You'll see 18/8, 18/10, 304, 316, and 430 on stainless kitchen gear, and they get treated like quality tiers. Mostly they just describe the alloy. What you want to know is which family each part belongs to, and whether the maker told you at all.
The numbers
- 18/8 and 18/10 are chromium and nickel percentages: about 18 percent chromium, with about 8 or 10 percent nickel. Both belong to the 300 series. Most cookware, bottles, and utensils marked 18/8 or 18/10 are grade 304 or a close relative.
- 304 is the standard austenitic grade, and what "18/8" usually means in practice. It's the default for food service equipment and for most well-made bottles, presses, and bowls.
- 316 adds about 2 to 3 percent molybdenum, which helps it resist chlorides and acids. You'll sometimes see it sold as "marine grade." Some cookware makers use it for the cooking surface. 360 Cookware states T-316 for its cooking surface, for example (manufacturer statement).
- 430, often labeled 18/0, has about 16 to 18 percent chromium and no nickel. It's ferritic and magnetic, which is why it's used for the base plates that let induction cooktops work, and for cheaper flatware and bakeware. It resists corrosion less well than 304.
- 201 and other 200-series grades swap some of the nickel for manganese. They're legitimate steels, but they resist corrosion less well than 304. They sometimes turn up in low-cost products described only as "stainless steel."
Chromium is what makes stainless steel stainless. Nickel helps the alloy stay non-magnetic and easy to form, and adds corrosion resistance.
One product, several grades
A bottle can have a 304 body, a 430 plate welded to the bottom, and a lid made of a different alloy.
A clad pan has a 304 or 316 cooking surface, an aluminum core, and a magnetic 400-series exterior so it works on induction. Heritage Steel, for example, states a 304 cooking surface with a 400-series exterior (manufacturer statement).
So when a product page says only "stainless steel," you can't tell which part is which. Ask which grade each part is.
Marketing words, translated
- "Food grade stainless" has no legal definition in the United States. It usually means 304. Ask for the grade.
- "Surgical grade" or "medical grade" has no consumer product definition. It usually means 316. Ask for the grade.
- "Lead free stainless" doesn't mean much. Lead isn't an alloying element in stainless steel, so the claim advertises the absence of something that was never there.
- "Nickel free" is only true of ferritic grades like 430. 304 and 316 contain nickel. If nickel sensitivity matters to you, ask for the grade. "Hypoallergenic" won't tell you which one it is.
The magnet test
A magnet sticks to ferritic steels like 430. It doesn't stick to austenitic ones like 304 and 316, or only weakly.
That tells you the family, not the grade. A magnet can't tell 304 from 316, or 304 from 201.
It can tell you that the base of your "304" bottle is actually a magnetic plate. That's normal, not a defect.
What we ask makers for
The grade of every stainless part, in writing. A specification sheet is good. A mill test certificate is better.
On our product pages, the grade appears per part with its evidence level. If a maker will only say "stainless steel," the profile says that.
Which grade do you want?
For bottles, presses, bowls, and utensils, 304 is the normal, reasonable choice.
316 is a sensible upgrade if you cook acidic food often, or you want more margin against pitting from salt. Some makers use it for exactly that reason.
430 is fine where it's used on purpose, like bakeware, base plates, and exteriors. It's less appealing as a hidden substitute in parts that hold liquid for long stretches.
We're comparing durability and corrosion resistance here. We don't rank any grade on safety.
Reviewed: 2026-10-15.
Read next: Uncoated stainless steel cookware: what it means, and what it doesn't tell you and Fully clad or disc bottom: how to choose a stainless pan that lasts.