BMI Calculator
Calculate body mass index from height and weight and understand the result using age-appropriate reference concepts.
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Medical & Health Calculators
Medical & Health Calculators
Practical, easy-to-use health calculators designed around established clinical formulas, reference ranges and guideline concepts. Use them for education, screening support and health tracking—not as a substitute for professional care.
Calculator methods are selected according to the intended population and clinical
purpose. Some results require age, sex, pregnancy status, laboratory units or other
context before they can be interpreted safely.
Available calculators
Start with the tools currently available on The Vatsalyam. Each calculator has its own methodology, clinical notes, limitations and supporting references.
Pregnancy Due Date Calculator
Estimate the expected date of delivery using LMP, ultrasound gestational age or embryo-transfer dating.
Open calculatorPregnancy Weight Gain Calculator
Compare pregnancy weight gain with established reference ranges based on pre-pregnancy BMI and singleton or twin pregnancy.
Open calculatorOvulation Calculator
Estimate your fertile window and probable ovulation date from menstrual-cycle information. The result is an estimate and does not confirm that ovulation has occurred.
Open calculatorFCM Dose Calculator & Recommendations
Estimate ferric carboxymaltose (FCM) iron requirements from relevant patient parameters and provide educational recommendations with formulation-specific clinical safety notes.
Open calculatorMaternal & Child Vaccination Guide
Review maternal and child vaccination suggestions, age- or pregnancy-stage reminders and practical follow-up prompts based on the selected vaccination context.
Open calculatorExplore all medical & health tools
Search by calculator name, health topic, or clinical area. Use the category filters to quickly find the type of tool you need.
Available
Weight & Nutrition
BMI Calculator
Calculate body mass index from height and weight and understand the result using age-appropriate reference concepts.
WHO BMI framework; child and adolescent BMI requires age- and sex-specific growth references.
Audience: Adults, adolescents and selected paediatric use cases
Available
Pregnancy
Pregnancy Due Date Calculator
Estimate the expected date of delivery using LMP, ultrasound gestational age or embryo-transfer dating.
ACOG methods for estimating the due date; WHO antenatal-care guidance supports early gestational-age assessment.
Audience: Pregnant people and healthcare education
Available
Pregnancy
Pregnancy Weight Gain Calculator
Compare pregnancy weight gain with established reference ranges based on pre-pregnancy BMI and singleton or twin pregnancy.
National Academies/IOM pregnancy weight-gain recommendations as presented by CDC.
Audience: Pregnant people and antenatal education
Available
Fertility & Reproductive Health
Ovulation Calculator
Estimate your fertile window and probable ovulation date from menstrual-cycle information. The result is an estimate and does not confirm that ovulation has occurred.
Cycle-based calculations provide an estimate of the fertile window and probable ovulation date. They should not be treated as confirmation of ovulation.
Audience: People tracking menstrual cycles, fertile windows, or planning pregnancy
Available
Pregnancy & Maternal Health
FCM Dose Calculator & Recommendations
Estimate ferric carboxymaltose (FCM) iron requirements from relevant patient parameters and provide educational recommendations with formulation-specific clinical safety notes.
Dose selection must follow the applicable ferric carboxymaltose product information, local protocol, patient assessment and maximum single-dose/total-dose limits.
Audience: Healthcare professionals, pregnancy care and health education
Available
Child & Maternal Health
Maternal & Child Vaccination Guide
Review maternal and child vaccination suggestions, age- or pregnancy-stage reminders and practical follow-up prompts based on the selected vaccination context.
Vaccination suggestions should be checked against the current national immunization schedule, pregnancy-specific recommendations, age, previous doses, contraindications and local public-health guidance.
Audience: Pregnant people, parents, children and healthcare education
Coming soon
Weight & Nutrition
Basal Metabolic Rate Calculator
Estimate resting energy expenditure using a validated equation and clearly distinguish BMR from total daily energy needs.
Equation-based estimate; individual energy requirements vary with activity, body composition and clinical factors.
Audience: Adults seeking educational energy estimates
Coming soon
Coming soon
Weight & Nutrition
Daily Calorie Needs Calculator
Estimate daily energy requirements from age, sex, body measurements and activity level, with appropriate clinical caveats.
Estimated energy requirement tool; not intended for individualized therapeutic diets.
Audience: Adults
Coming soon
Coming soon
Weight & Nutrition
Healthy Weight Range Calculator
Estimate a reference weight range from height while explaining why a single “ideal weight” number is not clinically definitive.
Uses reference ranges rather than a single target; clinical interpretation should include age, body composition and health context.
Audience: Adults
Coming soon
Coming soon
Weight & Metabolic Health
Waist-to-Height Ratio Calculator
Calculate waist-to-height ratio as an additional anthropometric screening measure alongside BMI and clinical assessment.
Anthropometric screening measure; thresholds depend on population, age and clinical context.
Audience: Adults and health education
Coming soon
Coming soon
Pregnancy
Pregnancy Week & Trimester Calculator
Calculate gestational age, pregnancy week, trimester and key pregnancy milestones from an established dating method.
Gestational age should be based on the clinically established pregnancy dating method.
