Fish Cooking Time by Thickness Calculator
Calculate exact fish cooking time based on thickness and cooking method.
Works for salmon, cod, tuna, tilapia, and more.
Fish is one of the most common foods to overcook or undercook, and the reason is simple: fish thickness varies enormously, and most people rely on time alone rather than time-plus-thickness. The standard professional rule is the Canadian Rule, and it works reliably across almost all species and cooking methods.
The Canadian Rule
Cook fish for 10 minutes per inch (2.5 cm) of thickness at the standard temperature for each method. Double the time for frozen fish.
This rule was developed by the Canadian Department of Fisheries in the 1970s and is still the most reliable universal guide for fish cookery.
Standard Temperatures by Method
| Method | Temperature |
|---|---|
| Oven bake | 200°C / 400°F |
| Oven roast | 220°C / 425°F |
| Pan-fry | Medium-high heat |
| Grill / BBQ | Medium-high direct heat |
| Poach / steam | 80–90°C / 175–195°F |
Cooking Time Formula
Cook time (minutes) = (thickness in inches × 10) × freshness modifier
- Fresh fish: × 1.0
- Frozen fish (not thawed): × 2.0
Internal Temperature Guide
| Fish Type | Safe Internal Temp |
|---|---|
| Most fish (salmon, cod, tilapia) | 63°C / 145°F |
| Tuna (if eating medium/rare) | 52°C / 125°F |
| Swordfish | 63°C / 145°F |
| Shrimp | 63°C / 145°F |
Visual Doneness Tests
For most fish: the flesh should be opaque and flake easily with a fork along the natural lines. The colour changes from translucent to white/opaque when fully cooked. Salmon turns from deep orange to pale pink.
Thickness Measurement Tips
Measure the thickest part of the fillet, not the thinnest. If cooking multiple fillets of different thickness, time to the thickest one. For rolled or stuffed fish, measure after rolling.
| Fish | Typical Thickness |
|---|---|
| Tilapia fillet | 1.5–2 cm (0.5–0.75 in) |
| Salmon fillet | 2.5–4 cm (1–1.5 in) |
| Cod fillet | 2.5–5 cm (1–2 in) |
| Tuna steak | 2–3.5 cm (0.75–1.5 in) |
| Whole trout | 4–6 cm (1.5–2.5 in) |