Lamb is a nutrient-dense red meat whose calorie and fat content varies widely by cut and cooking method. A lean roasted leg portion delivers roughly 250 calories per 100 g with more than 25 g of protein, while the same cooked weight of untrimmed rack of lamb can exceed 315 calories. This calculator helps you estimate the calories, protein, total fat, saturated fat, and key micronutrients in your actual serving, using typical cooked values based on USDA food composition data.
Choose your cut and trim level, enter a cooked serving weight in grams or ounces, and press Calculate. Quick-fill buttons set common portions such as 3 oz or 100 g in one click. The results include a full calorie and macro breakdown, plus iron, zinc, and vitamin B12 when the micronutrient option is enabled. A short step-by-step note also explains how the estimate was adjusted for visible fat trimming, so you can trust the number or adjust it when your portion looks different.
🍖 Lamb Nutrition Estimator
How the Estimates Are Calculated
This calculator derives each result in two straightforward steps. It first converts your serving size to grams — ounces are multiplied by 28.35 — then scales the per-100-gram nutrition profile of the selected cut to your serving. In a second step, it applies a trim adjustment to fat and saturated fat, because visible fat is the single biggest source of variation in lamb's calorie density.
The calorie total uses the standard Atwater system for meat: protein supplies 4 kcal per gram and fat supplies 9 kcal per gram. Cooked lamb contains only trace amounts of carbohydrate, so the formula simplifies to Calories = 4 × protein (g) + 9 × fat (g). Trimming affects the fat values only; the protein figures are unchanged. The trim factors are 93% of baseline fat when some visible fat is removed and 84% when the cut is trimmed to lean meat only.
All baseline values reflect typical cooked lamb as compiled in USDA food composition data, the same reference used by most nutrition tracking apps. That means you can expect your results to be reasonably close to what a verified food database would report for the same cooked cut and weight.
Reference Table: Cooked Lamb Per 100 g
The table below shows the per-100-gram values the calculator starts from, before any trim adjustment. Calorie figures are calculated from the protein and fat columns, so they will differ slightly from database entries that include trace carbohydrates.
| Cut (cooked) | Calories | Protein (g) | Fat (g) | Saturated fat (g) |
|---|---|---|---|---|
| Leg of lamb, roasted | 258 | 27.3 | 16.5 | 6.8 |
| Shank, braised | 241 | 30.7 | 12.3 | 4.6 |
| Ground lamb, broiled | 264 | 25.6 | 17.0 | 6.9 |
| Shoulder, braised | 297 | 27.0 | 20.0 | 8.3 |
| Loin chop, broiled | 285 | 25.1 | 19.5 | 8.1 |
| Chop (rib), broiled | 294 | 24.3 | 21.8 | 8.9 |
| Rack of lamb, roasted | 312 | 24.1 | 23.7 | 9.9 |
| Rib roast, roasted | 312 | 24.0 | 24.5 | 10.2 |
Values are typical cooked figures compiled from USDA FoodData Central entries for lamb. Individual cuts vary by animal, feed, and degree of doneness. You can browse the original data at fdc.nal.usda.gov.
Worked Examples
Two quick examples show how portion size, cut, and trim level interact in practice.
Example 1 — Roasted leg of lamb, 150 g, no trimming. The leg's per-100-g profile of 27.3 g protein and 16.5 g fat scales by 1.5×, giving about 41.0 g protein and 24.8 g fat. Calories = (4 × 41.0) + (9 × 24.8) ≈ 387 kcal.
Example 2 — Broiled rib chop, 85 g (3 oz), trimmed lean. The lean adjustment reduces the chop's fat from 21.8 to about 18.3 g per 100 g. An 85-g serving then provides roughly 20.7 g protein and 15.6 g fat, for about 222 kcal.
The same 85 g of untrimmed chop would come to roughly 250 kcal — a difference of about 28 kcal from trimming alone. Those gaps compound quickly across a week of meals, which is why the trim selector is included.
Tips for More Accurate Tracking
A few simple habits will make any lamb calorie estimate more reliable:
- Weigh the cooked portion rather than raw. Cooking drives off water and renders fat, so raw and cooked weights differ by roughly 20–30%.
- Trim visible fat before weighing, and leave any fat that stays on the plate out of your serving.
- If you cook with oil, butter, or a marinade, log those calories separately — this tool covers plain cooked lamb only.
- For restaurant meals, ask whether the dish is roasted, grilled, or braised and whether fat was trimmed; a breaded or butter-basted chop can easily add 50–100 kcal.
- Weighing is more accurate than estimating a "palm-sized" portion. A cooked portion the size of a deck of cards is roughly 85–100 g.
Quick reference: A typical cooked serving of lamb is 85–113 g (3–4 oz). For a lean cut like roasted leg or braised shank, that is around 215–280 kcal; for a fatty cut like rack or rib roast, the same weight runs closer to 265–355 kcal.
Frequently Asked Questions
Are the values based on raw or cooked weight? Cooked. Always enter the weight of the lamb as you ate it, since a raw chop that weighs 200 g might weigh only 150 g after cooking. Entering raw weight will overestimate calories.
Why do calorie counts differ so much between cuts? Fat content ranges from about 12 g per 100 g in a braised shank to more than 24 g in a rib roast, and fat carries more than twice as many calories per gram as protein. Marbling inside the muscle also varies between individual animals.
Is lamb a good protein source? Yes. Most cuts supply 24–31 g of protein per 100 g cooked, close to beef. Lamb is also an excellent source of iron, zinc, and vitamin B12, and the optional micronutrient panel in this calculator shows those amounts for your serving. The main trade-off is saturated fat, which adds up quickly in untrimmed cuts.
Does cooking method change the numbers? It can. Braising and roasting generally keep values close to the table above, but frying adds oil and grilling over high heat renders out a little more fat. If you use a sauce or a flour coating, add those ingredients separately.
Where do the nutrient values come from? The baseline data are typical cooked values from USDA FoodData Central. For general background on lamb and mutton, including cut names and cooking traditions, the Wikipedia article on lamb and mutton is a useful starting point.
Limitations to Keep in Mind
These results are estimates, not laboratory measurements. Marbling, animal diet, aging, cooking method, and seasonings can all shift the final numbers, often by 5–10%. Use the result for meal planning and portion control; when precision matters, weigh your cooked food and compare it against a verified USDA entry for the exact product you purchased.