Flat against ridged
A stovetop griddle is a flat plate with low edges, Lodge says, so a spatula slides under pancakes, French toast, eggs, sausage and grilled cheese, and a double-burner griddle spans two burners for a crowd. A grill pan has raised ridges instead: food sits on them, picks up grill marks and stays above the fat that runs between them.
One pan with both sides
Lodge's 16.75 by 9.5-inch Double Play is a reversible cast-iron plate with a grill on one side and a flat griddle on the other, made to cover two burners. It weighs 9.35 lb, and Lodge says it works on any stovetop, induction included, in the oven, on a grill or over a campfire. If you'd use both, one reversible plate takes less cupboard space than two pans; Lodge's 10.5-inch square grill pan alone weighs 7.33 lb.
Which one to buy
Choose a griddle if you cook breakfast for several people, make sandwiches or smash burgers, or want a big flat surface for fish and vegetables. Choose a grill pan if grill marks on steak, chicken and vegetables are the point. Choose a reversible grill and griddle if you want both and have two burners side by side.
How these comparisons are made
Questions about this choice
Is a griddle the same as a grill pan?
No. A griddle is flat; a grill pan has raised ridges. Some cast-iron plates, like Lodge's Double Play, have a griddle on one side and a grill on the other.
Can I cook pancakes on a grill pan?
Not well: the batter runs into the channels between the ridges. Use a griddle, the flat side of a reversible plate, or a skillet.