RubanTools

Free Clinical & Patient Calculators

18 curated health calculators for doctors and clinical use - BMI, pregnancy, ovulation, calorie, body composition and more.

BMI Calculator

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

Open Tool
BMR Calculator

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

Open Tool
Daily Calorie Calculator

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

Open Tool
Body Fat % Calculator

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

Open Tool
Ideal Weight Calculator

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

Open Tool
Waist-to-Hip Ratio

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

Open Tool
Water Intake Calculator

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

Open Tool
Heart Rate Zones

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

Open Tool
1RM Calculator

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

Open Tool
Pregnancy Due Date

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

Open Tool
Conception Date

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

Open Tool
Ovulation Calculator

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

Open Tool
Pregnancy Week Tracker

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

Open Tool
Period Calculator

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

Open Tool
Child Height Predictor

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

Open Tool
Sleep Calculator

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

Open Tool
Calorie Burn Calculator

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

Open Tool
Macro Calculator

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

Open Tool
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.

Open Tool
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.

Open Tool
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.

Open Tool

Other Professional Kits

For Accountants

GST calculator, invoice generator, TDS, income tax, salary and compliance tools for Indian accountants.

Browse
For Developers

JSON, Base64, hash, UUID, regex, diff, image tools, SEO generators and more for web developers.

Browse
For Real Estate

Area converters, stamp duty, home loan EMI, Vastu compliance and land-unit converters for property professionals.

Browse
For Astrologers

Numerology charts, compatibility, gemstone finder, Vastu and festival date tools for practising astrologers.

Browse
For Designers & UI Developers

Color picker, gradient generator, border-radius, box-shadow, SVG blob, glassmorphism, CSS grid, font pairing, image tools and more for designers.

Browse
For Students

Study timer, timetable, GPA planner, attendance, rank predictor, MCQ generator, notes formatter and more for students.

Browse
For Teachers & Trainers

MCQ generator, question paper builder, grade calculator, marksheet, attendance sheet, lesson planner, rubric and timetable tools for educators.

Browse
For Content Creators

Hashtag generator, caption generator, YouTube title, script timer, word counter, readability checker, image tools and more for influencers and YouTubers.

Browse
For Small Business Owners

Inventory calculator, expense tracker, budget planner, UPI QR, invoice generator, GST calculator, payroll and profit margin tools for shop owners and SMEs.

Browse
For Traders & Investors

SIP, FD, PPF, NPS, capital gains, CAGR, mutual fund, gold rate, inflation and retirement calculators for traders and investors.

Browse
For Event Planners

Budget planner, countdown timer, currency converter, city distance, QR code, invoice, date calculator and image tools for event planners.

Browse
For Travel Agents

Currency converter, world clock, city distance, dial codes, unit converters, age calculator, gold rate and QR generator for travel agents.

Browse
For Lawyers & Legal Professionals

Limitation period calculator, court fee estimator, legal notice generator, NDA, privacy policy, GSTIN/PAN validator and financial tools for Indian lawyers.

Browse
For Civil & Electrical Engineers

Ohm's Law, electrical load and MCB sizing, concrete mix design, beam deflection, wire gauge, unit converters and financial tools for civil and electrical engineers.

Browse

Clinical Calculators for Doctors

This collection of evidence-based calculators is designed for healthcare professionals who need quick, reliable reference values during patient consultations, ward rounds, or telemedicine sessions. Tools include BMI with Asian cutoff thresholds, BMR using the Mifflin-St Jeor equation, body fat percentage, ideal body weight (Devine formula), pregnancy due date (Naegele's rule), ovulation window, daily calorie requirements by activity level, sleep needs by age group, and target heart rate zones for cardiac rehabilitation.

Supporting India's Healthcare Workforce

India has approximately 1.3 million registered allopathic doctors as of 2023 (Medical Council of India data), serving a population of over 1.4 billion - a ratio of roughly 1 doctor per 834 people, below the WHO recommendation of 1 per 1,000. In busy outpatient departments at government hospitals - where a single doctor may see 80 to 150 patients per day - having instant access to clinical calculators reduces cognitive load and supports faster, more accurate clinical decisions. These tools are also useful for MBBS, MD, and DNB residents preparing clinical notes, and for Allied Health Professionals such as dietitians and physiotherapists who routinely use these metrics.

Clinical Calculators FAQ

Our BMI calculator uses the standard WHO formula: BMI = weight (kg) ÷ height² (m²). The WHO classification defines Underweight as BMI below 18.5, Normal as 18.5–24.9, Overweight as 25–29.9 and Obese as 30 and above. The calculator also shows the Asian cutoff thresholds recommended for South Asian populations (Overweight ≥23, Obese ≥27.5) alongside the standard WHO categories, so clinicians can apply whichever guideline is relevant to their patient population.

The estimated due date (EDD) is calculated using Naegele's rule: add 280 days (40 weeks) to the first day of the last menstrual period (LMP). This assumes a regular 28-day cycle. The calculator also accepts a known conception date and adjusts the EDD accordingly. Clinically, ultrasound-based dating in the first trimester (crown-rump length at 11–14 weeks) is more accurate than LMP-based dating and may override the calculated EDD. Our tool is intended as a reference; formal obstetric dating should follow ACOG and FOGSI guidelines.

The Mifflin–St Jeor equation, published in 1990 and validated as the most accurate predictive equation for resting metabolic rate, is: For men - BMR = (10 × weight in kg) + (6.25 × height in cm) − (5 × age in years) + 5. For women - BMR = (10 × weight in kg) + (6.25 × height in cm) − (5 × age in years) − 161. Our BMR calculator applies this formula alongside the Harris-Benedict equation and then multiplies by an activity factor (sedentary to very active) to calculate Total Daily Energy Expenditure (TDEE).

The US Navy circumference method estimates body fat without callipers using waist, neck and (for women) hip measurements. For men: Body Fat % = 86.010 × log10(abdomen − neck) − 70.041 × log10(height) + 36.76. For women: Body Fat % = 163.205 × log10(waist + hip − neck) − 97.684 × log10(height) − 78.387. Measurements are in centimetres. This method has an accuracy of ±3–4% compared to DEXA and is widely used in clinical and military settings as a quick non-invasive screen. Our body fat calculator accepts measurements in both cm and inches.