Your health numbers, finally explained
In-depth health guides paired with interactive tools. Every topic comes with expert-level articles, visual results, and citations from WHO, NIH, and peer-reviewed research.
Browse by Category
Every category covers both the tools and the knowledge to understand your results.
Pregnancy Weight Gain: Your Complete Guide
Understand healthy pregnancy weight gain week by week with IOM guidelines. Read our evidence-based guide, then use the interactive tracker to see where you stand with visual charts and personalized ranges.
All Calculators & Tools
39 tools available — each with an in-depth guide
Pregnancy Weight Gain Calculator
Pre-pregnancy BMI, current gain and total-gain guidance for singletons or twins.
TDEE Estimate
Mifflin–St Jeor resting estimate times an explicitly labeled site activity assumption.
BMI Calculator
Adult BMI from height and weight; screening limitations explained.
Perceived Stress Scale information
PSS permission and interpretation information.
Due Date Calculator
Estimated delivery date from LMP, conception, or IVF transfer.
Macro Calculator
Illustrative macro splits for selected calorie and diet preferences.
HCG Doubling Time
Arithmetic hCG change and doubling or halving time; no pregnancy diagnosis.
A1C to Blood Sugar Converter
Convert A1C percentage to estimated average blood sugar.
Body Composition Estimate
Apply a documented military circumference equation to entered measurements.
Calorie Difference Calculator
Subtract user-entered calorie values; no target or rate is recommended.
Ovulation Calculator
Estimated six-day calendar window with explicit assumptions and limits.
Sleep Quality Calculator
Estimate sleep duration and efficiency from a diary.
Fetal Weight Percentile Guide
Understand ultrasound weight percentiles and clinical references.
Protein Intake Reference
Apply the current U.S. guideline range to an entered weight; not a personal prescription.
BMI Calculator for Teens
Age and sex-specific BMI percentiles for ages 2-19.
GFR Calculator
Estimate kidney function using the CKD-EPI 2021 equation.
Pregnancy Safe Food Checker
Find source-linked food guidance; preparation and food type matter during pregnancy.
Resting Energy Estimate
Mifflin–St Jeor estimate for its original healthy adult age range.
One-repetition maximum estimate information
Published equations and population limits; no active estimator.
Historical Weight Equations
Four historical equation outputs; not personal weight targets.
WHO Burnout Guidance
WHO definition of burnout and occupational scope.
GAD-7 Screening Questionnaire
Seven-item symptom screen and its study-specific limits.
Lean Body Mass Equation Estimate
Calculate the Boer equation output with study limits.
Resting Energy Estimate for Women 50–78
Female Mifflin–St Jeor resting-energy estimate, not a calorie intake target.
Contraction Timer
Record contraction duration and start-to-start intervals; no labor assessment.
Adult ADHD Screening Guidance
Official adult ADHD screening resources and limits.
Anemia Risk Checker
Why anemia symptoms need clinical assessment and testing.
Teen Nutrition Guidance
NIDDK and Canadian teen nutrition guidance; no calorie target.
Protein Reference for Healthy Older Adults
ESPEN European population guidance; arithmetic range, not a personal prescription.
Adult eGFR Equation Calculator
Calculate an adult CKD-EPI 2021 eGFR estimate; no diagnosis or treatment guidance.
PCOS Nutrition Guidance
Evidence-based guidance on diet composition for PCOS.
IVF Due Date Calculator
Due date from IVF transfer — 3-day or 5-day, fresh or FET.
WHO Baby Weight-for-age Percentile
WHO daily weight-for-age reference from birth to five years; local clinical chart guidance may differ.
Sleep Calculator
Plan bedtime using wake time and desired sleep duration.
Cholesterol Ratio Calculator
TC/HDL, LDL/HDL, and triglyceride/HDL ratios.
Waist-to-Hip Ratio
Waist divided by hip circumference; measurement limits explained.
Vitamin D Calculator
US age-based recommended total intake reference.
Thyroid Function Calculator
Compare values with your own laboratory reference intervals.
EPDS information
Screening limits, source information and reproduction conditions.
Not just a number. A complete picture.
Most calculator sites give you a result and leave. We give you understanding.
Enter your data
Simple inputs with metric/imperial support. No signup, no accounts.
See visual results
Color-coded gauges, trajectory charts, comparison graphics.
Read the full context
Read the method, sources and limitations alongside your result.
Continue your journey
Related tools link together. TDEE → macros → protein — one flow.
Built on published science, not guesswork
Every calculator uses established, peer-reviewed formulas — Mifflin-St Jeor for TDEE, IOM guidelines for pregnancy, WHO growth standards for child development. We cite the exact equation and the original paper on every page.
Our articles pull information exclusively from authoritative sources: WHO, NIH, ACOG, Mayo Clinic, and PubMed studies. Every key claim is cross-referenced against at least two major medical references.
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