How to Use FreeBMIKit
Step-by-step guide for live FreeBMIKit tools. Jump to any section below.
BMI Calculator
- 1Select metric (cm/kg) or imperial (feet, inches, lbs) unit system.
- 2Enter your height and weight.
- 3Click Calculate — your BMI value and category appear instantly.
- 4Read the visual gauge showing where you fall: Underweight, Normal, Overweight, or Obese.
- 5Review the personalized health tips for your category.
- 6Use the history chart to track your BMI over time (saved in your browser).
TDEE Calculator
- 1Enter your age, gender, height, and weight.
- 2Select your activity level — from sedentary to very active.
- 3Choose your goal: lose weight, maintain, or gain muscle.
- 4Click Calculate to see your Total Daily Energy Expenditure (TDEE).
- 5View your macro breakdown — protein, carbs, and fat in grams.
- 6Compare results across 3 formulas: Mifflin-St Jeor, Harris-Benedict, and Katch-McArdle.
Pregnancy Calculator
- 1Enter the first day of your last menstrual period (LMP).
- 2Optionally enter your cycle length (default is 28 days).
- 3Click Calculate to see your estimated due date using Naegele's rule.
- 4View your current pregnancy week and which trimester you're in.
- 5Browse the week-by-week milestone timeline with baby size comparisons.
- 6See the countdown of days remaining until your due date.
Ovulation Calculator
- 1Enter the start date of your last period.
- 2Set your average cycle length (21–35 days; default is 28).
- 3Click Calculate to see your estimated ovulation day.
- 4View your 6-day fertile window on the calendar.
- 5Browse the 3-month calendar with fertile days and predicted period dates marked.
- 6Track multiple cycles for a more accurate average cycle length.
Cycle Tracker
- 1Log the start and end dates of each period.
- 2Add notes about symptoms, flow intensity, or mood.
- 3View your cycle history and average cycle length over time.
- 4See predicted next period dates based on your tracked history.
- 5Identify patterns: irregular cycles, PMS symptoms, or cycle changes.
- 6All data is stored locally — nothing leaves your device.
Sleep Calculator
- 1Choose mode: 'I want to wake up at…' or 'I want to go to sleep at…'.
- 2Enter your target time.
- 3Click Calculate to see optimal bedtimes or wake-up times based on 90-minute sleep cycles.
- 4Pick the option with 5 or 6 complete cycles for best rest.
- 5Check the age-based sleep hour recommendations table.
- 6Read the sleep quality tips at the bottom.
Blood Type Compatibility
- 1Select your blood type (A, B, AB, or O) and Rh factor (+ or -).
- 2View which blood types you can receive from and donate to.
- 3Check compatibility for transfusions and organ donation.
- 4See the universal donor (O-) and universal recipient (AB+) explained.
- 5Learn about the rarity of each blood type in the population.
Pet Age Calculator
- 1Select your pet type: dog, cat, rabbit, or other small animals.
- 2For dogs, select the breed size (small, medium, or large — they age differently).
- 3Enter your pet's age in years.
- 4Click Calculate to see the equivalent human age.
- 5Read life stage information: puppy/kitten, adult, or senior.
- 6Check care tips specific to your pet's current life stage.
Tips & Best Practices
- 1Browser-saved tool data, such as BMI history and cycle logs, stays local to your device.
- 2For most accurate BMI and TDEE results, measure yourself in the morning before eating.
- 3Track cycles for at least 3 months before relying on ovulation predictions.
- 4Use the Nutrient Encyclopedia (coming soon) alongside the TDEE macro breakdown for full nutrition insight.
- 5All tools work offline after the first page load — no internet needed for calculations.
- 6Always consult a healthcare professional before making medical or nutrition decisions.