Numbers, quacked open.
41 free calculators for loans, savings, everyday maths, dates, health and school. No sign-up, no ads, and everything runs in your browser tab.
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Not sure which calculator you need?
Describe the job in plain words and the helper will point you to the right one.
Popular right now
- EMI calculatorMonthly instalment, total interest and a year-by-year repayment table for any loan.
- SIP calculatorSee what a monthly mutual fund SIP could grow to.
- Percentage calculatorAll the common percentage questions in one place.
- Age calculatorExact age in years, months and days, and days to the next birthday.
- BMI calculatorBody mass index from your weight and height, with the healthy range.
- CGPA to percentage calculatorTurn a CGPA into a percentage, and a percentage back into a CGPA.
All 41 calculators
Pick a group to narrow the list, or press Ctrl K to search.
๐ฐ Loans & EMI
- EMI calculatorMonthly instalment, total interest and a year-by-year repayment table for any loan.
- Home loan EMI calculatorEMI for a home loan, with the interest you pay over 15 to 30 years.
- Car loan EMI calculatorEMI for a car loan over 3 to 7 years.
- Personal loan EMI calculatorEMI for an unsecured personal loan, usually 1 to 5 years.
- Loan prepayment calculatorSee how much interest and time an extra payment saves.
- Loan eligibility calculatorEstimate the largest loan your income can support.
๐ Savings & investing
- SIP calculatorSee what a monthly mutual fund SIP could grow to.
- Lumpsum calculatorWhat a one-time investment grows to over the years.
- Step-up SIP calculatorA SIP that rises every year as your income does.
- SWP calculatorHow long a corpus lasts when you withdraw every month.
- FD calculatorMaturity value of a fixed deposit with quarterly or monthly compounding.
- RD calculatorMaturity value of a recurring deposit with monthly instalments.
- Compound interest calculatorInterest on interest: growth with yearly, quarterly or monthly compounding.
- Simple interest calculatorInterest on the original sum only: principal ร rate ร time.
- CAGR calculatorThe steady yearly growth rate between a start and an end value.
- Inflation calculatorWhat things will cost later, and what your money will be worth.
- Retirement corpus calculatorHow much you need at retirement and the monthly SIP to get there.
๐งฎ Everyday maths
- Percentage calculatorAll the common percentage questions in one place.
- Percentage change calculatorPercent increase or decrease from an old value to a new one.
- Discount calculatorSale price after a discount, with an optional second discount.
- Profit and loss calculatorProfit or loss, as a percentage of cost, from cost and selling price.
- Average calculatorMean, median, mode, sum and range of a list of numbers.
- Ratio calculatorSimplify a ratio and find the missing number in an equal ratio.
- Fraction calculatorAdd, subtract, multiply and divide fractions, simplified.
๐ Dates & time
- Age calculatorExact age in years, months and days, and days to the next birthday.
- Date difference calculatorDays, weeks, months and years between two dates.
- Add or subtract daysThe date that is a number of days, weeks or months from a start date.
- Working days calculatorCount Monday to Friday days between two dates.
- Time duration calculatorHours and minutes between a start time and an end time.
- Countdown to a dateDays, hours and minutes left until a date you choose.
โค๏ธ Health
- BMI calculatorBody mass index from your weight and height, with the healthy range.
- BMR calculatorCalories your body burns at rest each day.
- Daily calories (TDEE) calculatorCalories you burn in a day, and targets to lose or gain weight.
- Body fat calculatorEstimate body fat percentage from tape measurements.
- Ideal weight calculatorIdeal body weight formulas and the healthy BMI range for your height.
- Water intake calculatorA daily water target from your weight and exercise.
- Pregnancy due date calculatorEstimated due date from the first day of your last period.
๐ Students
- CGPA to percentage calculatorTurn a CGPA into a percentage, and a percentage back into a CGPA.
- GPA calculatorWeighted GPA from your course credits and grade points.
- Marks percentage calculatorPercentage from marks obtained, and the marks needed for a target.
- Attendance calculatorClasses you must attend, or can still miss, to meet an attendance rule.
New and next
What we are building next. Tax and scheme rules are checked against official sources before any calculator goes live.
- Income tax, old vs new regimeNext up: side by side, from the official rules for the current financial year.
- Salary, HRA, gratuity, GST and TDSComing with the tax calculators, each showing the year and the date its rules were read.
- PPF, Sukanya Samriddhi and NPSGovernment scheme calculators, once the current rates and limits are checked.
- Basic and scientific calculatorsA keypad calculator for quick sums.
Your numbers stay with you
Every calculator runs in your browser. Nothing you type is sent to our servers.
No account, no ads
Open a calculator and use it. Nothing to install, nothing in the way.
Made for phones too
Every calculator works at phone size, with results that update as you type.
How-to guides
Short walkthroughs with worked examples. Each gives the answer first.
- How EMI is calculated, with a worked exampleLearn the EMI formula step by step, see how each instalment splits into interest and principal, and check a worked example for a โน10,00,000 loan.
- SIP vs lumpsum: which suits you, with numbersCompare a monthly SIP and a one-time lumpsum with a worked example, and learn when each one makes sense for your income and risk.
- How to calculate percentage: every common caseLearn the five percentage calculations people need most: percent of a number, what percent, percent change, increase and decrease, with simple examples.
Common questions
What is iDuckCalculator?
A free set of 41 calculators for loans and EMI, savings and investing, everyday maths, dates, health and students. Everything runs in your browser.
Is iDuckCalculator free?
Yes. There is no sign-up and there are no ads. Support is by tips only, and it is never required.
Is my data sent to a server?
No. Every calculation happens in your browser tab, so the numbers you type never leave your device.
Are the results accurate?
The maths is tested against known answers. Real loans, investments and tax can differ because of fees, rounding and rule changes, so treat results as estimates and check with your lender or adviser.
Do I need to install anything?
No. Open a calculator in any modern browser, on a computer or a phone.
Keep it free
No ads, no sign-up. Sharing it with a friend helps most.