How Long to Bake Salmon at 400°F | Thickness Is the Secret

Bake salmon for 12–15 minutes at 400°F for a standard 1-inch thick fillet, or 5 minutes per ½ inch of thickness for any size piece. The most reliable doneness check is an internal temperature of 145°F.

A dry, chalky piece of salmon is almost always a timing problem, not a cooking problem. The difference between tender, flaky fish and an overcooked disappointment is often just three or four minutes in the oven. Thickness, not a clock, should dictate your bake time. Here is the exact time window for every common oven temperature, how to measure doneness without guessing, and the one kitchen tool that makes it foolproof.

Bake Times by Oven Temperature

The table below shows bake times for standard fillets roughly 1-inch thick. Thick fillets (1.5 inches or more) need the longer end of each range; thinner wild salmon fillets (often under ¾ inch) need the shorter end. For the most precise result, skip the categories altogether and use the thickness rule instead.

Thickness rule: Bake salmon for 5 minutes per ½ inch of thickness, measured at the thickest part of the fillet. A 1-inch fillet gets 10 minutes. A 1.5-inch fillet gets 15 minutes. Combine this ratio with the temperature table above and match the shorter times for thinner pieces.

How To Tell When Salmon Is Done

The USDA sets the safe internal temperature for salmon at 145°F. Insert an instant-read thermometer into the thickest part of the fillet. If you prefer a moister, medium-cooked center — and many chefs do — pull the salmon at 140°F and let it rest for 2–5 minutes. The residual heat (carryover cooking) will lift the temperature the rest of the way, and the fish stays tender.

If you don’t have a thermometer on hand, press the thickest part with a fork. Fully cooked salmon flakes easily — the flesh separates cleanly along the white lines running through the fillet. When the fish turns opaque all the way through and the surface looks matte rather than translucent, it is done. The flaking test works, but an instant-read thermometer is significantly more reliable, especially for thinner fillets that can go from perfect to dry in one minute.

Common Mistakes That Ruin Baked Salmon

Overcooking is the single most frequent error. Salmon that bakes until all translucency is gone often turns dry and mealy. Aim for a fillet that is just opaque in the center — slightly translucent is fine for medium-rare and better for texture.

Ignoring thickness. A 15-minute timer for every fillet guarantees failure because wild sockeye salmon is often half as thick as farm-raised Atlantic salmon. Wild fillets (sockeye, coho) typically need 8–12 minutes at 400°F. Thicker Atlantic or king salmon can need 12–15 minutes or more. Measure the fish, not the recipe.

Skipping the thermometer lets visual cues mislead you, especially on dark-skinned fillets where the color change is subtle. An electronic meat thermometer removes all guesswork, and it pays for itself after one or two saved dinners.

Crowding the pan creates uneven heat. High-temperature methods (425°F and above) work best when the baking sheet holds salmon and nothing else. If you are cooking vegetables alongside, keep them on a separate tray or use a lower oven temperature.