Audience: Pregnant people and antenatal education
Coming soon
Coming soon
Child Health
Child & Adolescent BMI Calculator
Age- and sex-specific BMI assessment using growth-reference concepts rather than adult BMI cut-offs.
WHO BMI-for-age references for children and adolescents.
Audience: Children and adolescents
Coming soon
Coming soon
Clinical Measurements
Body Surface Area Calculator
Estimate body surface area from height and weight. Some clinical uses require a specific formula and professional verification.
Formula-based estimate; clinical dosing decisions should follow the medication-specific protocol.
Audience: Healthcare professionals and students
Coming soon
Coming soon
Vital Signs
Mean Arterial Pressure Calculator
Calculate mean arterial pressure from systolic and diastolic blood pressure as a basic clinical reference.
Derived blood-pressure measure; interpretation depends on clinical context and patient condition.
Audience: Healthcare professionals and students
Coming soon
Coming soon
Kidney Health
eGFR Calculator
Estimate glomerular filtration rate using an appropriate contemporary equation and clearly state its clinical limitations.
Equation choice, units and interpretation must follow current kidney-function guidance and laboratory reporting.
Audience: Healthcare professionals and adults
Coming soon
Coming soon
Kidney Health
Creatinine Clearance Calculator
Estimate creatinine clearance using the selected clinical equation with appropriate warnings about medication dosing.
Equation-based estimate; medication dosing should follow the drug label and current clinical guidance.
Audience: Healthcare professionals
Coming soon
Coming soon
Laboratory Calculators
Corrected Calcium Calculator
Estimate albumin-adjusted calcium when appropriate, with a clear warning that direct ionized calcium may be preferred in selected settings.
Formula-based estimate; laboratory and clinical context remain essential.
Audience: Healthcare professionals and students
Coming soon
Coming soon
Laboratory Calculators
Anion Gap Calculator
Calculate anion gap from electrolyte results and optionally show the albumin-adjusted interpretation framework.
Interpret with the complete clinical picture, laboratory reference ranges and acid-base assessment.
Audience: Healthcare professionals and students
Coming soon
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How The Vatsalyam calculators are designed
Medical calculators can be useful, but the quality of the result depends on the formula, population, input quality and clinical context.
Guideline-aware methods
Where applicable, calculator methodology is linked to established clinical or public-health references rather than presenting an unexplained number.
Population matters
Adult, child, adolescent, pregnancy and clinical-laboratory calculations can use different reference standards. The calculator should identify the intended population.
Results need context
A calculated value is not automatically a diagnosis, treatment recommendation or medication dose. Concerning results should be discussed with an appropriate clinician.
Clinical reference approach
The calculator library is intended to use the reference standard appropriate to the question. For example, adult BMI uses adult BMI definitions, while children and adolescents require age- and sex-specific growth references. Pregnancy calculators similarly depend on established gestational dating and pre-pregnancy BMI rather than a one-size-fits-all rule.
- BMI: WHO defines adult overweight from BMI ≥25 kg/m² and obesity from BMI ≥30 kg/m²; children require age-specific assessment.
- Children 5–19 years: WHO uses BMI-for-age z-scores rather than adult cut-offs.
- Pregnancy dating: the clinically established dating method should guide gestational-age calculations; early ultrasound is important when appropriate.
- Pregnancy weight gain: reference ranges are based on pre-pregnancy BMI and differ for singleton and twin pregnancies.
Medical disclaimer:
These tools are for health education and calculation support. They do not replace a medical
history, physical examination, laboratory testing, imaging, professional diagnosis or an
individualized treatment plan. Do not use an online calculator alone to start, stop or change
medicines, calculate high-risk drug doses, or make an urgent medical decision.
Frequently asked questions
Important information before using a medical or health calculator.
Are The Vatsalyam calculators medical advice?
No. They are educational and calculation-support tools. A result should be interpreted
in the context of symptoms, examination, medical history, medications, laboratory data
and the relevant clinical guideline.
Can the same formula be used for everyone?
No. Some calculations change according to age, sex, pregnancy status, body size,
laboratory units, clinical setting or population. For example, WHO uses BMI-for-age
references for children and adolescents rather than adult BMI categories.
Why does the pregnancy due date sometimes differ between methods?
Menstrual-history dating, ultrasound dating and assisted-reproduction dating use different
inputs. Once a clinically established estimated due date has been selected, subsequent
management should use the documented dating method rather than repeatedly changing the date
from later measurements without clinical justification.
Should I use a calculator result to change my medicine dose?
No. Medication dosing can depend on renal function, liver function, age, weight, indication,
interacting medicines, therapeutic range and the specific product label or clinical protocol.
A calculator result should not be used alone to change a prescribed dose.
Are the pregnancy weight-gain ranges a target for every pregnant person?
They are reference recommendations, not a guarantee that every pregnancy should follow the
same trajectory. Pre-pregnancy BMI, singleton or multiple pregnancy, medical conditions,
nutrition, symptoms and fetal growth all affect clinical assessment.
What should I do if a calculator gives an unexpected result?
First check the units and input values. If the result remains unexpected, or if you have
symptoms or a condition that could make the calculation unreliable, discuss it with a
qualified healthcare professional rather than relying on the number alone.
Explore The Vatsalyam
Continue with health information and practical tools across the website.