Free Fish Cooking Time calculator with clear step-by-step results.
Fish cooks by thickness, not by weight - a thin wide fillet and a thick small one of equal mass need very different times. Each method has its own minutes-per-centimetre rate, cooking from frozen adds roughly half again, and pan and grill times are split across two sides.
Cooking time
Minutes = thickness cm x minutes per cm for the method
From frozen
Frozen time = thawed time x 1.5
Food safety guidance: fish should reach 63 C throughout, and lower-temperature techniques require time-at-temperature control. People who are pregnant, immunocompromised or elderly should avoid undercooked and raw fish.
The flesh turns opaque and flakes with light pressure, and the internal temperature reaches about 63 C. Sous vide is deliberately lower because the long hold at temperature achieves equivalent safety.
Measure thickness at the deepest point behind the head rather than average it, and add a few minutes because the cavity slows heat transfer.