# Calculopedia

> Free online calculators for finance, health, dates and everyday math.

## Calculators

- [Age Calculator](https://calculopedia.darzh.xyz/date-time/age-calculator/): Calculate your exact age in years, months and days from your date of birth — plus total days and your next birthday.
- [Add or Subtract Days from a Date](https://calculopedia.darzh.xyz/date-time/date-add-subtract/): Calculate the date that falls a given number of days, weeks, months or years before or after any date.
- [Day of the Week Calculator](https://calculopedia.darzh.xyz/date-time/day-of-week-calculator/): Find out what day of the week any date falls on — past, present or future.
- [Days Between Dates Calculator](https://calculopedia.darzh.xyz/date-time/days-between-dates/): Count the exact number of days, weeks, months and business days between any two dates.
- [Hours Worked Calculator](https://calculopedia.darzh.xyz/date-time/hours-worked-calculator/): Calculate net hours worked in a shift — clock in, clock out, overnight and break time — as hours, minutes and a clean timecard text.
- [Leap Year Calculator](https://calculopedia.darzh.xyz/date-time/leap-year-calculator/): Check if a year is a leap year and find out how many days it has, plus the next leap year.
- [Time Duration Calculator](https://calculopedia.darzh.xyz/date-time/time-duration-calculator/): Calculate the duration between two times of day, in hours and minutes, including overnight shifts.
- [APR Calculator](https://calculopedia.darzh.xyz/finance/apr-calculator/): Convert a loan interest rate plus fees into its true annual percentage rate (APR), with the monthly payment.
- [Bike Mileage Calculator (Two Wheeler)](https://calculopedia.darzh.xyz/finance/bike-mileage-calculator/): Work out your motorcycle or scooty fuel efficiency in km/l, running cost per km and monthly commuting spend for Indian roads.
- [Break-Even Point Calculator](https://calculopedia.darzh.xyz/finance/break-even-calculator/): Find how many units you must sell — and at what revenue — to cover your fixed and variable costs.
- [Car Loan Interest Calculator](https://calculopedia.darzh.xyz/finance/car-loan-interest-calculator/): Calculate the total interest, EMI and total payable amount for your car loan.
- [Car Payment Calculator](https://calculopedia.darzh.xyz/finance/car-payment-calculator/): Estimate your monthly car payment from the price, down payment, interest rate and loan term — with a full amortization schedule.
- [Compound Interest Calculator](https://calculopedia.darzh.xyz/finance/compound-interest-calculator/): See how your money grows with compound interest — principal, rate, compounding frequency and final maturity value.
- [Cost of Sales Calculator](https://calculopedia.darzh.xyz/finance/cost-of-sales-calculator/): Calculate the cost of goods sold (COGS) for your business from opening inventory, purchases and closing inventory.
- [Credit Card Interest Calculator](https://calculopedia.darzh.xyz/finance/credit-card-interest-calculator/): See how much interest your credit card charges each month and how long it takes to pay off your balance.
- [Debt to Income Ratio Calculator](https://calculopedia.darzh.xyz/finance/debt-to-income-calculator/): Calculate your debt-to-income ratio — monthly debt payments as a share of gross monthly income — and see how lenders view it.
- [FD Calculator (Fixed Deposit)](https://calculopedia.darzh.xyz/finance/fd-calculator/): Calculate the maturity value and interest of a fixed deposit with compounding frequency and optional interest payout.
- [GDP Calculator](https://calculopedia.darzh.xyz/finance/gdp-calculator/): Calculate GDP using the expenditure approach: consumption, investment, government spending and net exports.
- [Gold Value Calculator](https://calculopedia.darzh.xyz/finance/gold-value-calculator/): Work out the value of your gold jewellery by weight and purity (24k, 22k, 18k), including making charges.
- [Gratuity Calculator (India)](https://calculopedia.darzh.xyz/finance/gratuity-calculator/): Estimate the gratuity you receive after 5+ years of service under the Indian Payment of Gratuity Act, 1972.
