Health & Fitness

Calculate your daily calorie needs using the Mifflin-St Jeor equation for BMR and activity-adjusted TDEE.

Split your daily calories into protein, carbs, and fat based on your goal and preferred macro ratio.

Estimate your body fat percentage using the US Navy method — just a few tape measurements required.

Calculate your ideal body weight using the Devine, Robinson, Miller, and Hamwi formulas.

Estimate daily water needs based on body weight, activity level, and climate. Results in liters, ounces, and glasses.

Estimate your one rep max from a submaximal lift using Epley, Brzycki, and Lombardi formulas.

Calculate running pace, finish time, or distance — with common race splits (5K, 10K, half, full).

Calculate your 5 training heart rate zones using age or resting heart rate (Karvonen method).

Find the best bedtime or wake-up time. Based on 90-minute sleep cycles — wake between cycles to feel refreshed.

Estimate Blood Alcohol Content using the Widmark formula. For informational use only — never drink and drive.

See how much caffeine remains in your system over time using the 5-hour half-life model. Enter dose and intake time to plan your last coffee before bed.

Estimate max heart rate using Fox (220-age), Tanaka (more accurate over 40), and Gulati (women-specific) formulas. Includes 5-zone training breakdown.

Look up CDC- and NSF-recommended sleep hours by age (newborn 14-17h, teen 8-10h, adult 7-9h) and get a bedtime calculator for your target wake-up time.

Plan your intermittent fasting schedule. Pick a protocol (16:8, 18:6, 20:4, or OMAD) and a first-meal time — see your eating window and last-meal cutoff.

Calories burned walking by speed, weight, and distance. Uses MET values (3.0 for casual 2.5 mph → 8.0 for 5 mph power walk) — the same method used in research.

Estimate ovulation date and the 6-day fertile window from your last period and average cycle length. Plus the predicted next-period date.

Convert HbA1c to estimated average glucose (eAG) and back. Uses the ADAG study formula: eAG (mg/dL) = 28.7 × A1C − 46.7.

Calculate your TDEE — total calories burned per day including activity. Uses the Mifflin-St Jeor BMR equation with cut, maintain, and bulk calorie targets.