Ounces of peanut butter to cups runs on one number, 0.10988187 cups per ounce. It is a measured property of this ingredient rather than a defined conversion, which is why a generic volume-to-weight tool cannot give you it.
Put next to water — 1 g per mL exactly — peanut butter measures 1.0905 g per mL. That ratio, 109.1%, is what separates this page from every other ingredient in the same units, and it is measured rather than defined.
A cup of peanut butter is 258 g when it is measured the standard way, but how it gets into the cup changes the answer: between about 256.7 g and 260.6 g covers the range from lightly spooned to firmly packed. That 1% spread is larger than most of the adjustments recipes fuss over, and it disappears entirely the moment the ingredient is weighed instead.
One cup of peanut butter is 9.101 oz. US kitchen scales usually step in eighths of an ounce, which is 3.54 g — around 1.37% of a cup of this ingredient, so the scale is precise enough for a full cup and coarse for a spoonful. That is why recipes mix the two systems: ounces for the bulk, spoons for the small amounts.
The condition this weight assumes: Smooth, at room temperature. Straight from the fridge it is far harder to level into a cup, and that shows up on the scale.
The formula
ounces- The amount of peanut butter you are converting, in ounces
0.109881872578- Cups per ounce for peanut butter, from its density of 1.0905 g/mL
cups- The equivalent quantity in cups
How it works, step by step
- Enter the quantity in ounces.
- It is multiplied by 0.109881872578, the cups-per-ounce figure for peanut butter.
- The result appears in cups, with a second reading in tbsp beneath it.
- Use the measure table if you want a standard recipe quantity rather than a number you type in.
Worked examples
2 oz of peanut butter in cups
A recipe calling for 2 oz of peanut butter needs 0.219764 cups on the scale. The arithmetic is 2 × 0.10988187 = 0.21976375, and halving the recipe halves the weight to 0.109882 cups.
4 oz of peanut butter in cups
A recipe calling for 4 oz of peanut butter needs 0.439527 cups on the scale. The arithmetic is 4 × 0.10988187 = 0.43952749, and halving the recipe halves the weight to 0.219764 cups.
12 oz of peanut butter in cups
A recipe calling for 12 oz of peanut butter needs 1.31858 cups on the scale. The arithmetic is 12 × 0.10988187 = 1.3185825, and halving the recipe halves the weight to 0.659291 cups.
How to read your score
Frequently asked questions
How many cups are in 1 oz of peanut butter?
One ounce of peanut butter is 0.10988187 cups. Half that quantity is 0.0549409 cups and double it is 0.219764 cups, so the figure scales straight up and down — there is no offset in this conversion, only the factor.
Why is a cup of peanut butter not 236 g like water?
Because weight per cup depends on what is in the cup. Peanut butter has a density of 1.0905 g per mL where water has 1.00, so a cup of it weighs 258 g rather than 236.6 g. That is a difference of 21.4 g per cup, and it is the reason a single volume-to-weight factor cannot be applied to every ingredient.
Does how I measure it change the weight?
Barely. Peanut butter does not compress, so a cup of it is 258 g however it is poured — within about 1%, which is inside the accuracy of a domestic scale. This is the group where measuring by volume is defensible.
Is a fluid ounce of peanut butter the same as an ounce?
No. A fluid ounce is a volume — one eighth of a US cup, 29.57 mL — and an ounce is a weight. One fluid ounce of peanut butter weighs 1.138 oz, so the two readings differ by 13.8%. They coincide only for something with the density of water, and then only roughly.
Is this a US cup or a metric cup?
US customary: 236.59 mL, which is the cup every US recipe means. A metric cup is 250 mL, so the same cup of peanut butter would weigh 272.63 g instead of 258 g — 14.6 g more, or 5.67%. Australian and some European recipes use the metric cup, and the difference is large enough to matter in baking.
Do I need a scale for this, or will measuring cups do?
A scale, if the result matters. Volume measuring carries a spread of about 1% for peanut butter — roughly 2.58 g on a 258 g cup — while a domestic scale is accurate to a gram or two. For anything where the ratio of ingredients drives the outcome, bread and pastry above all, weigh it.
How much does 2 cup of peanut butter weigh?
2 cup of peanut butter comes to 516 g, or 18.201 ounces. This page runs that calculation in reverse — enter a weight and it returns the volume — and the cups-to-ounces page does it in the direction the question is usually asked.
Peanut butter in ounces and cups
| Ounces | Cups | Unrounded |
|---|---|---|
| 1/2 oz | 0.0549409 cup | 0.05494093629 |
| 1 oz | 0.109882 cup | 0.1098818726 |
| 2 oz | 0.219764 cup | 0.2197637452 |
| 3 oz | 0.329646 cup | 0.3296456177 |
| 4 oz | 0.439527 cup | 0.4395274903 |
| 6 oz | 0.659291 cup | 0.6592912355 |
| 8 oz | 0.879055 cup | 0.8790549806 |
| 12 oz | 1.31858 cup | 1.318582471 |
| 16 oz | 1.75811 cup | 1.758109961 |
Based on 258 g per cup of peanut butter. One ounce of peanut butter is 0.10988187 cups.
| Measure | Grams | Ounces | Millilitres |
|---|---|---|---|
| 1 cup | 258 g | 9.1 oz | 236.6 mL |
| 3/4 cup | 193.5 g | 6.83 oz | 177.4 mL |
| 2/3 cup | 172 g | 6.07 oz | 157.7 mL |
| 1/2 cup | 129 g | 4.55 oz | 118.3 mL |
| 1/3 cup | 86 g | 3.03 oz | 78.86 mL |
| 1/4 cup | 64.5 g | 2.28 oz | 59.15 mL |
| 1 tbsp | 16.12 g | 0.569 oz | 14.79 mL |
| 1 tsp | 5.375 g | 0.19 oz | 4.929 mL |
US customary measures: 1 cup = 236.59 mL, 1 tbsp = 14.79 mL, 1 tsp = 4.93 mL.
| Ingredient | Grams per cup | Ounces per cup | Density (g/mL) |
|---|---|---|---|
| Tomato sauce | 245 g | 8.642 oz | 1.036 |
| Orange juice | 248 g | 8.748 oz | 1.048 |
| Evaporated milk | 252 g | 8.889 oz | 1.065 |
| Peanut butter (this page) | 258 g | 9.101 oz | 1.091 |
| Sweetened condensed milk | 306 g | 10.79 oz | 1.293 |
| Maple syrup | 322 g | 11.36 oz | 1.361 |
| Corn syrup | 328 g | 11.57 oz | 1.386 |
Ordered by weight. The spread across this group is why a single generic cups-to-grams factor cannot work.