Grapefruit is a refreshing citrus fruit that supplies a meaningful amount of potassium as well as vitamin C and fiber. The exact potassium value depends on the variety: pink and red grapefruit average about 135 mg per 100 g, white grapefruit about 148 mg per 100 g, and raw grapefruit juice about 162 mg per 100 g. This calculator turns your serving size into grams, applies the matching USDA food-composition figure, and returns potassium in milligrams plus a percentage of your chosen daily target.
Use it when you are tracking electrolytes for sport, following a DASH-style eating pattern, or keeping an eye on potassium for kidney or medication-related reasons. The tool supports grams, ounces, cups, and common fruit halves, so you can enter whatever is on your food scale, recipe, or nutrition label.
Pick the closest grapefruit type, enter the amount, and choose a daily reference value such as the FDA Daily Value of 4700 mg or a lower renal-diet target. The result includes a transparent formula breakdown so you can see exactly how the number was calculated.
🍊 Grapefruit type
USDA food-composition averages. Choose the closest match.
⚖️ Amount
Whole-fruit preset assumes a medium 3-3/4 in fruit; actual edible weight varies.
Daily potassium target
Step-by-Step Guide
Grapefruit potassium calculations are only useful when the inputs are entered consistently. Start by choosing the form of grapefruit that best matches what you are about to eat or drink. If you are not sure whether your fruit is pink, red, or white, use the pink/red option because it is the most commonly sold type in supermarkets.
- Select the grapefruit type: pink/red raw, white raw, or raw juice.
- Enter the amount you plan to eat or serve, then choose the matching unit: grams, ounces, cups, or half-fruit portions.
- Pick a daily potassium target. The FDA Daily Value is 4700 mg, while lower targets are common for kidney-friendly meal plans.
- Press Calculate and read the main potassium value, percentage of the daily target, per-100 g value, and banana equivalent.
Weigh the edible flesh, not the peel. For whole grapefruit, remove the rind and pith before placing the segments on the scale. For juice, weigh the juice or multiply fluid ounces by 29.6 to estimate grams, then add about 3% for density if you want extra precision.
Potassium Values Used
The calculator uses average values from the USDA FoodData Central database. These values can differ by a few milligrams depending on the variety, growing region, and harvest year, but they are reliable for everyday meal planning.
| Form of grapefruit | Potassium per 100 g |
|---|---|
| Pink/red grapefruit, raw | 135 mg |
| White grapefruit, raw | 148 mg |
| Grapefruit juice, raw | 162 mg |
For portion reference, a medium grapefruit half yields about 154 g of flesh, and a cup of grapefruit sections is roughly 230 g with juice. A typical whole medium grapefruit is close to 308 g. These are helpful estimates, but exact weights vary with fruit size and how carefully the segments are trimmed.
The Calculation Explained
The math is straightforward: potassium in mg = weight in grams × potassium per 100 g ÷ 100. If your input is in ounces, first convert to grams by multiplying by 28.35. If your input is in cups or half-fruit portions, the calculator applies its fixed conversion weight before performing the potassium calculation.
Example 1: 200 g of pink/red grapefruit contains 200 × 135 ÷ 100 = 270 mg of potassium.
Example 2: 150 g of white grapefruit contains 150 × 148 ÷ 100 = 222 mg of potassium.
Example 3: 250 g of raw grapefruit juice contains 250 × 162 ÷ 100 = 405 mg of potassium.
Example 4: 8 oz of pink grapefruit is 8 × 28.35 = 226.8 g, so potassium is 226.8 × 135 ÷ 100 ≈ 306 mg.
The banana equivalent shown in the results uses 422 mg per medium banana, which is the common reference value used in consumer education materials.
Who Should Pay Attention to Grapefruit Potassium?
Potassium plays a central role in nerve signaling, muscle contraction, and fluid balance. Athletes who sweat heavily may want to keep an eye on potassium-rich foods, and grapefruit can be part of a balanced post-exercise meal alongside fluids and carbohydrates.
People following a DASH-style dietary pattern for blood pressure are often encouraged to increase potassium intake from whole foods. A cup of grapefruit sections contributes roughly 7–8% of the FDA Daily Value, making it a reasonable choice when paired with other colorful produce.
Medical note: Grapefruit and grapefruit juice can change how certain medications are processed by the body, including some statins, blood-pressure drugs, and anti-anxiety medicines. If you take any prescription medication, ask your doctor or pharmacist before adding grapefruit to your routine. For kidney disease, potassium targets are highly individual, so work with a renal dietitian rather than guessing from a general percentage.
If you regularly track potassium from other foods, the same daily target can be applied to the kiwi potassium calculator or the curry potassium calculator to build a more complete view of your day.
Limitations & Accuracy Notes
- Natural variation: USDA values are averages. A grapefruit grown in one region may contain slightly more or less potassium than the average.
- Edible yield: The whole-fruit and half-fruit conversions assume typical edible flesh weights; if your fruit has thick rind or you trim aggressively, adjust the weight directly in grams.
- Juice density: The juice option uses 100 g, not 100 mL. One hundred millilitres of juice weighs about 103 g, so the difference is small but can matter on strict potassium targets.
- Daily value selection: The FDA Daily Value of 4700 mg is a labeling standard, not a personal prescription. The National Institutes of Health publishes more detail in its Potassium fact sheet for health professionals.
Frequently Asked Questions
Is grapefruit considered a high-potassium food?
It is moderate rather than very high. At 135–148 mg per 100 g, grapefruit provides less potassium per gram than bananas, dried apricots, potatoes, or white beans, but a typical one-cup serving still contributes a useful amount to daily totals.
Can I eat grapefruit on a low-potassium diet?
That depends on your personal limit. A half pink grapefruit (about 154 g) supplies roughly 208 mg of potassium, which may fit within a 2000 mg daily budget if other high-potassium foods are limited. However, the more urgent concern for many people is grapefruit's interaction with medications, so always confirm with your healthcare team first.
Does grapefruit juice have more potassium than fresh fruit?
Per 100 g, raw juice contains more potassium than fresh grapefruit flesh because the juice is a concentrated water phase of the fruit. But people usually drink larger volumes of juice, so a 250 mL glass can deliver more potassium than a single half-fruit serving. If you are tracking potassium, measure the actual volume or weight of juice you pour.