- [GST Calculator (India)](https://calculopedia.darzh.xyz/finance/gst-calculator/): Add GST to a price or extract GST from an inclusive amount, for 5%, 12%, 18% and 28% rates.
- [HELOC Payment Calculator](https://calculopedia.darzh.xyz/finance/heloc-payment-calculator/): Estimate your Home Equity Line of Credit payment — interest-only or fully amortized — from your drawn balance, rate and term.
- [Home Equity Calculator](https://calculopedia.darzh.xyz/finance/home-equity-calculator/): Find how much equity you have in your home — its value minus your mortgage balance — and your equity share.
- [Hourly Rate Calculator](https://calculopedia.darzh.xyz/finance/hourly-rate-calculator/): Convert an annual salary to an hourly rate, and see daily, weekly and monthly equivalents for any work schedule.
- [Income Tax Calculator (India)](https://calculopedia.darzh.xyz/finance/income-tax-calculator/): Estimate your Indian income tax under the new and old regimes, including 87A rebate and 4% cess, with a full slab breakdown.
- [Inflation Calculator](https://calculopedia.darzh.xyz/finance/inflation-calculator/): See how inflation erodes your money: what a given amount will be worth in the future, or how much value it has lost over the years.
- [Interest Per Month Calculator](https://calculopedia.darzh.xyz/finance/interest-per-month-calculator/): Convert an annual interest rate to a monthly rate and see the monthly interest on any principal amount.
- [Loan EMI Calculator](https://calculopedia.darzh.xyz/finance/loan-emi-calculator/): Calculate your monthly EMI, total interest and total payment for any home, car or personal loan — plus a full amortization schedule.
- [Loan-to-Value (LTV) Calculator](https://calculopedia.darzh.xyz/finance/ltv-calculator/): Calculate your loan-to-value ratio — the percentage of your property you are borrowing — and what it means for your loan terms.
- [MAGI Calculator](https://calculopedia.darzh.xyz/finance/magi-calculator/): Calculate your Modified Adjusted Gross Income (MAGI) by adding back specific deductions to your AGI.
- [Mileage Calculator (Car)](https://calculopedia.darzh.xyz/finance/mileage-calculator/): Calculate your car's fuel efficiency in km/l, cost per kilometre and total fuel cost.
- [Monthly Income Calculator](https://calculopedia.darzh.xyz/finance/monthly-income-calculator/): Convert hourly, daily, weekly, biweekly or annual income into monthly, weekly and annual figures — instantly.
- [Mortgage Payment Calculator](https://calculopedia.darzh.xyz/finance/mortgage-payment-calculator/): Estimate your monthly mortgage payment including principal, interest, property tax, home insurance and PMI — with a full amortization schedule.
- [RD Calculator (Recurring Deposit)](https://calculopedia.darzh.xyz/finance/rd-calculator/): Estimate the maturity value and interest of a recurring deposit based on monthly deposits, rate and tenure.
- [Real GDP Calculator](https://calculopedia.darzh.xyz/finance/real-gdp-calculator/): Convert nominal GDP into real GDP using the GDP deflator — measuring output after stripping out price changes.
- [Return on Investment (ROI) Calculator](https://calculopedia.darzh.xyz/finance/roi-calculator/): Calculate your ROI and annualized return from the amount invested, the final value and how long you held it.
- [Salary Calculator (CTC to In-Hand)](https://calculopedia.darzh.xyz/finance/salary-calculator/): Convert your CTC into monthly take-home salary, showing PF, professional tax and income-tax deductions.
- [Shipping Cost Calculator](https://calculopedia.darzh.xyz/finance/shipping-cost-calculator/): Estimate shipping costs for UPS, USPS or FedEx from package weight, delivery zone and package type — before you book.
- [SIP Calculator](https://calculopedia.darzh.xyz/finance/sip-calculator/): Estimate how much a monthly SIP investment can grow into, with expected annual returns and optional yearly step-up.
