A 16 oz jar of peanut butter holds about 1.7 cups. Peanut butter is dense — 270 g per cup, scooped — so a pound jar gives less than two cups, not the two and a half you might guess from the jar's size. One and three-quarter cups is enough for a batch of cookies, a satay sauce and a week's worth of toast, and the 16 oz jar is the size most recipes assume when they say 'a jar of peanut butter'.
How many cups in a 16 oz jar?
A 16 oz jar of peanut butter holds about 1.7 cups (454 g ÷ 270 g per cup).
| Amount | Cups | Grams | Tablespoons |
|---|---|---|---|
| Full 16 oz jar | 1.7 | 454 | 27 |
| Half 16 oz jar | 0.85 | 227 | 14 |
| Quarter 16 oz jar | 0.42 | 113.5 | 7 |
| 1 tablespoon | 0.06 | 16.88 | 1 |
The table gives the full package, half a package and a quarter of a package, plus a single tablespoon, so you can scale the answer to whatever your recipe asks for. If your packet is a different size from the one on this page, the same per-cup figure still applies — divide your packet's weight by the grams per cup, or its volume by 236.6 ml per cup, and you have your answer.
Worked examples
Peanut butter cookies that need a cup
A batch of peanut butter cookies takes 1 cup of peanut butter — 270 g, or a little over half the jar — creamed with 1/2 cup of butter, 1 cup of sugar and 1 egg. One cup is the classic ratio, and it is why the cookies taste of peanut rather than of butter. Press the peanut butter into the cup firmly and level it: a loosely scooped cup can be 10 percent short, and a short cup makes dry cookies. The remaining two-thirds of a cup in the jar covers a satay sauce or a smoothie.
Satay sauce that needs half a cup
A bowl of satay sauce for four takes about 1/2 cup of peanut butter — 135 g — whisked with 1/4 cup of soy sauce, 2 tablespoons of lime juice and 1 tablespoon of honey, then thinned with warm water. Half a cup is just under a third of the jar, so one jar makes about three bowls of sauce. Warm the peanut butter slightly first if it is stiff from the fridge: cold peanut butter seizes into lumps when the soy sauce hits it, while warm peanut butter blends smoothly.
Smoothies that need two tablespoons
A smoothie for one takes about 2 tablespoons of peanut butter — 34 g — blended with a banana, a cup of milk and a handful of oats. Two tablespoons is a small fraction of the jar, about a twenty-seventh, so a jar used only for smoothies lasts for weeks. Add the peanut butter before the liquid and let the blades pull it down: added last, it sticks to the sides of the jug and never fully blends. A tablespoon measure is more accurate than a spoon from the drawer for a small amount like this.
How the figure was measured
The weight figure on this page comes from King Arthur Baking: peanut butter weighs 270 g per cup, measured scooped, and that figure carries high confidence in CookScale's 120-ingredient table. Every cup-based result on this page is approximate, because a cup measures volume and the weight depends on how the ingredient settles, how it was measured, and how fresh it is. When the amount matters — a cake, a cheesecake, a sauce that must set — weigh the ingredient on a kitchen scale instead of trusting the cup. Package sizes vary by brand and region, so check the weight printed on your own packet before planning a recipe around this page.
How to measure it
Nuts are spooned into a dry cup measure and levelled, never packed — pressing them down crushes the pieces and fits far more weight into the same cup. Whole nuts, halves and chopped pieces all measure differently in the same cup: a cup of whole almonds weighs more than a cup of chopped almonds, because the pieces settle differently and the air gaps change. That is why the weight figures on this page are the anchor, not the cup. If a recipe says '1 cup chopped walnuts', chop first and then measure; if it says '1 cup walnuts, chopped', measure first and then chop. The difference is real — about a quarter of a cup in a batch of brownies. When it matters, weigh: 142 g of almonds is 142 g however you chop them.
Practical guidance
Nuts go rancid faster than almost anything else in the pantry because their oils are exposed to air. A bag opened in January and still sitting in a warm cupboard in June will taste stale and a little bitter, and no recipe can hide it. Store opened nuts in a sealed jar in the fridge, or in the freezer for months — they thaw in minutes and toast straight from frozen. Taste one before baking with an old bag: fresh nuts taste sweet and clean, stale ones taste like old oil. Toasting revives nuts that are merely flat, but it cannot rescue ones that have turned. Buy smaller bags more often rather than one huge bag that sits open.
One and three-quarter cups is the working figure, and the scooped-cup assumption is what makes it hold: peanut butter is measured scooped, pressed into the cup and levelled, not poured. If you spoon it loosely, a cup can be 20 g short, and across a batch of cookies that is enough to notice. Check the jar size before you start — 28 oz jars are common and hold about 3 cups, while small 12 oz jars hold about 1.3 cups — and the same 270 g per cup applies to all of them. And note the type: natural peanut butter is runnier than conventional, so it levels differently in the cup and is better weighed than measured.
Frequently asked questions
How many tablespoons are in a 16 oz jar of peanut butter?
There are about 27 tablespoons in a 16 oz jar of peanut butter, because the jar holds about 1.7 cups and there are 16 tablespoons in a cup. A tablespoon of peanut butter weighs about 16.9 g. For spreading on toast, a tablespoon is a thin spread and two tablespoons is a generous one, so a jar covers roughly a dozen generous servings.
Does crunchy peanut butter measure the same as smooth?
Almost. Crunchy peanut butter weighs about the same per cup as smooth — around 270 g — because the pieces are small and the difference is a few grams. In practice, treat them as identical for measuring. The difference matters for texture, not for weight: a cookie made with crunchy peanut butter has visible pieces, while smooth gives an even crumb.
Can I substitute almond butter for peanut butter cup-for-cup?
By volume, yes, and by weight approximately: almond butter is about 250 g per cup against peanut butter's 270 g, so a cup-for-cup swap is close but not exact. In cookies and sauces the difference is small. The bigger difference is flavour and price — almond butter is milder and considerably more expensive — and anyone with a peanut allergy should not assume almond butter is safe without checking.
How long does an opened jar of peanut butter last?
An opened jar of peanut butter lasts about three months in a cool cupboard, and longer in the fridge. Natural peanut butter, with no stabilisers, separates and should be stirred before each use; conventional peanut butter stays blended. Discard it if it smells stale or rancid, or if mould appears on the surface — a jar that has been double-dipped with a wet knife is the usual cause.
Why is there oil on top of my peanut butter?
Natural peanut butter separates because it contains no stabilisers: the oil rises and the solids settle. It is normal and harmless. Store the jar upside down so the oil migrates back through the solids, or stir it thoroughly once and keep it in the fridge, where the cold slows separation. Conventional peanut butter does not separate because it contains stabilisers that hold the oil in suspension.