You may have noticed the markings on the back of your spoons or the bottom of your pots: 18/8, 18/10, or even 18/0. You might not know what they mean for the durability of those items, but you’re about to find out what they can tell you.
These numbers reveal the constitution of the material used when making the item in question. Which means they can explain why some pans and cutlery have a life expectancy measured in years and some become rusty in a matter of months.
At a Glance
- The numbers 18/8, 18/10, and 18/0 tell you the chromium and nickel content in the steel alloy — chromium provides rust resistance; nickel adds shine and flexibility.
- 18/0 has no nickel → magnetic, harder, more prone to rust if the surface is scratched.
- 18/8 and 18/10 are non-magnetic (or very weakly magnetic), more corrosion-resistant, and the standard for quality kitchen tools.
- A simple magnet test in the store or at home can instantly tell you whether you’re looking at 18/0 (magnetic) or 18/8/18/10 (non-magnetic) — but it won’t distinguish 18/8 from 18/10.
- This guide gives you a stamp-inspection checklist and explains what the BIS mark actually means for Indian buyers.
Steel-grade stamps on kitchen tools — from spatulas and spoons to knives and graters — are a shorthand for the alloy’s composition, and that composition directly determines how long the tool resists rust, how well it holds an edge, and whether it feels substantial in your hand. The grade also influences price: 18/10 commands a premium over 18/8, and 18/0 is the budget tier you’ll find on basic knives and mass-market tools.
What the numbers on your kitchen tool actually mean
The first number — 18 — is always the chromium content: 18% chromium by weight. Chromium is what makes stainless steel “stainless”; it forms a passive oxide layer on the surface that self-repairs when scratched, as long as there’s enough oxygen present.
The second number is the nickel content: 8%, 10%, or 0%. Nickel adds ductility (the ability to bend without breaking), improves corrosion resistance, and gives the steel its characteristic shine.
Here’s the practical breakdown:
- 18/8 (Type 304): 18% chromium, 8% nickel. The most common food-grade stainless steel. Good corrosion resistance, easy to form, holds a decent edge. Used in most quality kitchen utensils, flatware, and cookware.
- 18/10 (also Type 304, higher nickel): 18% chromium, 10% nickel. Slightly better corrosion resistance and a brighter finish. Premium flatware and higher-end cookware often carry this stamp.
- 18/0 (Type 430): 18% chromium, 0% nickel. This is a ferritic stainless steel — magnetic, harder, but less corrosion-resistant. It’s the budget grade you’ll find on inexpensive knives and mass-market tools.
On LinkedIn, a buyer shared an experience where a 15-year-old stainless steel kitchen knife cracked from a single rust spot that went unnoticed. As they put it: “stainless steel does rust and with terrible consequences.” This happens because 18/0 steels and scratched 18/8 are susceptible to localized corrosion when the passive layer is breached, making surface care as important as the grade itself.
Why nickel content changes everything — from rust to magnetism
Nickel is the difference-maker. At 8% or 10%, nickel stabilizes the austenitic structure of the steel — the crystal arrangement that makes the steel non-magnetic (or only weakly magnetic after cold working). At 0% nickel, the steel takes a ferritic structure, which is magnetic.
This isn’t just a physics party trick. The magnetic property is a direct proxy for corrosion resistance:
- Non-magnetic (18/8, 18/10) → Austenitic structure → better resistance to rust and staining, even in acidic environments (lemon juice, tomatoes, vinegar).
- Magnetic (18/0) → Ferritic structure → more susceptible to corrosion, especially if the surface is scratched or exposed to salt and acid.
A simple neodymium magnet — the kind on your fridge — will stick firmly to 18/0 tools. It may barely cling or slide off 18/8 and 18/10 tools. This test is your first line of defense against mislabeled or counterfeit goods. But note: some 18/8 tools become weakly magnetic after being stamped or cold-formed; if the magnet sticks weakly, it’s still likely 18/8, not 18/0.
Try this before you buy: take a small magnet to the store. If it sticks firmly to the blade or bowl of a tool stamped “18/8” or “18/10,” be suspicious — that grade should be non-magnetic.
The BIS mark: what it tells you — and what it doesn’t
In India, the Bureau of Indian Standards (BIS) mandates that stainless steel utensils conform to IS 14756 (the current revision is IS 14756:2024). The BIS Standard Mark on a utensil means the product has been tested and licensed under the Bureau’s conformity assessment scheme.
But here’s what the BIS mark does not tell you:
- It does not specify 18/8 vs. 18/10 vs. 18/0. The standard sets minimum requirements for material, but the actual grade is not part of the mark.
- The BIS mark confirms the utensil meets safety and quality criteria for food contact — but it doesn’t guarantee you’re getting 18/10 over 18/8.
So if you see a BIS mark, that’s a good sign: the product has passed basic regulatory scrutiny. But you still need to read the steel-grade stamp and perform the magnet test to know what you’re actually buying. The BIS mark and the steel-grade stamp are complementary, not interchangeable.
Important: The Quality Control Order for stainless steel utensils was updated in 2025, with phased compliance deadlines. If you’re buying from a reputable brand, the BIS mark should be present. If it’s absent, that’s a red flag — but absence doesn’t automatically mean the product is unsafe; it may mean the manufacturer hasn’t obtained a license yet.
Check this in-store by: on the base or rim of the utensil, look for the BIS Standard Mark — a triangle with “ISI” inside — and the license number. If it’s not there, ask the seller why.
