Free fitness calculatorsKnow the math.
Know the math.
Then make it useful.
Estimate daily burn, a moderate goal target, protein, macros, and training volume. Every input stays visible—no mystery score and no email gate.
TDEE uses the Mifflin–St Jeor equation multiplied by the selected activity estimate. Macro calories use 4 kcal/g for protein and carbs and 9 kcal/g for fat. These are planning estimates, not medical advice.
Track the numbers in GemFit Get the iPhone app →01
TDEE is a starting estimate.
Activity multipliers are broad. Compare the estimate with two to four weeks of bodyweight and intake data before treating it as your maintenance level.
02
Protein is a range.
The displayed number is a practical bodyweight-based starting point. Preferences, training, kidney health, pregnancy, and clinical needs can change what is appropriate.
03
Volume needs context.
Sets × reps × load makes sessions comparable, but exercise selection, range of motion, effort, and recovery still matter.
Put the estimate to work
Use trends to correct the calculator.
Start with the displayed calorie and macro targets, then log consistently enough to compare them with what actually happens. A single weigh-in can move because of hydration, sodium, digestion, or training soreness, so use a multi-week bodyweight trend instead of reacting to one morning.
If the trend is moving faster or slower than intended, make a small adjustment and hold it long enough to evaluate. Training performance, hunger, recovery, sleep, and adherence belong beside the scale. GemFit keeps meals, workouts, body metrics, and goals together so the decision is based on a pattern rather than a disconnected number.
Workout volume is most useful when the exercise and technique stay comparable. More volume is not automatically better: a new movement, deeper range of motion, slower tempo, or harder set can change the training stimulus even when the calculated pounds are lower.