The problem with every other calculator site
Work out your BMI on a typical calculator site and you type in your age, sex, height and weight. Then you want your BMR, so you open another page and type the same four things again. Then your TDEE, and you type them a third time. The individual tools are usually fine. What is missing is any connection between them.
CalQlate stores those details once, in your own browser, and shares them with every calculator that needs them. Enter your height on the BMI calculator and it is already filled in when you open the BMR calculator, the TDEE calculator or the body fat calculator. Fill in three fields once and seven health calculators can answer you without another keystroke.
Health and fitness calculators
The health section covers the numbers people actually look up: body mass index, basal metabolic rate, total daily energy expenditure, body fat percentage, lean body mass, ideal weight, daily calorie targets, macro splits, water intake, heart rate training zones, running pace and pregnancy due dates.
These share the most inputs, so they benefit most from the shared profile. Filling in age, sex, height and weight is enough to answer seven of them immediately. Adding three tape measurements unlocks body fat, and a resting heart rate unlocks your training zones. Each result is plotted against the relevant clinical bands, WHO categories for BMI, standard athletic and fitness ranges for body fat, so you get an interpretation rather than a bare number.
Unit converters
There are 260 conversions across eight categories: length, weight and mass, temperature, volume, area, speed, digital storage and time. Common ones include kg to lbs, cm to inches, Celsius to Fahrenheit, km to miles and litres to gallons.
Every conversion page shows the exact factor, the formula, a worked example and a full reference table, plus a one-click swap to the reverse conversion. Where a pair has a genuine trap it is called out: US gallons are 20% smaller than imperial gallons, a decimal gigabyte is 7.4% smaller than a binary gibibyte, and temperature is the one conversion that is not a multiplication at all, because Celsius and Fahrenheit do not share a zero point.
Financial calculators
The finance section handles borrowing, saving and investing: EMI and home loan repayments with a year-by-year amortisation breakdown, compound interest, SIP and lumpsum investment projections, fixed and recurring deposits, inflation and purchasing power, ROI and CAGR, GST and VAT, and retirement corpus planning.
All of it is currency-agnostic. Pick your currency once (rupees, dollars, euros or pounds) and every financial page uses it, because the formulas themselves work identically on any currency. Each page shows the total interest as well as the monthly figure, since on a twenty-year loan the total is the number that actually matters and the one most calculators bury.
Maths and everyday calculators
The everyday section covers percentages, percentage change, fractions, mean, median and mode, ratios, age from a date of birth, the days between two dates, GPA, the score needed on a final exam, discounts and tips.
Several of these answer more than one question at once, because the questions get confused so often. "What is 15% of 200?" and "15 is what percent of 200?" use the same two numbers and give completely different answers, 30 and 7.5, so the percentage page shows every form together rather than making you guess which one you needed.
How the numbers are kept right
Every calculator states the formula it uses, cites the paper or standard it comes from, and works through an example with real values. Where a field has competing formulas (ideal body weight has at least four), all of them are shown, because the disagreement between them is itself the honest answer.
Underneath, the calculation functions are pure and covered by 238 automated tests that check them against published reference values, round-trip properties and edge cases: zero interest rates, month-end birthdays, division by zero, temperature below absolute zero. A change that broke the maths would fail the build rather than quietly ship.
Your data never leaves your device
There are no accounts, no server-side database and no analytics. Details you enter are stored in your browser's local storage, which means they are still there when you return, and they are never transmitted anywhere. You can clear them at any time from your browser settings. Read the full privacy policy. It is short, because there is very little to describe.
Results are estimates for general information, not medical or financial advice. The health calculators are screening tools built on population averages and individuals vary considerably; the financial ones are projections that exclude fees and tax. See the disclaimer for the full statement.