Fish Cooking Time by Thickness Calculator
Calculate fish cooking time by thickness and method — baking, frying, grilling, poaching, or steaming.
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, measured at the thickest point. Double it for fish going in frozen. That is the whole rule, and it is the baseline this calculator works from before adjusting for how you are cooking it.
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
The Canadian Rule was written for oven baking, so that is the baseline here. The other methods land either side of it, and this calculator nudges the time accordingly.
| Method | Temperature | Time vs baking |
|---|---|---|
| Oven bake | 200°C / 400°F | baseline |
| Oven roast | 220°C / 425°F | ×0.85, hotter oven |
| Pan-fry | Medium-high heat | ×0.9, direct contact with the pan |
| Grill / BBQ | Medium-high direct heat | ×0.9, fierce direct heat |
| Poach / steam | 80–90°C / 175–195°F | ×1.1, gentle and much cooler |
Cooking Time Formula
Cook time (minutes) = thickness in inches × 10 × method modifier × state modifier
- Fresh or fully thawed: × 1.0
- Frozen, straight from the freezer: × 2.0
So a 1 inch salmon fillet, fresh, poached, works out at 1 × 10 × 1.1 × 1.0 = 11 minutes. Roast that same fillet instead and it is 8.5, which the calculator rounds up to 9.
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 color changes from translucent to white and 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) |
How we build and check this calculator
This calculator runs entirely in your browser, so the numbers you enter stay on your device. The math behind it is written by hand and tested against worked examples and standard references before the page goes live.
SuperGlobalCalculator is independently built and maintained. See how we build and verify our calculators.