Mayonnaise labels don’t always make comparison easy. One jar says a single tablespoon (13 g) contains 9 g of fat; another says a 15 g serving has 10 g. Reading just the serving numbers makes it hard to tell which product is actually higher in fat. This calculator converts any nutrition label into the standard grams of fat per 100 g, so you can compare products and serving sizes on the same scale.
Enter the serving size and total fat shown on your mayonnaise label — in grams or tablespoons — and optionally add the amount you plan to eat. The tool returns fat per 100 g, calories from fat, fat in your actual portion, and a per-tablespoon breakdown. It is ideal for macro tracking, low-fat meal planning, and anyone checking how much fat is in their sandwich, salad dressing, or favorite condiment.
🧮 Mayonnaise Fat Per 100g Calculator
Convert your mayonnaise label to grams of fat per 100 g and see fat in the amount you actually eat.
📋 Nutrition label values
🍽️ Optional: your portion
Why Fat Per 100 g Is the Best Comparison
Serving sizes for mayonnaise vary from jar to jar. One brand may call a serving 1 tablespoon (about 13.8 g), another may use 15 g, and recipe-size containers sometimes list 100 g as the serving. Reading only Total Fat per serving makes it hard to tell which product is actually higher in fat. Converting to grams of fat per 100 g puts every product on the same scale, so you can compare a regular full-fat mayo with a light version in one glance.
This calculator is handy for macro tracking, low-fat meal planning, checking labels at the store, and estimating how much fat your sandwich or salad really contains.
Formula Explained
Fat per 100 g = (total fat per serving ÷ serving size in grams) × 100
If the label lists the serving in tablespoons, convert it to grams first. This calculator uses 13.8 g per US tablespoon. For the most accurate result, use the gram weight shown in parentheses on the label whenever it is available.
Each gram of fat provides 9 kcal. So a mayo with 72 g fat per 100 g provides about 648 kcal from fat in every 100 g. This is important because fat can make mayonnaise calorie-dense very quickly, even when the spoonful looks small.
Worked Examples
Example 1: Regular mayonnaise
Label: 1 tbsp (13.8 g) contains 10 g fat.
Fat per 100 g = (10 ÷ 13.8) × 100 = 72.5 g.
A 2-tbsp sandwich spread (27.6 g) supplies 20 g fat.
Example 2: Light mayonnaise
Label: 1 tbsp (14 g) contains 3.5 g fat.
Fat per 100 g = (3.5 ÷ 14) × 100 = 25.0 g.
The same 2-tbsp portion provides 7 g fat, about one-third of regular.
By converting to 100 g, you do not need to remember whether one label used a 13 g serving and another used a 15 g serving. The comparison becomes straightforward.
Reference Table: Typical Mayonnaise Labels
Commercial mayonnaise varies by recipe. The values below are typical rounded ranges for common product types per 100 g. Check your actual package label for exact figures.
| Type | Fat per 100 g | Calories from fat | Typical serving fat |
|---|---|---|---|
| Regular full-fat mayonnaise | 70–80 g | 630–720 kcal | 9–11 g per tbsp |
| Light mayonnaise | 20–35 g | 180–315 kcal | 3–5 g per tbsp |
| Olive-oil mayonnaise | 65–80 g | 585–720 kcal | 9–11 g per tbsp |
| Fat-free mayonnaise | 0–1 g | 0–9 kcal | 0 g per tbsp |
Common Mistakes to Avoid
- Treating tablespoons like grams. One tablespoon of mayonnaise weighs about 13.8 g, not 15 g. Use the label gram weight when present.
- Ignoring serving size. If the label says 2 tbsp, the listed fat is for two tablespoons. Enter 2 with the tbsp unit, or enter the gram weight for the full serving.
- Forgetting to scale portion fat. Fat per 100 g only applies to 100 g. A 30 g portion of 25 g-per-100g light mayo contains 7.5 g fat, not 25 g.
- Assuming light versions are all alike. Some light mayonnaises have around 20 g fat per 100 g, while others reach 35 g.
Frequently Asked Questions
Is fat per 100 g the same as percent fat?
Nearly. Grams of fat per 100 g of food equals the fat percentage by weight. If a mayonnaise has 72 g fat per 100 g, it is 72 percent fat by weight.
How many calories come from fat in one tablespoon?
Regular mayo contains about 10 g fat per tablespoon, which is about 90 kcal from fat alone.
Why does my label show both tablespoons and grams?
US nutrition labels are required to list a household measure along with a metric amount. Use the gram value for the most accurate per-100g calculation. More details are available at FDA Nutrition Facts Label and USDA FoodData Central.
If you also use yogurt-based spreads, the yogurt fat per 100g calculator can help you compare fat content the same way.