How thick should a griddle be?

For a freestanding propane griddle, anything from about 3.4 mm (10 gauge) upward is workable and 4.7 mm is noticeably better; for a plate that sits on a grill or a range, buy 3/16 in (4.8 mm) at minimum and 3/8 in (9.5 mm) if your appliance can take the weight. Thickness buys thermal mass, and thermal mass is the only thing standing between a full load of cold food and a collapsed surface temperature.

Every published thickness, in one unit

Griddle listings quote thickness in three different systems — sheet-metal gauge, millimeters and fractional inches — which makes them look incomparable. They are not.

Two findings fall straight out of that table. Pit Boss’s 4.7 mm plate is about 38% thicker than the 10-gauge plate Blackstone describes as thicker than most griddles in its class — and it is essentially identical to Steelmade’s 3/16 in grill insert. And Steelmade’s PRO Original, at 9.5 mm, carries close to three times the steel of any freestanding griddle here.

Gauge numbers run backwards, and they are not a measurement

“10-gauge” is the single most confusing number in griddle listings, for two reasons.

First, gauge runs backwards: a lower number is a thicker plate. 10 gauge is thicker than 11, 14 or 16. If you are comparing two griddles and one says 10 gauge and the other says 14, the 10 is the heavier plate.

Second, gauge is a reference to a standard table rather than a dimension. On the manufacturers’ standard gauge for steel sheet, 10 gauge is 0.1345 in — 3.416 mm. A listing that says “10 gauge” and a listing that says “3.4 mm” are describing the same plate, and a listing that says “4.7 mm” is describing a meaningfully heavier one.

Be suspicious of any listing that quotes cooktop weight instead of thickness. Weight includes the frame, the rails and the grease channel, so it tells you nothing about the steel under the food.

What thickness actually does

A thick plate is not hotter. Peak temperature is set by the burners, not the steel — which is the heat density argument, and a separate specification.

What a thick plate does is resist change. Steel stores heat. When eight cold patties land on a thin plate, they pull heat out of the small amount of steel directly beneath them faster than the burner can replace it, and the surface temperature in that area falls off a cliff. Food that should be searing sits in released moisture instead, and you get a gray patty rather than a crust.

On a thick plate, the heat comes from the reservoir of steel around and below the food while the burner catches up. The surface temperature dips less and comes back faster.

This is why smash burgers are the test case for plate thickness and why thin plates are perfectly fine for pancakes. Pancake batter is warm, light and spread thin; it barely draws on the plate at all.

The two costs of a thick plate

Thickness is not free, and the trade-offs are predictable.

• Preheat time. More steel takes longer to come up to temperature. Allow longer before the first cook — how long by size and thickness.
• Weight. Steelmade publishes 62 lb for the PRO Original and 51 lb for the Junior. That is a two-handed lift at an awkward height, and on a range top it is a load your appliance has to be able to carry. Check that before buying, not after delivery.

A thicker plate is also harder to warp — the failure that ends a thin cooktop’s life, usually from cold water hitting a hot surface.

What to buy at each level

For a freestanding griddle, the Blackstone 28 at 10 gauge is the sensible floor and the Pit Boss Deluxe at 4.7 mm is the thickest freestanding plate here — which, combined with 62,000 BTU over 753 square inches, is also the highest heat density on this site at 82.3 BTU per square inch.

For a plate that uses an appliance you already own, Steelmade is the whole category: 3/16 in for an outdoor gas grill and 3/8 in for a kitchen range, which is the most thermally stable surface covered anywhere on this site.