RubanTools

Health & Fitness Calculators

21 free wellness tools - body composition, blood pressure, diabetes risk, cholesterol, nutrition, pregnancy and fitness calculators.

BMI Calculator

Calculate your Body Mass Index with WHO category, healthy weight range and the interactive BMI scale bar.

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BMR Calculator

Find your Basal Metabolic Rate and TDEE using both Mifflin–St Jeor and Harris-Benedict formulas.

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Daily Calorie Calculator

Get your personalised calorie target for weight loss, maintenance or muscle gain with macro split estimates.

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Calorie Burn Calculator

Estimate calories burned during 60+ activities - walking, running, cycling, yoga, Bollywood dance and more.

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Ideal Weight Calculator

Find your ideal weight using Devine, Robinson and Miller formulas plus the healthy BMI range.

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Body Fat % Calculator

Estimate body fat percentage using the US Navy circumference method - no callipers needed.

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Waist-to-Hip Ratio

Calculate your WHR and cardiovascular risk category using WHO guidelines for men and women.

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Macro Calculator

Get protein, carb and fat targets by goal (cut/maintain/bulk) and diet preference (keto, low-carb, balanced).

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Water Intake Calculator

Find your daily water requirement based on weight, activity and climate - with an hourly drinking schedule.

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Heart Rate Zones

Find your max heart rate and 5 training zones - from fat burn to VO₂ max intervals - with Karvonen option.

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1RM Calculator

Estimate your one-rep max using 5 formulas (Epley, Brzycki, Lander…) with a full training percentage table.

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Pregnancy Due Date

Calculate your EDD from LMP with trimester display, days remaining and key milestone timeline.

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Conception Date

Find your estimated conception date and fertile window from your due date or LMP.

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Ovulation Calculator

Predict your fertile window and ovulation day for the next 3 cycles to plan conception.

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Pregnancy Week Tracker

Find your current pregnancy week, baby size and development milestones with a week-by-week guide.

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Period Calculator

Predict your next 3 periods, fertile windows and ovulation dates from your cycle history.

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Child Height Predictor

Estimate your child's adult height from both parents' heights using the mid-parent formula.

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Sleep Calculator

Find the best bedtime or wake-up time aligned to 90-minute sleep cycles so you wake feeling refreshed.

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Blood Pressure Checker

Enter your systolic and diastolic readings to instantly see your AHA blood pressure category - Normal, Elevated, Stage 1, Stage 2 or Hypertensive Crisis.

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Diabetes Risk Calculator

Check your type 2 diabetes risk using the Indian Diabetes Risk Score (IDRS) - the only validated screening tool designed specifically for the Indian population.

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Cholesterol Checker

Enter your Total Cholesterol, LDL, HDL and Triglycerides (mg/dL) to instantly see your ACC/AHA category with guidance on desirable ranges and next steps.

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Free Online Health Tools

Good health decisions begin with accurate information. This collection of 21 free health calculators covers the full spectrum of everyday wellness needs - from tracking your BMI and daily calorie intake to assessing blood pressure, cholesterol, and diabetes risk. Every tool follows evidence-based guidelines from bodies such as the WHO, AHA, and the Indian Council of Medical Research (ICMR) so you get clinically grounded results without any sign-up or fee.

Designed for Indian Health Needs

India carries a disproportionate share of the global non-communicable disease (NCD) burden. The Ministry of Health and Family Welfare's 2023 NCD report highlights that cardiovascular diseases, diabetes, and obesity together account for roughly 60% of all deaths in the country. Tools such as the IDRS-based diabetes risk screener and the India-specific BMI cutoff calculator (where 23 kg/m2 is the overweight threshold, lower than the standard 25) reflect these local clinical realities.

How to Use These Calculators

Each tool provides an instant result along with a brief explanation of what the number means and what action to consider. They are designed to complement - not replace - professional medical advice. Use them to prepare informed questions for your next doctor visit, monitor progress between appointments, or simply understand your numbers better.

Health Calculator Questions

BMI = weight(kg) / height(m)². WHO guidelines: below 18.5 is underweight, 18.5–24.9 is normal, 25–29.9 is overweight, and 30 or above is obese. Asian guidelines use lower thresholds - many Indian health bodies recommend a normal range of 18.5–22.9 and flag risk from 23 onwards. Our BMI calculator shows your category and healthy weight range instantly.

Your daily calorie need depends on age, gender, weight, height and activity level. Our calorie calculator uses the Mifflin-St Jeor equation - the most accurate formula currently recommended by dietitians. A typical Indian woman needs around 1,800–2,000 kcal per day, while a typical Indian man needs 2,200–2,500 kcal. The calculator also shows a macro split (protein, carbs, fat) for weight loss, maintenance or muscle gain goals.

The most common method is Naegele's rule: add 280 days (40 weeks) to the first day of your last menstrual period (LMP). This gives the estimated date of delivery (EDD). Our pregnancy due date calculator shows the EDD, which trimester you are currently in, days remaining and key milestone dates such as the anatomy scan, glucose screening and the third-trimester mark - so you can plan ahead.

The general guideline is 8 glasses (about 2 litres) per day, but this is a rough estimate. Our water intake calculator personalises the recommendation by weight, activity level and climate - an important adjustment for India where hot and humid summers can significantly increase fluid needs. Active adults or people living in warm climates like South India often need 3–3.5 litres per day. The tool also shows an hourly drinking schedule.