Start by deciding your goal: chewy bite (sandwich), airy crumb (open texture), or crusty toast (heat-and-stack).
Choose the closest substitute from the table and use the listed ratio (usually 1:1, except rolls).
If your substitute is softer than ciabatta, toast the cut sides 30–90 seconds per side to firm the crumb.
If your substitute is denser, slice a bit thicker and let it heat briefly so the interior softens without turning gummy.
Assemble and serve promptly—ciabatta’s best texture happens right after slicing or toasting.