- [Social Security Benefits Calculator](https://calculopedia.darzh.xyz/finance/social-security-calculator/): Estimate your monthly US Social Security retirement benefit from your average indexed monthly earnings (AIME).
- [SWP Calculator (Systematic Withdrawal Plan)](https://calculopedia.darzh.xyz/finance/swp-calculator/): See how long a lump-sum investment lasts with regular monthly withdrawals, and how much income it can generate.
- [Take-Home Pay Calculator](https://calculopedia.darzh.xyz/finance/take-home-pay-calculator/): Convert your annual gross salary to take-home pay after income tax, standard deduction and 4% cess — monthly and annual.
- [Arcana Check Calculator](https://calculopedia.darzh.xyz/fun/arcana-calculator/): Calculate your D&D 5e Arcana check — d20 roll + Intelligence modifier + proficiency — for recalling magical knowledge.
- [Dog Years Calculator](https://calculopedia.darzh.xyz/fun/dog-years-calculator/): Convert your dog's age into human years using the modern science-backed formula, adjusted for breed size.
- [FLAMES Calculator](https://calculopedia.darzh.xyz/fun/flames-calculator/): Check name compatibility the classic way — Friends, Lovers, Affectionate, Marriage, Enemies or Siblings — by comparing any two names.
- [Golf Handicap Calculator](https://calculopedia.darzh.xyz/fun/golf-handicap-calculator/): Calculate your golf handicap differential for a round — (score − course rating) × 113 ÷ slope — the basis of the World Handicap System.
- [Life Path Number Calculator](https://calculopedia.darzh.xyz/fun/life-path-number-calculator/): Find your numerology Life Path number from your date of birth — including master numbers 11, 22 and 33 — with its meaning.
- [Mulank (Moolank) Calculator](https://calculopedia.darzh.xyz/fun/mulank-calculator/): Find your numerology Mulank (birth-day root number) and Bhagyank (destiny number) from your date of birth, with their planet and meaning.
- [Passive Perception Calculator](https://calculopedia.darzh.xyz/fun/passive-perception-calculator/): Find your D&D 5e passive Perception score — 10 + Wisdom modifier + proficiency — for spotting traps and hidden creatures.
- [Ring Size Calculator](https://calculopedia.darzh.xyz/fun/ring-size-calculator/): Find your ring size from finger circumference or diameter in millimetres, converted to US, UK and EU sizes.
- [Biological Age Calculator](https://calculopedia.darzh.xyz/health/biological-age-calculator/): Estimate your biological age from your lifestyle — diet, exercise, sleep, smoking, alcohol and stress — compared with your calendar age.
- [BMI Calculator](https://calculopedia.darzh.xyz/health/bmi-calculator/): Calculate your Body Mass Index from weight and height, see your category, and the healthy weight range for your height.
- [BMR Calculator](https://calculopedia.darzh.xyz/health/bmr-calculator/): Calculate your Basal Metabolic Rate with the Mifflin-St Jeor and Katch-McArdle formulas — the calories you burn at complete rest.
- [Body Fat Percentage Calculator](https://calculopedia.darzh.xyz/health/body-fat-percentage-calculator/): Estimate your body fat percentage with the US Navy method from your height and waist, neck (and hip) measurements — plus your fat and lean mass.
- [Bra Size Calculator](https://calculopedia.darzh.xyz/health/bra-size-calculator/): Find your bra size from just two tape measurements — underbust and bust — using the US modern or traditional +4 method.
- [Calorie Calculator (BMR & TDEE)](https://calculopedia.darzh.xyz/health/calorie-calculator/): Find your daily calorie needs — BMR, TDEE and calories for losing, maintaining or gaining weight.
- [Calorie Deficit Calculator](https://calculopedia.darzh.xyz/health/calorie-deficit-calculator/): Work out your daily calorie deficit, the intake you need to hit it, and how quickly you will lose weight — based on your TDEE.
