Guides / Pricing
How shrimp size grades work, and why they drive most of your landed cost
September 26, 2026
If you ask a Vietnamese shrimp processor for a price on “frozen vannamei” you will get a number that means nothing. The same species, from the same plant, in the same week, can differ by several dollars a kilogram depending on the size grade alone. Grade is the first thing to fix in a spec and the first thing a plant looks for when it decides whether to quote you at all.
This guide covers how grades are written, what else moves the price once the grade is set, and the four lines you need in a request before a quote is worth comparing.
How a size grade is written
A shrimp size grade is a count: how many pieces make up one pound of product. It is written as a range.
| Grade | Pieces per pound | Rough pieces per kg | Typical use |
|---|---|---|---|
| U/15 | Under 15 | Under 33 | Premium retail, hotel, Japan foodservice |
| 16/20 | 16 to 20 | 35 to 44 | Premium retail, restaurant centre plate |
| 21/25 | 21 to 25 | 46 to 55 | Mainstream retail bags, foodservice |
| 26/30 | 26 to 30 | 57 to 66 | Retail, salad and pasta packs |
| 31/40 | 31 to 40 | 68 to 88 | Value retail, breaded value-add |
| 41/50 | 41 to 50 | 90 to 110 | Value-add, filler in mixed products |
Two conventions trip up new buyers. The count is per pound even when the price is per kilogram, because the US market set the naming convention and the rest of the trade followed. And a “U” prefix means “under”, with no lower bound: U/15 could be 12 pieces per pound and still be in grade.
Black tiger runs to larger grades than whiteleg because the species grows bigger. Whiteleg reaches far down into the small counts, which is why breaded and value-add programmes are almost always whiteleg.
Why grade dominates the price
Larger shrimp spend longer in the pond. Longer in the pond means more feed, more disease exposure and more chance of a loss before harvest. The farmer prices that risk in, and every step up the grade ladder inherits it.
The steps are not even. The jump from 31/40 to 26/30 is usually modest. The jump from 21/25 to 16/20 is often much steeper, because that is where retail demand concentrates and where supply thins out. If your recipe tolerates a grade either side, ask for both and let the market tell you which one is cheap this month.
The three things that quietly ruin a comparison
Once the grade is set, three details decide whether two quotes are actually comparable.
Glaze percentage
Frozen shrimp carries a layer of ice for protection. Glaze is expressed as a percentage of gross weight. A carton at 10 percent glaze and a carton at 20 percent glaze can show the same gross weight while the second holds noticeably less shrimp.
State the glaze you accept and insist that the price refers to net weight. A quote that looks 8 percent cheaper on gross can be the more expensive shrimp once you strip the ice out.
Processing form
Each step past head-on costs labour and loses yield.
- HOSO, head on shell on. Cheapest per kilogram of gross product, most weight that you cannot sell.
- HLSO, headless shell on. The common export baseline.
- PD and PUD, peeled and deveined, or peeled undeveined. More labour, higher price per kilogram, less waste at your end.
- PDTO, peeled deveined tail on. Presentation format for foodservice.
- EZ-peel, shell scored for the consumer to remove.
- Cooked, and breaded or other value-add. Highest price, and the format where a plant’s own capability varies most.
Comparing an HLSO price against a PD price tells you nothing. Compare like to like, or convert both to a cost per kilogram of edible meat.
Net weight per carton
Retail programmes often need a specific net weight, commonly between 0.9 and 2 kilograms per inner, with a master carton of 10 kilograms or more. A plant that already runs your net weight prices better than one that has to reconfigure a line for it.
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What else the plant is reading in your spec
Two more factors sit behind the number but rarely appear in a buyer’s first enquiry.
The certificate set. HACCP is mandatory for any export plant, so it costs nothing to ask for. Adding BAP, ASC, BRC or IFS narrows the list of plants that can serve you, and a narrow list prices higher than an open one. Ask for the certificates your own buyer demands and not one more.
Raw material season. Mekong Delta harvest cycles move raw prices through the year. A quote therefore has a validity window, often one to three weeks. Ask for the window in writing rather than assuming a price holds until you are ready to order.
The four lines that make a quote comparable
Put these in the request and a plant can price it without a back and forth:
- Species and size grade, for example whiteleg 21/25.
- Processing form and pack format, for example HLSO, IQF.
- Glaze percentage and net weight per carton, for example 10 percent glaze, 1.8 kg net.
- Certificates required and destination market, for example HACCP plus BAP plus BRC, European Union.
Add your volume and cadence and you have a spec. Anything less and the first reply you get will be a question, which costs you a week.
Where to go from here
If your grade is fixed and your certificate list comes from your own customer, the next question is which plants can actually hold both. That is a shorter list than the export directories suggest, and it changes with the season.
Count is one of the lines in our guide to the Vietnam shrimp export price.
Send the spec and we will match it against processors that run that grade and hold those certificates.
See also: the shrimp count chart: per pound, per kilogram and grams per piece.
Frequently asked questions
What does 21/25 mean on a shrimp carton?
It means 21 to 25 shrimp pieces per pound of net product. A lower pair of numbers means fewer and larger pieces, so 16/20 is larger than 31/40. U/15 means under 15 pieces per pound, with no lower bound stated.
Do Vietnam plants quote per pound or per kilogram?
Both appear. Size grades are conventionally written per pound because the US market set the convention, while the price is often quoted per kilogram. Always confirm which unit the price refers to before you compare two quotes.
Why is the same size grade priced differently by two plants?
Usually glaze percentage, net weight per carton, processing form or the certificate set behind the offer. Sometimes it is raw material timing. Put all four in the spec and the spread narrows sharply.
Is a larger size grade always more expensive per kilogram?
Almost always, because larger shrimp take longer to grow and carry more farm risk. The gap between adjacent grades is not uniform though, and the step from 21/25 to 16/20 is often steeper than the step from 31/40 to 26/30.
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