Bok choy is a wonderfully low-calorie leafy green, but a recipe rarely asks for 100 g exactly - it asks for slices, cups, or whole stalks. If you want to know what those few slices of bok choy add to your meal, this calculator does the math in seconds. Enter how many slices you plan to eat, the typical weight of one slice, and the calorie density of your bok choy (raw, cooked, or custom), and it returns the calories per slice plus the total for the whole serving.
Because bok choy is about 95% water, the numbers are small, but they still matter when you are logging meals, meal-prepping, or following a calorie-controlled diet. The tool also gives a quick estimate of protein, carbs, and fiber per slice so you can see the nutritional value behind those modest calories.
Use the preset buttons for quick entries, or type in values from your own kitchen scale and nutrition label. The results update with a clean breakdown, making this a handy companion for stir-fries, soups, and any recipe that calls for sliced bok choy.
🍃 Bok Choy Calorie Calculator
Enter your slice details below and click Calculate.
🧮 Results
| Nutrient | Amount |
|---|
Nutrient estimates use standard raw bok choy values (protein 1.5 g, carbs 2.2 g, fiber 1.0 g per 100 g). Cooking oil is not included in these macro estimates.
How to Measure a Slice of Bok Choy
Bok choy is sold as whole heads, baby bunches, and pre-cut bags, so there is no single standard slice weight. The most reliable method is to weigh the prepared vegetable on a kitchen scale and divide by the number of slices you cut. For example, if a trimmed stalk weighs 150 g and you plan to cut it into 6 slices, each slice will weigh about 25 g. If you are slicing leaves and stems together from a bunch, use the average weight of a representative slice.
Slice size guide: Thin cross-sections of baby bok choy run about 10-15 g, medium slices from a standard stalk about 20-35 g, and thick diagonal cuts about 35-50 g. These are starting points only; your knife angle and trimming habits change the numbers.
Many recipes list bok choy in cups rather than grams. One loosely packed cup of chopped raw bok choy weighs roughly 70 g, while a cup of cooked bok choy weighs about 170 g because the leaves collapse. Converting your recipe to slices first, then to grams, is the most accurate path.
How the Calculation Works
The tool uses a simple per-100 g rule, which is how most nutrition databases and food labels report energy. First convert the slice weight into a fraction of 100 g, then multiply by the calorie density.
Formula: Calories per slice = slice weight (g) × calories per 100 g ÷ 100. Total = calories per slice × number of slices.
For instance, a 25 g slice of raw bok choy with 13 kcal/100 g gives 25 × 13 ÷ 100 = 3.25 kcal per slice. Ten slices would be 32.5 kcal. The macro estimates in the results use the typical raw bok choy values from USDA FoodData Central: 1.5 g protein, 2.2 g carbohydrates, and 1.0 g fiber per 100 g. These are useful for rough tracking but are less precise if your vegetable is cooked in broth, blanched, or mixed with dressing. Because the formula is linear, you can also scale in the other direction: if a recipe contains 300 g of bok choy and serves four, you can work out the calories per serving without weighing individual slices.
Worked Examples
Example 1 - Raw bok choy side dish: You eat 5 thin slices weighing 20 g each, using raw bok choy at 13 kcal/100 g. Per slice = 20 × 13 ÷ 100 = 2.6 kcal. Total = 5 × 2.6 = 13 kcal.
Example 2 - Stir-fried bok choy: You use 4 thick 45 g slices and choose the 60 kcal/100 g stir-fried estimate. Per slice = 45 × 60 ÷ 100 = 27 kcal. Total = 4 × 27 = 108 kcal. The extra calories come almost entirely from oil absorbed during cooking.
Example 3 - Cooked bok choy: You boil a few stalks and serve 3 slices at 30 g each, using the 12 kcal/100 g cooked value. Per slice = 30 × 12 ÷ 100 = 3.6 kcal. Total = 3 × 3.6 = 10.8 kcal.
Reference Calorie Values for Bok Choy
Calorie values depend on water content, cooking method, and added fat. The table below shows common figures used by nutrition databases and dietitians. For a specific packaged product, use the value on the label instead.
| Form | Calories per 100 g | Notes |
|---|---|---|
| Raw bok choy | 13 kcal | Typical value in USDA FoodData Central |
| Cooked, boiled, drained | 12 kcal | Slight water loss; nutrient density becomes more concentrated |
| Baby bok choy, raw | 13 kcal | Very similar to mature bok choy |
| Stir-fried with 1 tsp oil | 45-70 kcal | Estimate; varies with oil type and absorption |
You can look up raw and cooked values directly in USDA FoodData Central by searching for 'bok choy'.
Common Mistakes to Avoid
- Forgetting the oil. Stir-fried bok choy can be 3-5 times more caloric than raw because oil adds roughly 120 kcal per tablespoon.
- Weighing the whole head including roots. Trim the base and any wilted leaves before weighing the portion you actually slice and eat.
- Using a single slice weight for very uneven cuts. If your slices vary a lot, weigh 2-3 representative slices and use the average.
- Entering calories per serving instead of per 100 g. Check the label unit; this calculator expects kcal per 100 g.
- Assuming all Asian leafy greens have the same calorie density. Yu choy, tatsoi, and napa cabbage differ slightly, so look up each vegetable when precision matters.
Note: The macro estimates in this tool describe the vegetable itself, not oil, butter, soy sauce, or other seasonings. If your stir-fry includes a sauce, track those calories separately for an accurate total.
Frequently Asked Questions
Is bok choy really only about 13 calories per 100 g? Yes for raw bok choy. A full 200 g stalk is only about 26 kcal, which makes bok choy one of the most calorie-friendly leafy greens. It is also high in water and provides vitamin K, vitamin C, and folate.
How many slices fit in one standard stalk? A medium stalk weighs roughly 150-200 g after trimming. Cut crosswise into 2 cm slices, you will get about 6-8 slices; thicker cuts give 4-5. Use the calculator's thin, medium, or thick presets as a rough starting point.
Should I weigh bok choy raw or cooked? For the most consistent tracking, weigh it raw before cooking. Cooking changes water content and weight, so the same 100 g cooked portion represents more raw vegetable and may contain a different calorie density. If your label only lists cooked values, enter those instead.
Can I use the macro estimates for cooked or stir-fried bok choy? The protein, carbohydrate, and fiber values are close for plain cooked bok choy, but not for stir-fried versions because added oil introduces fat calories. Use the vegetable-only macro rows as an approximation and track oil separately for a complete picture.
For a broader view of a complete meal, pair this with a salad calorie calculator or a spinach nutrition calculator to compare leafy greens side by side.