- [Creatinine Clearance Calculator](https://calculopedia.darzh.xyz/health/creatinine-clearance-calculator/): Estimate creatinine clearance (CrCl) with the Cockcroft-Gault formula from age, weight, gender and serum creatinine.
- [EDD Calculator (Estimated Due Date)](https://calculopedia.darzh.xyz/health/edd-calculator/): Calculate your estimated due date adjusted for your menstrual cycle length using Naegele's rule.
- [Heart Rate from ECG Calculator](https://calculopedia.darzh.xyz/health/heart-rate-ecg-calculator/): Calculate heart rate in beats per minute (BPM) from an ECG strip using the RR interval or count method.
- [Ideal Weight Calculator](https://calculopedia.darzh.xyz/health/ideal-weight-calculator/): Estimate your ideal body weight from height and gender using Devine, Robinson, Miller or Hamwi formulas.
- [Macros Calculator](https://calculopedia.darzh.xyz/health/macros-calculator/): Work out your daily protein, fat and carbohydrate targets in grams from your TDEE and your fitness goal.
- [Maintenance Calories Calculator](https://calculopedia.darzh.xyz/health/maintenance-calories-calculator/): Find the calories needed to maintain your weight from BMR and activity level, plus targets for cutting and bulking.
- [Max Heart Rate Calculator](https://calculopedia.darzh.xyz/health/max-heart-rate-calculator/): Estimate your maximum heart rate with the classic 220−age or the more accurate Tanaka formula, with all five training zones.
- [Ovulation Calculator](https://calculopedia.darzh.xyz/health/ovulation-calculator/): Find your ovulation date and fertile window from your last period and cycle length, with your next period date too.
- [Pregnancy Due Date Calculator](https://calculopedia.darzh.xyz/health/pregnancy-due-date-calculator/): Find your due date, gestational age and trimester from your last menstrual period (LMP).
- [Pregnancy Week Calculator](https://calculopedia.darzh.xyz/health/pregnancy-week-calculator/): Find your pregnancy week, trimester and due date from your last period — or work backwards from a due date.
- [Protein Intake Calculator](https://calculopedia.darzh.xyz/health/protein-intake-calculator/): Find your ideal daily protein intake based on your weight, activity level and fitness goal.
- [TDEE Calculator](https://calculopedia.darzh.xyz/health/tdee-calculator/): Find your Total Daily Energy Expenditure — the exact calories you burn each day — from BMR and activity level, with lose and gain targets.
- [VO2 Max Calculator](https://calculopedia.darzh.xyz/health/vo2max-calculator/): Estimate your VO2 max — your aerobic fitness — from your resting heart rate, with fitness categories for men and women.
- [Zone 2 Heart Rate Calculator](https://calculopedia.darzh.xyz/health/zone-2-heart-rate-calculator/): Find your Zone 2 heart rate range — the fat-burning aerobic zone — as a percentage of max HR or with the Karvonen method.
- [Average Calculator](https://calculopedia.darzh.xyz/math/average-calculator/): Calculate the mean, median, mode and range of any set of numbers — enter values separated by commas.
- [Cubic Feet Calculator](https://calculopedia.darzh.xyz/math/cubic-feet-calculator/): Calculate the volume of a box in cubic feet, cubic inches, cubic meters and liters from length, width and height.
- [Cut Off Marks Calculator](https://calculopedia.darzh.xyz/math/cut-off-marks-calculator/): Calculate your cut-off marks and percentage from up to 5 subjects — best of 4 for Indian board exam admissions.
- [Dipole Moment Calculator](https://calculopedia.darzh.xyz/math/dipole-moment-calculator/): Calculate the electric dipole moment from charge and separation distance with unit conversion.
- [Discount Calculator](https://calculopedia.darzh.xyz/math/discount-calculator/): Find the final price after a discount and see exactly how much you save.
- [Elevation Change Calculator](https://calculopedia.darzh.xyz/math/elevation-calculator/): Find the elevation change over a distance from a slope angle in degrees or a percent grade.
