Short answer: Price per kilogram of product misleads when grades differ in active matter. The number that matters is cost per kilogram of active matter: product price divided by active fraction, then adjusted for freight, packaging and duty. A 30% liquid can beat a 92% powder on this measure, or lose badly. Worked examples below show the arithmetic.
This article is written for procurement engineers and formulators comparing quotes across liquid and powder surfactant grades. Prices used here are illustrative example figures; replace them with your own quotes and the method stays the same.
What is the formula for cost per kg of active matter?
Two lines of arithmetic put every grade on the same basis:
- Active matter per tonne = 1000 kg x (active content % / 100)
- Cost per kg of active matter = price per tonne / active kg per tonne
Worked check: SLS 92% powder at 1,650 USD per tonne carries 920 kg of active matter, so 1,650 / 920 = 1.79 USD per kg of active matter. The same product sold as 30% liquid at 900 USD per tonne carries 300 kg of active, so 900 / 300 = 3.00 USD per kg. The liquid drum is nearly half the price of the powder tonne, and it is still 68% more expensive per kilogram of active matter.
Six grades on the same basis
| Grade | Active content | Illustrative price per tonne | Active kg per tonne | Cost per kg active |
|---|---|---|---|---|
| SLS 30% liquid | 30% | 900 USD | 300 | 3.00 USD |
| AOS 35% liquid | 35% | 1,500 USD | 350 | 4.29 USD |
| AOS 38% liquid | 38% | 1,550 USD | 380 | 4.08 USD |
| SLS 92% powder | 92% | 1,650 USD | 920 | 1.79 USD |
| SLS 95% powder | 95% | 1,750 USD | 950 | 1.84 USD |
| AOS 95% powder | 95% | 2,100 USD | 950 | 2.21 USD |
Read the table this way: SLS 92% is the cheapest kilogram of active matter in the set, AOS 35% liquid is the most expensive, and the 3% assay gap between SLS 92% and SLS 95% costs about 3% more per kilogram of active matter. Whether that 3% is worth paying depends on colour, odour and impurity specs for your end use, which is the question our SLS 92 vs 93 vs 94 vs 95 comparison answers grade by grade. If you are comparing full supplier quotes rather than list prices, the landed-cost quote comparison method and the AOS powder vs liquid buyer’s guide cover the same ground with freight and duty in the frame.
Worked example: one month of active matter for a dishwashing plant
A plant needs 10,000 kg of anionic active matter per month. Here is what each route costs, using the illustrative prices above and ignoring freight for the moment:
| Route | Product to buy per month | Monthly cost | Cost per kg active |
|---|---|---|---|
| SLS 92% powder | 10.87 tonnes | 17,930 USD | 1.79 USD |
| SLS 95% powder | 10.53 tonnes | 18,421 USD | 1.84 USD |
| SLS 30% liquid | 33.33 tonnes | 30,000 USD | 3.00 USD |
| AOS 95% powder | 10.53 tonnes | 22,105 USD | 2.21 USD |
The 30% liquid line is the one that surprises buyers. Its drum price is roughly half the powder price, so it looks like the value option until you divide by the active fraction. Liquids earn their place through handling: no dust, no dissolving step, easier dosing into a continuous blender. If your plant already handles paste, that labour and energy saving is real money; price it separately rather than hiding it in the surfactant comparison.
Adjusting for freight, packaging and duty
Landed cost is where liquid grades lose ground. Freight is charged on tonnes of product, and a 30% liquid ships 70% water. Example: SLS 92% at 1,650 USD per tonne FOB plus 120 USD ocean freight lands at 1,770 USD per tonne, or 1.92 USD per kg of active matter. The same freight added to SLS 30% liquid at 900 USD FOB gives 1,020 USD per tonne, or 3.40 USD per kg of active matter. The freight penalty per kilogram of active matter is nearly three times higher for the liquid.
Packaging moves the number too. Illustrative deltas: 25 kg bags add roughly 15-25 USD per tonne over bulk, 200 kg drums add more, and IBCs usually land between the two. Duty rates differ by grade and destination, so run the calculation with your own tariff line rather than a rule of thumb. MOQ matters for trial volumes: a first order of one pallet will not carry the per-tonne price of a full container, so ask for both prices.
How assay tolerance hits low-active grades harder
Active matter has a tolerance, and that tolerance costs more per kilogram of active matter on low-active grades. If a 92% powder delivers 91% instead of 92%, your cost per kg of active matter rises by about 1.1%. If a 30% liquid delivers 29% instead of 30%, the same one-point slip raises it by about 3.4%. Tightening the spec or the supplier’s process control is worth more, per kilogram of active matter, on the liquid grades.
Key takeaways
- One basis only: compare quotes on cost per kilogram of active matter, never on price per tonne or per drum.
- The formula: price per tonne divided by active kg per tonne; active kg per tonne is 10 x the active percentage.
- Freight punishes liquids: a 30% liquid pays freight on 70% water, so the gap widens on long routes.
- Assay risk: a one-point assay miss costs about three times more per kg of active matter on a 30% grade than on a 92% grade.
- Handling has value: liquids save dust and dissolving labour; count that saving separately, not inside the surfactant price.
Frequently asked questions
Which is cheaper per kg of active matter, SLS 30% liquid or SLS 92% powder?
With the illustrative prices in this article, the 92% powder at 1.79 USD per kg of active matter against 3.00 USD for the 30% liquid. The liquid only closes the gap if dissolving labour, dust control or dosing accuracy carries a cash value large enough to cover the difference, which is a plant-specific calculation.
How do I compare a quote in EUR per tonne with one in USD per kg?
Convert everything to cost per kg of active matter in one currency. Take the EUR per tonne figure, divide by active kg per tonne, then apply your EUR to USD rate. Doing the currency conversion first and the active-matter division second gives the same answer; what matters is that both quotes end up in the same units before you compare them.
Does packaging change the cost per kg of active matter?
Yes, because packaging cost is charged per tonne of product, not per tonne of active matter. On a 92% powder the packaging surcharge per kg of active matter is roughly one ninth of the surcharge on a 30% liquid carrying the same packaging. Ask for the price difference between bulk, bags and drums in writing.
Why does my 30% liquid cost more per active than the powder even though the drum is cheaper?
Because 70% of what you are buying and shipping is water. Freight, packaging and duty are all charged on the full tonne. The liquid earns its price back only if your process values the handling convenience enough to pay for that water twice: once at purchase and once at freight.
What data do I need from the supplier to run this calculation?
Price per tonne by volume tier, active matter percentage with its test method, packaging options and surcharges, MOQ, lead time, and the moisture or solids spec. With those six items you can reproduce every number in this article on your own quotes.
Request a quote or a sample
For bulk pricing, MOQ and lead time on SLS 30% liquid, SLS 92%, SLS 95%, AOS 35%, AOS 38% or AOS 95%, request a quote with your annual volume and destination port. If you are evaluating a grade for the first time, request a sample and request the COA and MSDS for the lot at the same time. Contact our team and we will send current prices by volume tier together with packaging, MOQ and lead time.
Written and reviewed by the ORID Chem technical team. Last updated: 25 October 2026. Prices in this article are illustrative example figures, not quotations. Confirm current specifications on the product TDS and lot COA before ordering.
