Health Tools

16 health calculators: daily calories (TDEE), body fat, sleep cycles and a pregnancy due date estimator. Every number stays on your device — no account, no upload.

Calorie Calculator
Daily calorie estimate with the Mifflin-St Jeor equation: BMR, activity-adjusted TDEE, goal target and macros.
Body Fat Calculator
Body fat percentage from tape measurements with the US Navy formula: fat and lean mass plus ACE categories.
Sleep Cycle Calculator
Work out the best bedtime from your alarm, or a wake time from your bedtime, with 90-minute sleep cycles.
Pregnancy Due Date Calculator
Estimate your due date from your last period or conception date, with today's gestational age and trimester.
Heart Rate Zone Calculator
Calculate your five heart-rate training zones from age and resting pulse, with % of max and Karvonen targets.
Running Pace Calculator
Turn a goal time into pace per km or mile with a cumulative split table, or predict a finish time from pace.
Water Intake Calculator
Daily water target in liters, cups and 500 ml bottles by weight, activity and climate. Runs in your browser.
Ideal Weight Calculator
Ideal weight ranges from four published formulas plus a BMI screening band, in kg and lb. Runs fully in your browser.
Height Predictor
Predict a child's adult height with the mid-parental method from the parents' heights, with an honest range.
Ovulation Calculator
Estimate your ovulation day and fertile window from your last period start and average cycle length, offline.
Breathing Timer
Guided breathing pacer with Box, 4-7-8, Calm and custom patterns, following one expanding circle. Silent, offline.
Steps Calculator
Turn daily steps into distance and calorie estimates from height, weight and pace. Runs fully in your browser.
Weight Gain in Pregnancy
Check the Institute of Medicine reference range for total pregnancy weight gain and weekly pace from your BMI.
One Rep Max Calculator
Estimate your 1RM with three published formulas plus a percentage table for training. Runs in your browser.
Dog Age Calculator
Convert dog years to human years with the vets' size-curve model, not the old multiply-by-7 rule.
Chinese Zodiac Calculator
Find your Chinese zodiac animal and element by exact birth date, using real New Year boundary dates.