Free tool
Restaurant meal calorie estimator
Choose a major chain item, start from the posted menu calories, then add a practical buffer before converting the meal into body-weight-adjusted buy-back minutes.
Posted calories
540
Big Mac — McDonald's
Likely real range:
513 – 648 kcal
Buy-back minutes
- Walking 3 mph130min
- Walking 4 mph72min
- Rucking 30 lb117min
- Standing227min
Posted calorie counts are based on standard recipes. Variations in prep, portion size, and modifications can push the actual number higher. Use the range as a planning buffer.
Log at the higher end of the range when in doubt. A consistent 100 kcal overestimate beats an underestimate that quietly tanks your deficit.
Buy it back
Open the CalBurndown app to log 648 kcal and see what to walk, ruck, or stand to stay on budget.
Formula & assumptions
This tool starts with the chain's posted menu calories for a standard recipe, then adds a narrow planning buffer for real-world prep variation:
likely_low = posted_kcal × 0.95 likely_high = posted_kcal × 1.20
The range is intentionally tighter than the broad variation seen across restaurant food in general because large chains use standardized recipes and are subject to federal menu labeling rules. It still leaves room for portion drift, oil, sauce, and assembly changes.
Buy-back math uses the same engine as the dedicated calculator. Walking and standing use MET conversion; loaded walking uses the Pandolf load-carriage equation:
kcal/min = MET × 3.5 × weight_kg / 200 minutes_needed = kcal / kcal_per_min
References
Food and Drug Administration. Food labeling; nutrition labeling of standard menu items in restaurants and similar retail food establishments. 21 CFR 101.11.
Bleich, S. N. et al. (2015). Restaurants With Calories Displayed On Menus Had Lower Calorie Counts Compared To Restaurants Without Such Labels. Health Affairs, 34(11), 1877–1884.
Ainsworth, B. E. et al. (2011). Compendium of Physical Activities: a second update of codes and MET values. Medicine & Science in Sports & Exercise, 43(8), 1575–1581.