 kg. Because a long ton unit holds slightly more metal, a price per ltu is about 1.6% higher than the same price per mtu. The unit converter on this site handles the conversions.
Common mistakes
- Treating a price per dmtu as a price per tonne of ore. It is a price per percentage point.
- Mixing up a tonne of ore with a tonne of contained metal. A tonne of contained manganese is 100 mtu, so $4.50 per mtu is $450 per tonne of contained manganese.
- Using wet weight. The price is paid on dry tonnes.
- Comparing quotes for different grades or delivery terms. A CIF price includes freight and insurance and a FOB price does not.
Related calculators
Frequently asked questions
What does dmtu stand for?
Dry metric tonne unit: one percent of a dry metric tonne of ore, or 10 kg of contained metal, with the weight counted on a dry basis.
How do I convert a price per dmtu to a price per tonne?
Multiply the dmtu price by the grade in percent. $4.50 per dmtu on 44% ore is $198 per dry tonne.
What is the difference between mtu and dmtu?
An mtu is a unit of 1% of a metric tonne. A dmtu is the same unit counted on dry weight, which is the basis for manganese ore prices.
How many dmtu are in a tonne of ore?
As many as the grade in percent. A tonne of 44% ore holds 44 dmtu.
Sources
- USGS Mineral Commodity Summaries 2026: Manganese
- Fastmarkets: manganese ore high grade index, CIF Tianjin, $ per dmtu
- Fastmarkets: manganese ore semi carbonate index, 36.5% Mn, CIF Tianjin, $/dmtu
Specifications published by index providers are revised over time. Where a figure comes from a pricing notice, confirm the version currently in force with the publisher before you use it in a contract. Corrections are welcome.