Protein head-to-heads · July 2026
Peanut butter vs Tofu (firm): which protein is cheaper?
USDA macros joined to current US grocery prices, reduced to the two numbers that decide it: dollars per gram of protein, and protein per calorie.
Peanut butter is 1.1x cheaper per gram of protein ($0.022/g vs $0.024/g), while Tofu (firm) is the leaner choice at 11.8 g protein per 100 kcal against 4.3 g. Budget favours one, a calorie cap favours the other.
| Food | $/g protein | 30 g protein costs | You need | kcal that come with it | Protein/100 kcal |
|---|---|---|---|---|---|
| Peanut butter | $0.022 | $0.66 | 120 g | 706 kcal | 4.3 g |
| Tofu (firm) | $0.024 | $0.71 | 176 g | 254 kcal | 11.8 g |
Full macros, per serving
| Food (per serving) | Price | kcal | Protein | Carbs | Fat |
|---|---|---|---|---|---|
| Peanut butter (100 g) | $0.55 | 588 | 25 g | 20 g | 50 g |
| Tofu (firm) (100 g) | $0.40 | 144 | 17 g | 3 g | 9 g |
A week of protein from each
Hitting a common 100 g/day protein target from peanut butter alone costs $15.40 a week; from tofu (firm) alone, $16.47. That is a gap of $1.07 every week for the same protein. In practice you mix sources: the planner computes the cheapest mix for your exact target and calorie cap, live from the same dataset.
Budget says one, calories say the other
Peanut butter costs $0.022 per gram of protein against $0.024, so it saves $1.07 a week at a 100 g/day target. Tofu (firm) answers a different question: 11.8 g of protein per 100 kcal against 4.3 g, which is what matters once calories, not dollars, are the thing you run out of first.
What the calories cost you
Getting 30 g of protein from peanut butter brings 706 kcal with it. On a 2,000 kcal day, three servings would be most of your budget before anything else goes on the plate. That is fine when you are eating at maintenance or building, and it is the reason this food falls apart on a cut no matter how good the price per gram looks.
On a cut these are not comparable
Tofu (firm) carries 2.8x the protein per calorie that peanut butter does. When you are eating at a deficit, that ratio is the whole game: the same 30 g of protein arrives with 254 kcal from one and 706 kcal from the other. The cheaper option stops being cheaper once you count what you had to give up elsewhere to fit it in.
Compare against other foods
- Peanut butter vs Oats (dry)Tofu (firm) vs Oats (dry)
- Peanut butter vs Lentils (cooked)Tofu (firm) vs Lentils (cooked)
- Peanut butter vs Black beans (cooked)Tofu (firm) vs Black beans (cooked)
- Peanut butter vs Whey protein (1 scoop)Tofu (firm) vs Whey protein (1 scoop)
- Peanut butter vs Greek yogurt (nonfat)Tofu (firm) vs Greek yogurt (nonfat)
- Peanut butter vs Eggs (~2 large)Tofu (firm) vs Eggs (~2 large)
- Peanut butter vs Chicken breast (raw)Tofu (firm) vs Chicken breast (raw)
- Peanut butter vs Canned tuna (in water)Tofu (firm) vs Canned tuna (in water)
Frequently asked
- Which is cheaper for protein, peanut butter or tofu (firm)?
- Peanut butter, at $0.022 per gram of protein against $0.024 for tofu (firm) (July 2026 US grocery prices). A 30 g protein serving costs $0.66 vs $0.71.
- Which has more protein per calorie, peanut butter or tofu (firm)?
- Tofu (firm), with 11.8 g protein per 100 kcal against 4.3 g for peanut butter, 2.8x leaner. That matters when you are cutting and calories are the binding constraint.
- Which should I buy, peanut butter or tofu (firm)?
- Depends on your constraint. On a tight budget with room in your calories, peanut butter is cheaper per gram of protein. On a calorie-capped cut, tofu (firm) gives you 2.8x more protein per calorie and is usually worth its $0.024/g price.
Prices are representative US grocery prices as of July 2026; your store will differ. Educational content, not medical or dietary advice. Dataset: free download, CC-BY.