Health & Fitness Calculators

Understand your body and reach your goals. Calculate BMI, body fat, calorie and macro needs, TDEE and BMR, plan a safe calorie deficit, track pregnancy and ovulation dates, find your running pace and heart-rate zones, and more. Metric and US units are supported everywhere.

BMI CalculatorFind your Body Mass Index in seconds using metric or US units, and see the healthy weight…Body Fat CalculatorAll you need is a tape measure: estimate your body fat percentage, fat mass and lean mass…Calorie CalculatorGet a personal daily calorie target for your goal — maintain your weight, lose it gradually,…Pregnancy CalculatorWork out your estimated due date, how far along you are in weeks and days, and when each…BMR CalculatorFind out how many calories your body burns at complete rest — the energy needed just to keep…Body Surface Area CalculatorCalculate body surface area in square metres — the measure clinicians use for drug dosing,…Calorie Deficit CalculatorSet a goal weight and a date. Find out the daily calorie deficit it takes, whether that pace…Calories Burned CalculatorEstimate how many calories you burn during exercise and everyday activities, based on your…Ideal Weight CalculatorSee what four classic medical formulas — and the healthy BMI range — suggest as a good…Lean Body Mass CalculatorEstimate how much of your body weight is muscle, bone, organs and water — everything except…Macro CalculatorTurn your calorie target into daily grams of protein, carbohydrate and fat — for your goal…One Rep Max CalculatorEstimate the most you could lift for a single rep — without testing it — and get training…Ovulation CalculatorFind your most fertile days. Enter the first day of your last period and your cycle length…Pace CalculatorWork out your running pace, finish time or distance — with kilometre and mile splits and…Period CalculatorKnow when your next period is coming. See your upcoming period dates for the months ahead,…Pregnancy Weight Gain CalculatorFind your recommended pregnancy weight gain based on your pre-pregnancy BMI, and check…Protein CalculatorGet an evidence-based daily protein target in grams — matched to your body weight and goal —…Sleep CalculatorWake up between sleep cycles instead of in the middle of one. Get the best bedtimes for your…Target Heart Rate CalculatorGet personal heart rate training zones based on your age and resting heart rate, so every…TDEE CalculatorSee how many calories you really burn in a day — and where they go — broken down into…Waist-to-Hip Ratio CalculatorFind out whether you carry weight around your middle — one of the best simple predictors of…Water Intake CalculatorEstimate your daily water needs from your body weight, then add what you lose through…

Frequently asked questions

Are the health & fitness calculators free?

Yes. All 22 health & fitness calculators on Calcivia are free to use with no sign-up, and they run privately in your browser.

How accurate are the results?

Each calculator uses standard, published formulas that are explained on its page, with a worked example. Results are estimates for planning — confirm important decisions with a qualified professional.

Can I save or share a calculation?

Yes. Every calculator updates its link as you type, so you can bookmark or share the exact inputs. You can also star favorites, copy results, download tables as CSV and print.

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