Where each grade belongs — and where it doesn’t
Not all kitchen tools need 18/10. Understanding where each grade excels helps you spend money where it matters.
| Tool Type | Recommended Grade | Why |
|---|---|---|
| Spatulas, spoons, ladles | 18/8 or 18/10 | Frequent contact with acidic foods; need corrosion resistance and a smooth finish |
| Knives (general purpose) | 18/8 (preferred) or 18/0 | 18/0 is harder and holds an edge longer but is more brittle and rust-prone; 18/8 balances edge retention and corrosion resistance |
| Graters, zesters | 18/8 | Constant exposure to acidic citrus and vegetables; 18/0 will rust at scratch points |
| Serving flatware (forks, spoons) | 18/10 | Premium feel, better shine, resists pitting from repeated washing |
| Budget knives, mass-market tools | 18/0 | Acceptable for occasional use if you dry immediately after washing; not for daily heavy use |
The trade-off: 18/0 is not “bad” — it’s just the wrong choice for wet, acidic, or daily-use applications. It’s harder (which means better edge retention) but more brittle and corrosion-prone. An 18/0 knife can be perfectly fine if you treat it like carbon steel: wash, dry, and oil occasionally.
18/8 is the sweet spot for most kitchen tools because it offers corrosion resistance at a lower price than 18/10; 18/10 is worth the premium only for flatware and high-end cookware where aesthetics matter. For knives, the steel grade also influences which sharpener works best — 18/0 blades, being harder, often respond better to a whetstone, while 18/8 knives can be maintained with a pull-through sharpener. (See our guide to whetstone vs. pull-through vs. electric sharpeners.)
How stamp placement reveals build quality
Where the steel-grade stamp is placed tells you something about the manufacturer’s confidence. A deep, cleanly struck stamp on the base of the handle or back of the bowl suggests the grade is part of the product’s identity — not an afterthought. A faint, shallow stamp on the edge of the rim or inside the handle recess may indicate the manufacturer is meeting a minimum requirement without wanting it to be prominent.
What to look for:
- Stamped vs. etched: Stamped marks (indented into the metal) are more durable and harder to fake than laser-etched marks, which can wear off.
- Consistency: If a set of tools claims to be 18/8 but some pieces have different stamp depths or placements, that’s a red flag.
- Missing stamps: Some budget tools omit the grade entirely. If there’s no stamp and no BIS mark, you’re buying blind.
This isn’t a definitive test of quality, but it’s a useful heuristic. Brands that invest in clear, permanent grade markings are generally more transparent about their materials.
Steel-grade identification checklist
Use this checklist before you buy any stainless steel kitchen tool. It works in-store or when a package arrives.
Step 1: Find the stamp
Look on the back of the handle, the base of the bowl, or the blade tang. If there’s no stamp, proceed with caution.
Step 2: Read the numbers
- 18/8 or 18/10: Proceed to Step 3.
- 18/0: Decide if you’re okay with a magnetic, harder, less rust-resistant tool. If you cook with acidic foods daily, consider passing.
- No stamp or unclear: Treat as unknown — assume 18/0 or lower-grade steel unless you can verify otherwise.
Step 3: Perform the magnet test
Use a small neodymium magnet (fridge magnets work, but neodymium is more sensitive).
- Strong stick → 18/0 or lower. Not ideal for wet/acidic use.
- Weak stick or slides off → 18/8 or 18/10. Good.
- No stick at all → Austenitic (18/8 or 18/10). Excellent.
Step 4: Check for the BIS mark
Look for the ISI triangle with a license number. This confirms the product meets IS 14756 standards for food-contact safety.
Step 5: Inspect the stamp quality
Deep, clear, permanent stamp → higher confidence. Faint, etched, or absent → lower confidence.
Step 6: Match the tool to the grade
- Spatulas, spoons, ladles → 18/8 minimum.
- Knives → 18/8 for daily use; 18/0 acceptable if you maintain it.
- Graters, zesters → 18/8 minimum.
- Flatware → 18/10 for premium; 18/8 for everyday.
The Bottom Line
The numbers on your kitchen tool aren’t marketing fluff — they’re a direct statement of the alloy’s chromium and nickel content, and that determines how long it will resist rust and how it will behave in your hand. Before you buy, find the stamp, read it, and run a simple magnet test; if the magnet sticks firmly to a tool stamped 18/8 or 18/10, something doesn’t add up. That 30-second check could be the difference between a tool that lasts a decade and one that rusts in your drawer before the year is out.
Frequently Asked Questions
Is 18/8 stainless steel food safe for Indian cooking?
Yes, 18/8 (Type 304) is the most common food-grade stainless steel used in kitchens worldwide. It resists corrosion from acidic ingredients like tomatoes, tamarind, and citrus, and meets BIS food-contact standards under IS 14756.
Can I use 18/0 stainless steel for a knife that I use daily?
You can, but it requires diligent maintenance because 18/0 has no nickel and rusts easily when wet. If you wash and dry it immediately after each use, it can work; for a low-maintenance daily knife, 18/8 is the better investment.
Does the BIS mark guarantee the steel grade on a utensil?
No. The BIS Standard Mark (ISI triangle) confirms the utensil meets the safety and quality requirements of IS 14756, but it does not specify whether the steel is 18/8, 18/10, or 18/0. The BIS mark and the steel-grade stamp are independent — you need both to fully understand what you’re buying.
Why does my 18/8 spoon attract a magnet slightly?
Cold-working — the process of stamping, forming, or bending the steel — can transform some of the austenitic (non-magnetic) structure into martensite, which is magnetic. A weak magnetic response on an 18/8 tool is normal; a strong, firm stick, however, suggests the steel is actually 18/0 or a lower-grade ferritic alloy.
