Leeks are a mild, allium-family vegetable that deliver a respectable amount of dietary fiber with almost no fat. This calculator converts any leek portion into fiber grams based on standard nutrition data, so you can log your serving quickly and see exactly what it contributes to your daily fiber target.
Use it for meal prep, diet tracking, or simply to compare leeks with other vegetables. Enter the amount in grams, ounces, or chopped cups, choose a preparation style, and optionally set a personal fiber goal to find out how many leeks you would need to reach it.
The default daily value reference is 28 grams of fiber for a 2,000-calorie diet, but you can turn that line off if you prefer to track only grams.
⚙️ Serving Details
🎯 Optional Fiber Goal
How to Use This Tool
Using the calculator takes just a few steps. Start by entering the amount of leek you plan to eat — the calculator accepts grams, ounces, or chopped cups, so it works for recipes and food logs alike. Next, choose the preparation that matches your meal: raw leeks or boiled/cooked drained leeks. Both are standardized to roughly the same fiber density, but the option is there for convenience.
If you are aiming for a specific daily fiber target, tick the “Add a fiber target” box and type in your goal in grams. The results panel will then show how much leek (and how many medium leeks) would be needed to reach that target on leeks alone. Finally, press Calculate fiber to see your fiber grams, fiber per 100 g, and percentage of the 28 g Daily Value.
Fiber Values and Calculation Method
The calculator is based on the USDA nutrient value for raw leeks: approximately 1.8 g of dietary fiber per 100 g of the edible bulb and lower leaf portion. Boiled and drained leeks are listed with a similar fiber density, around 1.8 g per 100 g, because boiling removes water but does not destroy the fiber. For a standard 89 g medium leek, that works out to about 1.6 g of fiber.
fiber (g) = serving weight (g) × 1.8 ÷ 100If you enter an amount in ounces, the calculator first converts to grams using 1 oz = 28.3495 g. If you enter chopped cups, it uses 89 g per cup, the typical trimmed chopped weight. These assumptions make the math simple and reproducible for everyday tracking. For detailed reference data, you can browse the USDA FoodData Central database.
Worked Examples
Example 1: 150 g raw leek. 150 g × 1.8 ÷ 100 = 2.7 g fiber, or about 10% of the 28 g Daily Value. That is a solid contribution from a single side dish.
Example 2: half a cup of chopped leek. 0.5 cup ≈ 44.5 g, so 44.5 × 1.8 ÷ 100 = 0.8 g fiber. Even a modest garnish adds a little to your daily total.
Example 3: reaching a 28 g fiber goal with leeks alone. You would need 28 g ÷ 1.8 g per 100 g × 100 = 1,556 g of trimmed leeks, which is roughly 17.5 medium leeks. That is why leeks work best as one part of a high-fiber vegetable mix rather than your only source.
Leek Fiber Compared with Other Vegetables
| Vegetable | Fiber per 100 g (raw) |
|---|---|
| Leek | 1.8 g |
| Broccoli | 2.6 g |
| Carrot | 2.8 g |
| Cabbage | 2.5 g |
| Onion | 1.7 g |
| Celery | 1.6 g |
| Cucumber | 0.5 g |
Leeks sit in the middle of the vegetable fiber range. They are not the highest-fiber vegetable, but their mild onion flavor makes it easy to eat generous portions. If you want to compare other leafy or allium vegetables, our Bok choy fiber calculator and soybean fiber calculator follow the same per-100 g approach.
Practical Tips for Getting More Fiber from Leeks
- Use the darker green tops in soups and stock. They are tougher but still contain fiber, and simmering softens them.
- Slice leeks into salads and stir-fries instead of onions occasionally; the change adds variety to your fiber sources.
- Remember that fiber is only part of the nutrition picture. Leeks also provide small amounts of iron and sodium, which you can explore with our leek iron calculator and leek sodium calculator.
- If you are tracking fiber for digestive health, add leeks gradually so your gut adjusts to the increase.
- For general fiber guidance, the Mayo Clinic offers practical recommendations for adults and children.
Frequently Asked Questions
Is the fiber in leeks soluble or insoluble?
Leeks contain both types. Their cell walls provide insoluble fiber such as cellulose, while the bulb also contains soluble fibers like inulin, which acts as a prebiotic and feeds beneficial gut bacteria. Because both matter, tracking total fiber is usually the simplest approach for daily planning.
Does cooking leeks destroy fiber?
No. Heat does not break down dietary fiber in any meaningful way. Boiling leeks can soften them and lower the fiber density slightly if they absorb water, but drained cooked leeks are still close to the raw value. The biggest change is usually volume, not fiber.
How accurate is this calculator?
The values are averages from food-composition databases and are accurate enough for meal planning. Individual leeks vary by size, season, cultivar, and how much of the darker green portion you include. The calculator also assumes a trimmed edible portion, so if you weigh the whole leek with roots and damaged outer leaves, you will overestimate slightly.