Calculators tools
51 free tools, all running in your browser. Percentages, loans, dates, tax, statistics — with the working shown.
- Age CalculatorEnter a date of birth to see the exact age in years, months, and days, updated instantly as you type.
- Aspect Ratio CalculatorEnter a width and height to see the simplified ratio, resize while keeping proportions, or fit dimensions inside a maximum box.
- Average CalculatorPaste or type a list of numbers to get the mean, median, mode and more, plus a separate weighted-average section.
- BMI CalculatorEnter your height and weight to see your body mass index, WHO category, and healthy weight range instantly.
- Body Fat Percentage CalculatorEstimate your body fat percentage from tape measurements using the US Navy circumference method.
- Break-Even CalculatorEnter your fixed costs, variable cost per unit and selling price to see how many units you need to sell before you start making a profit.
- CAGR CalculatorEnter a beginning value, an ending value and a time span to get the compound annual growth rate, or flip the mode to find how many years a target will take.
- Calorie CalculatorEnter your details to see how many calories you burn per day and what to eat to lose or gain weight.
- Combinations & Permutations CalculatorEnter n and r to get exact nCr and nPr values instantly, with or without repetition, including the worked formulas.
- Compound Interest CalculatorEnter a starting amount, monthly deposits and a rate to see how your savings grow over time.
- Crypto Profit CalculatorEnter your buy and sell prices manually to see profit or loss after fees — no live market data is fetched.
- Date Difference CalculatorPick two dates to see the exact time between them, updated as you type.
- Debt Payoff CalculatorList your debts, add an extra monthly payment and compare the avalanche and snowball strategies to find your debt-free date.
- Discount calculatorEnter a price and a discount to see what you pay and what you save.
- Function GrapherType an expression like sin(x) or x^2 - 3x and the graph redraws instantly as you edit.
- Fraction Calculator with StepsAdd, subtract, multiply, or divide two fractions and see the full working, including the common denominator and the GCD used to simplify.
- Fuel Cost CalculatorEnter your trip distance, fuel consumption and fuel price to see the total cost instantly.
- GCD & LCM CalculatorEnter two or more whole numbers to see their greatest common divisor and least common multiple, with the working shown.
- GPA CalculatorAdd your courses with credits and letter grades to see your GPA update as you type.
- Final Grade CalculatorCompute your weighted course average and find out what score you need on the final exam to reach your target grade.
- Hourly to Salary CalculatorConvert between an hourly rate and a salary — in either direction.
- Ideal Weight CalculatorEnter your height and sex to compare four ideal body weight formulas alongside the BMI-based healthy range.
- Inflation CalculatorSee how the buying power of the US dollar has changed between any two years since 1913, using official CPI data.
- Loan CalculatorEnter your loan details to see the monthly payment and total cost as you type.
- Logarithm CalculatorCompute logarithms with any base, natural and common logs, and solve exponential equations — results update as you type.
- Profit Margin CalculatorEnter your cost and selling price — or a target margin or markup — to see profit, margin and markup side by side.
- Matrix CalculatorEnter matrices A and B, pick an operation, and the result updates instantly — including determinant steps for 2×2 and 3×3.
- Mortgage CalculatorEnter your home price, down payment, interest rate and loan term to see your estimated monthly payment.
- Number Base ConverterConvert a number between any two bases from 2 to 36, with live results, fractional support and a step-by-step division table.
- Overtime Pay CalculatorCalculate a week’s pay when some of the hours are overtime.
- Ovulation CalculatorEnter the first day of your last period and your average cycle length to see your estimated ovulation date and fertile window for the next three cycles.
- Running Pace CalculatorEnter any two of distance, time and pace, and the third is calculated live, along with your speed and projected race splits.
- Percentage CalculatorThree quick calculations that update as you type.
- Pregnancy Due Date CalculatorEnter your last menstrual period or conception date to estimate your due date, current week of pregnancy, and key milestones.
- Prime Factorization CalculatorEnter any whole number up to 15 digits to see its prime factors, a factor tree, and its divisors.
- Probability CalculatorWork out the probability of a single event, combine two events, or find the chance of at least one success in repeated trials — every result shows the formula behind it.
- Pythagorean Theorem CalculatorPick which side of the right triangle is unknown, enter the two known sides, and see the missing side worked out step by step.
- Quadratic equation solverEnter the coefficients a, b and c of ax² + bx + c = 0 to see the roots, vertex, worked steps and a graph instantly.
- Ratio CalculatorSimplify a ratio, solve a proportion for the missing value, or scale a ratio to a new total — results update as you type.
- ROI CalculatorEnter what you invested, what you got back, and how long you held it to see simple and annualized returns.
- Salary to Hourly CalculatorType any one figure — hourly, daily, monthly, or annual — and the other three update as you type.
- Savings Goal CalculatorEnter your goal, current savings, monthly deposit and interest rate to see exactly when you’ll reach it.
- Scientific CalculatorType an expression or use the keypad — the result updates live, and pressing = saves it to the history below.
- Simple Interest CalculatorEnter any three of principal, rate, time, and interest — the fourth is solved instantly with the full I = Prt working shown.
- Sleep CalculatorPick a wake-up time to see the best bedtimes, or start from now to see when to set your alarm — based on 90-minute sleep cycles.
- Standard Deviation CalculatorPaste or type a list of numbers and get a full descriptive-statistics summary, updated live as you edit.
- Stock Average Down CalculatorEnter each purchase to see your average cost per share, test a new buy before you place it, and check your break-even price and unrealized profit.
- Tip CalculatorEnter your bill, choose a tip percentage, and see the total and per-person share update as you type.
- Triangle CalculatorPick what you know — three sides, two sides and an angle, or two angles and a side — and the full triangle is solved instantly.
- VAT calculatorAdd VAT to a net amount or work backwards from a gross price — results update as you type.
- Water Intake CalculatorEnter your weight, activity level, and climate to see an estimated daily water intake in liters and cups.
About these calculators tools
A calculator is only useful if you can trust the method, so these pages explain the arithmetic rather than just printing an answer. That matters most where the intuitive approach is wrong: reversing a percentage is not the same operation as applying it, and an age in years, months and days is not a division by 365.25.
The set covers everyday arithmetic, money questions such as loans, discounts and pay, date and time differences, and basic statistics. Everything is computed locally as you type, so nothing you enter — a salary, a loan balance, a date of birth — is transmitted anywhere.