Free Online Calculators
All Your Calculations in One Place
A growing collection of free online calculators designed to help you solve everyday calculations quickly — percentage math, age & date tools, and more.
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Scientific Calculator
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Enter values and select Calculate to see your result.
Complete Toolkit
All Calculators
170+ tools organized by category. Find exactly what you need.
Finance 55
Loan CalculatorMortgage CalculatorCompound Interest CalculatorInvestment CalculatorROI CalculatorSalary CalculatorInterest CalculatorInflation CalculatorBreak-Even CalculatorProfit CalculatorAmortization CalculatorAPR CalculatorAuto Loan CalculatorCD CalculatorCredit Card Payoff CalculatorDebt Payoff CalculatorFuture Value CalculatorPayback Period CalculatorPresent Value CalculatorSales Tax CalculatorSavings CalculatorSimple Interest CalculatorStudent Loan CalculatorVAT CalculatorCommission CalculatorDepreciation CalculatorBudget CalculatorAnnuity CalculatorAnnuity Payout CalculatorBond CalculatorCurrency ConverterRetirement Savings CalculatorDebt-to-Income Ratio CalculatorMortgage Payoff CalculatorTake Home Pay CalculatorPayment CalculatorHouse Affordability CalculatorRent CalculatorDebt Consolidation CalculatorRepayment CalculatorCollege Cost CalculatorMutual Fund CalculatorRoth IRA CalculatorIRA CalculatorCash Back or Low Interest CalculatorAuto Lease CalculatorAverage Return CalculatorBusiness Loan CalculatorPersonal Loan CalculatorBoat Loan CalculatorRefinance CalculatorRental Property CalculatorIRR CalculatorFHA Loan CalculatorHELOC Calculator
Math 32
Average CalculatorStandard Deviation CalculatorArea CalculatorBinary CalculatorCircle CalculatorDistance CalculatorExponent CalculatorHalf-Life CalculatorHex CalculatorLog CalculatorProbability CalculatorQuadratic Formula CalculatorGCF CalculatorLCM CalculatorMean Median Mode CalculatorNumber Sequence CalculatorPermutation Combination CalculatorPythagorean Theorem CalculatorRatio CalculatorRight Triangle CalculatorRoot CalculatorRounding CalculatorScientific Notation CalculatorSlope CalculatorTriangle CalculatorVolume CalculatorSample Size CalculatorStatistics CalculatorConfidence Interval CalculatorZ-Score CalculatorSurface Area CalculatorFactor Calculator
Other Utilities 29
Day CounterFuel Cost CalculatorGas Mileage CalculatorGPA CalculatorGrade CalculatorHours CalculatorSpeed CalculatorConcrete CalculatorFraction CalculatorRandom Number GeneratorPrime Factorization CalculatorP-Value CalculatorTime CalculatorTime Card CalculatorTime Duration CalculatorDay of Week CalculatorHeight CalculatorBTU CalculatorSquare Footage CalculatorVoltage Drop CalculatorResistor CalculatorElectricity CalculatorDensity CalculatorMass CalculatorMolarity CalculatorWind Chill CalculatorHeat Index CalculatorDew Point CalculatorHorsepower Calculator
Health 26
BMI CalculatorBMR CalculatorTDEE CalculatorCalorie CalculatorBody Fat CalculatorIdeal Weight CalculatorWater Intake CalculatorPregnancy CalculatorSleep CalculatorPace CalculatorBAC CalculatorBody Surface Area CalculatorCalories Burned CalculatorCarbohydrate CalculatorConception CalculatorDue Date CalculatorGFR CalculatorLean Body Mass CalculatorMacro CalculatorProtein CalculatorArmy Body Fat CalculatorPregnancy Weight Gain CalculatorHealthy Weight CalculatorOne Rep Max CalculatorFat Intake CalculatorBody Type Calculator
Age & Date 7
Percentage 5
Business & Price 5
Converters 3
Planning 1
Fun 1
Popular Tools
Most used calculators
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Scientific CalculatorAdvanced calculator with trigonometry, logarithms, powers and roots.Open calculator →Percentage CalculatorCalculate a percentage of a number or find what percentage one value is of another.Open calculator →BMI CalculatorCalculate your Body Mass Index from height and weight.Open calculator →Mortgage CalculatorCalculate monthly mortgage payments with interest and term.Open calculator →Age CalculatorCalculate your exact age in years, months and days.Open calculator →Discount CalculatorCalculate the final price and savings from a percentage discount.Open calculator →
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Quick Answers
Frequently Asked Questions
How do I calculate a percentage of a number?
Divide the percentage by 100, then multiply by the number. For example, 20% of 200 is 0.20 × 200 = 40.
How do I find what percent one number is of another?
Divide the value by the total and multiply by 100. For example, 25 divided by 200 equals 12.5%.
Can I calculate discounts and percentage changes here?
Yes. Flux Calculator includes focused tools for percentage change, discounts, markup, margins, tips and taxes.
Are the calculators free?
Yes. The calculators are free to use and do not require an account.