304 vs 316L Stainless Steel: Which Grade Should You Specify?

Short answer: 304 for almost everything, 316L where chlorides or salt are present. The price difference is roughly 25–40%, so the decision is worth ten minutes. Below is the full comparison and the cases where each grade is the wrong choice.

At a glance

	304	316L
Composition	18% Cr, 8% Ni	16–18% Cr, 10–14% Ni, 2–3% Mo
Carbon	≤ 0.08% (304) / ≤ 0.03% (304L)	≤ 0.03% (always low-carbon)
Corrosion resistance	Good in fresh water, food, indoor and rural atmospheres	Excellent in chlorides, salt spray, coastal and chemical environments
Pitting resistance (PREN)	≈ 18	≈ 24–26
Yield strength	≥ 205 MPa	≥ 170 MPa
Relative price	Baseline	+25% to +40%
Best for	Kitchen equipment, railings, tanks, general fabrication, indoor architecture	Marine, coastal facades, chemical plant, pharma, desalination, swimming pools
Standard	ASTM A240, EN 1.4301	ASTM A240, EN 1.4404

What the molybdenum actually does

The 2–3% molybdenum in 316L is what resists pitting and crevice corrosion caused by chlorides. Chlorides come from seawater, road salt, pool water, bleach and many process chemicals. In a dry indoor room, 304 will outlast the building. Ten kilometres from the coast, it can pit within two years.

That single fact drives the decision more than any other. If the part will ever see salt or chloride, specify 316L. If it will not, 304 is not a compromise — it is the correct choice.

When 304 is the right answer

• Indoor kitchen and food-service equipment
• Architectural trim, handrails, balustrades in inland cities
• Water tanks, pipework and vessels handling potable or process water without chlorides
• Appliances, sinks, cookware and general sheet-metal work
• Any application where the surface stays clean and dry

When 316L is worth the premium

• Coastal and marine — within roughly 5 km of the sea, or on any vessel
• Chemical and pharmaceutical — acids, chlorinated water, CIP cleaning
• Swimming pools and spas — warm chlorinated water is aggressive to 304
• Food processing with brine or salt — meat, dairy, pickling lines
• Medical and laboratory equipment that is repeatedly sterilised
• Welded assemblies that cannot be annealed — 316L's low carbon avoids sensitisation

Where people get it wrong

Over-specifying. Putting 316L on an indoor handrail doubles material cost for zero benefit. Buyers do this because it feels safer; it just makes the quote less competitive.

Under-specifying. Using 304 outdoors near the coast, or in a pool hall, is the expensive mistake — the part fails in 12–24 months and has to be replaced, including labour.

Ignoring 304L. If you weld thick sections, 304L (0.03% carbon) is the correct choice over standard 304. It is usually the same price.

What it costs

The nickel and molybdenum content sets the price. 316L typically runs 25–40% above 304 depending on the nickel surcharge at the time of order. For a 20-tonne order that is real money — which is exactly why the chloride question should be answered before the quote, not after.

Bottom line

Ask one question: will this part ever see salt or chlorides? If yes, 316L. If no, 304 — and put the savings into a better surface finish or a thicker gauge, which will serve you longer.

Both grades are in stock here in 0.3–200 mm sheet, coil, pipe and bar. See sheet and plate, or send us the application and we will confirm the grade in writing before you commit.