Health Calculators(44)

BMI, BMR, calorie and other health calculators

BMI Calculator

Check your body mass index (BMI) and weight status.

BMR Calculator

Calculate your basal metabolic rate and daily calorie needs.

Water Intake Calculator

Calculate daily recommended water intake based on weight and activity.

Body Fat Calculator

Estimate body fat percentage using the US Navy method.

Ideal Weight Calculator

Calculate ideal weight range based on height and gender.

Target Heart Rate Calculator

Calculate target heart rate zones by exercise intensity.

Blood Alcohol Calculator

Estimate blood alcohol concentration (BAC) from drinks consumed.

Sleep Calculator

Calculate optimal wake-up and bedtimes based on sleep cycles.

Daily Calorie Calculator

Calculate total daily energy expenditure.

Waist-to-Height Ratio (WHtR) Calculator

Assess abdominal obesity risk using the waist-to-height ratio (WHtR).

Child Fever Medicine Dose Calculator

Calculate a child's acetaminophen/ibuprofen syrup dose and interval by body weight.

Child Daily Water Intake Calculator

Calculate a child's daily maintenance fluid needs by weight using the Holliday-Segar method.

Pediatric Dehydration Fluid Calculator

Calculate maintenance fluid, fluid deficit, and the oral rehydration solution (ORS) volume and hourly rate for a dehydrated child.

Corrected Age Calculator

Calculate a preterm baby's chronological and corrected age from birth date and gestational age at birth.

Child Daily Calorie Needs Calculator

Calculate a child's estimated energy requirement (EER) from age, sex, weight, height, and activity level.

Body Surface Area (BSA) Calculator

Calculate body surface area (BSA) from height and weight using the Mosteller, DuBois, and Haycock formulas.

Apgar Score Calculator

Calculate a newborn's 1- and 5-minute Apgar score from heart rate, respiration, muscle tone, reflex response, and skin color.

Bishop Score Calculator

Score cervical dilation, effacement, station, consistency, and position to get the Bishop score and assess cervical favorability for labor induction.

Pediatric Weight Estimate Calculator

Estimate a child's weight from age alone using the APLS and Best Guess formulas, and compare the estimate with a measured weight.

Newborn Weight Loss Calculator

Calculate a newborn's weight loss from birth weight as a percentage and check it against the 7% and 10% thresholds, with birth-weight recovery progress.

Child Growth Velocity Calculator

Calculate a child's annual height growth velocity (cm/year) from two measurements and compare it with age-specific reference ranges.

Target Weight Date Calculator

Calculate how long it takes to reach your target weight and the expected date from your weekly loss goal.

Child Predicted Height Calculator

Estimate a child's adult height and range from parents' heights using the mid-parental method.

Smoking Pack-Year Calculator

Calculate smoking pack-years from cigarettes per day and years smoked, and check Korea's national lung cancer screening criteria.

Health Insurance Premium Calculator

Calculate health insurance premium and long-term care insurance for employees and self-employed.

Blood Sugar Calculator

Assess blood sugar status with fasting glucose, post-meal glucose, and HbA1c.

LDL Cholesterol Calculator (Friedewald)

Estimate LDL cholesterol with the Friedewald equation from total cholesterol, HDL, and triglycerides, and check it against lipid guideline targets.

Blood Type Inheritance Calculator

Work out which ABO and Rh blood types a child can inherit from both parents, with the probability of each and the combinations that are impossible.

eGFR Calculator (CKD-EPI 2021)

Estimate GFR from serum creatinine with the CKD-EPI 2021 equation and check your KDIGO stage.

Creatinine Clearance Calculator (Cockcroft-Gault)

Estimate creatinine clearance with the Cockcroft-Gault equation and check renal drug-dosing thresholds.

Anion Gap Calculator (Albumin-Corrected, Delta Ratio)

Compute the serum anion gap, albumin-corrected anion gap, and delta ratio to classify metabolic acidosis.

Serum Osmolality & Osmolal Gap Calculator

Calculate serum osmolality from sodium, glucose, and BUN, then derive the osmolal gap to screen for unmeasured osmoles.

QTc Interval Calculator (Bazett, Fridericia, Framingham, Hodges)

Correct the QT interval for heart rate with the Bazett, Fridericia, Framingham, and Hodges formulas and check for QT prolongation.

Caffeine Intake Calculator

Add up your daily caffeine from drinks and compare it with recommended limits for adults, pregnancy, and teens.

Fever Medicine Cross-Dosing Schedule Calculator

Calculate when your child can take the same or a different fever medicine again, based on the last dose's drug and time.

