Precision tools for your training
Your body, measured properly.
Five free tools built on validated sports-science formulas, made to be used, not just read. Private by design: the rep counter runs on your device and nothing is shared with gyms.
- Free
- Private
- No sign-up needed
Private by design
The rep counter and photo measuring never upload anything. Measurements you save are visible only to you, never to gyms, and you can delete them in Settings at any time.
Four tools. Zero guesswork.
The science
Built on research, not on trends.
Every number in RepFit Lab comes from a published, peer-reviewed method. We show you which one, and how confident the estimate is.
RepFit Lab gives estimates to guide your training, not medical advice. If you have a medical condition, are pregnant or have a history of disordered eating, talk to a doctor before changing how you eat or train.
- 01US Navy circumference methodHodgdon & Beckett, Naval Health Research Center, 1984
- 02Relative Fat MassWoolcott & Bergman, Scientific Reports, 2018
- 03Mifflin-St Jeor equationAmerican Journal of Clinical Nutrition, 1990
- 04Katch-McArdle equationResting energy from lean body mass
- 05Protein 1.6–2.2 g/kgInternational Society of Sports Nutrition position stand, 2017
- 06BlazePose body trackingGoogle MediaPipe, running entirely on your device
- 07Atwater energy factors4 kcal per gram of protein and carbohydrate, 9 per gram of fat; USDA FoodData Central
- 08Energy balance and adaptive maintenanceHall et al., The Lancet, 2011: about 7,700 kcal per kilogram of body weight