304 vs 316 stainless steel: is 316 worth the upcharge?

What's actually different between 304 and 316?

One ingredient: molybdenum. 304 is the classic 18/8 stainless, about 18% chromium and 8% nickel. 316 keeps that and adds 2-3% molybdenum, which is what defends the surface against chlorides, the salt-family chemistry that pits stainless. That's the whole story. Same family, same look, machines and welds much the same. You're paying for chloride resistance, so the buying question is simple: will this part live near salt or chlorine?

When is 304 all you need?

Any time the part lives away from salt. Indoor railings and handrails, kitchen and brewery fittings, shop fixtures, brackets, food-contact surfaces, machine guards, trailer trim that sees rain but not the ocean. 304 covers the huge middle of stainless work, and it's the deepest part of our stainless rack: round bar, flat bar, pipe, sheet, angle, square bar, hex bar, and square tube. If your project is indoors or inland, buy 304 and put the difference into the rest of the build.

When do you really need 316?

Within reach of chlorides. Around here that's most of the interesting work: wharf and boat hardware, anything living within a few streets of the Atlantic, pool and hot tub fittings. Add fish plant equipment and every part that gets washed with de-icing salt all winter. Chemical and marine environments are 316's whole job. We stock it in flat bar, hex bar, angle, and a deep pipe rack in schedule 40 and 80. Put 304 on a wharf and it'll still be standing, but it'll show tea-coloured staining and pitting long before 316 blinks.

How much more does 316 cost?

Less than its reputation says, and it depends on the shape. Two real pairs from our shelf, both priced per 12″ piece in CAD, as of June 2026:

So budget roughly 10-50% over 304 depending on shape, and check the live product page for today's number, prices update daily. On a $30 piece of boat hardware, the upcharge is a coffee. Replacing a pitted part twice is the expensive option.

Will 304 rust?

It can stain and pit, yes. Stainless resists corrosion, it doesn't ignore it. Near salt, 304 develops brown "tea staining" first, then pinhole pitting where chlorides sit in crevices. Inland, 304 stays clean for decades with an occasional wash. Two habits help either grade: rinse off salt and grime now and then, and don't let carbon steel grinding dust settle on it, those sparks rust and look like the stainless failed.

Which should you buy for your project?

Walk the part through one question: does it ever meet salt water, road salt, or pool chemistry? Yes means 316, and the table above says the hit is smaller than you feared. No means 304, and the savings are real on bigger builds. Mixed builds are normal too: 316 for the dock hardware, 304 for the parts that stay in the shed. Both grades come with mill test reports on marked products if your job needs the paper. Picking aluminum for the same build? Same logic, different alloys: our 6061 vs 6063 guide. And every piece orders the same way: type your length, see the price.

About Metals 'R' Us

Metals 'R' Us is a Canadian metal supplier in Dartmouth, Nova Scotia. Since 1997 we've sold steel, stainless, aluminum, brass, copper, bronze and tool steel, cut to the exact length you need. Pick your alloy, shape and size, type in your length in inches, and the price shows up right away. We ship pieces up to 96″ anywhere in Canada, with the best parcel rates under 48″, or you can pick up free at the shop in Dartmouth. $40 minimum order. Longer lengths (up to 21 feet), oversize loads, or custom plasma and CNC work? Send us a quick quote request and we'll price it for you.

Know your grade? Shop stainless and type your length in.