Child Recommended Sleep Hours Calculator

Calculate recommended sleep hours by age and the ideal bedtime range based on wake-up time.

Alcohol Calories Calculator

Add up the calories in your drinks from ABV and residual carbs, with pure-alcohol grams and exercise equivalents.

Blood Donation Interval Calculator

Work out your next eligible blood donation date from your last donation date and type, with age/weight eligibility and remaining donations for the year.

Overview

The CalKit Health category provides essential calculators for everyday wellness management, including Body Mass Index (BMI), Basal Metabolic Rate (BMR), body fat percentage, ideal weight, daily water intake, target heart rate zones, blood alcohol concentration (BAC), and optimal sleep timing. Every calculator is powered by medically established formulas such as Harris-Benedict, the U.S. Navy body fat method, the Karvonen formula, and the Widmark equation, delivering instant results once you enter personal details like gender, age, height, and weight. Tracking your health metrics regularly can significantly improve weight management, dietary planning, and exercise programming. Please note that all results are for informational purposes only and should not replace professional medical advice. CalKit supports both Korean and English, making it accessible to a wide audience seeking reliable health insights.

Tips

✔BMI does not account for muscle mass, so use it alongside the body fat calculator for a more complete picture of your body composition.
✔BMR represents calories burned at complete rest; multiply it by an activity factor to get your Total Daily Energy Expenditure (TDEE) for realistic calorie planning.
✔Daily water needs vary with body weight, climate, and exercise intensity — aim to drink consistently throughout the day rather than waiting until you feel thirsty.
✔Ideal weight ranges depend on frame size and muscle mass in addition to height, so treat them as a general guideline rather than an absolute target.
✔Target heart rate zones range from 50% to 85% of your maximum heart rate; beginners should start in the lower zone and gradually increase intensity over time.
✔Blood alcohol concentration estimates are approximations — never rely solely on a calculator to decide whether it is safe to drive after drinking.
✔Sleep cycles last roughly 90 minutes each, so timing your alarm to coincide with the end of a cycle can help you wake up feeling more refreshed.
✔Recording your health calculator results regularly helps you track long-term trends and make more informed lifestyle decisions.

FAQ

Q. Can I have a normal BMI but a high body fat percentage?

Yes. BMI is calculated solely from height and weight, so it cannot distinguish between muscle and fat. A person with low muscle mass and high body fat — sometimes called 'skinny fat' — may show a normal BMI while having an elevated body fat percentage. Using both the BMI and body fat calculators together gives a more accurate assessment.

Q. What is the difference between BMR and TDEE?

BMR (Basal Metabolic Rate) is the minimum number of calories your body needs at complete rest just to maintain vital functions. TDEE (Total Daily Energy Expenditure) adds the calories burned through daily activities and exercise on top of BMR. When planning a diet, TDEE is the more practical reference point for setting calorie targets.

Q. How much water should I drink per day?

A common guideline is approximately 30 to 35 mL per kilogram of body weight. For a 70 kg adult, this translates to roughly 2.1 to 2.5 liters per day. However, exercise, hot weather, and certain medical conditions can increase your needs. Use CalKit's water intake calculator to get a personalized recommendation.

Q. Can I use the blood alcohol calculator to decide if I am safe to drive?

No. The blood alcohol concentration calculator provides estimates based on the Widmark formula and cannot account for individual factors such as liver function, stomach contents, and medication use. Actual BAC may differ significantly from the estimate. Always follow local legal limits and, when in doubt, use a designated driver or public transportation.

Q. The sleep calculator recommends times that differ from my usual sleep pattern. What should I do?

The sleep calculator bases its suggestions on an average 90-minute sleep cycle. Because individual cycle lengths can vary, treat the results as a starting point and experiment over one to two weeks to discover the schedule that leaves you feeling most rested.

Q. How do I measure my resting heart rate for the target heart rate calculator?

The most accurate method is to count your pulse at your wrist or neck for 60 seconds immediately after waking up in the morning, before getting out of bed. You can also use a smartwatch or chest-strap heart rate monitor. Averaging measurements over at least three days provides a more reliable baseline.

Related Categories

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Fitness calculators for calories burned, 1RM, and exercise planning work hand-in-hand with health metrics to build effective workout routines.

Food/Cooking(17)

Pairing BMR and calorie data with food and nutrition calculators makes it easier to plan balanced meals and manage dietary intake.

Pregnancy(15)

During pregnancy, tracking changes in ideal weight, calorie needs, and hydration is essential, making the health and pregnancy categories a natural pair.