# 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. - [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. - [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. - [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. - [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. - [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. - [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. - [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. - [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. - [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. - [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. - [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. - [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. - [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. - [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. - [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). - [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. - [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. - [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?" - [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?" ## 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