Mr. Calco — Free online calculators with clear explanations.
Health
Activity Calories Calculator
Calculate energy burned during exercise or daily steps using standard MET values, your weight, and duration — or convert…
HealthBMI Calculator
Calculate your Body Mass Index (BMI) from height and weight, then see the matching WHO adult category. Use it as a quick…
HealthBody Fat Calculator
Estimate body fat percentage from neck, waist, height, and (for women) hip circumferences using the US Navy formula — a …
HealthCalorie Calculator
Estimate how many calories you need per day from age, sex, weight, height, and activity — starting with Mifflin–St Jeor …
HealthCalorie Deficit Calculator
Estimate how long weight loss takes at a given daily calorie deficit — or how large a deficit you need to reach a goal b…
HealthHeart Rate Zones Calculator
Enter your age (and optional resting heart rate) to see max HR and five standard training zones — from recovery to VO₂ m…
HealthIdeal Weight Calculator
Enter your height to see the weight range that corresponds to a healthy adult BMI (18.5–24.9). This is a screening guide…
HealthMacro Calculator
Estimate your daily macronutrient targets in grams from age, sex, weight, height, activity, and a macro preset (or custo…
HealthRunning Pace Calculator
Enter race or training distance and total time. Get pace per kilometre and average speed — useful for goal setting and s…
HealthPregnancy Due Date Calculator
Estimate a due date by adding 280 days (40 weeks) to the first day of your last menstrual period (LMP). Ultrasound and c…
HealthProtein Intake Calculator
Get a daily protein target range in grams based on your weight and goal — maintain, fat loss (cut), or muscle gain (bulk…
HealthSleep Calculator
Plan bedtime or wake time around roughly 90-minute sleep cycles so you are less likely to wake from deep sleep mid-cycle…
HealthWaist Ratio Calculator
Measure waist (and hip for WHR) to screen central adiposity — waist-to-height ratio or waist-to-hip ratio with establish…
HealthWater Intake Calculator
Estimate a daily fluid target from body weight using a common ~33 ml per kilogram guideline, then add a little for extra…
Finance
Auto Loan Calculator
Price a vehicle loan: subtract down payment and trade-in from the car price to get the amount financed, then see monthly…
FinanceCompound Interest Calculator
See how savings or investments can grow when interest is added to the balance and then earns interest itself — compound …
FinanceCredit Card Payoff Calculator
Enter balance, APR, and your planned monthly payment to estimate months to zero and total interest. If the payment canno…
FinanceDiscount Calculator
Enter the original price and discount percentage to see the sale price and how much you save — handy for sales, coupons,…
FinanceHourly to Salary Calculator
Enter any pay rate and period to see the equivalent hourly, daily, weekly, biweekly, monthly, and annual figures — based…
FinanceIncome Tax Calculator
Approximate annual income tax using simplified progressive brackets. See estimated tax owed and your effective rate — fo…
FinanceInflation Calculator
See what a past amount is worth in another year using approximate U.S. CPI-U annual averages — or project how today’s mo…
FinanceLoan Calculator
Estimate the monthly payment on a fixed-rate amortizing personal or auto loan from amount, annual interest rate, and ter…
FinanceMarkup vs Margin Calculator
Retail and wholesale pricing confuse markup (profit ÷ cost) with margin (profit ÷ price). Solve for price, convert betwe…
FinanceROI Calculator
Measure gain or loss relative to what you invested. Enter the initial outlay and the final (or current) value to get ROI…
FinanceSavings Goal Calculator
Set a target amount, what you have already saved, and how many months you have. See the flat monthly deposit needed if y…
FinanceTake-Home Pay Calculator
Convert gross annual pay to estimated net take-home after progressive income tax and optional payroll/social deductions …
FinanceVAT Calculator
Calculate VAT or sales tax both ways: tax-exclusive → inclusive, or extract net and tax from an inclusive price. Presets…
Math
Fraction Calculator
Work with two fractions: choose an operation, enter numerators and denominators, and get a simplified result plus a deci…
MathGPA Calculator
Compute a credit-weighted grade point average from your courses. Enter grade points paired with credits (or use the GPA …
MathPercentage Calculator
Work with percentages the way people ask them: find a percent of a number, reverse a percent, compare two values, or app…
MathStandard Deviation Calculator
Calculate population standard deviation from a comma-separated list of numbers — a measure of how spread out values are …
MathUnit Converter
Convert common length units through SI metres. Uses exact factors such as 1 inch = 2.54 cm and 1 international foot = 0.…
Everyday
Age Calculator
Find your chronological age in years, months, and days from any birth date — plus total weeks and days lived. Useful for…
EverydayArea Calculator
Pick a shape, enter the dimensions, and get the area in square metres and square feet — for rooms, plots, craft projects…
EverydayBra Size Converter
Estimate bra size from underbust (band) and bust circumference, with a measuring guide and cross-chart labels. Shape and…
EverydayCooking Converter
Switch between kitchen volume units, or convert a volume of a named ingredient to grams — densities differ, so weight al…
EverydayDate Difference Calculator
Count the calendar span between any two dates in days and weeks — handy for contracts, travel planning, project deadline…
EverydayDays Until Calculator
Pick a target date (and optional “from” date) to see days remaining, whole weeks, and a rough months estimate. Past date…
EverydayDress Size Converter
Enter your measurements to find a ready-to-wear size, or convert between major women’s dress-size charts. Brands still v…
EverydayFuel Economy Calculator
Enter distance driven, fuel used, and optional price per litre. You get metric consumption (L/100km), the same figure as…
EverydayHat Size Converter
Convert hat sizes from head circumference or labelled sizes. Measure above the ears and mid-forehead for the most reliab…
EverydayKids Clothing Size Converter
Estimate children’s clothing size from height. European labels often match height in centimetres; US/UK age bands are ro…
EverydayPants Size Converter
Convert waist sizes for pants and jeans across common labelling systems, and measure your waist the right way for a bett…
EverydayRing Size Converter
Convert ring sizes across major systems, or enter inside diameter/circumference in millimetres. Measure your finger for …
EverydayShoe Size Converter
Convert adult shoe sizes across major systems and learn how to measure your feet properly. Results are estimates — brand…
EverydaySplit Bill Calculator
Enter the bill, tip percentage, tax percentage, and party size. Get a clear breakdown and what each person owes when spl…
EverydayTime Calculator
Enter a start time and a duration to add or subtract. Results wrap past midnight and can show 12-hour or 24-hour format.…
EverydayTip Calculator
Enter the bill, tip percentage, and how many people are splitting. Get the tip amount, grand total, and each person’s sh…
Weather
Dew Point Calculator
Find the dew point — the temperature at which air becomes saturated so moisture can condense as dew, frost, or fog.…
WeatherHeat Index Calculator
Estimate the heat index: how hot it feels when humidity slows sweat evaporation. Based on the US National Weather Servic…
WeatherTemperature Converter
Convert air, oven, or science temperatures between Celsius, Fahrenheit, and Kelvin using the standard linear relationshi…
WeatherWind Chill Calculator
Estimate wind chill — how cold exposed skin feels when wind speeds up heat loss. Uses the modern North American (NWS/MSC…
Real estate
Mortgage Calculator
Estimate a fixed-rate mortgage payment from home price, down payment, interest rate, and term. Optionally add property t…
Real estateRent vs Buy Calculator
See how a fixed-rate mortgage payment stacks up against monthly rent for the same housing choice. A first-pass cash-flow…