1) Weigh the tuna steak first

Start by checking the label or weighing the steak on a kitchen scale. Protein estimates are most useful when you know the actual portion size. If you buy packaged tuna steaks, the weight is often listed in ounces or grams. If you’re at a restaurant, ask whether the listed weight is raw or cooked.

Use grams if possible, because nutrition data is usually easier to compare that way. A 100-gram serving is a common reference point for fish nutrition databases.

2) Convert the weight into protein

As a practical estimate, tuna steak usually provides about 23 to 29 grams of protein per 100 grams. That means a 150-gram steak has about 35 to 44 grams of protein, and a 170-gram steak has about 39 to 49 grams.

If you prefer ounces, a 4-ounce tuna steak often has around 25 to 30 grams of protein, while a 6-ounce steak is commonly closer to 38 to 45 grams. The exact number changes with the cut and species, but this range is a solid starting point for meal tracking.

3) Adjust for cooking and your nutrition goal

Cooking removes water, so a cooked tuna steak weighs less than the raw steak it came from. The total protein does not disappear, but the concentration per ounce can look higher after cooking. That’s why raw-vs-cooked comparisons can be confusing if you mix them up.

If you’re tracking macros for muscle gain, fat loss, or general meal planning, focus on consistency. Use the same method each time: weigh raw steaks before cooking, or use cooked weights every time. If you log workouts and meals in an app, tools like Fitnit can help keep your intake and training records organized, but the key is still using the same measuring method.

4) Avoid these common mistakes

Don’t assume every tuna steak is the same size. A small 3-ounce steak and a large 8-ounce steak can differ by more than 20 grams of protein.

Don’t confuse tuna steak with canned tuna without checking the serving size. Canned tuna is often packed differently and measured in drained ounces, so the protein per container is not the same as a fresh steak.

Don’t use a sauce, marinade, or breading to estimate protein unless those ingredients actually contribute meaningful protein. Most of the protein comes from the fish itself.

Don’t rely only on restaurant descriptions like “large” or “small.” Ask for the weight when possible if accurate macro tracking matters to you.

Tips

• Use a kitchen scale and weigh the steak raw for the most consistent estimate.
• Remember that 100 grams of tuna is roughly 23 to 29 grams of protein.
• If you cook tuna regularly, save one repeatable portion size so logging gets easier.
• Check whether your food log uses raw or cooked entries before entering the meal.
• If you track training too, pair meal logging with simple workout tracking so you can match protein intake to your goals.