Mayonnaise is mostly fat and water, so its carbohydrate content is usually lower than people expect. A standard full-fat mayonnaise typically has less than 1 g of carbs per 100 g, while light, vegan, and flavored versions can contain noticeably more because of added sugar, starch, or thickeners. This calculator helps you pin down the exact carb count in the mayonnaise you use — whether you're reading a nutrition label, following a keto plan, or tracking macros in a recipe.
Choose the label-to-per-100g mode when you know the serving size and carb grams from the back of a jar. Choose the per-100g-to-portion mode when you want to turn a typical nutrient value into tablespoons, teaspoons, cups, or grams. The tool also shows carb equivalents for common serving sizes, so you can estimate additions to sandwiches, salads, sauces, and dressings without guesswork.
🧴 Mayonnaise Carb Calculator
Convert nutrition label values or typical per-100g values into carbs per serving.
Label values
How to Use This Tool
This calculator gives you full control over how you convert mayonnaise carbohydrate values. Start by choosing the mode that matches the data you have: if you're reading a nutrition facts panel, pick Label → per 100 g; if you already know the per-100 g value and want to know a specific portion, pick Per 100 g → portion.
- In Label → per 100 g mode, enter the serving weight from the label (for example, 15 g) and the carbohydrates per serving (for example, 0.05 g). The calculator will convert this to grams of carbs per 100 g and also show what that means for one tablespoon (14 g), one teaspoon (4.9 g), and one cup (230 g).
- In Per 100 g → portion mode, enter the carbs per 100 g (or use a preset such as Regular 0.4 or Light 5), then enter the portion amount and select its unit — grams, tablespoons, teaspoons, or cups.
- Use the preset chips to load common values instantly, then adjust them if your brand differs.
- Press Calculate to see the result, or Reset to clear the form and start over.
Formula Explained
The calculation is simple proportional math. Every result comes from one of two relations.
Label to per 100 g:
Carbs per 100 g = (carbs per serving ÷ serving weight in grams) × 100
Per 100 g to portion:
Carbs in portion = (carbs per 100 g × portion weight in grams) ÷ 100
When you choose a volume unit like tablespoons or cups, the calculator first converts volume to grams using standard mayonnaise densities, then applies the per-100 g formula above.
Worked Examples
Example 1 — Reading a label. Your jar says a 15 g serving contains 0.05 g of carbs. Divide 0.05 by 15 to get 0.00333, then multiply by 100. The result is 0.33 g of carbs per 100 g. For a typical 14 g tablespoon, you'd get around 0.05 g — effectively negligible for most macro counts.
Example 2 — Portion planning. You're using a light mayonnaise with 6 g of carbs per 100 g, and your recipe calls for 2 tablespoons. Two tablespoons weigh about 28 g. Multiply 6 g by 28 and divide by 100: the portion contains about 1.68 g of carbs. If you're on a strict keto plan, switching to a full-fat mayo (0.4 g per 100 g) would give just 0.11 g for the same serving.
Typical Carb Values
The values below are real-world ranges based on popular commercial products in the United States and Europe. They should be used as a starting point, not a substitute for the label on your own jar.
| Type of mayonnaise | Typical carbs per 100 g |
|---|---|
| Full-fat regular mayonnaise | 0.3 – 1 g |
| Olive-oil mayonnaise | 0.5 – 2 g |
| Light / reduced-fat mayonnaise | 3 – 10 g |
| Vegan / egg-free mayonnaise | 0.5 – 4 g |
| Sugar-free keto mayonnaise | 0 – 1 g |
| Flavored (sriracha, garlic, honey mustard) | 1 – 8 g |
Light mayonnaises often make up for reduced fat with starches and sugar, which is why their carb numbers are noticeably higher. Always check the specific product because ranges overlap.
Common Mistakes to Avoid
- Using volume when the label uses weight. A tablespoon is a volume measure; a 15 g serving is a weight. Convert carefully using the densities above.
- Ignoring added sugar in flavored mayo. Flavored varieties like honey mustard or sriracha mayo can have eight times the carbs of plain mayo.
- Assuming all light mayonnaises are the same. Some have 3 g per 100 g, others 10 g — the spread is large, so read labels.
- Forgetting that mayo is mostly fat and water. Even at 100 g, a regular mayo serving rarely moves your daily carb budget; the risk is in sauces and sandwiches where multiple portions add up.
Frequently Asked Questions
Is mayonnaise completely carb-free? No, but most full-fat mayonnaises are very low. Commercial products typically contain 0.3 to 1 g of carbs per 100 g because of small amounts of sugar, lemon juice, or thickeners used in the recipe.
Can I use this calculator for vegan mayonnaise? Yes. Vegan mayo is often made with aquafaba, soy protein, or modified starch, and its carb content ranges from 0.5 to 4 g per 100 g depending on the brand. Enter the value from your label for the most accurate result.
How accurate are the volume-to-weight conversions? The calculator uses 14 g per tablespoon, 4.9 g per teaspoon, and 230 g per cup, which are close to the density of most commercial mayonnaise. If you measure your own mayo on a scale, you can use grams directly for exact numbers.
For exact values from thousands of branded products, you can search USDA FoodData Central. For guidance on reading nutrition labels, see the FDA Nutrition Facts label guide.