How do i find how many calories i am burning?

Don’t treat calorie burn estimates from smartwatches as exact. A 2020 systematic review by Fuller et al. found that consumer wearables often perform poorly at estimating energy expenditure, even when they measure steps and heart rate reasonably well. Across brands like Apple, Garmin, Polar, and Withings, calorie burn estimates frequently showed substantial error, often in the 15–40% range and sometimes exceeding 50%. Wearables can still be useful for tracking trends, but not for precise calorie calculations.

But remember an average 30-minute lifting session only burns about 150-210 calories (Hunter GR et al., J Strength Cond Res, 2003

The best way to figure out how many calories you're actually burning is to track your food intake against your weight changes over time which is best tracked by Adaptive TDEE tracking, you can find Maintenance Calorie Tracking Guide here.