- [Equivalent Weight Calculator](https://calculopedia.darzh.xyz/math/equivalent-weight-calculator/): Calculate the equivalent weight of a substance from its molar mass and n-factor for chemistry calculations.
- [GPA Calculator](https://calculopedia.darzh.xyz/math/gpa-calculator/): Calculate your weighted GPA from up to five courses and credit hours, on the US 4.0 scale or the Indian 10-point scale.
- [HCF Calculator (Greatest Common Divisor)](https://calculopedia.darzh.xyz/math/hcf-calculator/): Find the Highest Common Factor (HCF) of two numbers with step-by-step Euclidean algorithm work.
- [LCM Calculator (Least Common Multiple)](https://calculopedia.darzh.xyz/math/lcm-calculator/): Find the Least Common Multiple of two numbers — useful for adding fractions, scheduling and pattern alignment.
- [Markup & Margin Calculator](https://calculopedia.darzh.xyz/math/markup-margin-calculator/): Work out the selling price from cost plus markup, and the resulting margin percentage.
- [Moles Calculator (Chemistry)](https://calculopedia.darzh.xyz/math/moles-calculator/): Convert between mass, moles and number of molecules for common chemical substances.
- [Percentage Calculator](https://calculopedia.darzh.xyz/math/percentage-calculator/): Find what X% of Y is, instantly — the everyday percentage calculator for discounts, marks, tips and more.
- [Percentage Change Calculator](https://calculopedia.darzh.xyz/math/percentage-change-calculator/): Find the percentage increase or decrease between two values — from 80 to 100, or 100 to 80.
- [Percentage Decrease Calculator](https://calculopedia.darzh.xyz/math/percentage-decrease-calculator/): Take a percentage off a number — find the new value after a discount, price cut or reduction.
- [Percentage Difference Calculator](https://calculopedia.darzh.xyz/math/percentage-difference-calculator/): Compare two numbers and find the percentage difference between them — the symmetric measure used for prices, estimates and measurements.
- [Percentage Increase Calculator](https://calculopedia.darzh.xyz/math/percentage-increase-calculator/): Add a percentage to a number — find the new value after a price rise, salary increase or markup.
- [Ratio Calculator](https://calculopedia.darzh.xyz/math/ratio-calculator/): Simplify any ratio to its lowest terms and see the percentage breakdown of each part.
- [Reverse Percentage Calculator](https://calculopedia.darzh.xyz/math/reverse-percentage-calculator/): Find the original number when you know a value and the percentage it represents — "30 is 15% of what?"
- [Roof Pitch Calculator](https://calculopedia.darzh.xyz/math/roof-pitch-calculator/): Convert roof rise and run into pitch (X-in-12), angle in degrees and percent grade for roofing work.
- [SGPA to Percentage Calculator](https://calculopedia.darzh.xyz/math/sgpa-to-percentage-calculator/): Convert your SGPA (Semester Grade Point Average) to percentage for job applications and higher studies.
- [Square Footage Calculator](https://calculopedia.darzh.xyz/math/square-footage-calculator/): Find the area of a room in square feet and square meters from its length and width — for flooring, painting and real estate.
- [Water Tank Capacity Calculator](https://calculopedia.darzh.xyz/math/water-tank-capacity-calculator/): Calculate the capacity of a rectangular or cylindrical water tank in liters, gallons and cubic meters.
- [X is What Percent of Y Calculator](https://calculopedia.darzh.xyz/math/what-percent-of-calculator/): Find what percentage one number is of another — "30 is what percent of 200?"
- [Z-Score Calculator](https://calculopedia.darzh.xyz/math/z-score-calculator/): Calculate the z-score of a value from its mean and standard deviation, and see the corresponding percentile in the normal distribution.

## Key pages

- [All calculators](https://calculopedia.darzh.xyz/calculators/): full directory of tools
- [Glossary](https://calculopedia.darzh.xyz/glossary/): definitions of finance and health terms
- [Blog](https://calculopedia.darzh.xyz/blog/): explainers that link back to the calculators