All Health Calculators
This is the full library of our free health calculators, every tool runs instantly in your browser, and nothing you enter is ever stored or shared. From checking your BMI or blood pressure to estimating kidney function and daily protein needs, each calculator is built on the same clinically accepted formulas used in real medical practice.
Health π§¬
Track the everyday numbers that matter most like kidney function, blood pressure, blood sugar, and hydration. These calculators use the same clinical formulas your doctor's office relies on, from the CKD-EPI equation for GFR to ADA-based A1C conversion, so you can check where you stand between appointments.
BMI Calculator
Check your BMI in seconds with our free BMI calculator. See your weight category, healthy weight range, and what your number really means for your health.
Health βChronological Age Calculator
Free chronological age calculator. Enter your date of birth to get your exact age in years, months & days. Private, instant, works for any date.
Health βeGFR Calculator
Free eGFR calculator using creatinine, cystatin C, or both (CKD-EPI 2021 & 2012). Get your eGFR and CKD stage instantly. No sign-up, nothing stored.
Health βMAP Calculator (Mean Arterial Pressure)
Free MAP calculator: enter your blood pressure and get your mean arterial pressure instantly, with the 70 to 100 normal range and when it can mislead you.
Health βCorrected Calcium Calculator
Free corrected calcium calculator using the Payne formula. Get albumin-adjusted calcium in mg/dL or mmol/L, plus when the formula stops being reliable.
Health βWater Intake Calculator
Free water intake calculator. Get your daily hydration goal in oz, cups, liters & bottles, adjusted for your weight, age, activity, and climate.
Health βA1C Calculator
Convert A1C to estimated average glucose in mg/dL, mmol/L and mmol/mol. Works both ways, plus GMI for CGM users and the real range behind your number.
Health βAnion Gap Calculator
Free anion gap calculator with and without potassium, plus albumin correction and the delta ratio. See why your lab's normal range may not match the textbook.
Health βCorrected Sodium Calculator
Free corrected sodium calculator for hyperglycemia. Runs all five equations in clinical use, Katz, Hillier and three more, and shows where they disagree.
Health βSweat Rate Calculator
Free sweat rate calculator. Weigh in before and after exercise to get your fluid loss per hour in liters or ounces, plus what to drink and sport averages.
Health βFitness πͺ
Measure body composition and strength the way trainers and clinicians actually do it. U.S. Navy tape method, skinfold, RFM, and one-rep max estimates. Whether you're cutting, bulking, or just tracking progress, these tools turn your numbers into a clear picture of where you actually stand.
Body Fat Calculator
Free body fat percentage calculator using the U.S. Navy, RFM, skinfold, or BMI method. Get fat mass, lean mass, and your waist-to-height ratio instantly.
Fitness βBench Press Calculator
Estimate your bench press 1RM with the Epley formula, get training percentages, and see how your strength compares to real lifter data. Free and instant.
Fitness βFFMI Calculator
Free FFMI calculator. Get your fat-free mass index in seconds, see how you compare with the average adult, and check if you are near the natural limit.
Fitness βBody Recomposition Calculator
Free body recomposition calculator. Get your calories, protein and a real timeline to your goal body fat, built on the 2023 NASEM energy equations.
Fitness βBRI Calculator
BRI calculator with a healthy range set for your own age and sex, not one cutoff for everyone. See your body roundness index, body fat and visceral fat.
Fitness βVisceral Fat Calculator
Turn a tape measure into the number a CT scan reports. Your visceral fat calculator result in cmΒ², with its error band and the threshold that fits you.
Fitness βMilitary βοΈ
Official body composition standards for U.S. service members, rebuilt around the 2026 waist-to-height ratio rule. Enter your measurements to see exactly where you stand against your branch's current standard. No outdated tape-test math, just the formula your service actually uses today.
Army Body Fat Calculator (2026 WHtR Standard)
The Army body fat test changed on July 7, 2026. Calculate your official Waist-to-Height Ratio and see if you meet the new under-0.55 standard.
Military βNavy Body Fat Calculator
The Navy replaced its tape test in 2026. Run the official two-step BCA: waist-to-height screening plus body fat, with the max waist for your height.
Military βNavy PRT Calculator
Free Navy PRT calculator scored off the official Guide-5A tables. Push-ups, plank and cardio by age and sex, plus what you need for the next level.
Military βAir Force PT Calculator
Air Force PT calculator built on the official 2026 PFRA charts. Score the 2-mile run, HAMR, push-ups, plank and waist-to-height in seconds. Free.
Military βNutrition π₯
Know exactly what you're eating and how much you need. From counting calories, sugar, and caffeine in your Starbucks order to finding your daily protein target based on weight, activity, and goals. These calculators turn nutrition guidelines into numbers you can actually use.
Starbucks Calorie Calculator
Free Starbucks calorie calculator for 61 US drinks. Check calories, sugar, caffeine and protein for any order, with milk swaps, pumps and cold foam.
Nutrition βProtein Calculator
Find your daily protein target by weight, activity, and goal. Free protein calculator built on the 2025β2030 Dietary Guidelines. Instant, private results.
Nutrition βConversion π
Quick, accurate unit conversions for the numbers you track most often like height between centimeters and feet/inches, plus tools that build on those conversions, like predicting a child's future adult height from both parents' measurements using the Tanner mid-parental method.
Why Use Our Health Calculators?
Health Calculator exists because checking a health number shouldn't require an account, an app download, or handing over your personal data. Every tool on this page runs locally in your browser. We never see, store, or share what you enter.
Accuracy gets the same treatment a clinic would give it. Our calculators are built on published clinical standards: the race-free CKD-EPI 2021 equation for GFR, the ADA's eAG conversion for A1C, the Payne formula for corrected calcium, and WHO ranges for BMI. When guidelines change, we update the tools.
New calculators are added regularly across health, fitness, and nutrition. If there's one you'd like to see next, tell us through the contact page, reader requests decide what we build next.
These tools are for education, not diagnosis. Always discuss unusual results with a healthcare professional.