SYNCT tools
TDEE Calculator
What is my TDEE in kg or stone? This free UK-friendly calculator estimates maintenance calories (Mifflin-St Jeor or Katch-McArdle), plus cut and lean-bulk targets and macros. No email, no sign-up.
How to use the TDEE calculator
Enter age, sex, height, and weight (kg/cm or stone/feet). Choose an activity level to estimate maintenance calories (TDEE). Optionally add body fat percentage to switch from Mifflin-St Jeor to Katch-McArdle, which uses lean mass and is often better for lean, trained people.
We also show cut and lean-bulk targets and a simple macro split (protein ~1.8 g/kg, fat floored at ~0.9 g/kg, carbs fill the rest). Treat any calculator as a starting point: track weight for two to three weeks and adjust. The trend is the truth.
Frequently asked questions
Total Daily Energy Expenditure — BMR plus daily movement, training, and the energy cost of digesting food. It is your estimated maintenance calorie intake.
Mifflin-St Jeor is the default and best validated for most people. Enter body fat and we use Katch-McArdle (lean-mass based), which is usually more accurate if you are lean and trained.
Muscle is built slowly and fat is gained quickly. A modest surplus with enough protein and training captures most of the muscle with less cleanup later.
Yes. The calculator supports UK-friendly units (stone/pounds and feet/inches) as well as kg and cm.
No. Estimates only. If you have a medical condition or a complicated relationship with food, speak to a professional.
A number you can actually trust.
SYNCT pulls calorie data from your Apple Watch or Garmin, then refines it with the workouts you actually log, two sources beat one estimate.
