Last updated: March 2026
Frequently Asked Questions
How accurate are these health calculators?
Our calculators use established medical formulas: the Mifflin-St Jeor equation for BMR, the U.S. Navy method for body fat, and WHO-standard BMI categories. They provide reliable estimates for general health tracking and fitness planning. However, they are not a substitute for professional medical advice. For clinical decisions, always consult a healthcare provider.
Is my health data stored or shared?
No. All calculations happen entirely in your browser. Your height, weight, age, and other health data are never sent to any server, never stored in any database, and never shared with third parties. Your information stays on your device and disappears when you close the page.
Which calorie formula should I use for weight loss?
The calorie calculator uses the Mifflin-St Jeor equation, which research shows is the most accurate for estimating basal metabolic rate (BMR). For weight loss, we calculate your Total Daily Energy Expenditure (TDEE) and suggest a moderate deficit of 500 calories per day, which translates to roughly 1 pound of fat loss per week. Adjust activity level honestly for best accuracy.
How does the sleep calculator determine optimal bedtimes?
The sleep calculator is based on the science of sleep cycles. Each complete sleep cycle lasts approximately 90 minutes and includes light sleep, deep sleep, and REM sleep phases. Waking up between cycles (rather than in the middle of one) helps you feel more refreshed. The calculator works backward from your wake time to suggest bedtimes that align with complete cycles, accounting for the average 15-minute time to fall asleep.
Can I use the pace calculator for cycling or swimming?
The pace calculator is designed primarily for running, with built-in race distances (5K, 10K, half marathon, marathon) and running-specific split tables. However, you can use it for any distance-based activity by entering custom distances. For cycling-specific calculations like power zones or climbing speeds, a dedicated cycling calculator would be more appropriate.